Cardiac Catheterization in Congenital Heart Disease: Pediatric and Adult - Part 5 ppt

The inflated balloon catheter isadvanced over the wire from the right atrium until itpushes against the defect in the atrial septum.. When a large diameter septal opening is desired and w

C H A P T E R 1 2 Foreign body removal

carrier catheter, the straight thread wire is advanced out

of the carrier catheter and through the eye of the hook

The hook is then withdrawn into the carrier catheter and,

in turn, tightens against the thread wire on the opposite

side of the foreign body, thus encircling and grasping the

foreign body very securely (Figure 12.2)

The Needle’s Eye™ snare is the strongest of the

re-trieval systems and the most likely to be able to dislodge

securely embedded foreign bodies This same

character-istic makes this device more dangerous to use In addition

to being very large in diameter, the entire system is very

stiff When the hook is extruded, the wire loop of the hook

is capable of digging into the tissues as well as excavating

around foreign bodies As a consequence, perforations are

certainly possible both while extruding the hook and

when pulling the foreign body loose The Needle’s Eye™

system is very strong, and the grip on a foreign body is

very tight and secure Any tissues around a foreign body

that grip it securely will tear before the Needle’s Eye™

mechanism releases or gives way, so there is a real danger

of tearing vital tissues when extracting a foreign bodyforcefully with the Needle’s Eye™ device At the sametime, the Needle’s Eye™ can be released more readilyfrom a grasped foreign body The hook of the device is re-advanced to loosen it, the thread wire is withdrawn,and then the hook can usually be withdrawn from aroundthe foreign body

Adjunct devices for foreign body retrieval

There are several other catheter accessories or catheterdevices that are designed primarily for other uses which,however, are very useful adjunct devices for the retrieval

of foreign bodies These accessory devices are usuallyused in conjunction with another specifically designedretrieval device/system The most commonly used of these adjunct devices are the bioptome forceps and theAmplatz™ controllable deflector wires (Cook Inc.,Bloomington, IN)

Bioptome forceps

Relatively large bioptome forceps (6- or 7-French) areused as an adjunct in the retrieval of many foreign bodies.The bioptome is frequently used to loosen, to reorient or to

“expose” part of a trapped foreign body so that it can begrasped with another, stronger retrieval device, althoughoccasionally the complete retrieval can be accomplishedwith the bioptome The bioptome has the one majoradvantage of being able to grasp the side or a small por-tion of a foreign body without the necessity of encircling itcompletely Similar to the other retrieval systems, thebioptome is used through a large diameter, long sheathwith a back-bleed valve and a side arm flush port Thesheath should be 3–4 French sizes larger than the biop-tome catheter in order to accommodate the grasped for-eign body

The long sheath is delivered, as previously described, to

a position where the tip of the sheath is pressed against,and abutting a portion of the foreign body This usuallywill be against a portion that extends off the surface of themain mass of the foreign body Keeping the sheath in thisposition the bioptome is advanced in the sheath until thetip of the bioptome is just within the tip of the sheath The

bioptome jaws are opened as wide as possible within the

tip of the sheath and maintained in the maximum open

configuration as the bioptome catheter is advanced out ofthe tip of the sheath As the bioptome extends beyond theend of the sheath, the jaws open further and completely.The opened jaws are now forced against the loose or pro-truding piece of foreign body, and as the bioptome isadvanced, this piece of foreign body becomes forcedwithin the open jaws If the bioptome jaws are not posi-tioned exactly over the piece of foreign body, the sheathand the bioptome catheter are maneuvered together until

Figure 12.2 Needle and eye encircling a piece of catheter.

C H A P T E R 1 2 Foreign body removal

the open jaws can be pushed against the desired portion of

the foreign body By continuing to advance the bioptome

catheter with some forward force as the jaws are closed,

the force is applied against the foreign body and the jaws

close around a part of the foreign body Once the jaws

have gripped the loose piece of foreign body tightly, an

attempt is made to withdraw the bioptome catheter with

the attached foreign body into the sheath and completely

out of the body through the sheath The withdrawal is

observed on fluoroscopy to ensure that the foreign

mater-ial does not become dislodged within the sheath

Because of the small size of the “mouth” and the smooth

but sharp jaws of the bioptome, it is only usable with small

diameter pieces of catheters or other foreign bodies of

fairly small diameter, such as errant guide wires When

the foreign material is too large or rigid, the bioptome

jaws tend to slip off the foreign body Although the

biop-tome may not be able to grasp the foreign body securely

enough to retrieve it completely, it can often dislodge an

edge or part of the foreign body enough for another

retrieval device to grasp it more securely The bioptome is

most effective on pieces of foreign material that can be

crushed partially by the bioptome jaws such as a piece of

catheter, wire or small intravascular plastic tubing At the

same time, the grasped material cannot be too soft

Bioptome blades are designed for cutting rather than

grasping, and if the foreign material is too soft, the

biop-tome cuts through the material creating several pieces

instead of the original one piece of foreign material! The

bioptome is most useful when the foreign body is wedged

very far distally in a small vessel or when only the side of

an errant catheter, wire, or tubing is accessible with no

free ends protruding into the vessel lumen The bioptome

is particularly useful for retrieving or unwinding coils

that have embolized to the distal pulmonary arteries

The bioptome may not develop a strong enough grip to

pull the foreign material completely into the sheath or

completely free of the surrounding tissues without cutting

it, however, the bioptome is still very useful for

dislodg-ing or movdislodg-ing a foreign body from one area to another It

is also useful for dislodging and then holding a piece of

foreign material in a fixed position, allowing the foreign

material to be grasped with another retrieval device

For example, a partially opened snare can be

intro-duced over a bioptome catheter that is holding a piece or

the edge of a foreign body The snare loop is advanced

into the large long sheath with the partially opened loop

of the snare positioned around the bioptome catheter,

while the snare catheter passes through the sheath

adjacent to the bioptome catheter As the snare loop is

advanced out of the distal end of the sheath, the snare is

opened widely and advanced over the piece of foreign

material which is already grasped by the jaws of the

biop-tome Once past the jaws and now over the foreign body,

the loop of the snare is constricted around the foreignbody The foreign body is withdrawn into the sheathwhile it is grasped by both the bioptome and the snare,

or by the snare alone after it has been released from thebioptome

A bioptome type apparatus with toothed or slightly rated jaws would be a great adjunct for foreign bodyretrieval This would allow a secure grasp directly on theside of the foreign material and diversify the use of a biop-tome as a retrieval tool Even without serrated jaws, abioptome is a frequent adjunct device in the retrieval offoreign bodies

ser-Amplatz™ controllable deflector wire

The common Amplatz™ controllable deflector wire(Cook Inc., Bloomington, IN) with a distal curve radius of

10 mm is another very useful device that can be used as anadjunct during foreign body retrieval Although designedspecifically for “bending” or deflecting intravascularcatheters, the smaller 0.021″ or 0.025″ deflector wires form

a tight curve which creates a 360°, or greater, pigtail type

loop when deflected maximally outside of a catheter The

deflector wire is most useful for dislodging or movingembedded foreign bodies rather than for actually retriev-ing them A deflector wire that is curved around an errantcatheter or other foreign body usually does not hold thecatheter or foreign body tightly enough to withdraw itcompletely Often, however, the deflector wire can beused either to loosen or to fix a free floating foreignbody/catheter enough to allow one of the other retrievaldevices to grasp the foreign body more securely Thedeflector wire is best suited in the situation where neitherend of the foreign body is free or only the middle or side portion of an embolized tubing, wire or catheter isaccessible to the retrieval system

The Amplatz™ deflector wire is used through an hole carrier catheter that is long enough to pass com-pletely through the long, large diameter retrieval sheaththat is being used A catheter with good torque controland a stiff shaft facilitates the maneuvering of the de-flector wire into a position for grasping the foreign body.The deflector wire is introduced through a wire back-bleed valve/flush port on the carrier catheter in order

end-to prevent bleeding around the wire, clots within thecatheter, and binding of the wire within the catheter Thedistal end of the deflector wire must be able to extend farenough beyond the tip of the carrier catheter (2–4 cm) forthe “deflected” portion of the wire to form a complete 360°loop The long carrier catheter is introduced through aback-bleed valve of a valve/side flush port on the prox-imal hub of the long retrieval sheath, which must be largeenough to accommodate the grasped foreign body and thecatheter for the deflector wire as well as another retrievaldevice/catheter

C H A P T E R 1 2 Foreign body removal

The 0.021″ and 0.025″ wires usually form tight 360°

loops, however these loops are not very strong, and

straighten out if much force is applied to them The larger

diameter deflector wires form stronger loops, but they

usually do not form as complete or tight a 360° curve

around the foreign body Because of their minimal

strength, deflector wires are used primarily for freeing or

reorienting pieces of foreign bodies, wires, catheters or

tubing when there is no free end of the foreign body

avail-able Once loosened, a freed end or tip of the foreign body

or catheter can be grasped more securely by one of the

previously discussed retrieval devices

When using a deflector wire to grasp a foreign body, the

long retrieval sheath is positioned with its tip adjacent to,

and perpendicular to the piece of catheter, wire, or other

for-eign material The catheter that carries the deflector wire is

introduced into the sheath and manipulated out of the

sheath to a position immediately adjacent to the catheter,

wire, or other foreign body that is to be removed The

deflector wire is then introduced through the catheter and

advanced out of the tip of the carrier catheter, adjacent to

and eventually beyond the errant piece of foreign body

The carrier catheter, deflector wire and deflector handle

are rotated so that the concave surface of the carrier

catheter (and hopefully the deflector wire) faces the

for-eign body When oriented in this direction and the handle

of the deflector wire is activated, the concavity of the

curve of the deflector wire curves around the piece of

foreign body as the wire is advanced further

When the loose piece of foreign body is definitely

within the curve of the deflecting wire, the deflector

handle is tightened maximally With the end of the tip of

the deflector wire free outside of the catheter, this allows the

wire to create a tight, greater than 360° loop around the

loose piece, thus encircling it within the tightened loop

While maintaining a tight grip on the deflector handle, the

carrier catheter is advanced against the tip of the deflector

wire, which is curved tightly back on itself and holding

the piece of foreign body When the tip of the carrier

catheter is forced against the 360° loop of wire, it tends to

“lock” the curve on the wire The combination deflector

wire, carrier catheter and foreign body is withdrawn

toward and, if possible, into the sheath If the loop of the

deflector wire has a tight grip on the foreign body and the

tip of the curve on the deflector wire is entirely within

the sheath, the entire unit is withdrawn through and out

of the sheath If, on the other hand, the grip on the foreign

body is loose or slipping, once the foreign body is within

the sheath, it is better to remove the entire retrieval

sys-tem, including the long sheath, together as a single unit

As with all of the other foreign body retrievals, if the

foreign body or any portion of it that is grasped by the

loop of the deflector wire is still outside of the sheath, it

should not be withdrawn through a ventricle If the entire

loop of the deflector wire or the loose piece of foreignbody cannot be withdrawn completely into the sheath, thecombined sheath, catheter, deflector wire and foreignbody as a unit is withdrawn very slightly within the distalvessel until one end or a piece of the foreign body is free.Once a part of the foreign body is loosened or the foreignbody is in a location where another retrieval device can beused, a second, “true” retrieval device is introduced tograsp the foreign body The “true” retrieval device can bepassed through the same long sheath or through a separ-ate, large diameter, long sheath When the foreign body

is difficult to grasp with the curved deflector wire or is in

a precarious location, a separate sheath with the newretrieval device is introduced while the foreign body isheld with the deflector wire A tight enough grip then can

be created on the dislodged foreign material with thespecific retrieval device to allow its withdrawal into thenew sheath

An Amplatz™ deflector wire can be used adjacent to atrue retrieval system or device as part of the plannedretrieval system When a foreign body appears to betightly embedded, the true retrieval system is introducedsimultaneously with the deflector wire with the loop ofthe snare pre-positioned over the deflector wire before thetwo are introduced into the long sheath The snare and thedeflector wire are advanced out of the tip of the sheathtogether Once the deflector wire is adjacent to, or passesthrough, the foreign body, a loop is created on thedeflector wire and then tightened, as a result of which itpartially grabs and loosens the foreign body Once an end

or a loose piece of the foreign body has been freed, thesnare is opened completely and advanced around or overthe foreign body and the curved deflector wire that isgrasping it Once the foreign body has been graspedsecurely with the snare, the curve on the deflector wirecan be relaxed to straighten and release the deflector fromthe foreign body The loosened and now straight deflectorwire can be withdrawn from the foreign body, into, andthen out of the sheath

Occasionally, after the foreign body has been heldtightly for some time, the deflector becomes entangledwith the snare and/or the curve of the deflector wire doesnot straighten, even after the tension on the deflector handle has been released When the deflector wire cannot bewithdrawn from the foreign body or becomes entrappedwithin the second retrieval device, the deflector wire andthe true retrieval device, along with the foreign body,which is held by both devices, are withdrawn togetherinto the sheath This does require a slightly larger dia-meter retrieval sheath

A third alternative is to release the deflector wire pletely once even a part of the foreign body has been freed

com-by the deflector wire and before the true retrieval device isintroduced The loosened foreign body is released from

C H A P T E R 1 2 Foreign body removal

the curve of the deflector wire and the deflector wire is

removed from the long sheath The true retrieval device is

introduced through the same long sheath and used to

grab the now loosened piece of foreign body

Combinations of retrieval devices

Each of the various retrieval devices has a unique

applica-tion for different types and orientaapplica-tions of foreign bodies,

as described previously in this chapter However, the

vari-ous retrieval devices are frequently used together This

was discussed briefly under “adjunct devices” but holds

true for any combination of the “true” retrieval devices

One device may be used to loosen or reorient a foreign

body so that a different device can obtain a stronger grip

or better orientation on it The second device may be used

in addition to, and simultaneously with, the first one to

obtain an even stronger grip on a tightly fixed foreign body

Pacemaker lead extractioncspecialized “foreign

body” removal

Pacemaker leads are deliberately implanted very securely

in the myocardium In this sense, they are not an errant or

embolized foreign body However, an intravascular

pace-maker lead can be fractured and no longer function to

sense or pace the heart As such, they serve no positive

function and at the same time act as a source of thrombi,

mechanical irritation to the heart and heart valves, and act

as a nidus for bacterial growth and endocarditis In most

cases an attempt is made to remove intravascular

pace-maker leads when they are no longer functional The

transvenous pacemaker lead is usually larger than an

errant piece of intravenous catheter, wire, or tubing, and it

has been fixed very securely into the myocardium of the

heart Pacemaker leads have usually been in place in the

vascular system for very long periods of time, which

increases their adherence to the surrounding structures

throughout their course through the vasculature All of

these peculiarities of pacemaker leads make their retrieval

unique and complex, and have resulted in the development

of some very specialized equipment for their retrieval

The removal of intracardiac pacemaker leads is

per-formed only by individuals specifically trained in the use

of the specialized equipment and in the techniques of

pacemaker lead extraction This often involves the

com-bined efforts of the electrophysiologist and the

interven-tionist The tools for freeing up the leads are unique and

are designed especially for this procedure The

intravas-cular leads become tightly encased in dense fibrous

tis-sues (old clot!) This fibrous adherence often extends from

the site of entrance of the lead into the more peripheral

vein, along the entire course of the lead through the vein,

to the attachment within the heart

The special tools for the “excavation” and freeing-up ofthe encased lead from the surrounding adherent fibroustissues include large diameter, thin walled metal sheaths(Cook Inc., Bloomington, IN) and more recently, largediameter, long “Laser™” cutting sheaths (Spectranetics,Colorado Springs, CO)4 Laser™ sheaths emit a laser cut-ting beam from around the entire circumference of the tip

of the sheath They require a very large and expensiveLaser™ generator (Spectranetics, Colorado Springs, CO).The Laser™ sheath has the advantage over thin-walledmetal sheaths of being more flexible, and it can follow thelead through its curved course in the vein Also, with theLaser™’s cutting capabilities, somewhat less brute force

is required to push it over the encapsulated lead withinthe vein

The lead extraction procedure requires a cut-down atthe site of the previous, old, scarred cut-down where thelead was originally introduced, and where it enters thevein from the subcutaneous tissues The entrance site ofthe lead into the vein is where the lead extraction equip-ment is introduced This cut-down is usually in continuitywith the surgically formed “pacemaker pocket” and theold pacemaker generator, which is usually removed orreplaced The retrieval sheaths and dilators that are usedare larger than much of the comparable equipment usedfor other transcatheter foreign body retrieval proced-ures One piece of large, specialized retrieval equipmentdeveloped for lead extraction is the locking stylet andsheath that is now commercially available as the Needle’sEye™ Snare (Cook Vascular Inc., Leechburg, PA), whichhas already been discussed in this chapter5,6 The Needle’sEye™ is particularly useful for “digging” under a lead

or catheter that is embedded in the wall of a chamber orlarge vein

The first part of the lead extraction procedure is theloosening of the lead from the scarred adhesions along itscourse from its more peripheral entrance into the vein,centrally through the vein, and to the fixation point in theheart The cut-down for the lead extraction is usually onthe anterior chest wall in the area of the subclavian vein.The lead is freed-up from the subcutaneous tissues out-side of the vein and back to the previously implantedpacemaker by blunt and sharp dissection The lead is disconnected from the pacemaker and the connector isexcised from its proximal pacemaker end The snare end

of a special wire snare is introduced from the proximalend of the large extractor sheath and passed completelythrough the extractor sheath The extractor sheath can beeither a short metal extractor sheath or, preferably, aLaser™ extractor sheath, depending upon the particularcircumstances and the preference of the operator

The freed end of the pacemaker lead is grasped securelywith the snare wire and pulled into the distal end of theextractor sheath while still outside of the body Tension is

C H A P T E R 1 2 Foreign body removal

applied to the snare and, in turn, the freed end of the lead,

as the extractor sheath is advanced over the lead and to

and into the vein, which is opened with a small incision

While maintaining traction on the snare catheter (and

lead), the extractor sheath is forced into the vein and used

to cut around the lead, which is encased in scar or old

thrombus along its course in the vein This process requires

considerable to-and-fro as well as drilling motion on the

extractor sheath, while continually holding tension on the

proximal end of the snare wire As the extractor sheath

advances further over the encased lead in the vein and

dis-appears into the vein, eventually the original free end of

the lead appears at the proximal end of the extractor

sheath Only the more flexible Laser™ sheath can be used

once the subclavian/innominate vein makes its turn

caud-ally into the superior vena cava toward the heart With

the Laser™ sheath, intermittent laser energy is delivered

to the tip of the sheath as this pushing/drilling process

along the lead is carried out This procedure is continued

along the entire course of the lead through the vein until

the lead has been freed all of the way to its attachment in

the myocardium

Once the extractor sheath has reached the “tine” or

attachment mechanism of the lead into the myocardium

of the heart, the process is continued, but with

consider-ably less force and more cautiously Ideally, the tip of the

extractor sheath will drill just to the tip of the lead within

the myocardium but no further Specifically, the tip of the

extractor sheath must not drill through the myocardium!

While holding the long, stiff sheath in this fixed position

even more tension is applied to the proximal end of the

lead in an attempt to free the lead from the surrounding

myocardium When the lead has been freed from the

myocardium, it is withdrawn through the long sheath

If the lead cannot be withdrawn from its attachment in

the myocardium and, particularly, if the lead begins to

unravel or otherwise come apart, then a secondary

tech-nique for withdrawing the lead must be used

Once the entire course of the lead has been dissected

free from the surrounding tissues with the extractor

sheath, most of the remaining extraction of the lead is

per-formed from the femoral venous approach The 14-French

sheath of the Needle’s Eye™ snare set (Cook Vascular

Inc., Leechburg, PA) is introduced from a femoral vein

and advanced to a position adjacent to and perpendicular

to the side of the loosened lead and as close to the

attach-ment in the myocardium as possible The tip of the

Needle’s Eye™ sheath will be in either the right atrium or

the right ventricle, depending upon the type of lead being

extracted The Needle’s Eye™ snare in its carrier catheter

is introduced through this sheath and advanced to the tip

of the sheath The carrier catheter and sheath are

man-euvered so that they are touching the side of the lead

The hook of the snare is extruded while simultaneously

maneuvering it completely around a free portion of thelead Once the hook has encircled the lead completely, thethread wire is extruded and advanced through the eye atthe tip of the hook (see Figure 12.2) When the eye hasbeen threaded, the hook is withdrawn back into the car-rier catheter This grips the lead very tightly and allows aportion of the grasped lead to be folded on itself and with-drawn into the large sheath The lead is withdrawn as far

as possible into the sheath By pulling the more proximallead into the sheath, the tip of the large, long retrievalsheath is pulled against the attachment of the lead in themyocardium This occurs particularly when the proximalend of the lead has been disrupted or completely with-drawn away from the attachment in the myocardium bythe previous manipulations The side of the lead can still

be withdrawn into the sheath, even when the proximalend of the lead is intact and passing out through the super-ior vena cava and the subclavian vein

