Critical Care Obstetrics part 28 doc

Such volume shifts may be poorly tolerated by women whose cardiac output is highly dependent on adequate preload pulmonary hypertension or in those with fi xed cardiac output mitral ste-

75

50

25

0

During contractions Between contractions

Figure 20.2 Fluctuations in cardiac output

associated with normal labor, delivery, and

postpartum (Reproduced by permission from

Bonica JJ, McDonald JS Principles and Practice of

Obstetrics Analgesia and Anesthesia , 2nd edn

Lippincott, Williams & Wilkins, 1994.)

Table 20.4 Coagulation factors and inhibitors during normal pregnancy

Factor I (fi brinogen) 200 – 450mg/dL 400 – 650mg/dL

Factor II (prothrombin) 75 – 125% 100 – 125%

Factor V 75 – 125% 100 – 150%

Factor VII 75 – 125% 150 – 250%

Factor VIII 75 – 150% 200 – 500%

Factor IX 75 – 125% 100 – 150%

Factor X 75 – 125% 150 – 250%

Factor XI 5 – 125% 50 – 100%

Factor XII 75 – 125% 100 – 200%

Factor XIII 75 – 125% 35 – 75%

Antithrombin III 85 – 110% 75 – 100%

Antifactor Xa 85 – 110% 75 – 100%

(Reprinted by permission from Hathaway WE, Bonnar J Coagulation in

pregnancy In: Hathaway WE, Bonnar J, eds Perinatal Coagulation New York:

Grune & Stratton, 1978.)

some cases, an additional 50% by the late second stage The

potential for further dramatic volume shifts occurs around the

time of delivery, both secondary to postpartum hemorrhage and

as the result of an “ autotransfusion ” occurring with release of

vena caval obstruction and sustained uterine contraction Such

volume shifts may be poorly tolerated by women whose cardiac

output is highly dependent on adequate preload (pulmonary

hypertension) or in those with fi xed cardiac output (mitral

ste-nosis) Figure 20.2 illustrates the marked fl uctuations in cardiac

output associated with normal labor, delivery, and postpartum

[17]

The risk classifi cation presented in Table 20.2 assumes clean

delineation of various cardiovascular lesions Unfortunately, in

actual practice this is only rarely the case Optimal management

of a patient with any specifi c combination of lesions requires a thorough assessment of the anatomic and functional capacity of the heart, followed by an analysis of how the physiologic changes described previously will impact on the specifi c anatomic or physiologic limitations imposed by the intrinsic disease Such an analysis will allow a prioritization of often confl icting physiologic demands and greatly assist the clinician in avoiding or managing potential complications

Certain management principles generally apply to most patients with cardiac disease These include the judicious use of antepartum bed rest and meticulous prenatal care Intrapartum management principles include laboring in the lateral position; the use of epidural anesthesia, which will minimize intrapartum

fl uctuations in cardiac output (although the use of epidural nar-cotic rather than epidural local anesthesia may be more appro-priate for patients with certain types of cardiac lesions); the administration of oxygen; and endocarditis prophylaxis, when appropriate Positional effects on maternal cardiac output during labor with epidural analgesia have recently been detailed [18] Additional management recommendations may vary according

to the specifi c lesion present For patients with signifi cant cardiac disease, management and delivery in a referral center is recom-mended In many cases, management with peripheral pulse oximetry is replacing invasive hemodynamic monitoring

Congenital c ardiac l esions

As previously discussed, the relative frequency of congenital as opposed to acquired heart disease is changing [2,7,19,20] Rheumatic fever is less common in the United States, and more patients with congenital cardiac disease now survive to

reproduc-anesthesia are means to reduce cardiac work All ASDs have some degree of right to left shunting, particularly with valsalva - type maneuvers Hence, consideration of air trap fi lters applied to IV lines should be considered to reduce this possibility New recom-mendations regarding the use of antiobiotic prophylaxis for pre-vention of bacterial endocarditis have recently been published [28] The American Heart Association does not recommend anti-biotic prophylaxis for secundum atrial septal defects Further discussion regarding the latest recommendations antiobiotic pro-phylaxis against bacterial endocarditis for congenital heart defects

