mach mau chi duoi

Contralateral retrograde femoral artery access with a crossover sheath is very effective for most common iliac, internal iliac, and external iliac lesions.. Finally, brachial or radial a

Introduction

Approximately one-third of lower extremity occlusive disease

occurs in the iliac arteries, with the remaining two-thirds of

disease in the femoral, popliteal, and infrapopliteal systems

Surgical revascularization has been the mainstay of invasive

treatment of aortoiliac disease for decades More recently,

per-cutaneous techniques have been developed and shown to have

similar efficacy with less associated morbidity and mortality

As supporting technology improves and new percutaneous

techniques are developed, a greater number of patients and

their physicians are choosing percutaneous repair over

surgi-cal bypass Furthermore, symptoms can be treated sooner

with percutaneous repair due to its lower morbidity and

mor-tality, thus helping patients maintain active lifestyles that will

further slow the progression of atherosclerotic obstruction

Traditional surgical revascularization of iliac occlusive diseaseinvolved aortoiliac, aortofemoral, or femoral–femoral bypass

grafting and has been highly effective, its success only being

limited by its significant morbidity and mortality The

Veterans Administration Cooperative Study demonstrated in

a randomized trial nearly two decades ago that percutaneous

transluminal angioplasty (PTA) produced similar results to

surgery with similar symptomatic relief, durability, and

free-dom from amputation.1 PTA was somewhat less successful

acutely (15% failure rate) but had fewer complications and no

deaths while three deaths (2.4%) occurred in the surgical arm

At 4-year follow-up, these results were sustained and there was

a trend in survival favoring the PTA arm.2Similar results were

obtained in a randomized, single-center Swedish study with

similar success and complication rates for both arms.3

Advances in technology during the last two decades have

allowed more complicated lesions to be treated endovascularly

with ever-increasing procedural success

While most patients with iliac disease are asymptomatic,patients may present for evaluation with a range of symptoms

from mild exertional claudication to acute critical limb

ischemia Claudication from iliac occlusive disease usually

involves both the thigh and the calf of the ipsilateral leg, but

buttock claudication and vasculogenic impotence occur and

suggest iliac stenosis The severity of symptoms varies

accord-ing to the degree of stenosis, the recruitment of collateral

circulation, and the presence of other proximal and /or distal

stenoses Percutaneous intervention has become the mainstay

of therapy for patients with iliac occlusive disease who have

acute limb ischemia, critical limb ischemia, and stable

claudication refractory to exercise and medical programs

In addition, percutaneous revascularization of the iliac arterycan be critical in order to maintain a patent conduit for coronary and carotid catheters in these patients with diffuseatherosclerosis

Diagnosis

While most significant occlusive iliac disease is discovered inresponse to patient symptoms, more patients are being seenwith asymptomatic disease—in part because of the rapid proliferation of other angiography procedures, especiallycoronary, which require passage of guidewires and cathetersthrough the femoral and iliac systems to access the aorta andits branches Iliac disease may impede guidewire and catheteradvancement, require additional manipulation of guidewiresand catheters, or even prohibit passage altogether Finally,routine angiography of the iliofemoral system on the accessside is routinely done at the conclusion of these procedures toassess puncture location and adequacy for closure devices andthis may frequently uncover occult disease

Known or suspected iliac occlusive disease should prompt

a thorough history and physical exam Special attentionshould be given to history of co-morbidities, functional status,and cardiopulmonary symptoms including angina and dyspnea A detailed exploration of exertional limb discomfortshould be undertaken as ipsilateral limb claudication is themost common presenting symptom in patients with significant plaque burden Care should be taken to distinguishthe symptoms from those of other disease processes that mayoverlap significantly such as pseudoclaudication from spinalstenosis, peripheral neuropathies, and venous insufficiency.Any history of non-healing ulcers should be elicited andprompt further evaluation Correctable and treatable risk factors such as nicotine usage, physical inactivity, diabetesmellitus, hyperlipidemia, and hypertension should be identified and management options discussed with thepatient

Physical examination should focus on the cardiac and pulmonary systems to assess for co-morbid conditions ofsignificance such as obstructive pulmonary disease, valvularheart disease, cardiomyopathy, and arrhythmias A detailedexamination of the peripheral pulses in the upper and lowerextremities should be undertaken and documented Finally,non-invasive studies such as ankle–brachial indices with

or without segmental pressures, Doppler imaging of the extremities, and pulse volume recordings can assist in

Iliac occlusive diseases

DT Cragen and RR Heuser

68

Iliac occlusive diseases 607localizing obstructive disease as well as determining the sever-

ity Advances in both computed tomography and magnetic

resonance imaging allow these powerful modalities to more

exactly define the nature and extent of disease burden

Vascular access

An important part of planning any interventional procedure

is determining the access point that will permit the greatest

likelihood of procedural success and least risk of complication

Generally, the ipsilateral retrograde femoral artery (FA) can be

chosen for high iliac lesions if the FA is relatively free of

dis-ease and there is an adequate “landing zone” for the sheath

This ipsilateral approach is favored when intervention is

planned near the aortic bifurcation as positioning a PTA

balloon or a stent accurately using the crossover technique

from the contralateral FA can be very difficult due to the

angulation of the guidewire and /or sheath

Contralateral retrograde femoral artery access with a

crossover sheath is very effective for most common iliac,

internal iliac, and external iliac lesions This technique

provides excellent support and is especially useful if the

patient’s ipsilateral disease hinders access or advancement of

the vascular sheath Certain lesions may require both

ipsilateral and contralateral femoral access, particularly

with aortoiliac bifurcation disease (Figure 68.1), chronic

occlusions, and during interventions when a dissection may

have occurred and it is critical to preserve the vessel via the

true lumen In uncommon scenarios, popliteal access may also

be required (Figure 68.2)

Finally, brachial or radial artery access may be indicated in

patients with severe aortoiliac bifurcation disease or when

bilateral iliofemoral disease limits access from the femoral

arteries This approach can provide optimal guidewire

angulation for precise delivery of balloons and stents to the

aortoiliac bifurcation

Of critical importance is that once vascular access is

obtained via any route, care must be taken to avoid losing that

access It can often be quite difficult to obtain initial access

when there is a heavy disease burden and loss of access can

lead to multiple complications including hematomas, vascular

dissections, excess radiation exposure to the patient and

operators, and sometimes cancellation or postponement of

the procedure

Angiography

Angiography of the abdominal aorta and bifurcation is

gener-ally performed with a pigtail or similar side-hole catheter

placed in the mid-abdominal aorta As needed, each iliac can

be selectively entered with a catheter and/or sheath and

selec-tive views can be obtained to further demarcate lesion sites

and severity Both inflow and outflow of each lesion should be

clearly demarcated by the films and run-off views of bilateral

lower extremities should be obtained Once all views are

obtained, a working view should be selected A radio-opaque

ruler placed in the field adjacent to the diseased artery is

useful to establish landmarks to guide precise sizing and

deployment of balloons and stents

Over the past several years, endovascular methods have beenrefined, interventionists are becoming more adept at advancedtechniques, and stent technology in particular has improvedand greatly expanded the scope of endovascular management