Considerable force with intermittent torsion is applied

to the Needle’s Eye™ retrieval device that is grasping theembedded lead while counter force is applied by holding

or pushing the tip of the sheath over the lead and againstthe myocardium This is usually sufficient to pull the leadattachment out of the myocardium Occasionally, the lead

is disrupted further by these forces, leaving a loose ment attached to the myocardium with the free end dang-ling in the cavities of the right heart In that circumstance,the Needle’s Eye™ retriever is replaced with a basketretrieval device through the same large, long sheath Thebasket is manipulated to open around the free end of the lead The lead is grasped while closing and rotating the basket and, again, as much of the grasped lead as pos-sible is withdrawn into the sheath Considerable traction and some torque are applied to the basket while the tip

seg-of the sheath is pushed against the myocardium to free the lead

Obviously, there are considerable and sometimespoorly directed forces necessary during this procedure forlead extraction Also there is no direct control over wherethe long extractor sheath containing the Needle’s Eye™excavates between the lead and the vessel or chamber

wallaonly that the lead was originally within the vessel

or chamber and hopefully the extractor also remains close

to the lead and completely within the channel All of thesefactors make the extraction of pacemaker leads a fairlydangerous procedure In fact, because of the dense adher-ence of the lead to the vascular wall and the tight, oftendeep fixation of the tip of the lead in the myocardium, it isnot a question of whether there will be a complicationfrom a pacemaker lead extraction, but rather, when.Cardiovascular surgical facilities must be available imme-diately during the extraction of all transvenous pace-maker leads because of the probability of a major vascular

or cardiac perforation

C H A P T E R 1 2 Foreign body removal

Special foreign body circumstances

The extensive use of coils and other devices in the PDA,

the larger intravascular stents, and the large occlusion

devices for both atrial and ventricular septal defects have

created a whole new generation of intravascular foreign

bodies When any of these devices become free floating in

the circulation, they create an entirely different challenge

for foreign body removal The handling and removal of

these devices are covered in the specific chapters dealing

with each device, and are not repeated in this section

Intravascular thrombi and mechanical

thrombectomy

Although, strictly speaking, intravascular thrombi/emboli

do not represent a foreign body, they do constitute

intravascular masses that often need to be dissolved or

removed urgently Intravascular thrombi can be the

con-sequence of vascular stenosis with obstruction, localized

vascular trauma, underlying low blood flow situations,

the presence of a foreign body in the vasculature,

hyperco-agulable states, or a combination of any or all of the above

causes As a consequence of a high index of suspicion

combined with better imaging modalities, acute

thrombo-sis of large vessels can now be detected early, but unless

always considered, will go undetected Better imaging,

the very complex surgical repairs now being performed,

particularly in the venous circulation, the more frequent

intravenous therapy through indwelling lines that are in

place over long periods of time, and the extensive

manipu-lations in the vascular system with large catheters/sheaths,

may account for what appears to be an increase in large

vessel thrombi/occlusions When a large vessel thrombus

is detected, the earlier definitive management is started,

the better the chance of removing the thrombus and

main-taining or restoring patency of the vessel

Thrombolytics are quite effective at “dissolving” thrombi,

however, they are less reliable and slower than mechanical

removal, which in the presence of “visible” thrombi, is

more rapid and more definitive than thrombolytic

ther-apy alone Thrombolytic therther-apy can be used as a general

systemic infusion, infused directly into the thrombus, or it

can be used in conjunction with a mechanical

thrombec-tomy device When used alone, thrombolytic medications

are most effective when infused directly into the

throm-bus Thrombolytic therapy is covered in Chapter 2 on

medications

There are a variety of thrombectomy devices which, in

one way or another, fragment large thrombi into minute

particles Some of the devices fragment thrombi into

par-ticles that are similar in size to, or smaller than, blood cells,

which allows the debris to circulate, while some of the

devices also (attempt to) extract all (most of) the debris

created by the fragmentation Only one of the currentdevices that are available for the removal of thrombi from large vessels has a “distal protection” capability ofcapturing larger fragments that may be dislodged whilethe thrombus is being fragmented into micro particles orwithdrawn

The original thrombectomy device was the fairlystraightforward, Fogarty™ balloon (Edwards Lifesciences,Irvine, CA), which is very effective for extracting thrombifrom peripheral vessels The Fogarty™ device is a smallballoon mounted at the distal end of a 4-French cathetersimilar to a very small Swan™ balloon (Edwards Life-sciences, Irvine, CA) The catheter with the balloondeflated is usually introduced into the thrombosed vessel

by means of a cut-down on the vessel The tip of thecatheter with the balloon deflated is advanced past thethrombus The balloon is inflated and the catheter is with-drawn from the vessel, which pulls the now trappedthrombus, which is adjacent to the catheter and proximal

to (in front of) the balloon, back in the vessel The trappedthrombus is withdrawn through the incision in the vessel

or skin and out of the body This is still an effective cedure for removing thrombi from peripheral vessels,although it has been supplemented by the use of throm-bolytics and other more sophisticated thrombectomydevices

pro-The simplest and one of the earliest and most readilyavailable of the central thrombectomy devices was acatheter with suction applied to it7 Using the same prin-cipal, but using a long, large diameter (11–16-French)sheath instead of a catheter, makes this technique evenmore effective and very useful When a small or freshthrombus is detected within the vasculature, it can often

be withdrawn from the intravascular site by positioningthe tip of the large diameter sheath immediately adjacent

to the thrombus and then applying a strong vacuum with

a large volume (60+ ml) syringe to the proximal end of thesheath This is frequently sufficient to suck a loose throm-bus into the sheath Large sheaths are readily availableand usually require no additional (or expensive) equip-ment Occasionally the thrombus must be fragmented ordislodged with a separate catheter, wire, or basket device

A basket retrieval device can be used to try to grasp thethrombus, but usually it tends to slice through the throm-bus Distal embolization is always a potential problemwith this type of thrombus retrieval, but if performedexpeditiously, can prevent significant further problemsfrom very large thrombi In addition to these improvisedthrombectomy devices there is a variety of commerciallymanufactured devices

The Helix Clot Buster™ (ev3, Plymouth, MN) is a atic turbine driven impeller device that has been avail-able for over a decade The impeller has a rotating helical screw which is contained within a capsule at the distal tip

pneum-C H A P T E R 1 2 Foreign body removal

and rotates at 100,000 rpm The rotating screw creates a

very strong vortex of fluid, which macerates the thrombus

into particles between 13 and 1000 microns in diameter

The capsule of the Helix Clot Buster™ device is 7-French

and it is not introduced over a wire, which makes it more

difficult to maneuver into more remote or tortuous

loca-tions unless it is introduced through a long pre-positioned

sheath There is no extraction system with the Helix Clot

Buster™ with the result that it depends entirely upon all

of the resultant fragments being small enough to pass

through any distal capillary bed! This makes this device

less desirable for use in the systemic arterial circulation

The Thrombex™ device (Edwards Lifesciences, Irvine,

CA) is another rotating helical screw that macerates the

thrombus, but it then aspirates the thrombus into an

evacu-ation container The Thrombex™ is mounted on a

6-French catheter, which makes it usable in smaller patients

Even with built-in aspiration of the debris, there is still a

potential for some distal embolization

The AngioJet™ (Possis Medical, Inc., Minneapolis, MN)

macerates the thrombus with multiple, extremely

high-velocity jets of saline, which are directed backward from

openings adjacent to the tip of the catheter The

high-velocity jets create a partial vacuum by a Bernoulli effect,

which sucks the fragments out of the circulation through a

separate lumen in the catheter The extremely high

velo-city of the jets of saline macerates the thrombus very finely,

and the very localized distribution of the jets allows the

fragments to be withdrawn effectively from the circulation

AngioJet™ catheters are available in the 4-French XMI™,

the 5-French XVG™, and the 6-French Xpeedior™, and

they all pass over a wire, which makes them more

versa-tile for entering precise locations and traversing thrombi

in smaller vessels AngioJet™ catheters can be used with a

single-use pump set or with a fairly complex, multi-use

drive unit Because of the small size and the over-the-wire

use of AngioJet™ catheters, these are the most suitable for

smaller pediatric and congenital patients8 However, the

drive unit, in addition to being fairly complex, is

expens-ive and is usually not available in a purely pediatric/

congenital cardiac catheterization laboratory, unless the

laboratory has some association with an adult

cardio-vascular service The drive unit is mobile, so could be

moved between co-operating and near-by laboratories

The AngioJet™ system and catheters can be used to infuse

thrombolytics locally into the thrombus as part of the total

thrombus removal procedure

The Oasis™ Thrombectomy Device (Boston Scientific,

Natick, MA) has a single small nozzle at the tip of the

catheter, which directs a high-velocity jet of saline back

into the port of a separate lumen in the catheter The

high-velocity jet creates a Venturi effect, which fragments the

thrombus while, at the same time, it sucks the fragments

back into the catheter As with the other devices without

specific distal protection systems and although the ticles are very small, particulate matter that is dislodgedcan embolize distally

par-The Trellis Infusion System™ (Bacchus Vascular Inc.,Santa Clara, CA) utilized occlusion balloons in the lumen

of the vessel above and below the thrombus to “contain”the debris A catheter that rotated between the occlusionballoons macerated the clot into fine particulate matter,which, in turn, was evacuated from the area between the occlusion balloons The rotating catheter tended todenude the endothelium of the vessel where it touched.When the area of the vessel could be isolated with theocclusion balloons, this device had one of the best chances

of preventing distal embolization; as of this writing, ever, the Trellis™ device has been withdrawn from themarket

how-The Trerotola Percutaneous Thrombectomy Device™(PTD) (Arrow International Inc., Reading, PA) is a self-expanding, 9 mm diameter, stainless steel, wire basket,which rotates at 3,000 rpm The rotating basket fragmentsthe clot into “macro” particles that are as large as 3 mm,

but there is no evacuation system for these large

frag-ments The device can be delivered over a wire, whichmakes it easier to deliver to distal, more circuitous loca-tions such as branch pulmonary arteries The rotating basket denudes the wall of the adjacent vessel where ittouches The major disadvantage is the potentially largerresultant fragments As the thrombus is being broken up,the area distal to the thrombectomy must be able to toler-ate the embolization of the larger fragments

Complications of foreign body retrieval/removal

The removal of a foreign body is usually necessitated by

an adverse event that can become a complication, but theretrieval procedure itself can create complications Aswith all other complications, the best treatment is prevent-ing their occurrence The retrieval of all foreign bodies

requires extensive manipulation of often large and stiff

catheters and multiple exchanges of wires, sheaths,catheters and the retrieval devices themselves All of thesemanipulations and exchanges carry the same, or evenhigher, risks of the complications that occur from the routine manipulation of any cardiac catheter Meticulousattention to the details of normal catheterization pro-cedures for the manipulation of catheters, wires and sheaths, and the prevention of air and/or clot emboliza-tion are mandatory during every retrieval procedure.Each of the separate foreign body retrieval devices is asso-ciated with specific complications, which have been dis-cussed previously in the discussions of each of the devices.Intravascular structures can be torn or perforated when

a foreign body is pulled loose or withdrawn through avessel This occurs most frequently during intracardiac

C H A P T E R 1 2 Foreign body removal

lead extractions and is a known, half-anticipated, part of

the procedure It does occur, very rarely, with the forceful

extraction of any foreign body that has become embedded

in tissue and should always be anticipated With the

unex-pected or unexplained deterioration of a patient during

any foreign body extraction a tear or perforation is always

considered The treatment is intensive medical support of

the patient with the replacement of lost blood until

sur-gical intervention is available to repair the tear

A foreign body becoming entangled in a ventricle or a

cardiac valve is another complication of foreign body

retrieval, which for the most part is iatrogenic and should

be avoidable Most dislodged devices (e.g coils, occlusion

devices, stents) in the systemic venous system embolize

directly to the pulmonary artery or tumble through the

ventricles into the pulmonary artery when they become

dislodged during or after an implant They become lodged

in the ventricle when an attempt is made to withdraw a

partially or totally exposed device through the ventricle

during a retrieval procedure Any foreign body that

can-not be withdrawn completely into a sheath, should can-not be

withdrawn through a ventricle Avoiding this problem

requires a difficult judgment decision before the foreign

body is even grasped with a retrieval device Once a large

foreign body is grasped securely with a retrieval device,

occasionally neither can it be withdrawn completely into a

sheath nor can it be released from the retrieval device!

The probability of this combined problem should

always be considered before grasping a foreign body

with a retrieval device when the foreign body must be

withdrawn through a ventricle before its final extraction

When a large, catheter-delivered, intracardiac device

becomes trapped in the right ventricle, it usually requires

a sternotomy and cardiopulmonary bypass to remove the

device, while a direct surgical retrieval from the

pul-monary artery requires a thoracotomy, but usually does

not require cardiopulmonary bypass This should be

considered before an attempt at grasping or

withdraw-ing an exposed foreign body through a ventricle is even

contemplated

Occasionally, a foreign body is loosened with a retrieval

device, but before the foreign body can be withdrawn

from the body it becomes released inadvertently or is lost

back into the circulation This results in the embolization

of the device to another location Unless the device

embolizes to or through a ventricle, the inadvertent loss of

the device usually does not result in any permanent

sequelae, but does require a repeat retrieval procedure

Summary

With the professional expertise which should be present

in a well equipped pediatric/congenital catheterization

laboratory, and using one or a combination of the retrievalsystems described, the removal of virtually all intravas-cular foreign bodies is possible by a catheter technique.However, even with all of the latest equipment and the best techniques, there are a few circumstances when

a foreign body cannot, or should not be removed by a

trans-catheter technique This applies particularly to large andnot easily compressible intracardiac therapeutic devices.Very large devices (large ASD devices, fully expandedintravascular stents) may not compress sufficiently or foldenough to be withdrawn even partially into even thelargest, long sheath available Persistent attempts at theremoval of such devices, particularly if the foreign bodymust be withdrawn through a ventricle, have a high likelihood of causing significant and often permanentintravascular or intracardiac damage In that circum-stance, surgical assistance for the removal of the foreignbody is needed

When a patient in whom a large or difficult-to-removedevice has embolized must undergo cardiac surgery tocorrect the particular defect anyway, or there is someother major defect requiring surgery, there is little wis-dom or justification for pursuing an extensive trans-catheter removal procedure unless the device is causing

an immediate life-threatening problem Subjecting thepatient to the often long, complex, and potentially danger-ous transcatheter removal procedure with its large dose

of radiation is in no way justified when cardiac surgery

is inevitable This is true particularly when the originaldefect is not treatable by a similar or larger catheter-delivered device (e.g an embolized ASD occlusion device

in an unusually positioned or large ASD)

It requires more skill, judgment and maturity on thepart of the interventional cardiologist to determine when

a foreign body is too difficult or dangerous to remove, and

then to make the decision not to pursue the catheter

retrieval any further

4 Bracke FA, Meijer A, and Van Gelder B Learning curve

char-acteristics of pacing lead extraction with a laser sheath Pacing

Clin Electrophysiol 1998; 21(11 Pt 2): 2309–2313.

C H A P T E R 1 2 Foreign body removal

5 Fearnot NE et al Intravascular lead extraction using locking

stylets, sheaths, and other techniques Pacing Clin Electrophysiol

1990; 13(12 Pt 2): 1864–1870.

6 Byrd CL et al Intravascular lead extraction using locking

stylets and sheaths Pacing Clin Electrophysiol 1990; 13(12 Pt 2):

1871–1875.

7 Greenfield LJ, Kimmell GO, and McCurdy WC 3rd venous removal of pulmonary emboli by vacuum-cup catheter

Trans-technique J Surg Res 1969; 9(6): 347–352.

8 Kirby WC, D’sa R, and Shapiro SR Mechanical thrombectomy for treatment of postoperative venous obstruction in pediatric

patients J Invasive Cardiol 2004; 16(5/Suppl): S27–S29.

Rashkind™ Balloon Atrial Septostomy

The Rashkind™ Balloon Atrial Septostomy (BAS), which

was introduced in 1966, was the first intracardiac,

non-surgical interventional procedure to be developed and

used clinically1 The Rashkind™ BAS was not only the

first procedure, but it was exceptionally innovative and

daring for the timeaand even for today Dr William

Rashkind devised the non-surgical technique for the

cre-ation of an atrial septal defect as a pallicre-ation for newborns

with transposition of the great arteries at a time when

transposition was one of the most lethal congenital heart

defects The Blalock–Hanlon surgical atrial septectomy

was an alternative for the palliative creation of an atrial

defect, however, in a critically ill infant, the surgical

sep-tectomy was associated with a high morbidity and

mortal-ity in most centers at that time The Rashkind™ BAS

procedure, although “crude” by all standards, was

dram-atically and instantaneously successful, and has persisted

until today with little change from the original technique

as an essential procedure for many congenital heart lesions

Indications for a balloon atrial

septostomy

The need for an atrial septostomy is determined by the

underlying cardiac lesion and from the associated clinical

findings Infants or older patients whose clinical signs or

symptoms can be improved by better mixing or “venting”

of the systemic venous or pulmonary venous blood are

candidates for an atrial septostomy Patients with

trans-position of the great arteries have parallel systemic and

pulmonary circuits and benefit dramatically from mixing

of their systemic and pulmonary venous blood at the atrial

level Patients with pulmonary atresia, tricuspid atresia,

and other hypoplastic and poorly functioning right

ven-tricles require an adequate interatrial communication to

allow systemic venous blood to return back into the systemic arterial circuit Patients with severe mitral steno-sis, mitral atresia or other varieties of hypoplastic left ventricle represent an analogous situation, but for blood

to flow in the opposite direction where it is trapped on the left or pulmonary venous side of the circulation Thesehypoplastic left heart patients require an atrial sept-ostomy to vent the pulmonary venous blood back into the functional systemic circulation Patients with totalanomalous pulmonary venous connection require anatrial opening to permit both the systemic and pulmonaryvenous blood to re-enter the systemic arterial circulation.The BAS is accomplished by forcefully pulling (“jerk-ing”) a small spherical balloon through an essentiallyintact atrial septum, thereby tearing an opening in it Theadequacy of the opening that is created depends upon the toughness of the septum, the size and compliance ofthe balloon used for the septostomy and the force withwhich the balloon is pulled through the septum

Hemodynamics of restrictive atrial septal communications

The necessity for septostomy is suggested by an diogram with the demonstration of a patent foramenovale or tiny atrial septal defect with restricted flow in apatient with any of the previously mentioned anatomicdefects The restrictive nature of the defect is confirmed inthe catheterization laboratory by the pressure differencebetween the two atria or by angiography demonstratingrestrictive flow, or minimal or no mixing at the atrial sep-tal level The difference in pressure will be very significantwhen the predominant flow of blood is, or should be, fromleft to right through the atrial defect The left atrium is rel-atively non-compliant, and develops very high pressureswhen there is restriction to the outflow of the pulmonaryvenous blood from the left atrium The right atrium, onthe other hand, by itself and along with the hepatic veinsand the connected total systemic venous “pool”, is very

echocar-13 Balloon atrial septostomy

C H A P T E R 1 3 Balloon atrial septostomy

compliant The right atrium and the systemic venous

veins stretch or dilate almost infinitely and in doing so,

prevent the development of a gradient from right atrium

to left atrium across the atrial septum even with severe

restriction of flow and even when the atrial

communica-tion is the only outlet of blood from the right atrium!

Angiography will confirm the presence or absence of

obstruction at the atrial level

Angiography of the atrial septum

For angiographic confirmation of the atrial obstruction, in

lesions with a potential left to right shunt, an angled,

cra-nial–LAO angiogram with an injection at the mouth of the

right upper pulmonary vein is used to profile the atrial

septum This angiocardiogram usually demonstrates a

bulging of the septum toward the right atrium with a jet

of contrast passing through any existing opening in the

septum In lesions with a potential right to left shunt, a

straight PA and lateral X-ray view with injection in the

right atrium just at the junction of the IVC with the right

atrium is used to demonstrate the restrictive flow through

the existing atrial defect The lateral view demonstrates

the flow of contrast from right to left most clearly with a

vertical jet of contrast passing from the right atrium,

through the defect and toward the roof of the left atrium

Sizing the atrial septal communications in the

catheterization laboratory

There are occasions when the existing atrial

communica-tion is sized For larger patients there are static “sizing”

balloons that can be passed over a wire and through

the defect and used to demonstrate the exact size of

the existing atrial opening in questionable cases These

NuMED™ “sausage”-shaped sizing balloons (NuMED

Inc Hopkinton, NY), can be inflated at very lowaalmost

zeroapressure At this extremely low pressure, the

bal-loon within the defect conforms to the size (and shape) of

the defect without stretching or distorting it The true

siz-ing balloons, however, all are on large catheter shafts,

which make them unsatisfactory for use in newborn or

small infants As an alternative, a very small, standard

angioplasty balloon, when inflated at very low pressures,

can be used in the defect in a similar fashion

A Swan™ balloon (Edwards Lifesciences, Irvine, CA) or

the actual septostomy balloons were used in the past to

“calibrate” the atrial communications The results of this

type of sizing can be very misleading, and the technique is

no longer recommended When using a Swan™ or a

bal-loon septostomy catheter to size the defect, the balbal-loon

catheter with the balloon deflated is passed through the

defect from the right atrium to the left atrium The balloon

is inflated in the left atrium and gently withdrawn against

the septum until resistance is first encountered As the balloon is held gently against the septum, the balloon isdeflated in small decrements The diameter of the balloonwhen the balloon easily pulls through the septum pro-vides a rough estimate of the size of the opening Thistechnique is described in detail and illustrated in Chapter

28 (“ASD Occlusion”) There are several major flaws withthis type of sizing The spherical, Swan™ or Rashkind™type balloons create an acute angle between the edge ofthe balloon attachment to the catheter and the cathetershaft As the inflated balloon is withdrawn against the

septum this acute, 90° anglearather than the full diameter

of even a partially inflated balloonacatches on the edge of

the septal defect, providing resistance to the withdrawal,and gives a false impression of a much smaller defect

In addition, when the balloon is pulled from the leftatrium into the right atrium in the presence of a patentforamen with a sizable “flap valve”, the balloon actuallypulls the flap of the foramen closed against the septalopening and, in turn, give the impression of a very smallopening When the balloon does pull through the defectafter several withdrawals of even the partially inflatedballoon through the defect, the defect actually can bestretched and/or dilated significantly during this “sizing”procedure

The alternative technique for balloon sizing, whenusing a Swan™ type balloon, is to pass a guide wire fromthe right atrium through the defect into the left atrium.The Swan™ balloon is advanced over the wire only to theright atrial/inferior vena cava junction where the balloon

is inflated maximally The inflated balloon catheter isadvanced over the wire from the right atrium until itpushes against the defect in the atrial septum The balloon

is deflated decrementally while pushing its catheter overthe wire against the defect The size of the balloon as iteventually passes across the defect into the left atriumindicates the size of the defect Because of the complianceand compressibility of the partially inflated Swan™ typeballoons, the gas filled Swan™ balloons are easily com-pressed, which allows them to “milk” through the defect

in an elongated shape This can also give a false sion of the size of the defect Of even more importance,none of the sizing techniques provide any informationabout the functional significance of the defect

impres-Equipment for a “classic” balloon atrial septostomy

The Miller–Edwards™ (Miller™) balloon septostomycatheter (Edwards Lifesciences, Irvine, CA) is the pre-ferred septostomy balloon for all infants over 3 kg TheMiller™ balloon septostomy catheter has a small latex balloon of 4 ml capacity mounted at the distal end of a