is found later in this chapter and in Table 20.5

Ventricular s eptal d efect

Ventricular septal defect may occur as an isolated lesion or in conjunction with other congenital cardiac anomalies, including tetralogy of Fallot, transposition of the great vessels, and coarcta-tion of the aorta The size and locacoarcta-tion of the septal defect is the most important determinant of clinical prognosis during preg-nancy Small defects are tolerated well, while larger defects are associated more frequently with congestive failure, arrhythmias,

or the development of pulmonary hypertension Those VSDs that are associated with other congenital anomalies may be much more complicated and can be associated with much higher risk

of heart failure, arrhythmia, cyanosis or pulmonary hypertension, depending on the lesion type, prior surgery and residual lesions after surgical repair In general, pregnancy, labor, and delivery are generally well tolerated by patients with an uncomplicated VSD Schaefer et al [25] compiled a series of 141 pregnancies in 56 women with VSD The only two maternal deaths were in women whose VSD was complicated by pulmonary hypertension (Eisenmenger ’ s syndrome) Because of the high risk of death associated with unrecognized pulmonary hypertension, echocar-diography or cardiac catheterization is essential in any adult patient in whom persistent VSD is suspected, or in whom the quality or success of the previous repair is uncertain [29,30] The primary closure of a moderately restrictive or non - restrictive VSD in early childhood usually prevents the

tive age In a review in 1954, the ratio of rheumatic to congenital

heart disease seen during pregnancy was 16 : 1; by 1967, this ratio

had changed to 3 : 1 [19 – 21] A more recent report from Taiwan

suggested a rheumatic/congenital cardiac ratio of 1 : 1.5 during

pregnancy [7] Similarly, in the United Kingdom between 1973

and 1987, the number of deaths from congenital heart disease has

doubled, whereas the number of deaths from rhuematic heart

disease has halved [2] In the subsequent discussion of specifi c

cardiac lesions, no attempt will be made to duplicate existing

comprehensive texts regarding physical diagnostic,

electrocardio-graphic, and radiographic fi ndings of specifi c cardiac lesions

Rather, the discussion presented here focuses on aspects of

cardiac disease that are unique to pregnancy

Atrial s eptal d efect

Secundum atrial septal defect (ASD) is the most common repaired

and unrepaired congenital lesion that occurs in pregnant woment,

and, in general, it is asymptomatic and well tolerated even in

those with large left to right shunts [22 – 24] The three signifi cant

potential complications seen with ASD are arrhythmias, heart

failure and “ paradoxical embolism ” Although atrial arrhythmias

are not uncommon in patients with ASD, their onset generally

occurs after the fourth decade of life; thus, such arrhythmias,

however unlikely, are becoming more of a concern with the

recent prevalence of delayed childbearing In patients with ASD,

atrial fi brillation is the most common arrhythmia encountered;

however, supraventricular tachycardia and atrial fl utter also may

occur Antiarrythmic or rate - controlling agents or other

medica-tions may be indicated for symptomatic patients with these

arrhythmias and in some, cardioversion may be necessary (see

section on dysrrhythmia)

The hypervolemia associated with pregnancy results in an

increased left to right shunt through the ASD, and, thus, a

sig-nifi cant burden is imposed on the right atrium, right ventricle

and pulmonary vasculature Although this additional burden is

tolerated well by most patients, congestive heart failure and death

with ASD have been reported [25 – 27] In contrast to VSD or

PDA, large left to right shunts at the atrial level do not usually

result in pulmonary hypertension or even irreversible pulmonary

hypertension at childbearing age

An extremely rare and unusual potential complication that

exists with ASD is “ paradoxical embolization ” If this occurs, it is

most likely as a result of venous thrombosis but can be air or

amniotic in the pregnant woman Thromboemboli from leg or

pelvic veins may be directed across the ASD into the systemic

circulation, “ paradoxically, ” resulting in ischemic neurologic

complications such as transient ischemic attack (TIA) or stroke

or other arterial ischemic complications

The vast majority of patients with ASD, however, tolerate

preg-nancy, labor, and delivery without complication Neilson et al

[26] reported 70 pregnancies in 24 patients with ASD; all patients

had an uncomplicated ante - and intrapartum course During

labor, avoidance of fl uid overload, oxygen administration, labor

in the lateral recumbent position, and pain relief with epidural

Table 20.5 Guidelines from the AHA 2007 Prevetion of infective endocarditis:

Patients with highest risk of adverse outcomes from endocarditis

1 Prosthetic cardiac valves (mechanical, bioprosthetic, homograft)

2 Previous history of infective endocarditis

3 Unrepaired cyanotic congenital heart disease, including palliative shunts and

conduits

4 Completely repaired congenital heart defects with prosthetic material or

device, surgically or interventionally placed, during the fi rst 6 months after the procedure

5 Repaired CHD with residual defects at the site or adjacent to the site of a

prosthetic patch or prosthetic device

6 Cardiac transplanted heart with signifi cant valvulopathy (leafl et pathology

and regurgitation) Adapted from: Wilson W et al 2007

outcomes are generally favorable However, in those patients found to have irreversible pulmonary hypertension such as those with equivalent systemic and pulmonary artery pressures, cyano-sis or bidirectional shunting, the prognocyano-sis during pregnancy is extremely grave

Eisenmenger ’ s syndrome consists of congenital systemic arte-rial to systemic venous shunt (left to right shunt), development

of pulmonary hypertension and shunt reversal with bidirectional shunting/or cyanosis This syndrome may occur from a variety

of common congenital lesions including VSD, ASD, PDA and more complex anatomic disorders The risk of developing pulm-ononary hypertension and Eisenmenger ’ s syndrome from con-genital shunts is determined by the the type of shunt and degree

of left to right shunt as noted above Whatever the etiology, development of irreversible pulmonary hypertension or Eisenmenger ’ s syndrome during prengnacy portends a poor prognosis During the antepartun period, decreased systemic vas-cular resistance increases right to left shunting, acidosis and hypotension With systemic hypotension against a fi xed pulmo-nary vascular resistance the degree of right to left shunting and hypoxia further increases, with a vicious spiraling circle of hypotension, cyanosis, hypoxia and ultimate death

Such hypotension can result from hemorrhage or complica-tions of conduction anesthesia and may result in sudden death [32 – 35] Avoidance of such hypotension is the principal clinical concern in the intrapartum management of patients with pulmo-nary hypertension of any etiology

Maternal mortality in the presence of Eisenmenger ’ s syndrome

is reported as 30 – 50% [26,27,30,31] In a review of the subject, Gleicher et al [33] reported a 34% mortality associated with vaginal delivery and a 75% mortality associated with cesarean section In a more recent report, Weiss et al [36] reviewed the published literature from 1978 to 1996 investigating Eisenmenger ’ s syndrome, primary pulmonary hypertension and secondary pul-monary hypertension during pregnancy Despite advances in maternal and cardiac care during this interval, the overall com-posite mortality rate for Eisenmenger ’ s syndrome during preg-nancy remained 36% – relatively unchanged for the last two decades [37 – 41] In this series, however, there appeared to be little difference in mortality when comparing vaginal delivery (48%) to cesarean section (52%) These investigators also con-cluded that maternal prognosis depended on the early diagnosis

of pulmonary vascular disease during pregnancy, early hospital admission, and individually tailored treatment during pregnancy with specifi c attention focused on the postpartum period Table 20.6 reviews the management and outcome of pregnant women with Eisenmenger ’ s syndrome [36] In addition to the previously discussed problems associated with hemorrhage and hypovole-mia, thromboembolic phenomena have been associated with up

to 43% of all maternal deaths in Eisenmenger ’ s syndrome [33]

In the more recent report by Weiss et al [36] , however, pulmo-nary thromboembolism accounted for only 3 of the 26 (12%) maternal deaths in this composite analysis Sudden delayed post-partum death, occurring 4 – 6 weeks after delivery, also has been