It has become common practice for interventionists to treatTASC type B, C, and even complex D lesions successfully withendovascular procedures A recent study published by theCleveland Clinic presented their findings in 89 patients whounderwent 92 endovascular procedures for symptomatic iliacocclusions (TASC B, C, and D lesions).5Their reported proce-dural success was 91% overall but 95 and 94% in TASC B and

C lesions respectively The most common intraoperative plication was flow-limiting dissection (5/92) but all of thesewere successfully treated with prolonged balloon inflation andstent placement Primary and secondary (i.e after repeat revas-cularization) patency of the treated artery was 76% and 90%respectively at 36 months Limb salvage rate was an impressive97% Peri-procedural mortality was 3.3%: one patient died ofcomplications from distal embolization and two patients died

com-of cardiorespiratory events This compares favorably to openaortobifemoral grafting which also carries a peri-operativemortality of approximately 3.3% in recent studies.5

Endovascular treatment has become the mainstay of larization of iliac artery occlusive disease for the aforementionedreasons This has been paralleled by a significant and sustaineddecrease in aortobifemoral graft surgery as patients andproviders opt for the efficacy, safety, and durability of endovas-cular repair.6,7As further refinements occur, we can only expectthat endovascular repair will be more and more widely adopted

revascu-Peri-procedural medical considerations

Patients with known or suspected peripheral vascular diseaseshould be managed with aggressive medical therapy (aspirin,statins, cilostazol, etc.) before considering endovascular ther-apy for refractory symptoms If the patient is not on aspirin atinitial presentation, they should be started on a daily dose(preferably 325 mg daily) several days prior to planned intervention After completing diagnostic angiography,

if intervention is indicated then the appropriate interventionalsheath is placed in the access site Once the sheath exchange has been performed and before significant guidewire and9781841846439-Ch68 2/26/08 1:53 PM Page 607

(a) (b)

Figure 68.1 ‘Kissing’ stents at aortoiliac bifurcation A 61-year-old female with a 75-pack-year history of smoking, uncontrolled hypertension, and hyperlipidemia had 12 months of bilateral hip and buttock claudication and developed blue toe syndrome 6 weeks previously on the right Her ABIs were 0.53 and 0.58 on the right and left, respectively (a) Initial angiography with access obtained from the right common femoral artery revealed high-grade bilateral proximal common iliac artery stenoses A second arterial access was obtained in the left common femoral artery to permit simultaneous balloon deployment on both sides; (b) After predilatation with 6 × 40 mm kissing balloons, two 8 × 37 mm stents were deployed in ‘kissing’ fashion with approximately 1 cm overlap in the distal aorta; (c) Angiography performed after the stents were deployed revealed resolution of the disease proximally, but residual complex disease at the distal edge of the right common iliac stent; (d) A third stent, 8 × 27 mm, was deployed in an overlapping fashion and the final angiogram shows an excellent result On the day after this procedure, her ABIs were 1.0 and 0.91 on the right and left, respectively, and the patient was discharged home in good condition.

(a) (b)

Figure 68.2 A complicated external iliac artery case A 52-year-old man with a history of coronary disease, tobacco abuse, and hyperlipidemia presented for symptomatic claudication of the right leg reproducible at < 1 block of walking and refractory to medical therapy and exercise (a) Initial angiography showed occlusion of the external iliac artery just distal to the take-off of the internal iliac artery; and (b) reconstitution of the distal external iliac artery via collaterals; (c) After angioplasty and stenting of the external iliac artery, initial angiography showed a perforation with a free-flowing jet of contrast An angioplasty balloon was reinflated at the perforation site until a covered stent could be deployed; (d) Angiography after covered-stent deployment confirmed resolution of the perforation but poor distal run-off Further evaluation confirmed that the stents had been deployed in a dissection plane and there was no significant antegrade flow to the common femoral artery The patient returned 1 month later and access was obtained from both the contralateral femoral artery and the ipsilateral popliteal artery Once the true lumen was crossed, angioplasty and stenting was performed and the previously placed stents were crushed to the side.

Iliac occlusive diseases 6099781841846439-Ch68 2/26/08 1:53 PM Page 609

catheter manipulation, intravenous heparin (3000–6000 units)

is routinely given in our laboratory During prolonged (>1 hour)

procedures or if thrombus is observed in catheters or on

guidewires, strong consideration should be given to

administer-ing further heparin either empirically or to target a modestly

elevated activated clotting time (ACT) of at least 200 seconds In

the absence of serious perforation or bleeding complications, we

do not routinely reverse heparin after the intervention

Post-procedurally, sheaths should be left in place until the ACT is

<175 seconds We generally give a loading dose of 300–600mg of

oral clopidogrel in the catheterization laboratory at the

conclu-sion of the study if stents were employed and the patient is

continued on 75 mg daily for a minimum of 1 month thereafter

Balloon angioplasty

Because of their large lumen and high flow rates, the iliacarteries have less risk of restenosis and occlusion than mostother arteries of the periphery and are thus excellent targetsfor percutaneous reperfusion Percutaneous transluminal bal-loon angioplasty (PTA) of the iliac arteries is an established,safe, and effective technique with immediate technical successreported in various series in the 85–97% range.1,8–11In addition

to the VA Cooperative study previously mentioned, the durability of iliac PTA has been proven in multiple other

studies Becker et al performed a meta-analysis of 2697 iliac

PTA procedures in 1989 that showed 2-year vessel patency of81% and 5-year patency of 72%.12Other studies of iliac PTAreported 7-year follow-up patency rates as high as 92%.13,14Furthermore, in a randomized study between PTA and surgical bypass, there were no significant differences in vesselpatency rates at 3 years.15

While iliac PTA is safe and effective, it has clear limitationsand studies have shown that iliac occlusions are less likely thanstenoses to be successfully revascularized and have poorerlong-term patency rates One study showed that proceduralsuccess for PTA of iliac stenoses was 99.6% but the success ratefor PTA of iliac occlusions was markedly less at 81.9%.9,16Thesame study also showed that the presence of a flow-limitingtandem lesion dilated at the same time as the iliac occlusionmarkedly reduced the success and efficacy of the procedurefurther Cox regression analysis was used to predict 3-year iliac patency in vessels treated for occlusive disease and thepatency rate dropped from 66% for vessels with isolatedtreated occlusive lesions to 17% for vessels with tandemlesions PTA is also associated with causing flow-limiting dissections and rarely vessel perforations that limit procedural success

When planning iliac angioplasty, the vessel just proximal tothe stenosis provides a reference diameter for the vessel andaids in selecting balloon diameter Quantitative measurementsare preferred to minimize balloon to artery sizing mismatch

In cases of complete unilateral iliac occlusion, sizing of thecontralateral vessel (if not severely diseased) at the level of

(e)

Figure 68.2, cont’d (e) Final angiography confirmed excellent

antegrade flow and the patient experienced resolution of his

symptoms.