C H A P T E R 1 3 Balloon atrial septostomy

5-French catheter shaft The balloon material is slightly

redundant over the shaft of the catheter and usually

requires a 7-French sheath for its introduction Just at

the area where the balloon is attached, the Miller™

bal-loon catheter has a fixed, slight angulation of the tip of

the catheter, which is very helpful for maneuvering the

catheter with the balloon deflated from the right atrium to

the left atrium across a “closed” patent foramen ovale

(PFO) The Miller™ septostomy catheter has only the one

lumen, which communicates with the balloon, and no

separate catheter lumen, so it cannot be advanced over

a wire nor can pressures be recorded or injections

per-formed through the balloon catheter The Miller™ balloon

catheter comes with a very fine, smooth, metal wire stylet,

which extends the entire length of the catheter lumen

(including through the area of the balloon) The distal

end of the stylet can be bent and used like a rigid deflector

wire to form a greater or different curve on the tip of the

balloon catheter, or it can be used to clear the lumen of the

balloon catheter of any obstructions

The left atrial cavity of an infant who is larger than 3 kg,

can safely accommodate the Miller™ balloon inflated

with 6 ml of fluid when the balloon is free within the left

atrium Although rated and advertised at 4 ml capacity,

these balloons can actually accommodate 10–12 ml before

rupturing! When a large diameter septal opening is

desired and whenever the left atrium will accommodate

it, 6 ml of fluid is used in the Miller™ septostomy balloon

At 6 ml, the balloon not only becomes larger, but the

sur-face of the balloon becomes tense and far less compliant

These are very desirable characteristics for tearing and not

just stretching the septum When the Miller™ balloon is

inflated to less than 6 ml, it will be proportionally softer

and more compliant As a consequence Miller™ balloons

with lower volumes are smaller and less tense, and

“mold” through a smaller defect rather than tearing the

edges of it

There are special circumstances where the Miller™

bal-loon cannot be inflated to 6 ml In order to purposefully

create a smaller (usually temporary) septostomy or to

per-form a balloon septostomy in a very small infant, there

are smaller balloons available that inflate with a more

rigid wall tension at the smaller diameters The USCI

Rashkind™ balloon (United States Catheter, Inc [USCI]

BARD, Glens Falls, NY) was on a 6-French catheter, while

the newer and currently available NuMED™ septostomy

balloons (NuMED Inc., Hopkinton, NY) are on a 4-French

catheter shaft and pass through slightly smaller

intro-ducer sheaths

The more recent USCI Rashkind™ balloon

(manufac-turer as above) was a latex balloon mounted on and

recessed into a 6-French woven dacron shaft If the

bal-loon deliberately was not fully inflated, when it had been

being prepared and cleared of air and bubbles, it passed

through a 6-French sheath (as a minimum) Like theMiller™ balloon, this USCI Rashkind™ septostomy bal-loon did not have a second lumen The USCI Rashkind™balloon had the additional major disadvantage of having

a much smaller balloon size, with only a 2.5 ml capacity atits maximum inflation volume compared to the 6 ml of theMiller–Edwards™ balloon Even at its full inflation, theUSCI Rashkind™ septostomy balloon was fairly soft andmoderately compliant

The NuMED™ Z-5™ septostomy balloons (NuMEDInc., Hopkinton, NY) are available in two sizes These balloons are manufactured from a non-compliant thermo-plastic elastomer, which results in an essentially fixeddiameter, rigid balloon when inflated with the recom-mended volume The smaller Z-5™ balloon reaches adiameter of 9.5 mm when inflated with 1 ml of fluid whilethe larger Z-5™ balloon has a 13.5 mm diameter wheninflated with 2 ml of fluid As a consequence, althoughthey have a volume of only 1 or 2 ml when fully inflated,they produce very rigid balloons with diameters ofexactly 9.5 and 13.5 mm The deflated balloons passthrough 5- or 6-French sheaths, respectively

To facilitate crossing the atrial septum, the distal shafts

of the Z-5™ septostomy balloons are angled to imately 35° just proximal to the location of the balloon Inaddition, both of the NuMED™ Z-5™ septostomy ballooncatheters have a separate catheter lumen from the balloonlumen The separate lumen allows the smaller and largercatheters to be introduced over 0.014″ and 0.021″ wires,respectively The wire can be positioned securely in theleft atrium or a pulmonary vein separately through a moremaneuverable end-hole catheter, and then the balloonseptostomy catheter is passed over the pre-positionedwire This is very beneficial in directing the balloon into avery small or malpositioned left atrium and to be abso-lutely sure that the balloon is in the proper position Thewire through the balloon catheter can be left in place dur-ing the rapid balloon withdrawal during the septostomy.The wire remaining in place is helpful in re-entering theleft atrium for a repeated balloon withdrawal, and pro-vides a safety mechanism in the event of the balloon separ-ating from the catheter With the wire removed from thecatheter lumen, pressures can be recorded or small contrastinjections for angiograms can be performed through thisseparate lumen to verify the exact location of the balloon

approx-In patients in whom the shunting is right to left at theatrial level, particularly in those with total anomalous pulmonary venous return, the left atrial chamber is verysmall In these very small left atria, the Miller™ balloonconforms to the shape of the small left atrium and begins

to stretch and distort the atrium well before it reaches avolume of 6 ml (and its maximum diameter) In that situ-ation, the balloon will be fixed very firmly within the smallleft atrium and will have no “bounce” or movement In

C H A P T E R 1 3 Balloon atrial septostomy

addition, when the balloon is inflated and either filling the

atrium or pulled against the atrial septum, all systemic

cardiac output will be stopped totally! Under these

circumstances, the balloon inflation must be carried out

very cautiously to avoid over distention of the atrium, but

at the same time, rapidly to avoid too long a period of

hypotension, bradycardia and even cardiac arrest Once

the balloon has assumed the shape of the atrium and

stopped moving, inflation is stopped and the withdrawal

is performed rapidly with that degree of inflation (usually

less than 4 ml) This is the one situation where rapid

over-inflation to the full volume of the Miller™ balloon could

be disastrous and could cause rupture of the left atrium

When a very small left atrium is found, particularly in

very small infants under 2 kg in weight, in infants where

the venous system does not tolerate the 7-French

intro-ductory sheath, or in larger patients with right to left

shunting, the NuMED™ 2 ml septostomy balloon is used

in preference Neither of these balloons is satisfactory

when a large, permanent opening in the atrial septum

is desired The technique and precautions for a balloon

septostomy with either of these alternative balloons are

similar to those for the Miller–Edwards™ catheter

Balloon septostomy in the catheterization

laboratory

Whenever a balloon atrial septostomy is necessary in

neonatal patients, the patient’s hemodynamic stability is

often dependent upon the atrial communication As a

con-sequence, the balloon atrial septostomy is performed at the

beginning of the procedure before any extensive catheter

diagnostic studies, whether the septostomy is performed

in the catheterization laboratory or the newborn intensive

care unit under echocardiography guidance

The catheterization laboratory has many advantages

for the balloon septostomy All of the ancillary equipment

necessary for catheter introduction and the septostomy

procedure are available and immediately accessible

Overall visualization of the catheter in relation to the

remainder of the anatomy, and the septostomy procedure

itself are all visualized clearly using biplane fluoroscopy

With the ancillary equipment in the laboratory and with

the use of fluoroscopy, the procedure can be altered to suit

any variation in the patient’s anatomy The facilities for

cardiopulmonary resuscitation in the event of a problem

during the catheterization, and subsequent access to the

operating rooms, are usually better in the

catheteriza-tion laboratory Performance of the septostomy in the

catheterization laboratory does not preclude the use of

echocardiography in the catheterization laboratory as an

adjunct means of visualizing the septum, the balloon and

the results

Occasionally an umbilical venous line is already ent in these infants, and although it is a less desirableapproach, it is often used for balloon atrial septostomy out

pres-of “expediency”2 If the umbilical vein is used, the existingumbilical vein catheter is replaced over a wire with asheath/dilator set that will accommodate the septostomyballoon The sheath and dilator are advanced into theumbilical vein until the tip of the sheath is well into theright atrium The positioning of the sheath with its tipextending centrally past the entrance of the hepatic veinsinto the inferior vena cava/right atrium assures repeatedaccess to the right atrium and septum with the septostomycatheter When attempts are made at replacing the umbil-ical vein catheter directly with the septostomy catheter,often the ductus venosus spasms and the septostomycatheter becomes “detoured” and stuck in the hepatic/portal vein system and cannot be maneuvered to the atrium

at all from the umbilical approach This is a particularproblem when using a Miller™ septostomy balloon,which has no separate lumen for a wire

The femoral vein approach is preferred when a largeatrial septostomy is desired, and particularly when it isplanned for the atrial septal defect that is created, to lastany length of time after the procedure Although theumbilical vein is patent and even cannulated with anumbilical catheter, the results of the septostomy are lesssatisfactory from the umbilical vein approach When theballoon crosses the septum from the umbilical vein, there

is a very short distance between the balloon’s exit from thesmall ductus venosus (end of the sheath) to the foramenovale as compared to the distance from further down inthe inferior vena cava to the foramen This short distancerestricts the distance the balloon is able to travel duringand after the forceful pull through the septum and, inturn, limits the force that can be applied to pull (“jerk”) theballoon through the septum If the balloon is pulled too farand forcefully against the hepatic veins/ductus venosus,the veins can be disrupted or pulled off the right atrium,and if the balloon is pulled forcefully against the tip of thesheath, it can be ruptured or even totally dislodged fromthe catheter

When a smaller opening in the septum is necessary, and it only has to stay open for a few days before pro-posed surgery, for example in a patient with a simpletransposition or a hypoplastic left heart, then the umbil-ical approach is satisfactory The smaller NuMED™ bal-loons can be used and less force (a weaker “jerk”) appliedvia the septostomy catheter When using one of theNuMED™ septostomy balloons, first an end-hole torquecatheter is introduced into the umbilical vein, maneu-vered through the septum and into a pulmonary vein, and replaced with a wire that the NuMED™ balloon sept-ostomy catheter will accommodate When there is a pre-existing umbilical venous catheter, it is replaced with

C H A P T E R 1 3 Balloon atrial septostomy

a small spring guide wire that the septostomy catheter

will accommodate, and a torque-controlled end-hole

catheter is introduced over the wire and maneuvered into

the left atriumaand preferably into a left pulmonary vein.

The wire is advanced as far as possible and fixed in the

pulmonary vein, the catheter is withdrawn over the wire,

and the septostomy balloon catheter advanced over the

wire and directly into the left atrium When only a small or

temporary septostomy opening is necessary, this is the

most expeditious technique for performing a BAS Without

the sheath through the umbilical vein, there is slightly

more room for the withdrawal (without hitting against the

tip of a sheath), but the withdrawal distance is still limited

in order not to pull the balloon into the hepatic veins/

ductus venosus

During a balloon atrial septostomy procedure

per-formed in the neonatal intensive care unit or the

catheter-ization laboratory, an arterial monitoring line is desirable,

and in our laboratory is considered essential In the

new-born infant with congenital heart disease, the arterial line

is often present as an umbilical artery line when the infant

arrives in the catheterization laboratory If not, either the

umbilical artery is cannulated in the catheterization

lab-oratory with an umbilical artery catheter, or a femoral

artery is cannulated with a 20-gauge teflon Quick-cath™

while the sheath is being introduced into the femoral vein

When a large or persistent opening is desired, the

sept-ostomy balloon is introduced from the femoral vein

When a balloon atrial septostomy is the purpose of the

procedure or even if it is only a consideration, a sheath

that is large enough to accommodate the balloon

sept-ostomy catheter to be used is introduced into the femoral

vein at the onset of the procedure A standard, short sheath

with a back-bleed valve and flush port is used By starting

with the necessarily larger sheath, net trauma to the vein

is reduced by eliminating the subsequent exchange to a

larger sheath Starting with the larger sheath also reduces

the possibility of not being able to introduce it at all later

during the catheterization because of venous spasm of the

small femoral vein A 7-French sheath is required for

Miller™ balloons and a 6-French sheath for the larger

Z-5™ septostomy balloons When a balloon septostomy was

not planned initially and a smaller sheath was used

dur-ing the initial part of the catheterization, the existdur-ing

smaller sheath used for the diagnostic catheterization

should be replaced with the larger sheath and dilator as

soon as the decision to perform the septostomy has been

made The skin and subcutaneous tissues surrounding the

puncture site are re-infiltrated very liberally with local

anesthesia before exchanging the sheaths

Once the appropriate sheath for the septostomy balloon

has been introduced into the vein, the dilator is removed

very slowly, and the indwelling sheath with its side arm

and proximal valve chamber is carefully cleared of all air

by allowing it to bleed-back as the valve of the side port isopened very cautiously If the infant is experiencing anyrespiratory difficulty, particularly with excessive inspir-atory effort, no attempt is made to clear the sheath by free

or passive back bleeding With any strong inspiratoryeffort on the part of the patient, air is easily sucked into anopen sheath or an open side port on the back-bleed valve.When there is even minimal inspiratory obstruction, andafter the dilator and wire have been removed, the back-bleed valve of the sheath is covered tightly with a glovedfinger, a syringe is attached to the side port, and the stop-cock on the side port is opened while suction is appliedgently to the side port This allows blood to flow freelyfrom the side port while preventing air from being suckedinto the sheath through the valve by the suction on thesyringe or the patient’s inspiratory effort Once com-pletely clear of any air, the side arm is attached to a separ-

ate flush line and placed on a slow and continuous flush.

The septostomy balloon is prepared outside of thebody Normal saline (not dextrose with saline) is used forflushing the balloon and to dilute the contrast to be used inthe balloon Glucose solution, by itself, is sticky and canclog the small lumen of the septostomy catheter The sep-tostomy balloon is inflated with one, to at most 1.5 ml,

of normal saline This same volume is withdrawn alongwith any air from the balloon or catheter lumen Thefilling with fluid and the withdrawal of the fluid and anyair are repeated several times in order to remove as muchtrapped air from the balloon and catheter lumen as pos-sible Each time only a very small amount of saline flush is

used The septostomy balloon should not be inflated to its

full capacity during this preparation Inflation to the fullvolume stretches the materials of the balloons, whichcauses the balloon material to become more redundantaround the catheter shaft and, in turn, makes the introduc-tion through the appropriate sized sheath more difficult

or even impossible

The balloon is emptied completely In a separatesyringe, one ml of contrast is diluted with 9 ml of saline toprovide exactly 10 ml of a 9:1 dilution of saline to contrastsolution This syringe is attached to the previously flushedand emptied balloon lumen By starting with exactly 10 ml

in the syringe, it is easier and quicker to determine the precise amount of diluted contrast solution that is fillingthe balloon during the actual septostomy

The Miller™ septostomy balloon catheter comes with afine steel stylet within the entire length of the balloonlumen In preparing the balloon for use, the stylet isremoved but is kept on the sterile field The stylet has sev-eral potential critical uses If the balloon catheter cannot bemaneuvered readily from the right atrium into the leftatrium through a small or “tight” existing defect, a small,short, smooth 45° curve is formed on the distal end of thestylet The syringe is removed from the hub of the balloon

C H A P T E R 1 3 Balloon atrial septostomy

catheter and the stylet is inserted through the balloon

lumen to the tip of the balloon catheter The stylet within

the lumen serves as a rigid deflector wire, creating an

additional curve on the distal end of the balloon catheter

and stiffening the shaft of the catheter, both of which

facil-itate advancing the balloon catheter into the left atrium

The other very important use for the stylet is to assist in

the deflation of the balloon after the balloon septostomy

procedure has been completed Even when using very

dilute solutions of contrast with saline to fill the balloon,

there are occasions when the balloon does not deflate

following the septostomy In this situation, the stylet is

reintroduced into the lumen of the balloon septostomy

catheter to ream out any dried contrast or other

obstruct-ing material within the lumen This clearobstruct-ing of the lumen

usually allows the subsequent deflation of the balloon

when the stylet has been withdrawn

“Classic” balloon septostomy procedure

Regardless of the type of balloon septostomy catheter

being used, the surface of the balloon is moistened in the

saline flush solution and the rate of flush into the side port

of the hemostasis valve on the sheath is increased Using

the syringe attached to the proximal end of the balloon

lumen, mild negative pressure is applied to the balloon

and the balloon is introduced through the valve of the

venous sheath Very slight rotation on the shaft of the

bal-loon catheter often facilitates the passage of the deflated

balloon through the back-bleed valve and into the sheath

by wrapping the redundant balloon material around the

catheter slightly The balloon is advanced slowly through

the sheath while continuing the flush into the side port

until the balloon passes beyond the distal tip of the sheath

The redundant material of the deflated balloon advancing

within the lumen of the sheath acts as a “plunger” that can

create a partial vacuum behind it The continual flush

through the side port fills the sheath behind the balloon as

the vacuum develops and, in turn, prevents air from being

sucked in through the back-bleed valve by this vacuum as

the balloon is advanced through the sheath Once the

balloon has advanced past the end of the sheath, the

nega-tive pressure is released from the syringe attached to the

balloon lumen and the continual flush on the side port is

reduced to a slow drip The balloon is maneuvered

cepha-lad in the IVC and manipulated through the pre-existing

interatrial septal defect and/or PFO into the left atrium

In the presence of a very tense left atrium or any

distor-tion of the atrial anatomy, maneuvering across the atrial

septum can be difficult With Miller™ septostomy

bal-loons, the solid stylet is introduced into the catheter lumen

to help direct the balloon through the atrial

communica-tion When NuMED™ septostomy balloons are being

used there are several options to assist in crossing the

septum The stiff end of a small spring guide wire or aMullins™ wire (Argon Medical Inc., Athens, TX) can beused within the second lumen of the catheter to deflect thetip and support the shaft of the catheter for better maneu-verability A soft-tipped wire can be advanced out of thedistal end of the NuMED™ septostomy catheter and thewire maneuvered across the atrial septum and followed

by the septostomy catheter Finally, a separate end-hole,torque-controlled catheter can be maneuvered across thetight atrial communication and into a pulmonary vein andreplaced with the fine wire that the NuMED™ septostomycatheter will accommodate, and the septostomy catheteradvanced into the proper position over the wire

The position of the catheter tip within the left atrium isvisualized on both the posterior–anterior (PA) and lateral(LAT) fluoroscopy to ensure that the balloon tip is posi-tioned properly in the left atrium, and when available theballoon is visualized simultaneously on echocardiogram.The balloon is initially inflated slowly while its positionand motion in the atrium are observed intermittently but frequently on both the PA and LAT fluoroscopy (andecho) The systemic blood pressure and the electrocardio-gram (ECG) are monitored continuously and very care-fully while the balloon is being inflated As the balloonbegins to inflate, it should move freely within the leftatrium and, in fact, begin to “bounce” cephalad to cau-dally toward the mitral valve or left ventricle with eachatrial contraction The correct balloon bounce is perpen-dicular to the shaft of the catheter If this movement of theballoon is not seen, its inflation is stopped immediately.The exact position of the balloon is rechecked carefully onthe biplane fluoroscopy and echo When balloon move-ment or bounce does not occur or the balloon appears in

an abnormal location on echo, there are many dangers and abnormal areas where the balloon may be located.Abnormal positions of the balloon that must be excludedinclude:

1 The left atrial appendage A balloon in the left atrial

appendage appears slightly more anterior in the LATfluoroscopic view With the initial balloon inflation, theshape of the balloon begins to distort as the balloon con-forms to the shape of the appendage The balloon in theappendage is seen clearly on echo Further inflation in the appendage or withdrawal of the balloon when it istrapped in the appendage would tear or totally disrupt it

2 A pulmonary vein When the balloon is in a pulmonary

vein, the tip of the balloon catheter is positioned lateral to(outside of ) the outline of the left atrium on the PA fluoro-scopic view or posterior to the left atrium on the LATview With the initial inflation, the shape of the balloonelongates to conform to the size and shape of the pulmon-ary vein It is common that the balloon, or at least its tip,begins to inflate in a pulmonary vein, but with the initialpart of the inflation the balloon should “milk” out of the

C H A P T E R 1 3 Balloon atrial septostomy

vein and free into the left atrium This is probably the

safest starting location for the initial inflation as long as

the balloon is observed very closely and does milk out of

the vein on both fluoroscopy and echo If the balloon does

not milk out of the vein during inflation, the vein could be

split by the full inflation of the septostomy balloon

3 In a juxtaposed right atrial appendage A balloon

posi-tioned abnormally in a juxtaposed right atrial appendage

should always be considered a possibility It is the most

difficult abnormal position to recognize and absolutely

rule out The juxtaposed right atrial appendage passes

from the right atrium behind the great arteries to the left

heart boarder and is in very close approximation to the

left atrial cavity/left atrial appendage A juxtaposed right

atrial appendage should have been identified by prior

echocardiographic or angiographic studies and when

present, there should be a high index of suspicion of this

area as the balloon is being positioned A balloon

posi-tioned in a juxtaposed right atrial appendage appears in

a proper location (in the area of the left atrium) for a

septostomy on both PA and LAT fluoroscopy, but not on

echo when this is used simultaneously However, the high

index of suspicion, the rigid fixation in the position of

the balloon during the initial inflation, the distortion of

the shape of the balloon with the early inflation, and the

absence of “bounce” toward the mitral valve, will

differ-entiate the position in the juxtaposed appendage from

the correct position even without echo When there is a

known juxtaposed right atrial appendage, it is advisable

to visualize the balloon with echo as well as fluoroscopy

before withdrawing it Withdrawal from a juxtaposed

atrial appendage can totally disrupt the appendage or tear

it loose from the right atrium

4 In the left ventricle As the balloon is inflated in the left

atrium and begins to “bounce” properly, it can easily be

sucked across the mitral valve and into the left ventricle

if there is significant slack on the shaft of the balloon

catheter as the balloon is inflated If the balloon inflation

continues with the balloon in the ventricle, the balloon is

positioned caudally and laterally in the PA projection and

more anteriorly and caudally in the LAT projection The

balloon in the left ventricle becomes relatively fixed in its

position on fluoroscopy compared to the bounce when it

is in the left atrium The very caudal location in the

ven-tricle is very apparent unless there are marked distortion

and peculiarities in the overall position of the heart

and/or the chambers in relation to each other The balloon

in the left ventricle moves and is distorted slightly with

each ventricular systole In the left ventricle, the shaft of

the balloon catheter tends to pull away from the operator

along the long axis of the catheter in the direction of the

apex of the ventricle, rather than the usual bounce

perpen-dicular to the long axis when the catheter is correctly

posi-tioned in the left atrium The balloon in the left ventricle

and the catheter passing through the mitral valve are veryobvious on echocardiography A forceful withdrawal ofthe balloon from the left ventricle would disrupt the leftatrioventricular valve

5 The right ventricle When the septostomy balloon is

grossly malpositioned in the right ventricle, the position

of the balloon is far anterior on the LAT fluoroscopy and moves (bounces) perpendicular to the long axis of the catheter, but cephalad toward the right ventricularoutflow tract during each systole The abnormal location

on lateral fluoroscopy alone should identify this abnormalballoon position and certainly, a simultaneous echo easilyconfirms this abnormal location A rapid, forceful with-drawal of the septostomy balloon from the right ventricleresults in disruption of the tricuspid valve

6 The coronary sinus A balloon positioned in the

coro-nary sinus appears very posterior and caudal on LATfluoroscopy The otherwise round septostomy balloonassumes a sausage-like shape and becomes very fixedwith the initial inflation of the balloon A septostomy balloon inflated in the coronary sinus usually causes discomfort for the patient, ST changes on the electro-cardiogram, or bradycardia Full inflation of the balloon

in, or a forceful withdrawal from, the coronary sinuscould tear or split it

Correct positioning of the septostomy balloon catheter

As the balloon begins to inflate when positioned properly

in the left atrium, it begins to “bounce” perpendicularly tothe long axis of the catheter shaft and toward the mitralvalve As soon as this motion toward the mitral valve

is seen, the balloon is carefully and gently withdrawntoward, and fixed against, the intact interatrial septumduring the remainder of the inflation to the desired vol-ume As the balloon is inflated further, continued care istaken to prevent it from being sucked through the left A-Vvalve and into the ventricle This is avoided by maintain-ing gentle tension on the balloon and careful observation

of its motion on fluoroscopy or echo during its initial

posi-tioning and entire inflation.