subsequent development of secondary pulmonary vascular

hypertension and therefore permits an uneventful pregnancy

Fortunately, signifi cant postoperative electrophysiologic

conduc-tion abnormalities are rarely encountered

Although very rarely indicated, successful primary closures of

VSDs during pregnancy have been reported Intrapartum

man-agement considerations for patients with uncomplicated VSD or

PDA are similar to those outlined for ASD In general, invasive

hemodynamic monitoring is usually unnecessary

Patent d uctus a rteriosus

Although patent ductus arteriosus (PDA) is one of the most

common congenital cardiac anomalies, its almost universal

detection and closure in the newborn period makes it uncommon

during pregnancy [20] As with uncomplicated ASD and VSD,

most patients are asymptomatic, and PDA is generally well

toler-ated during pregnancy, labor, and delivery As with a large VSD,

however, the high - pressure – high - fl ow left to right shunt

associ-ated with a large, uncorrected PDA can lead to pulmonary

hyper-tension In such cases, the prognosis becomes much worse since

shunt reversal can occur with fall in systemic vascular resistance

during pregnancy, delivery and early postpartum leading to a

spiraling cycle of cyanosis, acidosis and hypotension In one study

of 18 pregnant women who died of congenital heart disease, three

had PDA; however, all of these patients had severe secondary

pulmonary hypertension [27] In most circumstances, however,

an asymptomatic young woman with a small or moderate - sized

PDA, without pulmonary hypertension, will have a relatively

uncomplicated pregnancy Apart from a single case report of a

spontaneous postpartum rupture of a PDA, in a patient with

normal pulmonary pressure and without ductal aneurysm [31] ,

the risks are minimal

Pulmonary h ypertension and Eisenmenger ’ s s yndrome

As discussed in the previous section, women with secundum ASD

rarely manifest pulmonary hypertension in the childbearing age

range and those with VSD or PDA are more likely to develop

pulmonary hypertension compared to those with ASD Patients

with left to right shunts may have a continuum of progressive

pulmonary artery pressure elevation and varying degrees of

reversibility It should be of note that with large left to right

shunts, echocardiographic studies may suggest the presence of

pulmonary artery systolic hypertension Elevated pulmonary

artery systolic pressures can be seen with high fl ow states in left

to right shunts and should not be confused with irreversible

pulmonary hypertension Degree of left to right shunting and

degree of pulmonary artery hypertension reversibility can usually

be assessed before pregnancy or even during pregnancy with

clinical evaluation, echocardiography along with other laboratory

tests A general rule of thumb is that pulmonary artery systolic

hypertension in association with a left to right shunt of 1 : 5 : 1 or

higher has some reversibility, otherwise, there would be no

capcity for shunting In these patients, in the absence of profound

uncompensated left heart failure from volume overload, maternal

hypertension, and the pregnancy is desired, pulmonary artery catheterization with direct measurement of pulmonary artery pressures may be performed on an outpatient basis in early preg-nancy This can be done with no to minimal radiation exposure

in experienced hands using a brachial or internal jugular approach Where signifi cant fi xed irreversible pulmonary hyper-tension exists, pregnancy termination in either the fi rst or second trimester appears to be safer than allowing the pregnancy to progress to term [44] Dilation and curettage in the fi rst trimester

or dilation and evacuation in the second trimester are the methods

of choice Hypertonic saline and F - series prostaglandins are con-traindicated, the latter due to arterial oxygen desaturation seen with the use of this agent [45] Prostaglandin E 2 suppositories appear to be safe under these circumstances

It is highly recommended that the woman with signifi cant pulmonary hypertension/Eisenmenger ’ s syndrome who elects to continue pregnancy undergoes hospitalization for the duration

of pregnancy Alternatively very close clinical follow - up and early hospitalization at a center specialized in treatment of this condi-tion at the fi rst sign or deteccondi-tion of clinical deterioracondi-tion may be considered on a case - by - case basis Continuous administration of oxygen, the pulmonary vasodilator of choice, is suggested and may improve perinatal outcome Consideration of anticoagula-tion in the peripartum period has been suggested as a method to lower this risk but there has been concern that this may instead contribute to a fatal outcome Patients with Eisenmenger ’ s syn-drome have abnormalities with coagulation factors, and with platelet function and number The very real possibility of fatal intrapulmonary hemorrhage and hemoptysis while on anticoagu-lants has to be weighed against the possible risk of suspected peripartum thromboembolism as the cause of death in these patients during the third trimester and postpartum Since death has been reported with fatal hemorrhaging while on anticoagu-lants and benefi t of this therapy is not proven, routine endorse-ment of this treatendorse-ment modality cannot be given

In cyanotic heart disease of any etiology, fetal outcome corre-lates well with maternal hemoglobin, and successful pregnancy is unlikely with a hemoglobin greater than 20 g/dL [13] Maternal