Table 68.1 TransAtlantic Inter-Society Consensus Statement on Classification of Iliac Stenotic Lesions 4

TASC type A iliac lesions:

1 Single stenosis < 3 cm of the CIA or EIA (unilateral/bilateral)

TASC type B iliac lesions:

2 Single stenosis 3–10 cm in length, not extending into the common femoral artery (CFA)

3 Total of two stenoses < 5 cm long in the CIA and/or EIA and not extending into the CFA

4 Unilateral CIA occlusion.

TASC type C iliac lesions:

5 Bilateral 5–10-cm-long stenosis of the CIA and/or EIA, not extending into the CFA

6 Unilateral EIA occlusion not extending into the CFA

7 Unilateral EIA stenosis extending into the CFA

8 Bilateral CIA occlusion

TASC type D iliac lesions:

9 Diffuse, multiple unilateral stenoses involving the CIA, EIA, and CFA (usually > 10 cm)

10 Unilateral occlusion involving both the CIA and EIA

11 Bilateral EIA occlusions

12 Diffuse disease involving the aorta and both iliac arteries

13 Iliac stenoses in a patient with an abdominal aortic aneurysm or other lesion requiring aortic or iliac surgery

CIA, common iliac artery; EIA, external iliac artery; CFA, common femoral artery.

planned intervention would suffice as an estimate of vessel

size It may also be appropriate in some instances to use

intravascular ultrasound guidance to facilitate vessel

measure-ments and assess lesion morphology and composition The

balloon diameter should be chosen 0–1 mm larger than the

reference vessel diameter such that when inflated it causes

15–20% overdilation of the lesion.16The length of the balloon

should allow it to extend just beyond the lesion margins

proximally and distally to minimize barotrauma to the

surrounding segments

Inflation of the balloon should be carried out at the

minimal pressure that eliminates the waist, or pinching, of the

balloon at the site of stenosis Repeat angiography should

be performed to determine success of the procedure; generally

a residual stenosis of < 30% is considered acceptable and

appropriate with balloon angioplasty A translesional gradient

should be measured with the sheath or guide catheter and

should be < 5 mmHg to document resolution of the

hemody-namically significant stenosis If results are not optimal

(> 30% residual stenosis or translesional gradient of>5 mmHg)

or if a significant dissection occurs, consideration should be

given to further angioplasty and/or stent placement

Stents

As described above, PTA alone of the iliac artery is highly

suc-cessful but limited by elastic recoil of the vessel which

decreases acute gain, acute closure, and restenosis of the

occluded segment; and by intimal dissections which can

sometimes be flow limiting In addition, PTA has been less

successful with certain lesion characteristics: irregular,

ulcerated stenoses, occlusions, eccentric, or long lesions The

deployment of stent endoprostheses primarily or immediately

after PTA has significantly reduced the impact of each of these

limitations and contributed to the success of endovascular

revascularization

A 4-year multicenter trial done by Palmaz et al documented

the results of placing the Palmaz stent in the iliac artery of

486 patients and 567 limbs and showed angiographic patency

was 92% at 8.7 months.17 A smaller study examined the

results of deployment of Palmaz stents in the iliac arteries of

83 patients and 103 limbs.18 This study showed a primary

patency rate of 87.5% at a mean follow-up of 10.4 months

and sustained clinical benefit in 86.4% of patients at 4 years

A retrospective study of 288 patients showed high initial

success rates, low complication rates, and similar patency data

as had previously been reported with PTA use alone.19

More recent reports have sought to examine long-term

results of stent deployment Vorwerk et al reported a 4-year

primary patency of 78% and secondary patency of 82% in a

small study of 100 patients.20,21 Schurmann and colleagues

reported a similar patency rate of 83% at 5-year follow-up

using nitinol self-expanding stents in 110 patients.22Park et al.

recently reported 10-year follow-up data on 249 limbs in

203 patients in which technical success was very high (98%)

and the primary patency of the stents was 87%, 83%, 61%,

and 49% at 3, 5, 7, and 10 year follow-up, respectively.23

Factors that predicted loss of stent patency included stent

diameter and lesions in the external iliac artery alone and

tandem lesions in the common and external iliac artery These

results are comparable to results obtained with surgery but

with significantly less complications, morbidity, and mortalityassociated with the index procedure.24

Given the favorable data supporting the use of stents, theyare utilized in the vast majority of percutaneous interventions

in the iliac arteries Deployment of the stents is similar to PTA

as described above in terms of sizing of the stent As stent nology improves, stents are increasingly lower profile, moreflexible, and hence more deliverable

tech-Balloon-expandable stents are preferred when preciseplacement is desired Occasionally, the stent may be difficult todeliver to the region due to calcification or vessel irregularity

In these cases, it may be useful to advance the delivery sheath

or catheter across the lesion, advance the stent to the ment site, and then unsheathe the stent by withdrawing thesheath while fixing the stent in place Balloon-expandablestents are generally sized 1:1 to the reference vessel diameter

treat-As with PTA, during deployment of balloon-mounted stents,the operator should seek to achieve full expansion of the balloon and stent with no evidence of a “waist” within thestent length Post-dilatation may be required for persistentnarrowing within the stented region or if there is a concern ofmalapposition of the stent to the vessel wall There is concernthat post-dilatation may be a significant source of intraproce-dural embolic material as material is extruded through thestent struts, so it should be employed judiciously