The final positioning, the inflation of the balloon in theleft atrium, and the withdrawal of the balloon are thetimes when the adjunct use of the echocardiogram in the catheterization laboratory is extremely useful, andwhere echo guidance may have a slight advantage overfluoroscopy guidance The balloon itself and all of theadjacent structures or areas mentioned are seen clearly onthe echo Any abnormal position or motion of the balloon

is recognized on the echo image immediately It is moreapparent on the echo image if the balloon is too large forthe particular atrium and the left atrium is being distortedextensively during the inflation

C H A P T E R 1 3 Balloon atrial septostomy

Once confident that the balloon is correctly positioned

in the left atrium, and not in any of the danger areas, the

balloon is inflated more rapidly to its maximum volume,

or at least to the maximum volume and diameter tolerated

by the infant’s anatomy For the first withdrawal (“pull

through”) and in order to achieve maximum effect from

the septostomy, the balloon is filled with the maximum

volumethat it is planned to use or that can be tolerated by

the infant The balloon withdrawals should not start with

a smaller volume and should not be performed with

gradu-ated and/or gradually increasing diameters of the

bal-loon Performing balloon withdrawals with gradually

increasing volume is more likely to stretch the existing

opening temporarily, rather than actually tear a new opening.

As long as the balloon is being inflated, it is observed

very frequently or even continuously on biplane

fluoro-scopy and/or echocardiography Fluoroscopic observation

is predominantly in the PA projection, but it is also

inter-mittently checked in the LAT view to watch for not only

the danger areas, but to be sure that the balloon is not

exceeding the volume/diameter of the left atrium If the

balloon reaches the maximum atrial volume before it

reaches the desired maximum balloon volume, the balloon

becomes distorted as it assumes the shape of the atrium,

becomes unusually fixed in the atrium, and usually causes

the patient’s hemodynamics to “crater” This is more

likely to occur in very small infants or in infants with right

to left shunt lesions with very small left atria

The electrocardiogram and systemic blood pressure are

observed very carefully during the entire process As the

balloon volume approaches the volume of the atrial

cham-ber, the heart rate slows and the systemic pressure drops

This is a result either of the inflated balloon’s occluding all

systemic output or of the abnormal stretch on a small left

atrium Such a reaction does not preclude continuation of

the septostomy, but is an indication for (1) reassessment of

the location of the balloon and its size-relationship to the

LA by both biplane fluoroscopy and echocardiogram; (2)

pre-treatment with atropine; and (3) a more rapid and

dextrous inflation and pull-through of the balloon

When the balloon is fully inflated to the maximum

diameter for the septostomy (up to 6 ml for the Miller™

balloon), the catheter with the balloon is maintained fixed

gently against the septum The shaft of the catheter is

grasped with a very firm grip (even to the point of

wrap-ping the shaft of the catheter around a finger several

times) A recording with biplane angiography or stored

fluoroscopy is started While recording continuously, the

balloon catheter is withdrawn with a very rapid and

force-ful “jerk” At the same time, the withdrawal or jerk from

the left atrium back into the right atrium is for a very short

distance and must be very controlled Extreme care is

taken to assure that there is no “wind-up” on the catheter

just before this rapid withdrawalai.e the operator must

avoid the almost instinctive tendency to push the shaft ofthe balloon catheter (and the balloon) forward into the leftatrium just before withdrawing it through the septum.Such a “wind-up” allows the balloon to drop away fromthe septum and potentially through the left atrioventricu-lar valve into the ventricle just before the pull on the balloon starts!

The forceful pull or jerk on the balloon should be

per-formed with the fingers and wrist, not with the arm and

elbow Withdrawal of the balloon should be so rapid that,when filmed at sixty frames per second, the actual with-

drawal is visible on only one frameai.e it lasts only

1/60th of a second! The balloon is yanked forcefully back,and completely into, the right atrium during the with-drawal, but it is not withdrawn any further down into theinferior vena cava (or hepatic veins) In the presence of

a high-pressure left atrium, the atrial septum bulges to theright, is displaced into the right atrium, and, as a con-sequence, the foramen is often low and very close to the inferior vena cava In this situation (and during any sept-ostomy withdrawal) it helps to position the hand that isnot pulling the catheter on the infant’s leg 5–6 cm caudal

to the site where the septostomy catheter is grasped withthe other hand or fingers During the septostomy with-drawal, the second hand serves as a stop to the with-drawal and helps to prevent pulling the balloon too farinto the inferior vena cava

The heart rate and blood pressure drop very ficantly immediately following a successful septostomy.While observing the balloon on fluoroscopy, it is immedi-ately pushed back toward (into) the mid right atrium and deflated as rapidly as possible by suction applied tothe proximal end of the balloon lumen When pushedcephalad after a successful pull through the septum, theballoon moves anteriorly on the LAT fluoroscopy while,

signi-if the septum was only displaced and the balloon did not pull through it, the balloon moves posteriorly backinto the left atrium when pushed cephalad Following asuccessful balloon atrial septostomy, the heart rate and blood pressure return rapidly to normal without any extraexternal effort

Once the infant stabilizes, the deflated balloon is euvered into the left atrium, and the procedure repeatedthree to six times, or until absolutely no resistance is felt

man-as the balloon is withdrawn rapidly through the defect.Each balloon withdrawal is performed with the ballooninflated to its maximum volume and diameter as deter-mined for that particular patient Although no increase

in balloon size is used during the repeated balloon withdrawals, the repeated withdrawals tend to extendany tears in the septum that were initiated by the initialwithdrawal

Once the operator feels secure that the septum isopened to the maximum possible diameter with the

C H A P T E R 1 3 Balloon atrial septostomy

particular balloon, the status of the opening is tested by

reintroducing the balloon into the left atrium, inflating

it with a slightly smaller volume of the dilute contrast,

and performing a slow, gentle withdrawal, allowing the

balloon to “float” through the newly created opening

The amount of dilute contrast in the balloon is increased

in small amounts until slight resistance to the withdrawal

is felt, i.e starting with 1 ml and working up in

approx-imately 1 ml increments When an adequate opening has

been created, the balloon should float through the defect

even with the increasing increments of fluid

When echocardiography is available in the

catheteriza-tion laboratory or when it is used for an echo-guided

septostomy, the atrial septum and the defect are viewed

on the echo The actual defect is usually defined very

clearly and the flow through the defect can be seen on

color Doppler

Once convinced that the opening is adequate, the

balloon catheter is withdrawn by applying suction to the

proximal end of the balloon lumen while it is being

with-drawn through the inferior vena cava, back into the sheath

and out of the body Occasionally, the balloon cannot be

withdrawn into the venous sheath In that case, the

bal-loon is re-advanced several centimeters into the IVC and a

0.025″, soft-tipped, spring guide wire is introduced into

the back-bleed valve adjacent to the balloon catheter at the

proximal end of the sheath The guide wire is advanced

well into the cardiac silhouette, or even the superior vena

cava The balloon is withdrawn back to the distal end

of the sheath and as far into the sheath as possible The

sheath and the balloon catheter are withdrawn together

over the wire out of the skin This allows the removal of

the septostomy balloon along with the sheath, but leaves

a wire in place for reintroduction of the sheath and a

subsequent diagnostic catheter

An angiographic catheter is introduced and pressure

measurements are recorded during a recorded

with-drawal from the left to the right atrium This documents

the elimination of the gradient between the atria The best

visual documentation of the atrial communication is with

an angiocardiogram In patients with left atrial to right

atrial shunting, an injection is performed in a right upper

pulmonary vein with recording in a 45° left anterior–

oblique X-ray projection with cephalad angulation (i.e

4-chambered view) In patients with predominately right to

left shunt lesions, the angiocardiogram is performed with

an injection into the right atrial–inferior vena cava

junc-tion, and recorded in a straight lateral projection

Echo-guided balloon atrial septostomy

Considerable enthusiasm has been generated for

“echo-only-guided” balloon atrial septostomies, which are

performed in the neonatal intensive care unit (ICU)3

Originally, all balloon atrial septostomies were performed

in the cardiac catheterization laboratory during the nostic catheterization, when the underlying defect wasbeing diagnosed and evaluated The majority of infantsare now diagnosed definitively by an echocardiogram inthe neonatal or nursery ICU, and many balloon atrial sept-ostomies in neonates are performed in the ICU usingechocardiographic guidance only When the septostomy

diag-is performed in the neonatal ICU, usually one or more,nurses or technicians from the catheterization laboratorywho are familiar with the equipment and the procedureassist with the procedure The catheterization laboratorypersonnel provide a special balloon septostomy tray or

“cart” containing most of the essential equipment for aroutine septostomy The special tray is brought to the bedside from the catheterization laboratory The sep-tostomy trays or carts are maintained and restocked in thecatheterization laboratory after each use

The echocardiogram provides an excellent picture ofthe atrial septum and of the immediately surroundingstructures, but not all of the structures can be seen at thesame time Before the septostomy balloon has beeninflated and while it is being manipulated, the septostomycatheter is often seen only fleetingly, if at all Echo views

do not provide even two-dimensional perspectives to thestructures to aid in catheter manipulations As a conse-quence, the maneuvering of the septostomy catheter to theatrium and across the existing defect into the left atrium issemi-blind and more difficult (and occasionally impossible)under echo-only guidance without adjunct fluoroscopy

A very slight inflation of the balloon during these lations will help the visualization of the balloon and thetip of the catheter on echo

manipu-Once the septostomy catheter is in the left atrium andthe septostomy balloon begins to inflate, the balloon, theseptum and the surrounding structures are all seen verywell with echocardiography The exact relationship of theballoon size to the size of the left atrium and the exact loca-tion of the balloon against the septum are seen vividly,and their relative sizes are appreciated even better by echoimages than by fluoroscopy The same technique for theactual “ballooning” that is used in the catheterization lab-oratory is used in the echo-guided procedure in the ICU.Once the balloon pulls through the septum, the hole in theseptum and the adequacy of the septostomy are apparentimmediately on the echo At the same time, the balloondisappears completely from the echo field until searchedfor by readjustment of the position of the echo probe Evenwith the balloon out of the field of view, it is still re-advanced from the position of maximum pull until it can

be seen in the echo field After a successful septostomy,the inflated balloon can very easily float from the rightatrium into the right ventricle as it is being re-advancedfrom out of the field This position must be watched for

C H A P T E R 1 3 Balloon atrial septostomy

very carefully on the echo before further maneuvering of

the balloon

Echo-guided septostomy that is performed in the

neonatal ICU has the one advantage of not having to

transport a sick baby to the catheterization laboratory

Depending upon the availability of staffing, this may

be more expedient overall as long as everything goes

smoothly However, in the neonatal ICU there is no option

for changes in technique or equipment without incurring

a significant delay and disruption of the patient’s

environ-ment The size of the sterile field for the procedure in the

neonatal ICU is always compromised Unless the infant

already has an indwelling arterial line (umbilical or radial

artery) or the catheterization team introduces a separate

arterial line, the infant undergoing a septostomy in the

neonatal ICU does not always have the benefit of arterial

monitoring during the septostomy In the cyanotic infant

the determination of which femoral vessel has been

accessed is more difficult by echo where all of the blood is

very “blue” and the wire positions in the thorax cannot be

checked easily

Because of the limitations with the totally echo-guided

balloon atrial septostomy procedure, it is used mostly

for those infants who need a very temporary opening in

their septumai.e those patients who are expected to have

surgery within a few days or weeks and who will be

dependent upon their mixing or shunting only until the

time of the surgery Under these circumstances, it is more

reasonable to use the umbilical vein for access and to use

smaller septostomy balloons for the procedure In a

com-plex heart where the patient will be dependent on the

sep-tal communication for months or years, balloon atrial

septostomy is performed preferentially in the

catheteriza-tion laboratory, where there is in a much more controlled

environment and more optimal results can be obtained

Dilation of the atrial septum (dilation

septostomy)

The creation or enlargement of a communication in the

atrial septum with a dilation balloon is a balloon dilation

procedure that is not exactly a vascular dilation nor is

it considered a usual septostomy Dilation balloons are

used for the creation or enlargement of atrial septal

defects as an alternative to the fairly crude, and often

poorly controlled, rapid withdrawal of inflated, standard

atrial septostomy balloons through the septum4 A

dila-tion septostomy is used to enlarge a pre-existing opening

or, after a transseptal puncture of the septum, to create an

entirely new opening Dilation septostomies are

particu-larly efficacious in the presence of a very thick or tough

atrial septum The shunt created by the atrial septal defect

can be right to left or left to right depending upon the

underlying hemodynamics and anatomy When a dilation

balloon is used, one or more low-profile angioplasty loons that are significantly larger than the existing atrialopening, is (are) inflated exactly within the atrial septum

bal-As the balloon(s) expand(s) beyond the diameter of theoriginal opening, it (they) theoretically and hopefullytear(s) a larger opening in the septum Because of the highdegree of control over the rate of inflation and, in turn, theexact diameter of the opening created with dilation bal-loons, some operators prefer dilation septostomy for allballoon septostomy procedures, particularly in very smalland/or very sick infants At the other end of the spectrum,atrial septostomy performed with a dilation balloon isparticularly useful in older, larger patients with very thick or tough interatrial septae, especially when used inconjunction with a blade atrial septostomy Blade sept-ostomy with dilation septostomy is covered in detail inChapter 14

Balloon dilation atrial septostomies are used to enhanceboth right to left and left to right shunting at the atriallevel A right to left shunt at the atrial level is created inorder to vent blood away from the right ventricle whileenhancing systemic output by allowing the shunted sys-temic venous blood to enter directly into the systemic arte-rial flow In patients with hypoplastic right ventricles this

is the only means of egress of blood from the systemicvenous system, and the atrial opening should be as large

as possible The creation of a vent for the right ventricle

is also desirable in patients who have a high and fixed pulmonary vascular resistance and have no other intra-cardiac communication When an atrial defect is created

or enlarged in these patients, the right to left shuntingcauses the net systemic cardiac output to increase, and thesystemic pressure is expected to increase, while there is aconcomitant drop in the systemic arterial saturation, andthe arterial oxygen saturation is expected to decrease

In older patients, the goal is to reduce the systemic gen saturation by only 8–10% A sudden decrease of morethan 10% in systemic oxygen saturation is usually not tol-erated by these patients The balloon dilation septostomythat is performed in order to enhance right to left shunting

oxy-is initially performed very conservatively, starting withsmaller (6–8 mm) balloons and then gradually increasingthe diameter of the balloons as tolerated by the patient

If the systemic arterial oxygen saturation does not drop by

at least 6%, the original balloon is replaced with a balloontwo millimeters larger in diameter, and the dilation andobservation procedure repeated until the desired drop insystemic oxygen saturation and, hopefully, increase incardiac output, are accomplished This slow, progressivedilation is necessary to prevent a catastrophic drop in sys-temic oxygen saturation, particularly in older patientswith Eisenmenger syndrome

When atrial septal dilation is performed to vent a high leftatrial pressure, it is often performed to relieve inoperable,

C H A P T E R 1 3 Balloon atrial septostomy

obstructive, left heart lesions in order to allow trapped

pulmonary venous return to rejoin the general circulation

Infants and children with congenital mitral valve stenosis,

mitral atresia and aortic atresia, all with some degree of

hypoplastic left heart, are the usual patients undergoing

dilation of an interatrial communication for this purpose

In these patients the atrial defect represents the only (or

dominant) means of egress of blood from the pulmonary

venous circulation, and the defect created should be as

large as possible to eliminate all resistance to flow across

the septum The initial balloon (or balloons) used to dilate

the septum for this indication should be as large as can

be accommodated by the length of the atrial septum

Often these openings are maintained with the implant of

an intravascular stent in the atrial septal opening This is

discussed in Chapter 14

Patients with transposed arterial (TGA) or venous

(TAPVC) circulations require an interatrial

communica-tion to allow mixing of blood in both direccommunica-tions in order

to maintain systemic circulation and oxygenation and to

lower the pulmonary venous pressure The larger these

communications can be made, the better are the venting

and mixing In these patients dilation of the atrial septum

is performed with the largest diameter balloon(s) that the

septum can accommodate

Procedure for atrial septal dilation

When an atrial septal defect is being created using a dilation

balloon alone, the balloon that is used should be

consider-ably larger in diameter than the desired size of the defect

An end-hole catheter is advanced across the septum through

either the small existing atrial septal opening or through a

transseptal puncture through an intact atrial septum From

the left atrium the catheter is manipulated out into a left

upper pulmonary vein and is replaced with a Super Stiff™

(Medi-Tech, Boston Scientific, Natick, MA) exchange

length guide wire with a short floppy tip The wire should

be of the largest diameter that the balloon dilation catheter

that is proposed for the dilation will accommodate

A dilation balloon that is approximately twice the

dia-meter of the desired defect is advanced over the wire and

positioned precisely straddling the atrial septum The

bal-loon should be long enough to easily straddle the septum

but at the same time must not be long enough to become

entrapped in adjacent, narrow vessels Usually a 2 cm

long balloon is used in infants and a 3 or even 4 cm long

balloon is used in older patients All balloons used

to dilate the atrial septum should have very short

“shoulders” in order for the tip of the balloon not to

ex-tend into unwanted, adjacent vessels

The balloon is inflated slowly while recording each

inflation–deflation angiographically in both PA and LAT

views The balloon is observed closely not only for the

“waist” near the center of the balloon, but also to ensurethat no “second waist” appears on the balloon as a result

of the balloon being positioned erroneously in, and/orthat it does not move forward into the pulmonary vein orbackward into the inferior vena cava during the inflation.When the central waist on the balloon disappear duringthe inflation or the balloon reaches its maximum pressure,

it is deflated The inflation–deflation is repeated, movingthe balloon forward or backward very slightly with eachre-inflation

Often two balloons, positioned side by side across theatrial septum, are used to perform the dilation septostomy

By using two, smaller diameter balloons with theirsmaller deflated profiles instead of a single very largediameter balloon with a large rough deflated profile, alarge diameter atrial septostomy can be accomplishedusing two much smaller introductory venous sheaths inthe peripheral veins as opposed to one very large dia-meter sheath for the introduction of the large balloon Forexample two 12 mm balloons can be introduced throughtwo 6-French sheaths as opposed to the necessity of a large8- or 9-French sheath for a single 18–20 mm balloon.When two small balloons are used for dilation of theatrial septum, each balloon individually has an inflateddiameter of the desired atrial defect Ideally, in order tocreate one large atrial defect, both deflated balloonsshould pass through the same atrial communication ini-tially With any pre-existing communication, the secondend-hole catheter is maneuvered through the same open-ing and then into the same or even a separate left pul-monary vein and replaced with a second, identical, SuperStiff™ wire The two balloons are placed side by sidewithin the defect and the dilation septostomy carried outsimilarly to the single-balloon technique

When there is no pre-existing opening in the septum,there are two alternatives for introducing the two wiresand then the two balloons through the same initial open-ing The simplest procedure is to perform an initial, partialdilation of the septum with the first smaller balloon,which is introduced and positioned across the atrial septum after an initial transseptal puncture This creates

a septal opening through which the second end-holecatheter and eventually the second balloon can be intro-duced immediately adjacent to the first balloon and in theexact same opening The second, slightly more compli-cated alternative is to perform a second transseptal punc-ture immediately adjacent to (touching) the first transseptalcatheter before either balloon is introduced When per-formed precisely, using biplane visualization, the secondpuncture will almost join the first opening, and whendilated with separate balloons the openings will coalesceinto one larger hole

Following the inflation–deflation with either one or twoballoons, the angiograms are reviewed for the appearance

C H A P T E R 1 3 Balloon atrial septostomy

and then disappearance of the waist(s) with the initial

inflation(s) and the absence or reappearance of the waist(s)

at the lowest initial pressures during the subsequent

inflations When the septostomy is successful, the waist(s)

on the balloon(s) does (do) not reappear at all, or only

reappear very late at full inflation during the subsequent

balloon inflations Once satisfied with the inflations, the

balloon(s) is (are) withdrawn from the septum over the

wire(s) The patient is allowed to stabilize following

the septal dilation, the hemodynamics are remeasured, and

an angiogram is performed to visualize the atrial defect

which has been created A straight lateral view with

injec-tion into the right atrium is usually optimal for

visualiza-tion of defects that shunt right to left, while a left anterior

oblique view with cranial angulation and an injection into

the right upper pulmonary vein is optimal for

visualiza-tion of lesions that shunt left to right.