P a O 2 should be maintained at a level of 70 mmHg or above [46] Third - trimester fetal surveillance with antepartum testing is important because at least 30% of the fetuses will suffer growth restriction [33] Although the overall fetal wastage with Eisenmenger ’ s syndrome is reported to be up to 75%, more recent information suggests a more favorable outcome Weiss

et al reported a neonatal survival rate of nearly 90% in cases

of Eisenmenger ’ s syndrome Unfortunately, since only late pregnancy cases were reviewed, no conclusions can be drawn about the rate of early fetal wastage

For pregnant patients with Eisenmenger ’ s syndrome some experts previously advocated placement of a Swan – Ganz catheter

in the intrapartum period in an effort to minimize changes in cardiovascular hemodynamics, cyanosis and the shunt that occurs with uterine contractions [47] However, placement and stabilization of a right heart catheter in a pulmonary artery

reported [33,36,42] Such deaths may involve a rebound

worsen-ing of pulmonary hypertension associated with the loss of

preg-nancy - associated hormones, which leads to decreased pulmonary

vascular resistance during gestation [17]

Caution should be exercised when evaluating for the presence

of pulmonary hypertension with non - invasive techniques such as

Doppler/two - dimensional echocardiogram The assumptions

used by many cardiologists for assessment of pulmonary

pres-sures do not take into account viscosity (Hb) nor pregnant state

when assessing the tricuspid jet or estimating the right atrial

pres-sure based on IVC size The ordering physician should directly

communicate with the interpreting physician these issues when

trying to determine pulmonary artery pressures since other

methods to assess these values may be available Otherwise, these

techniques have a clear tendency to signifi cantly overestimate the

degree of pulmonary hypertension during pregnancy and may

incorrectly diagnose the presence of pulmonary hypertension in

up to 32% of cases when compared with cardiac catheterization

[43] If any question exists regarding the presence of pulmonary

Table 20.6 Management and outcome of pregnant women with Eisenmenger ’ s

syndrome ( n = 73)

survival

Maternal mortality

Number (%) 47 (64%) 26 (36%)

Age (years) 26.4 ± 4.8 24.9 ± 4.5

Hospital admission (weeks of pregnancy) 26.7 ± 6.5 31.4 ± 5.9

Toxemia of pregnancy 2 (4%) 3 (12%)

Delivery (weeks of pregnancy) 35.1 ± 3.5 34.4 ± 4.4

Vaginal delivery 27 (57%) 11 (48%)

Operative delivery 20 (43%) 12 (52%)

Non - invasive, not reported 24 (51%) 15 (63%)

Invasive SAP and/or CVP 23 (49%) 9 (37%)

Invasive PAP 8 (17%) 6 (25%)

Anesthesia/analgesia

Not reported 13 (28%) 5 (22%)

Regional techniques 22 (47%) 8 (35%)

General anesthesia 12 (25%) 7 (30%)

Local anesthesia/analgesia 0 3 (13%)

Oxytocic drugs 14 (30%) 4 (17%)

Antithrombotic therapy 28 (60%) 12 (46%)

Neonatal survival 43 (96%) * 20 (77%)

Maternal death, days postpartum – 5 (0 – 30)

Data presented are mean value; ± SD, number (%) of patients, or median

(range)

* In two cases neonatal outcome was not reported Three patients died before

delivery and 23 died after delivery

CI, confi dence interval; CVP, central venous pressure; PAP, pulmonary artery

pressure; SAP, systemic arterial pressure

(From Weiss BM, Zemp L, Burkhardt S, Hess O Outcome of pulmonary vascular

disease in pregnancy: a systemic overview from 1978 through 1996 J Am Coll

Cardio 1998;31:1650 – 1657.)

functional right ventricle beyond the apically displaced tricuspid valve provides effective forward pulmonary blood fl ow However,

at times the functional right ventricle may be extremely small and barely able to produce enough forward pulmonary fl ow to sustain adequate blood pressure Those women who reach childbearing years may have either the acyanotic or cyanotic form of Ebstein ’ s anomaly Since pulmonary hypertension is not seen in this anomaly, as noted, the cyanosis is determined by the degree of right to left shunting across the patent foramen ovale from tri-cuspid regurgitation Fetal prematurity, loss and low birth weight are more common in the cynanotic form of Ebstein ’ s anomaly, refl ecting this fi nding It is extremely unusual for the non - cyanotic form of Ebstein ’ s anomaly to convert to a cyanotic form once patients have reached maturity However, this is dependent upon the degree of tricuspid regurgitation and the functional capacity of the non - atrialized portion of the right ventricle Therefore, evaluation of oxygen and volume status is an impor-tant consideration during gestation, labor and delivery