Self-expanding stents are generally sized approximately

1 mm larger than the reference vessel diameter such that theywill continue to exert radial pressure along the length of thelesion They are also sized approximately 1 cm longer than thelesion due to the difficulty in precise deployment of the stentand because the stent will shorten beyond its nominal length

as it is dilated Once positioned and deployed, dilatation is routine with self-expanding stents to assure wallapposition circumferentially and to prevent migration of thestent

post-Perforation of the iliac artery, or its major branches, waspreviously often catastrophic due to the large vessel size andhigh flow rates through the artery Initially, a balloon was rein-flated at the site of perforation to tamponade the artery untildefinitive therapy could be performed or hemostasis wasachieved Recently, placement of a polytetrafluoroethylene-covered stent has become routine and has been safe and effec-tive (Figure 68.3) These stents are either available inballoon-mounted versions for precise delivery or the morecommon self-expanding variety

Conclusion

The care of iliac occlusive disease has been revolutionized overthe last two decades with the advent and development of per-cutaneous endovascular techniques Angioplasty and stenting

of the iliac artery is the procedure of choice for the vast ity of patients and clinicians when local expertise in theseendovascular procedures is available Studies have consistentlyshown that percutaneous intervention in the iliac artery iseffective, safe, and produces durable results that rival those ofsurgical bypass techniques As interventionists become morefacile with advanced endovascular techniques and incorporatethe latest technological advances, the scope and severity of diseasethat can be treated percutaneously will continue to grow

major-Iliac occlusive diseases 6119781841846439-Ch68 2/26/08 1:53 PM Page 611

Figure 68.3 Exclusion of an internal iliac aneurysm A 64-year-old man with hypertension, hyperlipidemia, and recent onset impotence was found to have an infrarenal abdominal aortic aneurysm (AAA) on computed tomography of the abdomen performed for unrelated reasons It was recommended that he proceed with angiography and then endoluminal grafting (ELG) of the AAA (a) On angiography, he was found to also have aneurysmal dilatation of the left common iliac artery and a focal aneurysm of the proximal left internal iliac artery with occlusion of the right internal iliac artery Given the difficulty of contralateral access after placement of ELG, we opted to proceed with exclusion of the left internal iliac artery aneurysm prior to placement of the ELG; (b) Once access was obtained with a 0.035-inch guidewire, a balloon-mounted 7 × 59 mm iCast PTFE-covered stent (Atrium Medical Corp, Hudson, NH) was deployed across the aneurysm with successful; (c) exclusion of the aneurysm The patient underwent successful ELG placement a few weeks later.

1 Wilson S, Wolf G, Cross A Percutaneous transluminal angioplasty

versus operation for peripheral arteriosclerosis Report of a

prospective randomized trial in a selected group of patients J Vasc

Surg 1989; 9: 1–9

for peripheral vascular disease: a randomized clinical trial Principal

investigators and their Associates of Veterans Administration

Cooperative Study Number 199 J Vasc Interv Radiol 1993; 4: 639–48

ischaemia A prospective randomised controlled study comparing

the 1-year results of vascular surgery and percutaneous

translumi-nal angioplasty Eur J Vasc Surg 1991; 5: 517–22

Inter Society Consensus (TASC) J Vasc Surg 2000; 31(suppl.): 1–296

aorto-iliac occlusive disease: a meta-analysis J Vasc Surg 1997; 26: 558–69

artery occlusions: extending treatment to TransAtlantic Inter-Society

Consensus class C and D patients J Vasc Surg 2006; 43: 32–9

aortoiliac reconstruction: a 7-year audit Br J Surg 1996; 83:

1367–9

the iliac and femoral arteries: follow-up results without

anticoagu-lation Radiology 1981; 141: 347

angio-plasty Radiology 1993; 186: 207–12

dilatation of the iliac artery: long-term results Radiology 1985;

156: 321

angioplasty of the arteries of the lower limbs: a 5 year follow up.

Circulation 1984; 70: 619–23

Radiology 1989; 170: 403–12

dilatation of the iliac artery Long term results Radiology 1985; 156: 321–3

of angioplasty in aortoiliac disease Circulation 1991; 83(suppl I): 153–60

angio-plasty versus operation for peripheral atherosclerosis J Vasc Surg 1989; 9: 1–9

bal-loon angioplasty for arterial occlusive lesions World J Surg 1996;

20: 630–417 Palmaz JC, Laborde JC, Rivera FJ et al Stenting of the

iliac arteries with the Palmaz stent: experience from a multicenter trial Cardiovasc Intervent Radiol 1992; 15: 291–7

placement with the Palmaz stent: follow-up study J Vasc Interv Radiol 1995; 6: 321–9

a randomized 5-year study: iliac stent implantation versus PTA Vasa – Supplementum 1992; 35: 192–3

place-ment for chronic iliac artery occlusions: follow-up results in 103 patients Radiology 1995; 194: 745–9

follow-up results of stent placement after insufficient balloon angioplasty in 118 cases.

10 years after iliac arterial stent placement Radiology 2002; 224: 731–8

occlusive disease: the results of 10 years experience in a single institution Kor J Radiol 2005; 6: 256–66

aortoiliac occlusive disease: a meta analysis J Vasc Surg 1997; 26: 558–69

REFERENCES

Iliac occlusive diseases 6139781841846439-Ch68 2/26/08 1:53 PM Page 613

Introduction

For a long time the hypogastric artery was a neglected vessel,

with few procedures being performed by interventional

radi-ologists except for a limited number of angioplasties done for

significant claudication or erectile dysfunction Recently, this

vessel has become of prime importance to various procedures

Fibroids are currently treated by embolizing the uterine artery

as it stems from the anterior division of the hypogastric artery

Pudendal arteriography and iliac angioplasty are being performed

for evaluation and management of impotency Rarely, buttock

claudication, which can be due to significant hypogastric

artery stenosis, can be treated by angioplasty The most frequent

intervention of the hypogastric artery performed at our

insti-tution is preoperative hypogastric artery coil embolization

for stent-graft or operative repair of abdominal aortic and iliac

artery aneurysms to prevent collateral endoleaks This chapter

will review these indications and techniques that have now

become commonplace in the angiography suite

Claudication

Since angioplasty for claudication has been around for

many years, we will begin with this topic, Isolated hypogastric

artery stenosis causing significant claudication occurs rarely

(Figure 69.1).1Occasionally, an external iliac artery occlusion

occurs with a proximal hypogastric artery stenosis In this

situation, where the common femoral artery and the distal

vessels are supplied by the hypogastric artery, a focal stenosis

of the hypogastric artery may lead to severe thigh or calf

claudication and thus may warrant treatment via angioplasty An

alternative to angioplasty would be recanalization of the external

iliac artery, which is significantly more invasive than a focal

hypogastric artery angioplasty Unfortunately, there are no large

series reporting the initial and long-term results of hypogastric

artery angioplasties for the treatment of claudication

Erectile dysfunction

The evaluation and possible treatment of impotency is another

procedure that involves the hypogastric artery Although there

are many methods of evaluation of the cause of impotency,

such as duplex ultrasonography, magnetic resonance imaging,

and radionuclide imaging, pudendal arteriography remains

the gold standard for penile arterial assessment Pudendal

arteriography allows for an anatomic study of the causes of

impotence, which is necessary when considering penile arterialreconstructive surgery The distal aorta, common iliac artery,proximal hypogastric artery, and pudendal arteries must beevaluated Pudendal arteriography is best performed by bilaterally catheterizing the hypogastric arteries and using theimage intensifier to visualize in the ipsilateral anterior obliqueprojection, with the penis positioned across the contralateralthigh so that the dorsal and cavernosal arteries become visible(Figure 69.2) The angiogram is performed after injecting 60