When the septum is totally intact before the dilation or

it is very tough, a blade septostomy (covered in detail in

Chapter 14) is performed initially before any “ballooning”

of the septum is attempted This includes all patients who

require an atrial septostomy who are more than three or

four weeks old Although the septum can be ballooned at

this age, ballooning by itself usually only stretches rather

than tears the septum, and only a temporary defect is

cre-ated By first making a small incision in the septum with

the blade, less wall tension is necessary on the balloon to

create a tear and there is more control over the opening

created with the balloon Small incisions in the septum

become the beginning of more controlled, linear tears

in the specific directions of the cuts as they are split or

torn further with the balloon dilation A controlled tear

with the use of less force is accomplished instead of the

whole circumference of the opening in the septum being

stretched until it forcefully “explodes” in any direction

Once an opening is created in the septum by stretching the

hole with a balloon septostomy alone, then a subsequent

blade septostomy only stretches and elongates the defect

to accommodate the width of the blade as it slides through

the opening, and does not incise the septal tissues at all A

dilation septostomy following an initial blade septostomy

is very effective when a controlled diameter of the

open-ing is desired

The hole in the atrial septum formed by dilation, even

with preceding blade incisions, as with the other atrial

septostomies, often has the same problem of not

remain-ing open There are now several techniques for stentremain-ing

the opening in the septum to keep it open These techniques

are described in Chapter 14 on “Special Septostomies”

There is also a new fenestrated Amplatzer™ device,

which was developed for this problem and for creating

atrial septal openings of very specific sizes; this is also

dis-cussed in Chapter 14 This device has been used

success-fully in experimental animals and in a few compassionate

cases and appears very promising, but is not available yetfor routine clinical use in the United States

Bioptome septostomy

As an alternative to any type of balloon septostomy for thecreation of an atrial defect in a patient with a very smallleft atrium that cannot accommodate even the smallestseptostomy balloon, a biopsy forceps catheter using echoassistance in the positioning of the bioptome jaws hasbeen used successfully for creating a large septal open-ing5 Small pieces of the septum are “chewed” away fromthe edge of the atrial septal opening with the “jaws” of a 5-

or 6-French bioptome catheter This has been particularlyuseful in hypoplastic left heart patients, where the leftatrium is usually very small and the septum is very tough.The biopsy forceps is advanced to the right atrium,opened in the right atrium and, using both biplane fluoro-scopic and echo guidance, purposefully engaged on the

edge of the existing atrial septal opening A simultaneous

2-D echo image of the edge of the atrial septum and thebioptome forceps is essential for the final precise position-ing of the open bioptome jaws on the edge of the septalopening before each “bite” Once engaged on the edge ofthe septal opening, small pieces of the edge of the originalseptal opening are “nibbled away” by a series of bites with the bioptome Biopsy forceps septostomy is co-vered in detail in Chapter 14, on blade and biopsy forcepsseptostomy

Complications of balloon atrial septostomy

In spite of the crude and rough nature of the balloon atrialseptostomy procedure, there are surprisingly few compli-cations from it when it is properly performed Virtually all patients have a significant bradycardia and drop in systemic pressure immediately following the forcefulwithdrawal of the balloon Almost all of them recoverspontaneously and rapidly For those few who have a sus-tained, or even progressive bradycardia or hypotension, adose of atropine and epinephrine appropriate for thepatient’s weight is given intravenously In order for this

to be administered expeditiously, the appropriate doses

of atropine and epinephrine are drawn up and ready toadminister before the actual septostomy procedure iseven begun for every patient undergoing an atrial sept-ostomy Unless there is an associated major catastrophicinjury during the septostomy, all of the patients recoverfrom the “vagal-like” response with atropine, epinephrineand, rarely, a few external compressions of cardiac massage.Catastrophic major tears due to gross malpositioning ofthe balloon before the withdrawal have been discussed

C H A P T E R 1 3 Balloon atrial septostomy

Abnormal initial balloon positions and how to recognize

them and prevent the catastrophe are fairly

straightfor-ward There seldom, if ever, are minor tears during an

atrial septostomy Once a major tear of an appendage, an

atrioventricular valve or an atrial wall occurs, the result is

a massive blood loss and a rapid demise of the patient

The only real treatment of these tears is prevention

Prevention is possible in almost all cases by meticulous

attention to every detail of the procedure no matter how

mundane it seems, nor how many septostomies have

been performed

The one major tear that might not be preventable, is a

tear at the junction of the right atrium and inferior vena

cava from the balloon’s being pulled into the inferior vena

cava at the end of the forceful jerk, particularly through a

bulging or prolapsing septum Judging the precise

dis-tance and controlling the force and disdis-tance of the pull

on the balloon are often difficult and, unfortunately, are

learned only by experience Fortunately, the inferior vena

cava is somewhat compliant or forgiving and “accepts”

the inflated balloon for a considerable distance When a

tear occurs at this location, it is in a lower-pressure venous

area and often is not as extensiveaand therefore not as

catastrophicaas a tear within the heart itself When

recog-nized, the infant is supported with volume replacement

and observation while preparing to move them to the

operating room If deterioration continues rapidly, an

attempt is made at tamponading the area with a

very-low-pressure inflation of the septostomy balloon or an

equivalent diameter angioplasty balloon positioned just

caudal to or immediately adjacent to the suspected area

of tear

Balloon septostomy, like the many other interventions

on the systemic side of the circulation, involves

consider-able manipulation in the blood that reaches the systemic

circulation directly Most newborns do not receive

sys-temic heparin for a balloon atrial septostomy procedure,

so extra attention must be paid to keeping catheters and

sheaths flushed and not leaving them in place for long

periods of time The atrial septostomy procedure involves

the introduction of balloon catheters into sheaths where

air and/or clot easily become trapped, with the

ever-present potential for systemic embolization if either the air

or thrombi are pushed out of the sheath Again, the only

really effective treatment is recognition of the potential

and meticulous attention to the details for prevention

Several complications are unique to the balloon atrial

septostomy procedure Rupture of the septostomy

bal-loon with or without the loss of the balbal-loon material has

occurred in the past, and probably will occur again in the

future6 This problem is less common with the current

universal single use of balloon septostomy catheters and

the newer Miller™ and NuMED™ septostomy balloons

When a septostomy balloon that has been properly

emptied of air prior to inflation with fluid, ruptures butdoes not lose part of the balloon, it creates an inconveni-ence, but does not create a real problem or complication.The ruptured balloon occasionally does not deflate com-pletely and is more difficult to withdraw, but its with-drawal can be accomplished by withdrawing the sheathalong with the septostomy catheter A wire is introducedthrough the valve in the sheath adjacent to the shaft of the balloon catheter, through the sheath and advancedinto the central circulation before the original sheath iswithdrawn This preserves the venous access for the intro-duction of a new sheath

When a septostomy balloon ruptures and all or part ofthe balloon material embolizes, it potentially represents

a major catastrophe, but amazingly, usually does not create even a small problem The balloon material is notradio-opaque The only indicators of the location of theembolized particle are the signs or symptoms of a vascularocclusion somewhere in the patient, depending uponwhich organ the piece of balloon lodges in Any symp-toms are treated supportively Again, prevention byinspection of the balloon and its specifications beforeusing it is the best treatment for balloon rupture If the bal-loon catheter is old, past its labeled expiry date, or hasbeen stored in an unfavorable environment, rupture withdisruption of the balloon is more likely and the balloonshould not be used

A balloon septostomy catheter shaft can break off and apiece of the catheter embolize with the entire balloon7 Thepiece of catheter is radio-opaque and has a radio-opaquemarker that allows the location of the errant piece to beascertained In the one reported case of such an incident,the piece lodged in a systemic artery and was retrievablewith a catheter retrieval (snare) device This apparentlywas an isolated incident and hopefully was a qualityassurance problem that will not recur

Another problem, which is a problem of balloon catheters

in general and not unique to septostomy balloons, is thefailure of the balloon to deflate after inflation for a sept-ostomy or dilation Contrast in the balloon catheter lumenwhich is not diluted sufficiently, or during a prolongedprocedure when the contrast remains in the catheterlumen for a long time, both contribute to, but are probablynot the only causes of, this problem Assuming that theballoon is in the right atrium and not lodged in a vitalstructure or critical orifice, the failure of the septostomyballoon to deflate does not compromise the hemodynam-ics, but does create a problem of balloon removal Thereare several alternative means of overcoming a “non-deflate” problem The first means of deflating the balloon

is to use the stylet that comes with the balloon and trycleaning out the lumen of the catheter by passing themoistened stylet repeatedly in and out of the catheterlumen and all of the way to the balloon Usually the

C H A P T E R 1 3 Balloon atrial septostomy

balloon does deflate very slowly after this reaming out

with the stylet

On the rare occasions that the balloon does not deflate

using a stylet, it must be punctured externally This is

accomplished using a second catheter introduced through

a second vein A standard transseptal dilator (alone) as the

second catheter and used with a transseptal needle

pro-vides the best control as a puncturing device A small

end-hole catheter along with a Mullins™ wire with the safety

tip bead cut off, also functions similarly and may allow the

use of a smaller second catheteraparticularly in small

infants Once the second catheter has been introduced and

advanced almost to the right atrium, the non-deflated

sept-ostomy balloon is withdrawn into the right atrial–inferior

vena caval junction in order to stabilize the balloon in the

side-to-side direction The septostomy balloon is pulled

tightly into the inferior vena cava, which fixes it in a fairly

stable, non-mobile, position in this location while the

sec-ond, puncturing catheter approaching from the inferior

vena cava is directed at the caudal surface of the balloon

When the catheter tip is against the balloon in both planes

of the fluoroscopy, the needle or sharp wire is extruded

from the end of the catheter and poked into the balloon This

maneuver is repeated until the balloon has been punctured

If the fully inflated balloon that will not deflate becomes

trapped in a critical location in the course of the blood

flow (the tricuspid valve, right ventricular outflow tract

or mitral valve), there is usually no time to introduce the

second catheter, or the location of the balloon prohibits

access for a puncture The only recourse is to over-inflate

the balloon and rupture it deliberately! For Miller™ balloons, this requires 12–13 ml of fluid This, in itself, is apotential hazard to the infant but when cardiac output istotally blocked by the inflated balloon, there is no alterna-tive This emphasizes the importance of always knowingthe location of the inflated septostomy balloon and theprevention of its moving into critical locations

Meticulous attention to the details of the septostomy cedure prevents most, if not all, of the previously mentionedcomplications and remains the best treatment for them

pro-References

1 Rashkind WJ and Miller WW Creation of an atrial septal defect without thoracotomy; a palliative approach to complete

transposition of the great arteries JAMA 1966; 196: 991–992.

2 Abinader E, Zeltzer M, and Riss E Transumbilical atrial

sept-ostomy in the newborn Am J Dis Child 1970; 119(4): 354–355.

3 Perry LW et al Echocardiographically assisted balloon atrial

septostomy Pediatrics 1982; 70(3): 403–408.

4 Mitchell SE et al Atrial septostomy: stationary angioplasty balloon techniqueaexperimental work and preliminary clin-

ical applications Pediatr Cardiol 1994; 15(1): 1–7.

5 Boucek MM et al Management of the critically restrictive atrial septal defect awaiting infant cardiac transplantation Am J

Cardiol 1992; 70: 559.

6 Vogel JH Balloon embolization during atrial septostomy.

Circulation 1970; 42(1): 155–156.

7 Akagi T et al Torn-off balloon tip of Z-5 atrial septostomy

catheter Catheter Cardiovasc Interv 2001; 52(4): 500–503.

Blade atrial septostomy

The blade atrial septostomy catheter and procedure, as the

name implies, utilize a blade to incise an opening in the

atrial septum It was designed to create an incision in a

resistant or tough atrial septum using the blade to initiate

the creation of a larger opening in the septum The

proced-ure and the unique blade catheter were developed by Dr

Sang Park in collaboration with Cook Inc (Bloomington,

IN)1 For introduction into the heart, the blade is recessed

in a metal housing or “pod” at the distal end of the

catheter Once across the septum, the blade is extended

out of the metal housing and withdrawn across the

sep-tum to create the incision A standard Rashkind™ balloon

atrial septostomy or a dilation septostomy is used to

extend or tear the incision created by the blade

Indications for a blade atrial

septostomy

The indications for a blade atrial septostomy are the same

as those for a balloon atrial septostomy, however the

blade procedure is used in older patients or in infants

with a particularly tough septum Any patient who has

a restriction in the communication between the right and

left atria where access of the systemic and/or pulmonary

venous blood back into the functional circulation is

essen-tial, requires the creation or enlargement of an opening

between the two atria Often such patients do not present

clinically until two to three months or even many years of

age There are six general categories of these older

congen-ital heart patients who present from weeks to years after

the newborn period, and who are often in desperate need

of a new or enlarged atrial communication that usually

requires a blade incision to initiate the opening There is

also a growing group of older patients with acquired

car-diac problems who benefit from the creation of an atrial

communication and require a blade incision to initiatecatheter atrial septostomy

1 The first group of patients who require the creation

of an interatrial communication are those with tion of the great arteries, who have insufficient mixing ofsystemic and pulmonary venous blood with resultanthypoxemia or pulmonary over-circulation/congestion.These patients fall into two subgroups The first comprisesthose with an intact ventricular septum without an atrialcommunication or with an atrial communication that istoo small Patients with an intact ventricular septum or asmall or non-existent atrial septal defect have no mixing ofsystemic and pulmonary blood and usually present veryearly or are very ill These infants need an atrial commun-ication created as an emergency regardless of what surgery

transposi-is planned for them subsequently

The second subgroup of transposition patients are thosewith transposition of the great arteries and an associatedventricular septal defect These patients either have a pre-existing atrial septal defect that is too small or, more often,

no atrial communication at all2 Patients with tion of the great arteries, a ventricular septal defect, and aninadequate or absent atrial defect, all need a larger atrialcommunication for free atrial mixing, but usually not asurgently, and often they do not present for this procedureuntil several months of age These patients with only alarge ventricular communication “trap” a large percent-age of their blood in their pulmonary circulation, developpulmonary congestion and pulmonary hypertension and,

transposi-in short order, pulmonary vascular disease unless theyhave an adequate interatrial communication created

2 The second major group of patients who require a blade septostomy are those with left atrioventricular valvestenosis/atresia and an associated underdeveloped orhypoplastic left ventricle2 Regardless of other intracardiaccommunications, without an adequate atrial septal open-ing, the pulmonary venous blood is trapped in the leftatrium, creating very high pulmonary venous pressures,preventing adequate systemic oxygenation, and leading

14 Blade/ balloon atrial septostomy,

special atrial septostomies, atrial

“stent septostomy”

C H A P T E R 1 4 Blade and special atrial septostomies

to acidosis Usually the existing atrial communication in

hypoplastic left heart patients is very small, making the

creation of an opening in the atrial septum an urgent

pro-cedure Even though these patients are very young with

very small left atria, they usually have very tough

inter-atrial septae which require some type of blade or other

special septostomy

3 The third group of patients is those with pulmonary

valve or tricuspid valve atresia/hypoplasia with

hypo-plastic right ventricles, in whom the systemic venous return

is trapped in the right atrium by the absence ofaor a small

aatrial communication3 In the presence of either a very

tiny right ventricular cavity or persistent very high right

ventricular end-diastolic and systolic pressures, the right

ventricle is not capable of accommodating an adequate

volume of systemic venous return with each diastole In

turn, the very small or restrictive right ventricle does not

pump an adequate volume through the lungs to the left

ventricle to supply an effective systemic output Without

an adequate vent at the atrial level, the systemic venous

return remains in the right atrium, the right atrium

becomes massively dilated with stasis of systemic venous

return, and the cardiac output remains low Under these

extreme circumstances, balloon or blade and balloon atrial

septostomy is performed during the initial diagnostic

catheterization

When there is a possibility that the right ventricle will

be able to sustain cardiac output once the pulmonary

stenosis/atresia has been relieved, the atrial septum is left

intact during the initial catheterization Once the infant

has stabilized after the valve perforation/dilation with or

without stenting of the ductus or a systemic to pulmonary

shunt, then clinical assessment will determine the need for

a subsequent atrial septostomy or other intervention

If the systemic output remains low or the right atrium

and liver become distended and enlarged, the atrial

sept-ostomy can be performed hours, days or weeks later

If however, the atrial septostomy was performed at the

initial catheterization when, in fact, an elevation in right

atrial pressure would be essential to augment the right

ventricle filling, the potential growth of the right ventricle

could be compromised permanently by the adequate

atrial communication created by the septostomy In each

individual case of hypoplasia of the right ventricleaand

until more data are available on which ventricles will

grow with adequate stimulus and with what type of

stimulusathe decision as to when to create the

septost-omy remains an-on-the-spot judgment decision for each

individual case in the catheterization laboratory

4 The fourth group of patients who benefit dramatically

from an atrial septostomy are those with total anomalous

pulmonary venous connection (TAPVC) In TAPVC both

the systemic and pulmonary venous blood returns to the

systemic venous circulation and is restricted from

return-ing to the systemic circulation for systemic cardiac put4 All of these patients need, or benefit markedly from,

out-a lout-arge interout-atriout-al communicout-ation Unless these pout-atientshave associated, separate obstruction of the pulmonaryveins, they present much later in life (weeks, months oreven years!) and a blade septostomy is required to initiatethe atrial septostomy When the atrial septum is wideopen and the pulmonary veins are non-obstructed, theclinical presentation of patients with TAPVC can be verysimilar to that of patients with a large atrial septal defect!

5 The fifth group of older congenital heart patients whowould benefit from an atrial septostomy are those withpulmonary vascular disease and severe pulmonary hyper-tension5 An atrial septal defect in these patients allows afinite amount of systemic venous blood to shunt fromright to left at the atrial level The right to left shunt vents

or decompresses the right heart volume/pressure slightlythrough the atrial communication and also supplementsthe blood volume for their systemic cardiac output, as thissystemic venous blood is added to the pulmonary venousblood in the left atrium The admixture of systemic venousblood in the systemic circulation creates some systemicdesaturation

6 The sixth and final group or category of congenital heartpatients who benefit from or require the creation of a special atrial communication are those who have under-gone a single ventricle cavopulmonary repair and who forone reason or another are “failing”, with resultant lowsystemic cardiac output or refractory protean loosingenteropathy These patients frequently receive consider-able symptomatic relief by the creation of a small restrict-ive interatrial communication The tissues are alwaystough and always require some special procedures both to create and to maintain a septostomy The interatrial com-munication usually increases systemic cardiac output, butthis is always at the expense of some systemic desatura-tion The size of this opening is critical in order to createthe optimal balance between increased cardiac output and some desaturation, but without causing symptoms

of hypoxia or even resulting in the death of the patient

As already mentioned, there is also a group of olderpatients with acquired cardiac problems who would also benefit from an atrial communication These are thepatients with acquired severe progressive right or leftheart failure where blood from the failing side of the heartneeds to be vented acutely into the better functioning

or supported side of the circulation The creation of an atrial septal communication is required to vent the leftheart in patients on extracorporeal membrane oxygena-tion (ECMO), where left-sided over-circulation and dis-tention can be a significant problem6,7 Venting the rightheart with an emergent septostomy following acquiredacute right heart decompensation has also been done8,9.Almost all patients requiring ECMO are older, and in

C H A P T E R 1 4 Blade and special atrial septostomies

order to create a septal communication that can be relied

upon for the period of ECMO and recovery, the opening

should be initiated with a blade atrial incision

When an atrial septostomy is necessary in any patient

over one month of age, a blade septostomy procedure is

performed as the initial procedure before proceeding with

any type of balloon septostomy Although a standard

bal-loon atrial septostomy or a balbal-loon dilation septostomy

(Chapter 13) is usually possible in these older patients,

the Rashkind™ type pull-through balloon septostomy is

often ineffective against the tougher septum primum

tis-sues of the older patient The balloon dilation septostomy

alone will merely stretch the opening of the foramen and

not tear a permanent opening in the much tougher septae

of the older infant/patient When the opening in the

sep-tum is only stretched and not torn, the beneficial results

obtained are very temporary

If there is a pre-existing septal opening that is over

5 mm in diameter, or if the septal opening has been

stretched by any other balloon septostomy procedure

that was performed immediately prior to the blade

sept-ostomy, a subsequent blade septostomy through this

same opening usually only stretches the opening and

pro-duces no increase in the septal opening, or at the very best,

a very unsatisfactory and still restrictive opening As

the open blade is withdrawn through even a small

pre-existing opening, the blade, which is not particularly

sharp, distorts (elongates) the pre-existing opening to

conform to the linear shape of the blade The elongation of

the septal opening allows the blade to pull through the

atrial septal opening by merely stretching the pre-existing

opening without incising the septal tissues at all

When-ever there is a question of the septal thickness or when the

patient is over one month of age, the septostomy should

be started with the blade procedure to reduce the

possibil-ity of only stretching rather than cutting and then tearing

the atrial opening

In older patients with a pre-existing small to moderate

sized atrial communication but, at the same time, the

pre-existing defect is too small for adequate atrial mixing, the

blade incision in the septum is performed through a

separ-ate transseptal atrial puncture that is at least 5 mm (or

more) away from the original opening in the atrial

sep-tum The transseptal perforation is performed with either

a standard transseptal needle set or with a

radio-frequency perforation catheter10 The transseptal puncture

is performed 5–10 mm away from the pre-existing opening

In order to create one larger opening, the new opening can

be extended into the original opening by angling the blade

toward the original opening during the blade

pull-through As an alternative, an entirely separate, second

opening can be created with no intention of coalescing the

two openings Trans-thoracic or trans-esophageal echo

guidance is helpful for determining the proper distance

away from the original opening on the septum for thelocation of the transseptal puncture

Equipment for blade/balloon atrial septostomy

For the optimal safety of the patient, the blade septostomy

procedure should always be performed using a biplane

fluoroscopic system and an adjunct echocardiogram

Although the procedure can be performed using a

single-plane system, single single-plane X-ray fluoroscopy can only beused when the X-ray tube is capable of rapid rotation tothe straight lateral position and, even then, the safety ofthe procedure is compromised Patients requiring a bladeseptostomy are often small patients and often have a verysmall left atrium A transseptal perforation to introducethe blade catheter through a very precise area of the sep-tum or just the safe positioning of the blade catheter prior to the incision both require the capability of simul-taneous, perpendicular X-ray views in order to “men-tally construct” the three-dimensional anatomy Once thetransseptal or the blade catheter is in position, the echocar-diographic image provides additional reassurance thatthe particular catheter is in the proper position

Park™ blade septostomy catheters (Cook Inc.,

Bloom-ington, IN) are available in three sizesathe PBS 100, the

PBS 200 and the PBS 300 The cutting surface or blade

of the PBS 100 is 0.94 cm in length; that of the PBS 200

is 1.34 cm in length; and that of the PBS 300 is 2.0 cm

in length Although fairly sharp, the blades on the

sept-ostomy catheters are not finely honed cutting instruments

and do not cut on mere contact with tissues, but rather,must have some “slicing” effect to incise tissues Theretracted cutting blade is contained in a tubular metalholder (pod) at the distal end of the catheter The bladeextends to the open position through a slit along one edge

in the wall of the pod Opening and closing of the bladeare controlled by a long, stiff, straight, steel wire whichextends through the length of the lumen of the catheterfrom its proximal end to the blade mechanism within thepod at the distal end At the proximal end of the catheterthe stiff wire passes through an adjustable Tuohy™ valvethat is attached to the proximal hub of the catheter TheTuohy™ valve has a “Y” side port that communicatesthrough the catheter lumen to the chamber in the pod con-taining the blade mechanism, which is used for flushingthe catheter lumen and the pod The proximal, free end ofthe stiff wire, which extends out of the Tuohy™ valve, has

a separate tightening sleeve, which is cinched securelyaround the wire

At its distal end, the stiff wire within the catheterattaches to the proximal end of the blade mechanismwithin the pod The blade mechanism is tested, adjustedand flushed outside of the body before use When the stiffwire is pushed into the proximal end of the catheter, the

C H A P T E R 1 4 Blade and special atrial septostomies

blade mechanism is pushed open and the cutting edge of

the blade is extended out of the slit on the pod When the

blade mchanism is opened in the heart, the extended

blade mechanism forms a “triangle” in which the apex of

the triangle extends away from the shaft of the catheter

and perpendicular to the long axis of the body The blade

or sharp cutting edge of the open blade mechanism forms

the caudal limb of the triangle When the blade is extended

to the desired 45–60° angle off the shaft (and pod) of the

catheter, the loosened tightening sleeve is advanced over

the stiff wire until it touches the Tuohy™ valve The sleeve

is cinched tightly on the wire at that position When fixed

at this position on the stiff wire, the tightening sleeve

limits the distance the wire can be pushed into the

cathe-ter which, in turn, limits the degree of opening of the blade

to the desired angle

The PBS 100 and 200 blades are recessed in catheters

with a 6-French shaft, while the PBS 300 is in an 8-French

catheter Because of a bulge at the attachment of the steel

housing of the tubular blade container to the shaft of the

catheter, blade catheters usually require an introducer

sheath one size larger than the advertised diameter of the

blade catheter The PBS 200 (1.34 cm blade) is the blade

catheter used routinely for infants, while the PBS 100

(0.94 cm blade) is reserved for very low weight infants or

infants with a very tiny left atrium The PBS 300 (2.0 cm

blade) not only has a larger blade but is manufactured

from heavier materials and, as a consequence, is a much

sturdier device The PBS 300 is used for all larger infants,

older children, and adults Because of its larger size it can

naturally produce a larger incision Because of the longer

length of the blade, withdrawal of the blade through the

septum can be performed with the blade extended at a less

acute angle off the shaft of the catheter This less-acute

angle off the catheter shaft/carrier pod reduces the

dia-meter of the cut which is made and actually increases the

ability of the blade to cut and truly make an incision in the

septal tissues Because of its sturdier construction, the PBS

300 blade is less likely to distort or bend when pulled

through a tough septum The PBS 300 is recommended for

all patients past infancy.