Paroxysmal atrial arrhythmias have been reported to occur in

up to one - third of non - pregnant women with Ebstein ’ s anomaly and represent a potential concern during pregnancy The Wolff – Parkinson – White syndrome is an arrhythymia classically associ-ated with Ebstein ’ s anomaly and may represent a risk factor for excessively rapid ventricular rates in response to the increased incidence of atrial arrhythmias that are associated with Ebstein ’ s anomaly [56]

Despite these concerns, in a review of 111 pregnancies in 44 women, no serious maternal complications were noted Seventy six per cent of pregnancies ended in live births, with a 6% inci-dence of congenital heart disease in the offspring of these women [55]

Coarctation of the a orta

Coarctation of the aorta accounts for approximately 10% of all congenital cardiac disease The most common site of coarctation

is usually at the origin of the left subclavian artery Associated anomalies of the aorta and left heart, including VSD and PDA, are common, as are intracranial aneurysms in the circle of Willis [57] Coarctation is often asymptomatic Its presence is suggested

by hypertension confi ned to the upper extremities, although Goodwin [58] cites data suggesting a generalized increase in peripheral resistance throughout the body Resting cardiac output may be increased; however, increased left atrial pressure with exercise suggests occult left ventricular dysfunction Aneurysms also may develop below the coarctation or involve the intercostal arteries and may lead to rupture In addition, ruptures without prior aneurysm formation have been reported [59]

Over 150 patients with uncorrected and corrected coarctation

of the aorta have been reported during pregnancy, with maternal mortality ranging from 0% to 17% [25,59,60] In a 1940 review

of 200 pregnant women with coarctation of the aorta, Mendelson [61] reported 14 maternal deaths and recommended routine abortion and sterilization for these patients Deaths in this series were from aortic dissection and rupture, congestive heart failure,

branch can be quite diffi cult in the presence of markedly elevated

pulmonary pressures These patients require ICU monitoring,

and are increased risk of pulmonary artery rupture, pulmonary

infarction, and dysrhythmia They also require suspension of any

oral anticoagulation before placement,with increased risk of

pul-monary artery thrombosis Many now believe the risk of this

technique far outweighs the its benefi ts in patients with cyanotic

heart disease [48] and its use is rare In many cases, pulse

oxim-etry may offer appropriate guidance in the intrapartum

manage-ment of these patients without the need for and/or the associated

risks of, pulmonary artery catheterization Because the primary

concern in such patients is the avoidance of hypotension, any

attempt at preload reduction (i.e diuresis) must be undertaken

with great caution, even in the face of initial fl uid overload We

prefer to manage such patients on the “ wet ” side, maintaining a

preload margin of safety against unexpected blood loss, even at

the expense of mild pulmonary edema Recently, the use of

inhaled nitric oxide and intravenous prostacyclin therapy have

shown promise as potentially helpful agents in reducing the

pul-monary vascular resistance while relatively sparing the systemic

vascular resistance [49,50]

Anesthesia for patients with pulmonary hypertension is

con-troversial Theoretically, conduction anesthesia, with its

accom-panying risk of hypotension, should be avoided However, there

are several reports of its successful use in patients with pulmonary

hypertension of different etiologies [51,52] The use of epidural

or intrathecal morphine sulfate, a technique devoid of effect on

systemic BP, represents perhaps the best approach to anesthetic

management of these diffi cult patients

Although the AHA recommendations for antibiotic

prophy-laxis to prevent endocarditis have been extensively revised, the

recommendations regarding cyanotic congenital heart disease

have not Endocarditis prophylaxis continues to be recommended

for cyanotic congenital heart disease [28]