mg of papaverine directly into the cavernosum using a 25 or 27gauge needle.2 This causes a partial or complete erection inmost patients, which improves flow and helps visualize thedorsal penile artery The classic penile anatomy is the dorsalpenile, cavernosal, and bulbar arteries stemming from eachpudendal artery.3,4A great deal of variation exists, with only18% of cases in one study having the classic pudendalanatomy.5To avoid misinterpretation of normal variants, such

as the dorsal penile artery branching from the iliac or commonfemoral artery, these variants should be searched for if a dorsalpenile artery is not seen with hypogastric artery injection(Figure 69.3) If a stenosis is identified in one of the inflowvessels such as the common iliac or proximal hypogastricarteries, the patient may benefit from transluminal angioplasty

In addition, a focal lesion in the pudendal artery can be dilatedwith a small vessel balloon.6 However, many patients witharterial erectile dysfunction do not have a focal lesionamenable to angioplasty These patients can benefit from asurgical bypass to the dorsal penile artery

Uterine artery embolization

Transcatheter uterine artery embolization was once anuncommon procedure performed for emergency control ofhemorrhage related to pelvic trauma, post-partum and post-cesarean bleeding, placental abnormalities, ectopic pregnancy,hemorrhage from gestational trophoblastic disease, intraoperativebleeding, and pelvic arteriovenous malformations.7Recent use ofuterine artery embolization for the treatment and management

of symptomatic uterine leiomyomas has further stretched theapplication of this procedure Uterine leiomyomas producesignificant morbidity by causing uterine enlargement, abnormalbleeding, anemia, pelvic pain, and infertility Prior therapeutictechniques, such as treatment with gonadotrophin-releasinghormone (GnRH) analogs, myomectomy, or hysterectomy,have proved to be either inadequate or associated with significant morbidity, mortality, and potential infertility.Thus, the utilization of uterine artery embolization to shrink

Procedures for the hypogastric artery

J Cynamon and P Prabhaker

69

Procedures for the hypogastric artery 615

leiomyomas by obstructing their blood supply appears to

be a better and less-invasive approach to the treatment of

symptomatic fibroids.8,9

Uterine artery embolization is performed via selective

catheterization of the hypogastric and uterine arteries

Bilateral embolization is required for treatment of

sympto-matic leiomyomas since bilateral arterial anastomoses provide

the blood supply to fibroids The most common agents used

include Gelfoam sponges and polyvinyl alcohol particles

(Figure 69.4).10Other agents such as Biospheres and Onyx are

being evaluated Complications have been infrequent, with

the most common complication being groin hematomas and

arterial perforations Post-embolization pain resulting from

leiomyoma ischemia is also fairly common and is controlledwith appropriate narcotics Other observed but very rare complications include endometritis and ischemia to pelvicorgans seen with emergency embolization done for hemostasis.Studies have shown a high rate of success, with decreasedsymptomatology and reduction in leiomyoma volume ofbetween 20 and 80% Limited follow-up of patients under-going uterine artery embolization has prevented knowledge ofthe exact frequency of embolization failure and of the conse-quences on post-embolization fertility However, successfulpregnancies have been reported after the procedure, whichoffers hope that uterine artery embolization may one day be themain modality of treatment for symptomatic uterine fibroids

Figure 69.1 (a) A 62-year-old man with three block buttock claudication with a focal stenosis of the proximal hypogastric artery (b) Percutaneous transluminal angioplasty (PTA) with a 6 × 4 balloon performed via an ipsilateral common femoral artery puncture (c) Post-PTA angiogram demonstrating a good result The patient no longer suffered from buttock claudication.

(b)(a)

Figure 69.2 Right anterior oblique view of a selective right hypogastric artery (a) before and; (b) after injection of 60 mg papaverine The pudendal artery is visualized and is seen as it enters the dorsum of the penis and becomes she dorsal penile artery The cavernosal and bulbar arteries are also seen Note this elongated view of the dorsal penile artery can only be obtained in the anterior oblique projection with the penis draped across the contralateral thigh.

9781841846439-Ch69 2/26/08 3:29 PM Page 615

Randomized clinical trials should be performed to further

elucidate the applications of and indications for uterine artery

embolization.7,11–13

Hypogastric artery embolization

Stent-grafts have become an alternative to standard surgical

repair in the management of aortoiliac aneurysms Two grafts

are currently FDA (Food and Drug Administration) approved

and others are in clinical trials If an endoleak occurs, which is

the leakage of blood into a treated aneurysm, the procedure is

considered a failure, Endoleaks may occur as a result of an

incomplete seal around the proximal or distal attachment of a

stent-graft (type I) or due to retrograde flow from collateral

arterial branches (type II) Midgraft tears or modular

discon-nections are called type III endoleaks, and type IV endoleaks

are due to graft porosity When a stent-graft crosses the origin

of one of the hypogastric arteries, cross-pelvic collaterals may

allow retrograde flow through the hypogastric artery and into

the treated aneurysm, resulting in a type II endoleak To

pre-vent this occurrence, coils can be placed in the hypogastric

artery prior to placing the endovascular graft across its origin

Stent-grafts will cross the origin of the hypogastric artery in

the following circumstances:

1 abdominal aortic aneurysms (AAAs) with short common

iliac arteries (CIAs), making stent anchorage in one of thecommon iliac arteries difficult;