It is recommended that a long, transseptal type delivery

sheath is used to advance the fairly rigid blade catheters

from the right atrium into the left atrium even in the

pres-ence of a pre-existing opening The long delivery sheaths

now have a radio-opaque band at their distal tip and a

back-bleed valve with a side flush port at the proximal

end, both of which make their use much safer The two

smaller blade catheters require a 7-French long sheath,

while the larger PBS 300 requires a 9-French sheath These

long sheaths must be long enough to reach from the

femoral vein to the left atrium, but at the same time cannot

be longer than the blade catheter, which is only 80 cm long

Although most patients who require a blade septostomy

are infants or young children and a sheath 30–40 cm longwould be sufficient (preferable!), most of the availablelong sheaths are transseptal length sheaths and are con-siderably longer than necessary for blade septostomy and definitely longer than standard balloon septostomy

catheters When the blade catheter is introduced through

any transseptal length sheath, it becomes necessary toexchange this sheath for a shorter venous introductorysheath after the blade procedure, before a Rashkind™pull-through type balloon septostomy can be performed

Although the distal end of a long transseptal sheath can be

cut off to accommodate the balloon septostomy catheter,this must be done before its initial introduction When thedistal end is excised, it removes the distal radio-opaquemarker on the sheath and results in a very poor fit over the dilator, and a much rougher and more traumatic tip onthe sheath

Transseptal sheaths come from the manufacturer with

a 180° curve at the distal end The curve on the sheath/dilator set is straightened to a gentle 20–30° curve beforebeing used for the blade procedure All blade septostomyprocedures are followed by a balloon atrial septostomy ofsome type (Chapter 13), and the necessary equipmentmust be available for this procedure

Technique of blade atrial septostomy

The usual blade atrial septostomy catheter/sheath isintroduced percutaneously through a femoral vein

Although a pre-existing atrial septal defect can be crossed

from a jugular/superior vena caval approach, the plane

of the atrial septum when approached from cephalad isexactly parallel to the course of the catheter coming fromthe superior vena cava With this angle of approach, atransseptal puncture with a needle is very difficult, par-ticularly in a small infant In addition, once the blade catheter has passed through the atrial septum from thesuperior vena caval approach, a blade incision pulling

in this direction will be into the junction of the rightatrium–superior vena cava with little intervening septum

A blade pulled forcefully (successfully!) in that direction

has a high likelihood of incising the wall of the heart at the

right atrial–superior vena caval junction or of damagingthe sinoatrial node Because of this, a blade atrial sept-ostomy from the superior vena cava is contraindicatedeven if technically it could be accomplished

A blade septostomy catheter can be introduced throughthe umbilical vein, however, the umbilical vein has usu-ally closed by the time a patient is in need of a blade sept-ostomy procedure A transhepatic venous access gives adirect access to the atrial septum The tip of virtually anycatheter introduced successfully from the transhepaticapproach is directed toward the atrial septum almost assoon as it enters into the right atrium from the hepatic

C H A P T E R 1 4 Blade and special atrial septostomies

veins The catheter/needle/blade catheter approach to

the atrial septum from a hepatic vein is almost

perpendic-ular to the septum, which makes this approach ideal for

crossing a pre-existing defect or for performing a

transsept-al atritranssept-al puncture However, when the blade which has

been introduced from the transhepatic route is opened,

the open blade aligns exactly parallel to, and lies flat

against, the atrial septum when it is withdrawn As a

con-sequence, the cutting edge of the open blade, which is not

particularly sharp, is pulled flat against the surface of the

septum This eliminates any incising effect when the open

blade is withdrawn further against or into the septum

Because of this absence of any angle of the blade against

the septum, much more force must be used to pull the

blade through the septum Compounding this problem of

the angle from the hepatic venous approach, when the

blade catheter is introduced from the hepatic veins, there

is almost no separation between the atrial septum and

the entrance into the hepatic veins where they enter the

hepatic parenchyma This allows much less distance or

“free space” for the open blade to “pop into” after it has

been pulled forcefully through the septum The

transhep-atic route is used for a blade septostomy only after all

pos-sibilities of approaching from the femoral veins have been

exhausted

After the hemodynamics have been obtained and the

decision has been made to perform a blade atrial

sept-ostomy, a biplane angiocardiogram is recorded to

visual-ize the left atrium This is recorded either from a direct left

atrial injection or from a “recirculation left heart”

angio-cardiogram following an injection into a more proximal

location in the pulmonary artery or right ventricle The

biplane left atrial angiocardiogram demonstrates the size

and details of the anatomy of the left atrium and provides

the fixed radiographic landmarks for the subsequent

septostomy A biplane freeze frame “road map” of the left

atrium is saved Although not always necessary, this

angiographic information about the left atrial anatomy

contributes significantly to the safety of the procedure

Once this information is available, the diagnostic catheter

and original sheath in the femoral vein are removed over

a wire

The catheter and short sheath are replaced with a long

transseptal sheath/dilator set which is large enough to

accommodate the blade septostomy catheter Before the

standard transseptal sheath/dilator set is used for a

septostomy procedure, the original 180° transseptal curve

at the distal end of the sheath is straightened into a very

gentle, 15–20° curve This curve is straightened by pulling

the sheath/dilator repeatedly through the thumb and

forefinger of the opposite hand or by using heat from a

water bath, steam or a heat gun to soften the sheath/

dilator and then hand straightening them A 7-French

transseptal set is used if a small (PBS 100) or medium (PBS

200) blade catheter is to be used A 9-French transseptal set

is necessary for the large (PBS 300) blade catheter

If the original diagnostic catheter and a wire were in theleft atrium before the diagnostic catheter was removed,the catheter is removed over an exchange length guidewire, which remains in the left atrium The sheath/dilatorset is advanced over this wire and directly into the leftatrium Once the tip of the sheath is well within the leftatrium, the wire and the dilator are withdrawn veryslowly while maintaining the tip of the long sheath in theleft atrium Once the wire and dilator have been removed,the sheath is cleared meticulously of any air and/or clot

by allowing it to bleed back passively through the sideport of the sheath whenever possible

When there is a very small pre-existing atrial opening or

a patent foramen ovale, which has not been crossed with acatheter or wire, the long sheath and dilator are advancedover the wire, but only to the area of the right atrium Thewire (only) is withdrawn, the dilator is cleared of any air

or clots, attached to a flush/pressure line and flushed

In the presence of even a very small pre-existing atrialcommunication, the long sheath/dilator combination canoften be advanced carefully, using biplane fluoroscopy,directly from the right atrium into the left atrium after the wire has been removed This manipulation must bevery gentle and careful since the tip of the dilator of thetransseptal set is sharp and capable of puncturing theatrial wall if any force at all is used The sheath/dilator is

not advanced when there is any suggestion of resistance or

other difficulty in crossing the original septal defect with it.When a definite pre-existing opening in the septum can-not be crossed easily with the sheath/dilator combination,the dilator is removed slowly from the sheath, and afterthe sheath has been cleared carefully of all air or clots,

an end-hole catheter of the same French size as the sheath

is introduced through the long sheath The end-holecatheter is advanced beyond the sheath and manipulatedinto the left atrium through the pre-existing small atrialseptal defect or patent foramen Once the dilator orcatheter is within the left atrium, the long sheath isadvanced over the dilator or catheter and well into the leftatrium The catheter or dilator is withdrawn slowly out ofthe sheath and the sheath is again cleared of any air orclots by very carefully allowing the passive free flow offluid/blood through the side port of the valved back-bleed device on the sheath Once completely cleared ofany air and/or clot, the long sheath is attached to theflush/pressure system and placed on a continuous flush.When the interatrial septum is intact, or if a second holeadjacent to a small pre-existing atrial septal defect isdesired, the long transseptal set is advanced over a wireuntil the tip of the dilator is in the superior vena cava

as the initial position after introduction into the vein The left atrium is then entered by a standard, long sheath,

C H A P T E R 1 4 Blade and special atrial septostomies

transseptal needle puncture or, in the very small patient,

by a radio-frequency wire transseptal perforation (Chapter

8) using biplane fluoroscopy as well as echocardiographic

guidance Once the tip of the long sheath has been

posi-tioned well into the left atrium, the needle and then the

dilator are removed slowly and separately Every time

the needle, dilator or catheter is removed from the sheath,

the sheath must be cleared meticulously of all air and clots

before it is flushed at all Preferably, the sheath is always

allowed to bleed back passively through the side port of

the back-bleed valve of the sheath without applying any

suction to the sheath lumen through the side port If there

is no flow through the side port after the dilator has been

removed, the valve at the proximal end of the long sheath

is covered tightly with a gloved fingertip and gentle

suc-tion is applied with a syringe to the side port of the

back-bleed valve If no blood returns with very gentle suction,

the sheath is withdrawn slightly or rotated slightly and

mild suction reapplied It is very important that the

with-drawal of blood or air from the sheath is performed very

gently The “end-hole only” sheath very easily becomes

trapped or totally blocked in a pulmonary vein or against

the left atrial wall When the tip of the sheath is occluded,

vigorous suction will preferentially suck air through the

back-bleed valve at the proximal end of the sheath! This

causes an air-lock within the back-bleed valve chamber

and within the lumen of the long sheath, in which case the

sheath serves as a direct route into the left atrium for air as

well as for the blade septostomy catheter! This air will

subsequently be flushed into the left atrium and systemic

circulation unless prevented or cleared from the sheath!

Once the sheath has been cleared of air and clots, it is

flushed very carefully, the side arm of the back-bleed

device is attached to the pressure/flush system, and the

sheath is placed on a slow continuous flush

In a very small infant, because of the small veins and/or

venospasm, occasionally it is not possible to advance a

long 7-French sheath all of the way to the heart or the left

atrium In that circumstance, the blade catheter is passed

through a short sheath in the femoral vein and very

care-fully and under continuous direct biplane fluoroscopic

visualization it is advanced up the inferior vena cava to

the area of the right atrium Once the tip of the blade

catheter is in the right atrium, the patient’s shoulders are

bent (not twisted) from the mid thorax toward the

pa-tient’s right side, by sliding his shoulders to the papa-tient’s

right (without rotating the body) This maneuver is

ident-ical to that described previously in Chapter 8 for the

transseptal procedure in the presence of a very vertical

interatrial septum or when the atrial transseptal puncture

is being approached from the left groin With the patient’s

trunk bent in this manner, the septum becomes more

perpendicular to the long axis of the body (and the inferior

vena cava) and allows the straight pod of the blade

catheter to pass across the interatrial septum into the left atrium

Prior to the introduction of the blade catheter into thelong or short sheath, all of the fittings on the blade catheterare inspected, tightened and adjusted The pod actuallyhas a slight convex bow or bend on the surface where thegroove is located on the tubular pod This bend is neces-sary to assure that the apex of the blade mechanism ispushed out of the groove when the stiff control wire ispushed forward There should be no leakage at the junc-tions of the blade catheter with the catheter flush port

or around the Tuohy™ valve through which the controlwire passes The blade is tested and should extend easily

to the desired angle and retract into the catheter pod out resistance The degree of extension and the angle ofthe blade are adjusted and set after all of the other fittingshave been tightened The blade angle is determined bymoving the proximal end of the stiff control wire in or out

with-of the proximal Tuohy™ valve The Tuohy™ valve is part

of the flush port, which is attached to the proximal hub ofthe blade catheter When the blade has been opened to thedesired angle, there is a small plastic cylinder containing a

“compression adjuster vice” which fits over the wire Thissmall vice is advanced over the stiff wire, against the flushport and is tightened on the wire in this position on theproximal end of the wire With the compression vice tight-ened at the desired location on the control wire, the bladeopens to only the predetermined angle when the distalend of the cylindrical vice on the proximal end of the wire

is flush against the proximal hub/valve of the catheter.The control vice and the control wire of the blade must not

be twisted or torqued during the adjustments, checking oropening and closing of the blade Any twist on the controlwire can distort or change the angle of the control wire-to-blade attachment and twist the blade in the slot on the catheter, and can cause the blade to jam in either theclosed or the open position The blade should never be

withdrawn or retracted forcefully back into the recess of

the groove in the pod on the catheter This is particularlytrue with the two smaller-blade catheters A forcefulretraction into the pod causes the hinge at the tip of theblade (at the apex of the “triangle”) to “over-straighten”within the slot of the metal pod Even with the slight bend

on the pod, the forceful withdrawal can “retroflex” theapical hinge point of the blade backward into the groove

in the pod If the angle of this hinge is directed toward the back of the groove, the blade cannot open when theproximal wire mechanism is advanced

Both the side port on the blade catheter and the side arm

of the back-bleed device on the long sheath are attached tothe flush system Once the sheath is in its proper position

in the left atrium and the blade mechanism on the tablehas been checked thoroughly, both the sheath and bladecatheter are on a continuous flush, the blade catheter is

C H A P T E R 1 4 Blade and special atrial septostomies

introduced into the long sheath and passed through the

sheath directly into the left atrium While the blade is

introduced into the back-bleed device and once within the

sheath, both the side port of the back-bleed device on the

sheath and the side port of the blade catheter are

main-tained on a thorough and continuous flush If the long

sheath does not have a distal radio-opaque marker, the

distance from the skin puncture site back to the hub of the

sheath is measured accurately on the sheath and recorded.

This measurement is used as a reference distance in the

event that the distal end of a sheath without a marker

band cannot be distinguished clearly when the blade

catheter is within the sheath and, consequently, the exact

position of the tip of the sheath cannot be determined

Once the entire length of the metal pod of the blade

mechanism is in the left atrium as visualized on biplane

fluoroscopy and echocardiography, the blade catheter is

fixed in position and the sheath is withdrawn off the blade

catheter and well down into the inferior vena cava (IVC)

This leaves the entire exposed but unopened blade

mech-anism in the left atrium Both the sheath and the blade

catheter are maintained on a flush

Occasionally, in a very small left atrium, the entire

metal pod containing the blade does not fit all of the way

into the left atrium and extends partially back through the

septum into the right atrium In this case, the blade and

the groove containing the blade also extend partially back

through the septum, which, in turn, will not allow the full

length of the blade to open in the left atrium In this

cir-cumstance, the blade catheter is advanced with a mild, but

extra, forward push, which, in turn, indents the tip of the

blade catheter into the wall of the left atrium as seen on

echo This “extra push” on the catheter allows more of the

groove of the pod and the blade to advance into the left

atrium Once this groove is at least half way into the left

atrium, the blade will open entirely in the left atrium as

the blade emerges out of the groove When the blade is

retracted, the hinge at the tip of the blade is at the very

cen-ter of the length of the groove within the metal pod The

hinge at the distal end of the actual blade forms the apex of

the triangle of the open blade mechanism As the blade is

opened, this hinge point exits first from the very center of

the groove along the metal pod As long as the center of the

groove is on the left side of the septum at the onset of

opening the blade, the center of the opening blade will

open on the left side of the septum and, in turn, hold the

entire blade mechanism on the left side of the septum as

the blade is opened to its full extent As the blade opens,

the apex of the triangle moves further into the left atrium

In the case of a very small left atrium, the catheter and

blade mechanism can actually be advanced slightly into a

pulmonary vein or into the left atrial wall to permit the

proximal portion of the blade to open within the left

atrium During all of these maneuvers, the blade catheter

is observed intermittently with alternate planes of biplanefluoroscopy and continuously with echo imaging Thelumens of both the blade catheter and the sheath are maintained on a continuous flush with heparinized flushsolution

Once the blade has been positioned within the leftatrium as determined by comparison of the previously

“road-mapped” pictures of the left atrial anatomy on boththe PA and LAT angiocardiograms and/or by echocardio-gram, the blade mechanism is opened slowly by advanc-ing the control-wire mechanism at the proximal hub of the catheter The blade mechanism is observed on biplanefluoroscopy and echo to ensure that the blade is notentrapped within a pulmonary vein or the left atrialappendage To allow a wider opening of the blade in theleft atrium, once it is partially opened, the blade catheter iswithdrawn very slightly toward the atrial septum to freethe tip of the extending blade from the area of the pul-monary veins or left atrial appendage

Once opened, the blade is angled anteriorly This angle

is determined not only by the angle of the flush port at theproximal end of the blade catheter (which supposedly cor-responds to the angle of the blade), but by direct visualiza-tion of the tip of the blade within the left atrium as seen onboth PA and LAT fluoroscopy The tip of the blade can beangled either to the right or to the left, but is always at

least slightly toward the anterior chest wall in order to avoid

the possibility of incising the A-V conducting system.With the blade facing the proper direction, and whilemanually holding the proximal open/close slide mechan-ism securely in order to maintain the blade in the openposition and at the correct angle, the blade catheter is

withdrawn slowly, which draws the edge of the blade

against the atrial septum At this point, the hands holdingthe blade catheter are held against the tabletop to providestability for the catheter Withdrawal of the catheter withthe open blade is continued slowly, but forcefully towardthe IVC until the open blade “pops” through the septum.Prior to this, it is usually necessary to apply considerableforce or pull against the septum The force applied to theblade frequently results in a marked displacement of theatrial septum and the entire cardiac silhouette toward the diaphragm before the blade actually incises and cutsthrough the septum If the blade does not cut through theseptum, even with a moderate amount of force and inspite of a very significant displacement of the heart, thetraction on the blade catheter is relaxed while the catheterwith the open blade is re-advanced back into the leftatrium The open angle or cutting angle of the open blade

is decreased very slightly by withdrawing the proximalcontrol wire very slightly, which retracts the blade (anddecreases the angle of the triangle) slightly into the groove

on the catheter The compression vice is readjusted on thecontrol wire to fix this new angle of the blade when the

C H A P T E R 1 4 Blade and special atrial septostomies

vice is advanced against the hub Withdrawal through

the septum is reattempted with the reduced angle on the

blade until the blade pulls successfully through the

sep-tum If the entire heart is displaced considerably toward

the diaphragm without the blade pulling through the

sep-tum, the long sheath in the IVC should be withdrawn even

further down into the IVC before repeating the

with-drawal Although the blade is withdrawn very slowly and

meticulously, when the blade successfully pulls through

the septum there is the sensation of the blade “snapping”

or “popping” through the septum as the heart “snaps”

back in a cephalad direction into the thorax As soon as

the blade pops through the septum, it is immediately

retracted back into the catheter by pulling back on the

compression vice mechanism on the proximal wire

After a successful withdrawal of the blade through

the septum and with the blade retracted into the pod of

the catheter, the blade catheter alone can usually be

re-advanced cephalad and back into the right atrium, and

from the right atrium, easily back through the newly

cre-ated septal opening into the left atrium If the angle of the

metal pod of the blade catheter is not sufficient to allow

this, the sheath is re-advanced carefully over the tip of the

pod of the blade catheter to a position 1–2 mm distal to the

tip of the pod With the sheath in this position, the

curva-ture of the sheath, together with the slight bend in the

blade catheter, is usually sufficient to direct the combined

blade and sheath into the left atrium with gentle

to-and-fro and/or torque motion of the sheath/blade catheter

combination To facilitate the passage back into the left

atrium when there is any resistance, it is helpful to bend

the patient’s thorax to his right similarly to the maneuver

when performing a transseptal puncture from the left

groin This tends to position the new opening in the atrial

septum more perpendicular to the long axis of the blade

catheter

If the blade catheter cannot be reintroduced into the left

atrium very easily, it is withdrawn from the sheath while

continually flushing the side port of both the sheath and

the catheter The blade catheter is removed from the long

sheath and replaced with a diagnostic catheter, which, in

turn, is manipulated back into the left atrium The sheath

is re-advanced over this diagnostic catheter into the left

atrium, the catheter removed, the sheath cleared of any air

and the blade catheter reintroduced through the sheath

Extreme care must be taken to avoid the introduction of

air or clots with the catheter and blade exchanges

When the blade catheter is out of the sheath, it is very

important to inspect the pod which holds the recessed

blade to be sure that it is free of any clots or debris, since

the entire groove cannot be flushed adequately only by

flushing the lumen of the catheter The lumen of the blade

catheter is maintained on a continuous flush while the

blade mechanism is inspected and the groove in the pod is

cleared of any clot or fibrin The groove with the distalblade mechanism can be flushed directly by using a needle on a hand-held syringe of flush fluid and forcefullyinjecting a jet of fluid directly into the groove, over andaround the blade