2 CIA aneurysms extending near the CIA bifurcation;

3 an AAA with an aorto-unifemoral stent-graft, a cross-femoralbypass, and a contralateral CIA occlusion device, such as thetype placed frequently at our institution (The MontefioreEndovascular Graft System (MEGS)) (Figure 69.5).Hypogastric artery coil embolization can decrease the incidence of these endoleaks It will prevent retrograde flowvia the hypogastric artery into the aneurysm The hypogastricartery branches can still continue to be perfused via cross-pelvic collaterals Unfortunately, many patients treated in thismanner will develop buttock claudication This occurred in41% of all patients in a study conducted at our institution.14The location at which the hypogastric artery is coilembolized is important in reducing the incidence of buttockclaudication A more proximal embolization may have a lowerincidence of buttock claudication In our study, 10% ofpatients with proximal hypogastric artery coil embolizationsdeveloped buttock claudication versus 55% of those with distalembolizations Coils, as opposed to other embolic agents,permit proximal placement while also preventing backflow,but still preserve distal vessel patency, thus minimizing possi-ble resultant ischemia, Proximal occlusion of the hypogastricartery at its origin, before its anterior–posterior bifurcation,sufficiently impedes retrograde filling of the aneurysm and thedevelopment of endoleaks, In addition, proximal occlusion stillallows collaterals to contribute to the anterior and posteriordivisions of the hypogastric artery and permits continuedcommunication between the anterior and posterior divisions

(b)(a)

Figure 69.3 (a) The left dorsal penile artery is not seen on the selective hypogastric artery injection; (b) An external iliac artery injection demonstrates the dorsal penile artery to be a branch off the superficial femoral artery, which is an unusual variant.

The vessels distal to the embolization site continue to fill

via collaterals and can thus help prevent ischemia-induced

claudication (Figure 69.6).14,15

To ensure more accurate proximal placement of

emboliza-tion coils and maintain communicaemboliza-tion between the branches

of the hypogastric artery, non-fibered GDC coils can be used

in conjunction with Gianturco coils GDC coils may be used

in cases where Gianturco coils are likely to embolize to the

hypogastric bifurcation or beyond, which can occur in

patients with difficult anatomy, such as a hypogastric artery

that does not taper as one moves distally towards its

bifurca-tion A non-fibered GDC coil will prevent microcoils and

Gianturco coils from embolizing into the branches of the

hypogastric artery while still allowing communication

between the anterior and posterior divisions of the

hypogas-tric artery even if it is lodged at the hypogashypogas-tric bifurcation In

addition, GDC coils can be useful in difficult ipsilateral

hypogastric artery catherterizations where a reversed curve

catheter may be necessary to adequately seal the proximal

hypogastric artery Gianturco coils cannot always easily advance

through a reverse curve catheter Instead, a non-fibered GDC

coil can be first placed to prevent distal embolization and then

followed by Tornado or Vortex coils placed through a Tracker

catheter (Figures 69.7 and 69.8).16

When treating a hypogastric artery aneurysm, one mustocclude the distal and proximal end of the hypogastric artery

If the anterior and posterior divisions arise from the body ofthe aneurysm, as they often do in a hypogastric aneurysm,proximal embolization would not be possible Coil emboliza-tion of its branches and a common iliac artery to external iliac artery endoluminal graft would isolate or occlude the aneurysm If there is enough space in the proximalhypogastric artery, an occluder can be placed in this vesselinstead of the common iliac to external iliac stent-graft(Figures 69.9 and 69.10).17

Common iliac aneurysms or arteriovenous fistulas ing the common iliac arteries provide another challenge Theusual hypogastric artery embolization may not preventendoleaks into the aneurysm or flow through the fistula evenafter the proximal common iliac artery to external iliac arterystent-graft is placed This occurs because of a communicationbetween the iliolumbar and lumbar arteries that allows flowinto the common iliac artery and through the fistula, in thesecases, coils should extend above the iliolumbar artery or beplaced into the iliolumbar artery to prevent a persistentlumbar to iliolumbar collateral (Figure 69.11).14

involv-Hypogastric artery embolization prior to the surgical repair

of aortoiliac or iliac aneurysms may also prove advantageous

(b)(a)

Figure 69.4 (a) A 44-year-old patient with a large fibroid and severe pelvic pain related to menstruation Pelvic angiogram demonstrates hypertrophied uterine arteries Bilateral uterine artery embolization performed with polyvinyl alcohol (250–400 µm particles); (b) The hypertrophied uterine arteries are no longer seen The patient’s symptoms have dramatically improved.

Procedures for the hypogastric artery 6179781841846439-Ch69 2/26/08 3:29 PM Page 617

Cases where hypogastric artery embolization would be most

useful include those in which the proposed surgical procedure

would require either a surgical anastomosis at the common

iliac artery bifurcation or ligation of the hypogastric artery

This can be difficult with a common iliac artery aneurysm,

especially on the left side because of the need to mobilize

the sigmoid mesocolon A study performed at our institution

revealed that in all cases after hypogastric artery embolization,

the actual surgical procedure was modified to an external iliac

artery or common femoral artery bypass with ligation of theproximal artery, thereby excluding the common iliac arteryaneurysm This technique avoids the need to operate in theregion of the iliac aneurysm, thus signifi-cantly simplifyingthe operation Our study demonstrated simplification of theopen aneursysm repair with a low occurrance of complications,which suggests that hypogastric artery embolization should beconsidered for patients with iliac aneurysms prior to openaortoiliac or iliac aneurysm repair (Figure 69.12)

Figure 69.5 (a) Common iliac artery with enough normal distal common iliac artery so anchor the distal stent-graft above the hypogastric artery Therefore, embolization of the hypogastric artery is not needed; (b–d) Iliac and aortoiliac aneurysms with insufficient normal common iliac artery requiring extension of the stent-graft into the external iliac artery Coil embolization of the hypogastric artery is thus indicated.

Procedures for the hypogastric artery 6199781841846439-Ch69 2/26/08 3:29 PM Page 619

Procedures for the hypogastric artery 6219781841846439-Ch69 2/26/08 3:29 PM Page 621

So far, our discussion has focused on unilateral hypogastricartery, Bilateral hypogastric artery embolization is usually

avoided for fear of causing significant morbidity in the form

of perineal necrosis, severe lower extremity neurological

deficits, ischemic colitis, impotency, and buttock claudication.18

Bilateral occlusion is more likely required in aortic aneurysm

cases that also affect the iliac arteries This occurs in about

20% of aortic aneurysms, which often involve the distal common

iliac artery.19 Interruption of one or both hypogastric

arteries may be necessary in these cases along with aortoiliac

or aortofemoral bypass in order to completely exclude the

aneurysm A study performed by vascular surgeons at our

institution reveals that the incidence of severe morbidity

might actually be quite low for bilateral hypogastric artery

interruption.20 No patients in this study suffered perineal

necrosis, ischemic colitis, or death In addition, only a small

percentage experienced impotency, neurological deficits,

or persistent buttock claudication after occlusion of thehypogastric artery unilaterally or bilaterally These results suggest that unilateral or bilateral hypogastric artery occlusion is most probably not a dangerous procedure andthus can be performed to completely exclude aneurysms that involve the iliac bifurcation or hypogastric arteries It isproposed that the complications seen in other series are more likely due to other intraoperative events such ashypotension and severing of important collaterals that stemfrom the distal external iliac, common femoral, and profundafemoral arteries

In conclusion, the hypogastric artery has become a very important vessel in interventional radiology Moreknowledge and research is needed to prevent unanticipatedcomplications that may occur when treating claudication,impotency, uterine leiomyomas, and most importantly,aortoiliac aneurysms

(a) (b) (c)

(d) (e) (f)

Figure 69.11 (a) A 49-year-old man s/p back surgery developed a right common iliac artery-to-vein fistula; (b, c) The planned procedure was a common iliac artery to external iliac artery stent-graft to prevent retrograde flow in the hypogastric artery from leaking into the common iliac artery behind the stent-graft and having a persistent fistula, and thus the hypogastric artery was embolized; (d) Follow-up 3 months later shows a persistent small fistula; (e) There was no proximal or distal endoleak; (f) The leak turned out to be a lumbar to iliolumbar collateral in retrospect, the most proximal coil was just beyond the iliolumbar artery This allowed a persistent lumbar to iliolumbar collateral with retrograde flow in the proximal hypogastric artery and in the common iliac artery behind the stent-graft and through the fistula.

1 Smith G, Train J, Nitty H, Jacobson J Hip pain caused by buttock

claudication Clin Orthop Ref Res 1992; 284: 176–80

anatomy in arteriogenic impotence Int J Impot Res 1997; 6: 93–7

10th edn Baltimore: Urban & Schwartzberg, 1983: 200–1

Philadelphia: WB Saunders, 1991: 227–93

details of intrapenile arterial anatomy Am J Radiol 1987; 146: 883–8

arteriogenic impotence CVIR 1988; 11: 245–52

the management of symptomatic uterine leiomyomas Obst Gynecol Sur 1999; 54(12): 746

REFERENCES

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8 Wallach E Myomectomy In: Thompson J, Rock J, eds Je Lindess

operative gynecology, 7th edn Philadelphia: Lippincott, 1992:

647–62

C, Diamond M, eds Endoscopic surgery for gynaecologists.

London: WB Saunders, 1993: 71–6

embolization successfully embolized with a liquid polymer isobutyl 2-cyanoacrylate Am J Obst Gynecol 1987; 156: 1179–80

Minimally Invas Ther Allied Technol 1996; 5: 336–8

artery embolization Urology 1977: 9: 670–1

embolother-apy effects on menses and pregnancy Radiology 1996; 201: 179

emboliza-tion prior to endoluminal repair of aneurysms and fistulas: buttock claudication, a recognized but possibly preventable complication.

J Vase Intervent Radiology 2000; 11(5): 573–7

occlusions during endovascular treatment of aortoiliac aneurysmal diseases J Vase Intervent Radiology 2000; 11(5): 567–71

detachable coils in the treatment of wide-necked cerebral aneurysms Am J Neuroradiol 2000; 21(7); 1312–4

inter-nal iliac artery aneurysm with use of a stented graft and tion coils J Vase Intervent Radiology 1995; 6: 509–12

bilateral internal iliac artery ligation Report of a case Dis Colon Rectum 1985; 28(3): 183–4

aneurysms in patients with abdominal aortic aneurysms Eur J Vase Endovas Surg 1998; 15(3): 255–7

artery interruption during aortoiliac aneurysm repair in 154 patients:

a relatively innocuous procedure Presented at the 54th Annual Meeting of the Society of Vascular Surgery, June 10–14, 2000

In the proximity of the inguinal ligament, the common

femoral artery gives origin to the profunda femuris,

continu-ing its straight course in the thigh as the superficial femoral

artery (SFA) The profunda originates several small branches

and, besides supplying blood to the thigh, builds up a network

of collaterals interlacing with the distal arteries of the limb

This profunda network may eventually partially replace a

chronically occluded superficial femoral artery in supplying

blood to the leg and foot Occlusive diseases of the profunda,

when it is not associated with stenosis or occlusion of the SFA,

will often give no clinical symptoms If the SFA is occluded,

severe stenosis of the profunda will produce critical ischemia;

the simultaneous complete occlusion of the profunda and the

SFA will induce ischemic loss of the limb The profunda is

usually the last of the two branches affected by stenosis, often

due to the extension of severe calcific disease at the femoral

bifurcation

The SFA is the vessel that is most often affected by

sympto-matic disease in the lower extremities and its occlusive disease

produces pain when walking (claudicatio) In diabetic

patients, FSA disease, in presence of neuropathy or infection,

may produce non-healing ulcerations and gangrene of the

foot, thus requiring immediate therapeutic attention in all

patients with tissue loss

The SFA runs initially in the anterior aspect of the

thigh, then moves medially, crosses the adductor canal

and travels posterior to the distal part of the femur It

then becomes the popliteal artery as it reaches the knee

area The popliteal artery, which runs behind the knee, is

most affected by the repetitive movements of the knee

and may kink sharply during squatting and extreme joint

flexion.1

Due to its length and course, the femoropopliteal artery

needs to adjust to the complex, repetitive movements of

the knee and thigh that produce elongation, torsion,

shorten-ing, smooth or sharp curvshorten-ing, and even temporary kinking.2

Studying in depth the behavior of this vessel under

physiologic conditions has helped us to better understand the

correct way to approach occlusive femoral artery disease

Advancement in age and appearance of calcifications in

vari-ous segments of the femoral artery further complicate the

adaptation of the artery, due to its increased rigidity in the

affected segments Several advancements in knowl-edge,

technique and materials have had a significant influence on

the progress of interventional technique involving the SFA.3

Treatment

Claudicatio

Occlusive disease of the femoropopliteal artery, if symptomsare absent or limited to mild claudicatio, can be treated conservatively with smoking cessation, control of cholesterol,maintenance of arterial blood pressure below 140/90 in non-diabetics and 130/80 in diabetics, accurate control of bloodsugar, and antiplatelet therapy If symptoms of claudicatio impairthe quality of life, a supervised exercise program should beconsidered Several drugs have been evaluated in the medicaltreatment of claudicatio Cilostazol (a phosphodiesterase IIIinhibitor) is the most effective available drug and has beenshown to be superior to pentoxifylline in increasing peaktreadmill performance and quality of life However, it can haveside-effects such as headache, diarrhea, and palpitations and iscontraindicated in congestive heart failure.4,5Naftidrofuryl (a5-hydroxytryptamine type 2 antagonist with few, mild side-effects) improves by 26% treadmill performance when com-pared with placebo.6Pentoxifylline and buflomedil have fewside-effects but their clinical impact on claudicatio seems verylimited when compared with placebo Vasodilators are ineffec-tive, as are antiplatelet drugs, but this latter group is essential