The reintroduction of the blade catheter into the leftatrium and the blade withdrawal are repeated four or fivetimes With each withdrawal, the angle of the open blade

is extended to at least 45° off the shaft of the catheter andthe side-to-side angle of the blade within the 180° anteriorarc within the heart silhouette is changed with each with-drawal The blade is always directed anteriorly and either

to the right, straight anterior or to the left during sequent withdrawals It is to be hoped that at least severalsmall incisions are made at different angles around theanterior 180° circumference of the incised opening in theatrial septum The posterior 180° is avoided to stay awayfrom the A-V conduction tissues During the repeatedmanipulations of the blade, the blade catheter and thesheath are kept under a continuous flush After four to sixblade withdrawals have been performed at different side-to-side angles, or once the blade no longer meets anyresistance, it is retracted into the catheter and withdrawnthrough the introductory sheath

sub-Following the multiple blade incisions, a balloon atrial septostomy is performed This can be accomplished with a standard Miller™ septostomy balloon (EdwardsLifesciences, Irvine, CA) or with a static angioplasty bal-loon In order to use the Rashkind™ pull-through type

of balloon, the long sheath must be replaced with a short7-French, valved back-bleed sheath Although the longsheath is of the same French size as the short sheath, aMiller™ septostomy balloon will not pass easily through along sheath to the left atrium without binding within it.Also unless the long transseptal sheath was shortenedbefore it was introduced initially, it will be too long forboth Miller™ and NuMED™ (NuMED Inc., Hopkinton,NY) balloon septostomy catheters

The side port of the introductory sheath is flushed tinuously while the balloon for the septostomy is passingthrough the sheath into the venous system The deflatedseptostomy balloon acts as a plunger within the lumen ofthe sheath during its introduction into the sheath and cre-ates a significant vacuum behind it Unless the space in thesheath is filled with flush solution, the vacuum will suckair through the valve on the sheath and into the sheath.Once advanced through the sheath, the septostomy bal-loon is manipulated across the incised atrial communica-tion and into the left atrium The balloon is inflated to themaximum volume that can be tolerated by both the balloon and the anatomy of the patient The fully inflatedballoon is jerked very forcefully, but in a controlled fashion, across the septum as with any other Rashkind™septostomy The septostomy balloon is pulled through the

con-C H A P T E R 1 4 Blade and special atrial septostomies

septum four or five times, each time using the maximum

volume that can be tolerated by the size of the left atrium

The goal is to extend the initial incision(s) made by the

blade catheter with significant further tear(s) in the

sep-tum In older patients, often the septum is very tough and

the maximally inflated balloon cannot be jerked through

the septum even after multiple blade incisions

In these older patients and others with a very thick or

tough atrial septum, enlargement of the septum after it

has been incised with the blade is performed with

angio-plasty dilation balloons A single balloon or, preferably,

two balloons side by side are used, depending on the

venous access for the balloons and the size of the atrial

septal communication that is to be created Although the

femoral approach is preferred, if necessary one or both of

the angioplasty balloons can be introduced via an internal

jugular or even a subclavian vein approach

To use an angioplasty balloon following the blade

pro-cedure, the blade catheter is replaced with an end-hole

catheter which is passed across the newly created defect,

into the left atrium and into a left pulmonary vein The

catheter is replaced with a stiff exchange length guide

wire and the angioplasty balloon introduced over this wire

The balloon is centered across the septum over this wire

and inflated in the defect to its maximum pressure As

with other dilation procedures, a waist appears on the

balloon and with full inflation the waist disappears If two

balloons are used for the dilation septostomy, the second

balloon is introduced over a wire from a separate venous

introductory site The second balloon is positioned across

the atrial septum side by side with the first balloon and the

two balloons are inflated simultaneously, observing for

the waists on both of them Using two balloons side by

side has the advantage of allowing the use of significantly

smaller balloons, which allows venous access from two

separate, smaller veins Double balloons also allow for the

creation of much larger openings in a very large patient

than is possible with a single balloon The use of dilation

balloons has the advantages of producing a more

con-trolled tear in the septum and allowing access for the

septostomy from a greater variety of sites Furthermore

there is far less likelihood of the balloon being disrupted

and a piece or all of the balloon material being lost

some-where in the circulation

The adequacy of the newly created defect is verified by

one of several techniques following the balloon

sept-ostomy Measurement of the hemodynamic data

includ-ing the systemic saturation, right and left atrial pressures,

and pulmonary artery pressure gives the best estimate of

the functional success of the procedure The Miller™

sept-ostomy balloon in the left atrium is partially inflated with

1–4 ml of dilute contrast and gently pulled, or allowed to

float, through the newly created defect The “stretched

size” of the defect is determined by the diameter of the

balloon at that volume of inflation which demonstratesslight resistance at the beginning of the withdrawal Afairly accurate assessment of the newly created atrialdefect at least in one dimension is obtained from an angio-graphic measurement of the diameter of this balloon as it

“milks” through the septum In the presence of left to rightshunting, a left atrial angiocardiogram with the injection

in the mouth of the right upper pulmonary vein andfilming in the four-chamber (45° LAO–45° cranial angu-lated) view is performed This angiocardiogram usually

“cuts” the newly created atrial defect on edge and vides a visualization of the new opening When the shunt-ing through the newly created defect is predominantlyright to left, a straight lateral view with injection into thelow right atrium/inferior vena caval junction usually pro-vides the optimal angiographic view of the defect Thesize and persistence of the newly created atrial defect canalso be visualized and the size estimated by echocardio-graphy (especially transesophageal echo)

pro-When performed properly using biplane fluoroscopicand echocardiographic guidance and by always payingmeticulous attention to the details of the procedure, theblade septostomy procedure is extremely safe and effect-ive The actual blade “pull-through” produces a very con-trolled incision in the septum with the only uncontrolledand unsafe portion of the procedure being the subsequentballoon septostomy enlargement of the defect using aRashkind™ type, pull-through technique The greatesthazard of the blade septostomy procedure is not from theblade withdrawal itself or damage produced by the bladeincision, but from the potential for the inadvertent intro-duction of air or clot during the many exchanges of wires,catheters, blades and balloons Whenever venous access

is possible from the femoral approach, the blade/balloon atrial septostomy produces a very effective atrialcommunication which precludes the need for a surgicalatrial septostomy When femoral venous access is notavailable or there is a very tough atrial septum with a verysmall left atrium, alternate routes/procedures are avail-able to create an atrial communication non-surgically

Cutting balloon septostomy

Often the septum is very tough and resistant to even

a dilation balloon, or the opening which is created hasbeen stretched rather than torn and “rebounds” closedvery shortly after the dilation If the patient is a very smallinfant with a very small or non-existent atrial opening, orthe left atrium is too small for even a PBS 100 bladecatheter, then a dilation septostomy can be initiated with acutting balloon catheter (Boston Scientific, Natick, MA).The maximum diameter of the available cutting bal-loons is 8 mm The alternative of using a cutting balloon is

C H A P T E R 1 4 Blade and special atrial septostomies

only applicable when starting with a very small or,

prefer-ably, non-existent opening in the septum When there is a

pre-existing opening which has stretched rather than torn

with a dilation balloon and when proceeding to use a

cut-ting balloon, it is better to perform a transseptal puncture

with a long sheath set and to start using the cutting

bal-loon in this new, very restrictive opening

In very small patients, a radio-frequency transseptal

perforation as described in Chapter 8 is preferable to a

standard needle transseptal puncture because of the size

constraints of the patients and their left atria along with

better control of the puncture11 Once the septum has been

crossed with the radio-frequency “burn”, either a 0.014″

Iron-Man™ (Guidant Corp., Santa Clara, CA) stiff wire

orapreferablyaa 6-French long sheath/dilator is

posi-tioned through the puncture and into the left atrium The

cutting balloon is advanced directly over the wire or,

preferably, through the long sheath and positioned across

the septum If a sheath is present, it is withdrawn

com-pletely off the balloon and the cutting balloon is inflated to

its maximum pressure/diameter in the atrial septum

When inflated, the cutting balloon is moved slightly

for-ward or backfor-ward over the wire within the opening to

enhance the “incising” effect of its micro blades The

cut-ting balloon is deflated, rotated slightly within the septal

opening and the “inflation–incision” repeated After at

least two separate inflations–incisions with the cutting

balloon, it is withdrawn through the long sheath and

replaced over the wire with a dilation balloon of a

dia-meter several millidia-meters larger than the opening that is

desired The dilation is repeated with the larger balloon

with the expectation that the incisions made with the

cut-ting balloon will tear further and extend the opening The

size of the dilation balloon is increased incrementally to

increase the size of the atrial communication

Biopsy septostomy

Another alternative to a blade septostomy when the left

atrium is extremely small or when there is no access to the

septum from the femoral vein is to use a biopsy forceps

catheter to “bite away” small segments of the atrial

sep-tum in order to create a larger opening in the sepsep-tum This

procedure was first described by Boucek et al for use in

infants with hypoplastic left heart syndrome, intact atrial

septum and a very small left atrium12 In these patients, it

is not possible to open even the very small P 100 blade in

the tiny left atrial cavity, and a standard NuMED™ K-5

balloon septostomy catheter (NuMED Inc., Hopkinton,

NY) cannot tear the very tough septum

To perform a bioptome septostomy, a slight curve is

formed at the tip of a standard biopsy forceps catheter

The larger the bioptome catheter that can be used, the

larger the “bite” and the more effective is the opening that

is produced by the bite A 5- or 6-French biopsy forcepscatheter is advanced through a long sheath, which is introduced from the femoral vein and pre-positioned in the right atrium adjacent to the septum This allows thebioptome catheter to be withdrawn and reintroduced ex-peditiously without significant manipulation in order toapproach the septum between bites The bioptome isdirected using biplane fluoroscopic and echocardio-graphic guidance, with the fluoroscopy directing thebioptome to the immediate area of the septum and theecho defining exactly where the bioptome bites on the sep-tum The biopsy forceps is opened in the low right atriumand the jaws are advanced cephalad and posteriorly until

a jaw catches on the limbus of the foramen in the atrialseptum If the edge of the septum is not grasped initially,the maneuver is repeated while rotating the biopsy for-ceps catheter or the long sheath until the edge of the atrial septal opening has been caught by the open jaws ofthe forceps

If not successful after several attempts, the bioptomecatheter is withdrawn and the curve at the tip of the biop-tome is changed slightly to correspond better to the intra-cardiac anatomy The rim or edge of the existing foramen

is grasped with the jaws of the biopsy forceps and a bite

is taken similar to any biopsy The excised piece is drawn and the procedure is repeated until a satisfactoryopening has been created in the septum or until asignificant slit or cut in the edge of the original septalopening has been created The long sheath remaining inthe right atrium facilitates the repeated bites Once theedge of the original opening has been incised or “dis-rupted” with the bioptome, the opening can often be tornfurther with a dilation balloon septostomy as described inChapter 13

with-The biopsy forceps technique can be used in a patient ofany age It is useful particularly when the septum isextremely tough and resistant to cutting with a bladecatheter or when the left atrium is extremely small and cannot tolerate the opening of even a small bladewithin it

The biopsy forceps septostomy technique is also usefulwhen there is interruption of the femoral veins/inferiorvena cava When the catheter is introduced from the neckthrough a superior vena cava approach, the bioptome isdirected caudally and the bite with the forceps is on thecaudal rim of the original defect When the bites are takenfrom this area on the caudal rim of the septum, the proced-

ure must have echo guidance to ensure that the

atrioven-tricular valves are not being damaged When biting on theinferior rim of the atrial septal defect, there is always dan-ger of damage to the atrioventricular conduction system

A more conservative removal of tissue with the bioptome

is performed from the superior vena cava approach The

C H A P T E R 1 4 Blade and special atrial septostomies

initial opening created with the bioptome bite is expanded

further with a dilation balloon

Stent atrial septostomy

Occasionally it is desirable to maintain the opening in the

atrial septum for the temporary, or sometimes even

per-manent, palliation of complex congenital heart defects

Often the openings or fenestrations created in the atrial

septum or atrial baffles by surgery, balloon, or blade and

balloon atrial septostomies spontaneously shrink in

dia-meter or even close completely To prevent this, a standard

intravascular stent can be implanted in the atrial opening

to maintain its patency Intravascular stents are used in

the interatrial septum or baffles in two different

circum-stances In neonates with hypoplastic left hearts, as large

an opening as possible is desired in the septum, but

the stenting of the septum will usually only be necessary

for a matter of months The other circumstance is in

patients who need venting of high right heart or systemic

venous pressure, not only to lower the venous pressure

but also to enhance systemic cardiac output These

open-ings may be necessary for an indefinite period of time

and usually must be of a specific, much more restricted

diameter

Commonly, rigid P 188 or P 308 stents (Johnson &

Johnson, Warren, NJ) are used for stenting the

inter-atrial septum, although recently the “large”, pre-mounted

Genesis stents (Johnson & Johnson–Cordis Corp., Miami

Lakes, FL), which can be dilated to 11 or 12 mm diameter,

have been used in newborns where the opening will only

be necessary for 3–12 months The even larger Genesis XD

stents (Johnson & Johnson–Cordis Corp., Miami Lakes,

FL) are used for the creation of the more permanent larger

“fenestrations” Both the initial “dumb-bell” expansion of

balloon expandable stents and the overall shrinkage in

length as the stents expand, are used to advantage during

this particular application in order both to center the stent

on the septum and to secure the stent once it has been

implanted

After it has expanded fully and after the shrinkage in

length of the stent with expansion, the shorter P 188 stent

is almost ideal in length to bridge the usual thickness of

the atrial septum However, this short length is often very

difficult to center precisely on the “invisible”, moving and

relatively thin membrane of the atrial septum Positioning

a shorter stent is made more difficult by the angle that

always exists between the delivery wire/balloon/stent

and the angle of the septum in small patients P 308 stents,

which are twice as long, provide some margin of error for

centering the stent on the septum; however, they have

a greater likelihood of extending away from the septum

and interfering with access to adjacent areas or to the vital

structures themselvesathe tricuspid valve in particular.

When using the large Genesis™ stent, the choice isbetween a 19 mm and a 29 mm long one Since these stentscannot be dilated beyond 12 mm in diameter, the shrink-age in length is less and the 19 mm long large Genesis™stent is usually sufficient to open the newborn atrial septum completely

An intravascular stent is particularly useful to splint theatrial septum open in infants with hypoplastic left heartswhere there is a restrictive interatrial communication andwhile the patients are awaiting or have undergone a firststage palliation In these patients, the left atrium is toosmall or the interatrial septum is too short and tough toallow the creation of an effective and persistent openingwith the usual blade or balloon atrial septostomy A pre-mounted 19 mm long large Genesis™ or a P _ _ 8 stent,which is mounted as far distally on as short a balloon aspossible, is used in these patients The balloon for the de-livery of the stent should have a diameter of only 1–2 mmless than the maximum diameter of the infant’s total interatrial septum, and should be significantly larger indiameter than any existing opening in the atrial septum.The forceful over-expansion of these stents into the rim ofthe existing septal defect is the only mechanism that holdsthese stents in place in the septum!

The stent placement is controlled using angiography,which is usually performed through a separate catheter.The separate controlling catheter is introduced from a second venous entry site Transesophageal echo (TEE) orintracardiac echo (ICE) is extremely useful in largerpatients, but the large size of the TEE probe or the largesheath necessary for the ICE catheter make both of thesemodalities in their standard usage too large for use in thenewborn infant The ICE probe has been used successfully

as a TEE probe for transesophageal imaging in the born infant and may be a viable option to obtain TEE assis-tance during stent implants The septum in a small infant

new-is seen very well by trans-thoracic echo When there new-is aquestion about the exact location of the interatrial septum,

a small tag of contrast can be placed in the septum with atransseptal needle as described previously in Chapter 8.This is particularly useful in older or larger patients wherethe opening is being created as well as held open

An end-hole catheter from one venous access site ismaneuvered into a left upper pulmonary vein and isreplaced with the largest and stiffest wire which the par-ticular dilation balloon catheter for the selected stent willaccept Whenever possible, it is advisable to introduce anangiographic catheter into the right atrium from a secondvenous puncture This catheter will be used for position-ing angiograms during the implant of the stent in the sep-tum For P _ _ 8 stents, a long sheath through which theballoon/stent combination must be delivered is advancedover the wire with its appropriate dilator to the area of the

C H A P T E R 1 4 Blade and special atrial septostomies

atrial septum, and the sheath alone is advanced off the

dilator to the mouth of the pulmonary vein The dilator is

withdrawn from the sheath over the wire and the sheath

meticulously cleared passively of any air or clot The

posi-tion of the sheath/wire in relaposi-tion to the pulmonary

vein and the atrial septum is visualized with a biplane

angiocardiogram (through the sheath or, preferably, the

separate venous catheter) and on echocardiogram A

pre-mounted, 19 or 29 mm, large Genesis™ stent can be

deliv-ered to the septum directly over the wire without the use

of a long sheath, although such a sheath does add some

security and additional support

With the structures adjacent to the septum recorded or

committed to memory according to radiographically

vis-ible landmarks, the stent/balloon is advanced through the

sheath, over the wire or, in the case of the Genesis™ stents,

directly over the wire to a position exactly straddling the

atrial septum The sheath is withdrawn off the P _ _ 8

bal-loon/stent and the position of the stent/balloon in

rela-tion to the septum checked angiographically and by echo

with either type of stent In small infants and because of

the small size of the atrial structures combined with the

stiff delivery wire/balloon/stent combination, the

bal-loon/stent over the wire is always aligned tangentially

across the septum, necessitating some delicate

manipula-tions to center the stent on the septum Once the stent has

been centered exactly across the plane of the atrial

sep-tum, the balloon catheter and the wire are fixed very

firmly and the balloon/stent inflated very slowly With

any movement of the balloon or stent, the inflation is

stopped and the position of the stent/balloon is checked

with a repeat angiogram and adjusted as necessary

Usually, a considerable simultaneous forward force must

be maintained on the balloon dilation catheter and the

wire in order to keep the stent in position

When the stent is in the proper position, it is inflated

fully Usually the stent pushes the rim of any true septal

tissue out of the way and no apparent residual waist

per-sists on the stent When it appears that there is still a

sig-nificant atrial rim around the fully expanded stent, and

if a long sheath was used to deliver the stent, the balloon is

inflated to a low pressure within the stent While the

bal-loon is being deflated and while the balbal-loon still is within

the stent, the sheath is re-advanced over the balloon and

into the stent The original balloon is withdrawn over the

wire and through the sheath, which is now within and

through the stent The original balloon is exchanged for a

larger diameter balloon in order to expand the stent to the

maximum diameter of the interatrial septum When a long

sheath is not used for the delivery, the replacement with a

larger balloon is accomplished over the wire, directly

through the stent and very, very cautiously! The larger the

final diameter of the stent, the better its fixation will be in

the thin atrial septal tissues

Small persistent atrial communications of a fixed, smalldiameter are desired in patients with pulmonary hyper-tension and in some patients with intracardiac baffles fol-lowing single ventricle, “Fontan” surgical repairs Atrialseptal or baffle openings are created to vent the right heart

or systemic venous blood while, at the same time, ing systemic cardiac output with the additional volume ofthe added venous blood The placement of an intravascu-lar stent in the atrial septum in these patients is usuallyperformed only after a balloon or blade and balloon atrialseptostomy during previous catheterizations have failed

enhanc-to maintain an atrial communication at least once Smallatrial defects created either surgically or in the catheter-ization laboratory are particularly prone to spontaneousclosure, while slightly larger defects in these particularpatients can result in severe and often uncontrollablehypoxemia, which is usually catastrophic An intravascu-lar stent that is expanded to a very specific diameter at thecenter of the stent, creates a defect in the atrial septum of aspecific size and can maintain the patency of the smallerdefect for an extended period of time13,14

The stent is prepared ahead of time in order to ensurethat the center of the stent expands only to the specificsmall opening that is desired in these patients, althoughthere now are dumb-bell shaped balloons (NuMED Inc.,Hopkinton, NY), which expand the center of the stent only

to a specified diameter while expanding the ends of thestent to their full diameter When using a standard balloonand before the stent is mounted on the balloon, a restrain-ing band or loop of suture of a predetermined fixed dia-meter is fixed around the center of the stent The diameter ofthe loop formed by the restraining band is the same as thediameter of the desired opening in the septum To create

an opening of a very specific diameter which cannot beenlarged further, the restraining band is made from aheavy 1-0 or 2-0, non-resorbable suture or even a fine sur-gical wire This creates a very secure band around thestent, but does not allow for any further dilation of theopening even much later in the future When there is anyconsideration that in the future the opening in the septummight need to be enlarged, an equally heavy resorbablesuture is used to create the band around the stent Aresorbable suture will restrain the lumen of the stent at thediameter which is desired at the time of implant, but it willresorb over several months and allow the stent to bedilated further when desired

To form the constricting band or loop with either type ofsuture, the stent is first dilated with an 8–10 mm diameterballoon Once the stent has been inflated to this diameter,the balloon is deflated and removed from the stent Thepartial expansion of the stent separates the struts of thestent by a small amount, creating slight openings betweenthe struts around the circumference of the stent The open-ings between the struts allow the suture to be threaded