in preventing further complications and advancement of diovascular disease Intravenous prostaglandins improve per-formance in the treadmill test while effectiveness of oralprostaglandins has not been proven and cannot be currentlyrecommended in the treatment of claudicatio.4 Research isstill under way to evaluate the efficacy of fibroblast growthfactor and vascular endothelial growth factor

car-If supervised exercise programs, drug therapy, and smokecessation fail to obtain improvement of symptoms and if thepatient observes a worsening in the quality of life, then a moreaggressive approach is justified

Critical limb ischemia

Prostanoids have been used to reduce limb loss and help healulcers with mixed success.4Because of their limited effectivenessand unpredictable response, their use is currently reservedexclusively to those patients who cannot be revascularized in ahighly specialized center and after issuance of a reliable secondopinion on the possibility of surgery or PTA Conservativetherapy has very limited success in critical limb ischemia(CLI) and its use is not justified whenever surgical or endovas-cular reconstructions are feasible If a medical center does not have sophisticated endovascular or surgical experience in

limb salvage, the patient should be rerouted to a highly

competent service that can handle the most distal bypasses

and complex endovascular procedures Time is critical and

patients should be referred as rapidly as possible to obtain

appropriate treatment whenever SFA occlusion is associated

with foot infection, skin lesions, tissue loss, or significant

trauma Maximal blood flow is needed to heal most lesions,

even if they were not originally caused by ischemia Antibiotic

delivery to infected areas is maximized with optimal blood

supply, increasing the chances of healing Increasing the flow

by opening a stenotic or occluded SFA may help save a limb

even if infragenicular disease is not amenable to corrective

treatment Either surgery or interventional procedures, or both

combined, can usually increase blood flow across the femoral

artery and help save the limb

TASC

The Trans-Atlantic Inter-Society Consensus for the

Management of Peripheral Arterial Disease (TASC) was

updated in 2007 (TASC II) with arterial lesions still stratified

in four groups but with the recommendations for preferred

treatment changed, due to advances in techniques.4

TASC II recommends that type A lesions be treated preferentially with the endovascular technique due to its

excellent results in this group The endovascular technique

should also be the initial approach in type B lesions unless

there are specific reasons that indicate a surgical approach

Type C lesions do better with surgery and the endovascular

approach should be reserved for patients who are at a high risk

for open repair Type D lesions, in TASC II stratification, do

not yield good enough results with endovascular methods to

justify them as primary treatment TASCII classification of

femoropopliteal lesions for the year 2007 is reported as follows:

● Type A lesions:

䊊 Single stenosis <10 cm in length

䊊 Single occlusion <5 cm in length

● Type B lesions:

䊊 Multiple lesions of<5 cm in length

䊊 Single lesion not involving infragenicular poplitealartery and <15 cm in length

䊊 Single or multiple lesions with non-tibial-vessel continuity

䊊 Heavily calcified occlusion <5 cm in length

䊊 Single popliteal stenosis

● Type C lesions:

䊊 Multiple lesions >15 cm in length

䊊 Recurrent lesions after two endovascular interventions

Endovascular treatment in type C lesions should be chosen

only if there are significant co-morbidities that discourage a

surgical approach as a primary choice, if the patient prefers

endovascular over surgical treatment, and if the operator has

extensive experience and good personal results with the

endovascular approach

The endovascular approach in type D lesions of thefemoropopliteal tract should be chosen only for limb salvageand if no other viable options are available, with surgery not feasible or absolutely contraindicated, or if the patientadamantly refuses bypass surgery and the operator has extensiveexperience and acceptable results in complex distal endovas-cular procedures Only centers with extensive experience

in limb salvage should be involved in treating type D lesionswith the endovascular technique, and only in carefullyselected cases as a last resort for limb salvage.7

Endovascular treatment

As techniques and instrumentations have improved over time,endovascular techniques for revascularization of the diseasedsuperficial femoral artery have been gaining ground over surgery In a meta-analysis of several reported series, Muradin

et al observed a technical and clinical success rate of PTA

generally exceeding 95%.8 Bolia’s subintimal technique hasbeen successful in restoring patency in long segment occlusionand appear effective in long term studies.9

A study published in the Lancet in 2005 showed no significant

difference between bypass surgery and PTA in amputation-freesurvival at 6 months.10 Earlier studies still showed a clearsuperiority of surgery in treating long SFA occlusions, butsuch a difference seems to be disappearing with the advance-ment of stenting techniques and the advent of subintimaltechniques Patients with critical limb ischemia have poorerresults than those with simple claudicatio: the length of lesionand presence and degree of infragenicular disease have a directinfluence on long term success of PTA procedures Schillinger

et al in 2002 observed the impact of elevated CRP (C-reactive

protein) levels on the 6-month patency rate.11The understanding of the limits of balloon expandablestents with their limited flexibility and their susceptibility topermanent deformation from extrinsic pressure have helpedadvance research on new materials and design The advent

of nitinol self-expanding stents, their improvement in design

to achieve both flexibility and sufficient stability, and theirmetallurgic refinements to increase resistance to repeated stresshave made better stents available to the operators.3

Permanent deformation of balloon-expandable stentsinterfering with flow and patency were originally reported by

Rosenfield et al who observed how such problems could

not be easily detected on standard angiography Intravenousultrasound (IVUS) helped detect stenoses, which recurred inall cases after redilatation Most operators have long sinceabandoned the use of balloon-expandable stents in the SFA12(Figure 70.1)

A German multicenter retrospective study comparing thestainless steel BS Wallstent with nitinol Cordis SMART stentsshowed a highly significant difference in 1-year primarypatency rates (61 ±5% in the SMART group and 30 ±5% in

the Wallstent group; p < 0.0001) Results were also better

in the SMART group when assisted and secondary patencywere evaluated.13 The authors concluded that nitinol gaveoverall superior results when compared to steel In this study,superiority could have been affected by the completely different design and construction behavior of the two stents.The Wallstent is a closed cell system that increases rigidity of