C H A P T E R 1 4 Blade and special atrial septostomies

through the adjacent openings at the center of the stent

and around the entire circumference of the stent Once

the suture is in place through the struts, a balloon with the

precise diameter of the desired opening is placed in the

stent and the stent crimped down to that diameter When

the stent has been crimped tightly on the balloon, the

suture is tied securely around the stent/balloon to form a

loop of the desired diameter This smaller diameter

bal-loon is deflated and removed The stent is placed over a

deflated balloon that is at least twice, and preferably three

to four times, the diameter of the suture loop (and of the

desired defect) and recompressed and hand crimped over

this larger deflated balloon for delivery

Two venous introductory routes are secured An

angio-graphic catheter is advanced into the right atrium and

positioned either through a pre-existing small opening in

the atrial septum or immediately adjacent to the site where

the septum will be punctured If there is a pre-existing

opening in the septum or a small fenestration in a

baf-fle, an end-hole catheter is advanced from the second

venous site and through the septal opening until it is

secured distally within the pulmonary venous atrium or

preferably in a left upper pulmonary vein The catheter is

replaced with a short floppy-tipped, Super Stiff™ wire

and the catheter removed over the wire A slight curve,

which conforms to the course from the right atrium

through the septum to the left atrium, is formed at the

dis-tal end of the long, large diameter transsepdis-tal

sheath/dila-tor The long sheath of the delivery sheath/dilator must

be large enough in diameter to accommodate the dilation

balloon with the stent mounted on it, including the

addi-tional diameter of the suture around (intertwined in) the

stent (usually 1–2 French sizes larger) The long

trans-septal sheath/dilator set is introduced over the

pre-positioned wire and advanced until the tip of the sheath

is in the left atrium In the case of a very small left atrium,

the sheath must be advanced off the dilator and into

the atrium

When there is no pre-existing opening in the atrial

sep-tum or baffle, the sepsep-tum or baffle is crossed using a

transseptal puncture and a 7- or 8-French transseptal

sheath/dilator set When there is a very tough septal

patch/baffle, an original USCI™ Mullins™ transseptal

sheath/dilator set (Medtronic Inc., Minneapolis, MN) is

used for the puncture The dilators of these sets have a

much finer taper and fit very tightly over the needle and,

as a consequence, will penetrate very tough tissues when

the other transseptal sets will not! Once the sheath is

across the septum or baffle, the needle and dilator are

replaced with an end-hole catheter which will

accommo-date a 0.035″ Super Stiff™ wire The catheter is

maneu-vered into a left upper pulmonary vein and replaced with

the Super Stiff™ wire The transseptal sheath is replaced

with a larger long sheath/dilator set which is large

enough to accommodate the stent/balloon/suture loop.When the created or existing opening in the baffle is verysmall or very tough, the opening may need to be dilatedwith a small dilation balloon in order to accommodate thelarger sheath/dilator for the stent delivery

When implanting a stent in the atrial septum or a baffle,either within a small pre-existing opening or through atransseptal puncture, it is very helpful to place a small tag

of contrast solution in the tissues of the atrial septum orbaffle immediately adjacent to the opening where thestent is to be placed This tagging of the septum is per-formed frequently during standard transseptal punctures

of the atrial septum (Chapter 8) and the tag is plished easily through a transseptal needle just before thetransseptal sheath/dilator set is advanced into the leftatrium If the sheath has already passed through a pre-existing opening in the septum, the tag can still be pro-duced using the transseptal needle advanced through asecond catheter which is at least 6-French in size and lessthan 55 cm long, or through a separate transseptal sheath/dilator The tag on the septal tissues provides a distinctvisible marker, which can be seen on fluoroscopy in order

accom-to identify the exact position of the septum, which is oftenvery mobile, during the implant Since the contrast mater-ial in a tag tends to dissipate from the tissues fairlyrapidly, the tag is placed in the tissues immediately beforethe stent is to be delivered to the septum

Once the stent has been prepared completely with thefixed diameter loop of suture around it, it is mounted onthe balloon and everything is prepared for the stent deliv-ery, the transseptal needle in the second catheter/dilator

is positioned on the atrial septum with the tip of the dilator

firmly against the septum either immediately adjacent tothe small existing opening or in the position where thetransseptal puncture will be performed With the tip of the catheter/dilator, which contains the needle fixedagainst the septal tissues, the needle is advanced into the atrial septum or the tissue of the baffle just beyond the tip of the dilator or catheter With the tip of the needle “buried” in the atrial septal tissues and before theneedle punctures through the septum, a small (0.3 ml)injection of contrast is forced through the transseptal needle producing an opaque tag or plaque of contrast on the septum

When there is a pre-existing small, natural atrial ing and/or when a new transseptal puncture is performed

open-in true atrial septal tissues, the atrial septum should not be

pre- or re-dilated prior to the subsequent implant of the

stent However, when the stent is being implanted in abaffle and even if there is a pre-existing small opening inthe baffle, the baffle should first be pre-dilated to thediameter of the desired eventual opening with a balloon

before the long transseptal sheath for the stent delivery is

passed through the opening

C H A P T E R 1 4 Blade and special atrial septostomies

Occasionally the pre-existing opening or the newly

created puncture cannot be dilated with even a small

high-pressure balloon, in which case the opening is

incised with a blade septostomy catheter or the dilation

is performed with a cutting balloon of the appropriate

size The blade incision in the baffle or the cutting balloon

dilation of the baffle is created the same diameter as the

eventual desired opening This is to ensure that the

thick, tough, often synthetic baffle material can be dilated

at least to the desired restricted diameter of the stent

Once the sheath of the long sheath/dilator set that is to

be used to deliver the stent is in the left atrium over a wire,

and the wire is positioned securely on the left side of the

baffle, the dilator or end-hole catheter is removed and the

sheath meticulously cleared passively of any air and/or

clot as previously described in Chapter 8 (“Transseptal

Technique”) The tag of contrast in the septal tissues

should demarcate the position where the sheath passes

through the septum very clearly The stent, which is

mounted on the large balloon with its constraining suture,

is introduced over the wire and through the back-bleed

valve on the long sheath The stent/balloon/loop of

suture must be covered with a short, protective “sleeve”

for their introduction into the sheath through the

back-bleed valve The sleeve is made from a short (5–6 cm long)

segment of a sheath of the same diameter as the long

delivery sheath The balloon/sheath/suture combination

is introduced into the short sleeve before it is introduced

into the back-bleed valve in order to prevent the stent with

the encircling suture from being displaced proximally on

or even off the balloon as it passes through the tight valve

The stent/balloon with the suture around it is advanced

over the wire, out of the short sheath, and into and

through the long sheath until the stent/balloon, which is

still within the sheath, straddles the septum with the center

of the stent exactly aligned with the tag on the septum

The long sheath is withdrawn well off the balloon/stent

combination leaving the stent straddling the septum The

exact position of the balloon/stent straddling the

sep-tum is confirmed with an angiogram after the sheath

has been withdrawn by injecting through the second

catheter, which is positioned in the right atrium

immedi-ately adjacent to the stent/balloon in the defect A TEE

or ICE may be helpful in visualizing the position on a

true atrial septum but may not be of any help in

visualiz-ing the specific site of puncture in a baffle of synthetic

material

When satisfied that the center of the stent is straddling

the defect exactly, the balloon is inflated slowly while

recording on biplane angiography or biplane stored

fluoroscopy The “dumbbelling” of the stent as the ends of

the balloon expand initially, tends to self-center the stent

in the defect within the septum or baffle as the balloon/

stent expands The suture around the center of the stent

(or the restriction in the special “dumbbell” balloons)restricts the expansion of the center of the stent to pre-cisely the desired diameter for the opening The two ends

of the much larger diameter balloon expand the two ends

of the stent on each side of the septum as the balloonexpands completely Once the balloon and stent are fullyexpanded at both ends, the balloon is deflated and thesecurity of the stent checked by slight, careful, to-and-fromovements of the balloon catheter

If the stent seems at all precarious when the techniquewith the suture securing the central diameter has beenused, the balloon is reinflated at a low pressure and then,

as the balloon is deflated, the sheath is advanced into andthrough the stent over the deflating balloon The originalballoon is removed and a larger diameter balloon is intro-duced over the wire and through the sheath and centeredwithin the stent The sheath is withdrawn off the balloonand the ends of the stent are expanded even further withthe larger balloon When satisfied with the security of the stent in the septum, the balloon catheter is removedover the wire leaving the stent in place with a new fixeddiameter atrial septal opening This further expansion

of the ends is not possible when the stent is delivered over a dumbbell shaped balloon without a central suturetied around the stent unless a very special order balloonwith the same central diameter but with larger ends

is available

An alternate technique for fixing a stent in the atrial tum at a specific predetermined central diameter is to use

sep-a loop of non-stretchsep-able, rsep-adio-opsep-aque, flexible wire

fixed at a specific diameter but only around the balloon

under the stent The loop of wire remains attached to one

long strand of the wire, which will extend out of the body.The wire loop is fixed at the specific diameter by first tying

it tightly around a fully inflated, separate, small balloon ofthe same size as the desired defect which is to be created.The intention is to remove the restraining wire loop alongwith the balloon after the implant of the stent, whichleaves no fixed restraint around the stent even immedi-ately after implant To accomplish this, the wire looparound the balloon remains attached to one very longstrand of wire, which extends off the loop, out from under the proximal end of the stent, along and adjacent

to the shaft of the balloon catheter within the deliverysheath, and eventually out of the body adjacent to theproximal shaft of the catheter The long strand of wireallows the loop of wire to be withdrawn along with theballoon after the stent has been implanted and the balloondeflated

The loop of wire, which is created to the very specificdiameter of the desired opening in the septum, is placed

around the exact center of a much larger diameter balloon, which is to be used to implant the stent The stent is

expanded partially and then advanced over the partially

C H A P T E R 1 4 Blade and special atrial septostomies

expanded balloon, which has the wire loop centered

loosely on it It is essential to partially inflate/expand the

balloon in order to hold the loop in its precise position

on the balloon during the mounting process This also

requires a significant but still partial pre-expansion of the

stent in order for the stent to be advanced over the

bal-loon Once the loop has been positioned properly at the

center of the partially expanded balloon and centered

under the stent, the stent is crimped progressively over

the balloon and wire loop as the balloon is gradually

deflated It is a challenge to maintain the loop, which is

rel-atively loose around the deflated balloon, under the stent

and at the exact center of the balloon/stent15 When the

stent has been mounted securely over the balloon with

the loop around it, the balloon/stent/wire loop

combina-tion is advanced into and through the long delivery

sheath while the long strand of one end of the wire

loop trails behind the balloon/stent adjacent to the

bal-loon catheter

This technique is slightly more cumbersome as it is

significantly more difficult to maintain the wire loop in

the exact position on the balloon while the stent is being

mounted, since the wire loop is larger in diameter than the

totally deflated balloon and has no attachment to the stent

or the balloon Another disadvantage of this type of loop

is that if there is any displacement of the stent on the

bal-loon as the balbal-loon and stent are being delivered or as the

balloon is being inflated, the wire loop may not remain

exactly at the center of the stent In addition, once the

balloon has been deflated after the initial expansion of

the stent, the wire loop will be loose on the balloon,

leav-ing no permanent central band around the stent to

main-tain the central constriction while the ends are flared

further if desired or necessary immediately after implant

However, the absence of the fixed suture around the stent

allows the restriction in the stent and, along with it, the

opening in the septum to be expanded further

immedi-ately after implant as well as at any time in the future

The central diameter of a stent that has been implanted

securely in the atrial septum can be reduced in size with

the use of a Goose-Neck™ Snare (ev3, Plymouth, MN)

The snare catheter is introduced from the femoral vein

and the open loop of the snare is passed over the proximal

end of the stent, which extends out into the right atrium

Once maneuvered over the proximal stent, the snare is

slowly tightened around the central portion of the stent

until the desired diameter is achieved This does have the

disadvantages that the technique cannot be used to reduce

the diameter very precisely, and it loosens the stent from

its secure fixation within the septum as the narrowest area

is decreased further The precise technique for preparing

and delivering a “restricted” stent will depend upon the

particular immediate and future needs of each individual

patient

Special devices designed for the creation

of a fixed diameter interatrial communication

Small interatrial communications of a specific size areoften essential in older patients with pulmonary vasculardisease and in patients following “Fontan” types of repairwhere a specific and small amount of right to left shunting

is beneficial, while a larger amount of shunting can becatastrophic

In order to simplify the process of maintaining the fixedpatency of these communications, the AGA™ Company(AGA Medical Corp., Golden Valley, MN) produced a

“splint” or “Fenestrated ASD Shunt Device”, which haspre-formed holes of specific diameters through its centralhub These devices are manufactured from the same mater-ials and are very similar to the Amplatzer™ ASD occlud-ers (AGA Medical Corp., Golden Valley, MN), except thatthe splints are manufactured with one or two channels ofpredetermined size that pass completely through the hub

of the device The hub or central portion of the initialsplint prostheses had a diameter of 14 mm and a thickness

of approximately 4 mm The retention disk on each side ofthe hub varied between 2 and 10 mm depending upon therelation of the hole in the device to the edge of the reten-tion disk The initial prototype devices had one 10 mmhole or “fenestration” while subsequent clinical modelshave one or two 5 mm diameter holes

When these Amplatzer™ fenestrated devices are panded into the atrial septum, the channel(s) that passcompletely through the two end disks and the central hub

ex-of the device create one or two small channels between the two atria When the device is expanded completelyand properly in the septum the holes that are created expand to the diameters of the originally manufacturedchannel(s) in the device16 The technique for implantingthese “fenestrated” devices is similar to that for implant-ing Amplatzer™ atrial septal occluders The channel(s) inthe fenestrated device can be expanded a small amountafter implant by balloon dilation of the opening with orwithout the implant of a stent or could be occluded with aseparate occlusion device if necessary Amplatzer™ shuntprostheses require a significantly larger initial opening inthe septum than the opening that is usually found or cre-ated in patients requiring these small fixed communica-tions, and this opening in the septum must be very close tothe diameter of the hub of the device

Before the fenestrated Amplatzer™ device is implanted,the atrial opening usually requires a blade, and then a bal-loon dilation, septostomy to a size that will accommodatethe hub of the splint device exactly Since most patientsneeding this procedure are older and/or have very toughatrial septae or baffles, the sturdier PBS 300 (2 cm) blade is

C H A P T E R 1 4 Blade and special atrial septostomies

used for the blade incisions The PBS 300 is delivered to

the septum through a 10-F long sheath that has been

posi-tioned across the septum/baffle through the pre-existing

opening or transseptally through a new area During each

exchange of wires, catheters or devices through the sheath,

it is cleared meticulously of all air or clot as described

previ-ously The aim of the septostomy preceding the implant of

the fenestrated splint device is to create an opening that is

large enough to allow the hub of the device to open

com-pletely and to assume its natural flattened shape when

placed in the atrial septum If the device does not open

completely, the retention disks and the hub remain

elong-ated, which compresses the lumen(s) of the channel(s)

which extend(s) through the device The large hole

cre-ated in the septum before the fenestrcre-ated device can be

implanted creates another major problem for these

particu-lar patients by allowing an excessive amount of right to

left shunting, causing marked desaturation and

destabi-lization in some of them, before the fenestrated occluder

can be implanted to restrict the opening The Amplatzer™

fenestrated device along with its precise delivery system

must be prepared and ready for immediate implant before

any enlargement of the atrial septostomy is begun

The device is attached to a standard Amplatzer™

deliv-ery cable Before the device is pulled into the loader, a

0.035″ exchange length wire is advanced through the

fenes-tration or channel in the device leaving 4–5 cm of the soft

tip of the wire extending distal to the device, and the

prox-imal wire passing through the loader and running parallel

with and adjacent to the delivery cable The wire which is

pre-positioned through the device is available in case

fur-ther dilation of the channel should be necessary acutely

after implant of the fenestrated device Since blade

sept-ostomy in these patients is performed using a PBS 300

blade through a 9- or 10-French long sheath, and the

device can be delivered through the same sheath, this

allows the use of the larger and much sturdier 0.035″ wire,

as mentioned above The proximal ends of the delivery

cable and wire are passed through a 9- or 10-French loader

or from the distal to the proximal end of a short 10-French

sheath, and the cable and extra wire are withdrawn until

the attached fenestrated device is against the distal tip of

the loader/short sheath and all ready to be loaded

The fenestrated Amplatzer™ device is delivered using

TEE or ICE guidance exactly like the Amplatzer™ ASD

occluder (Chapter 28) Since implant of the fenestrated

device may be relatively urgent after the septostomy, and

echocardiography can be useful during the septostomy,

the echo probe which is to be used for the implant is

intro-duced and the intracardiac structures are visualized

before the septostomy is begun Only after the fenestrated

device has been prepared for delivery and echo images

established, are the blade and then the balloon

septost-omies performed

A 10-French long sheath is advanced (with a dilator andover a wire) into the left atrium either through a pre-existingopening or through a transseptal puncture opening Thelarge, sturdier, PBS 300 blade catheter is advancedthrough the sheath into the left atrium and the sheath iswithdrawn back to the inferior vena cava In order to pro-vide a good cutting angle and not to create too large anopening initially, the blade is opened to at most 45° off thecatheter for the withdrawals of the blade Following thecreation of several incisions at different locations aroundthe circumference with the blade, the blade is replaced

in the long sheath with an end-hole catheter, which isadvanced into a left upper pulmonary vein The catheter isreplaced with a stiff exchange length wire that the selecteddilation balloon will accommodate The wire passesthrough the long sheath, which remains positioned at thejunction of the right atrium and inferior vena cava If thepatient is not on anticoagulants already, he or she is given

100 mg/kg of heparin at this time A 14 mm diameter balloon (assuming this is the diameter of the “waist” or

“hub” of the fenestrated Amplatzer™ device) is duced over the wire and advanced through the longsheath, and the septum is dilated At the end of the dila-tion there should be no residual waist on the balloon, if theballoon has the same diameter as the hub of the device.Once the opening has been dilated and there is no residualwaist, the sheath is advanced over the balloon, into the leftatrium and into the mouth of the pulmonary vein The bal-loon is slowly withdrawn through the sheath followed bythe wire, leaving the sheath in the left atrium or, prefer-ably, in the mouth of the left upper pulmonary vein.During each exchange of wires, catheters, or devices, thesheath is cleared meticulously of all air and/or clot asemphasized earlier The large sheath through the newlycreated defect should reduce flow through the defectslightly; however, even with the sheath there the patientmay desaturate significantly, and delivery of the fenes-trated occluder should proceed as quickly as possible.The fenestrated Amplatzer™ device is placed in a bowl

intro-of flush solution and the device and the wire passingthrough it are withdrawn into the loader or short sheath.The device is withdrawn to the proximal end of the loader

in order to allow the distal tip of the wire that passesthrough the fenestration to be completely within the tip ofthe loader The loader is maintained on a continuous flushwhile it is introduced through the valve of the long deliv-ery sheath The device, with the wire passing through it, isadvanced into and through the long sheath until the tip ofthe device reaches the tip of the long sheath This shouldallow 4–5 cm of the wire that is passing through the device to extend into the left atrium/pulmonary veinbeyond the tip of the sheath From this point on, with theexception of the wire passing through the device and dan-gling in the left atrium/pulmonary vein, the delivery of

C H A P T E R 1 4 Blade and special atrial septostomies

the fenestrated Amplatzer™ device is identical to the

delivery of any other Amplatzer™ ASD device (Chapter

28) Once the device has been successfully implanted and

the delivery sheath and cable are away from it, the extra

wire will still be positioned through the channel in the

device, but will be loose within the channel through

the device The wire through the device can be used for

the introduction of a balloon dilation catheter for further

acute dilation of the channel16, or even for the implant of

a stent within the channel if it does not stay expanded

acutely17 The device is examined by echocardiography

and a right atrial angiogram is performed adjacent to it to

define the adequacy of the newly created defect(s) The

systemic saturation in patients with either prior “Fontan”

type procedures or with pulmonary vascular disease will

usually drop to the low 90s or high 80s with a successful,

but not too large, atrial communication

Even these communications can reduce or close

com-pletely either acutely or over time as a result of either

intimal proliferation, distortion of the fenestrated device if

it is not fully expanded, or by acute thrombosis In each

situation, the channel through the device can usually be

recrossed (transseptally if necessary) using both

echocar-diography and biplane fluoroscopic guidance Once

cro-ssed, the channel can be dilated with a balloon or stent17

These devices have been used successfully in animals

and in several compassionate cases in humans, however,

are not yet commercially available in the United States

Because of the size of the opening required for these

devices, they are significantly more difficult to implant in

the atrial septum than an intravascular stent

Complications of blade and “special”

atrial septostomies

The potential for emboli of air and/or thrombus in the

systemic circulation is the greatest danger of a blade or

balloon septostomy or any other means for the creation or

enlargement of an atrial septal defect The procedures

require the use of a long sheath and many exchanges of

wires, catheters, balloon catheters, blade and device

catheters through the sheath The blade mechanism has

a very small lumen and a potential “dead space” within

the groove in the metal pod containing the blade, which

is difficult to flush adequately from the lumen of the

catheter Thromboembolic phenomena for the most part

are preventable by meticulous attention to clearing air or

clot from the sheath and by specific and repeated flushing

of the grooves of blade catheters This flushing of the

groove, as described earlier in the chapter, is performed

between each “pull-back incision” with a blade catheter

and/or every few minutes when the blade is in the

circulation

An overly successful atrial septostomy in patients wherethe defect is created to vent the systemic venous bloodinto the systemic arterial circulation can result in cata-strophic desaturation, hypoxemia and even the death ofthe patient Prevention by performing these septostom-ies very conservatively and enlarging the opening incre-mentally until the desired effect is achieved is the besttreatment of this complication If a patient should decom-pensate progressively, the defect can be re-occluded acutelyusing an atrial septal or PFO occluder

Blade catheters can incise the wrong structures if tioned improperly The use of biplane fluoroscopy and

posi-echocardiography to guide the procedures and lous attention to the details of the technique should pre-vent blade incisions in any improper location There havebeen mechanical problems with the blade mechanism not retracting back into the groove of the pod after theblade has been pulled through the septum This occursparticularly with the smaller sizes of blade catheters, after

meticu-a very forceful pull through very tough tissues meticu-and/orwhen the control wire of the blade mechanism is twisted.Prevention by using the sturdier PBS 300 whenever pos-sible is the best treatment In all of these cases, the blade

has retracted partially back into the groove and the partial

retraction into the groove allows partial withdrawal of thepartially exposed blade into a long sheath along with themetal pod With the cutting edge of the blade withdrawninto the tip of the sheath, the blade can be withdrawn out

of the body along with the sheath This does incur sometrauma to the vein and, unless the sheath is much largerthan the blade catheter and a wire can be passed throughthe sheath adjacent to the blade catheter, it results in theloss of immediate access through that sheath/venous site.Since most blade and special septostomies are followed

by a balloon atrial septostomy, all of the complications ofthe balloon septostomy itself are present and are at leastpotentially as significant as the complications of the bladeprocedure alone A transseptal puncture is necessary tocross the septum for some blade septostomy procedures.The transseptal puncture not only adds the potential com-plications of a standard atrial transseptal puncture butoften the transseptal puncture is in a patient with a verysmall left atrium or the puncture is performed through

an unusual or very tough area of the septum These plications are discussed in Chapter 8

com-Stent septostomies also have potential problems of theirown In small patients, the stents are difficult to positionsecurely on the septum, while at the same time not imping-ing on other intracardiac structures When an opening of

a precise diameter is desired, the stents must be prepared” with one of the various central restrictingbands Acute and/or late embolization of these atrial sep-tal stents is always a potential problem Meticulous atten-tion to the details of the location of the implant and of the