Ebstein ’ s a nomaly

Because it accounts for less than 1% of all congenital cardiac

disease, Ebstein ’ s anomaly is uncommonly encountered during

pregnancy [53 – 55] This anomaly consists of apical displacement

of the tricuspid valve into the right ventricle, sometimes markedly

so, with secondary tricuspid regurgitation of varying degrees, and

enlargement of the right atrium by incorporation of the right

ventricle situated above the tricuspid valve (the so called “

atrial-ized right ventricle ” ) A patent foramen ovale may be present in

the interatrial septum and thus these patients may have non

-cyanotic or -cyanotic form of the anomaly The presence or

absence of cyanosis and hemodynamic consequences of Ebstein

anomaly result from the degree of displacement of the tricuspid

valve leafl ets and extent of atrialization of the right ventricle The

severity of tricuspid regurgitation and hence shunting across the

patent foramen ovale depends on the extent of leafl et

ment, ranging from mild regurgitation with minimal

displace-ment to severe tricuspid regurgitation with more apical

displacement and atrialization of the right ventricle Usually the

unproven, to decrease the force of left ventricular ejection into the aorta and to reduce aortic wall stress Despite these concerns, most patients with a successfully repaired coarctation of the aorta have a relatively unremarkable pregnancy Saidi, et al [63] fol-lowed 18 pregnancies in women who had undergone a successful repair of their aortic coarctations All 18 women had uneventful pregnancies Interestingly, the incidence of pre - eclampsia in this series was no different than that reported in the normal popula-tion Maternal risk, however, is clearly increased if pre - eclampsia develops [66] In a recent retrospective study of 100 women [65] ,

a higher incidence of hypertension and pre - eclampsia was found in women who had previously had a repair of coarctation

of the aorta Interestingly, 80% had had end - to - end surgical resection at a median age of 6 years, 13% had required interven-tion for recoarctainterven-tion and 30% were noted to have hypertension

at the time of the review This supports the contention that chil-dren often outgrow their initial surgery and that hypertension is quite common even after successful repair of coarctation of the aorta

In the presence of aortic or intervertebral aneurysm, known as aneurysm of the circle of Willis, or associated cardiac lesions, the risk of death may approach 15%; therefore, termination of preg-nancy should be strongly considered

Tetralogy of Fallot

Tetralogy of Fallot refers to four key anatomic features which lead

to cyanosis: VSD, overriding aorta, right ventricular hypertrophy, and pulmonary stenosis In the United States, most cases of tetral-ogy of Fallot are corrected during infancy or childhood Most of the women with this condition at childbearing age have had it surgically corrected but many have residual lesions such as ongoing VSD through a VSD patch, pulmonary insuffi ciency of varying degrees with right heart enlargement, prosthetic pulmo-nary valve, residual right ventricular outfl ow tract obstruction, or

a combination of these A few will have only had palliative pro-cedures and are cyanotic [67] Rarely do they present in the cyanotic state without any prior surgical correction

Several published reports attest to the relatively successful outcome of pregnancy in patients with totally or partially cor-rected tetralogy of Fallot [66,68] For the totally corcor-rected patient, pregnancy outcome is similar to that of the general population For those with residual lesions including mild pulmonic and/or tricuspid regurgitation, mild pulmonary stenosis, or small VSD patch leak, the maternal and fetal risk is minimal If there is sig-nifi cant right heart enlargement from residual pulmonary

insuf-fi ciency, right ventricular outfl ow obstruction or pulmonic stenosis, the risk is higher for development of arrhythmias or heart failure during pregnancy However, these patients still can

be managed successfully if they fi rst present during pregnancy Women with uncorrected tetralogy of Fallot do not fare as well

In a review of 55 pregnancies in 46 patients, there were no mater-nal deaths among nine patients with correction of this lesion before pregnancy; in patients with an uncorrected lesion, however, maternal mortality has traditionally ranged from 4% to 15%,

cerebral vascular accidents, and bacterial endocarditis Six of the

14 deaths occurred in women with associated lesions In contrast

to this dismal prognosis, a more recent series by Deal and Wooley

[60] reported 83 pregnancies in 23 women with uncomplicated

coarctation of the aorta All were NYHA class I or II before

preg-nancy In these women, there were no maternal deaths or

perma-nent cardiovascular complications In one review, aortic rupture

was more likely to occur in the third trimester, before labor and

delivery [62] More recent reviews have also supported the fi nding

that improved surgical and percutaneous techniques, medical

therapy for hypertension, and improvement in the management

of these women during pregnancy have resulted in more

favor-able maternal outcomes [63 – 65]

Thus, it appears that today, patients with coarctation of the

aorta uncomplicated by aneurysmal dilation or hemodynamically

signifi cant associated cardiac lesions who enter pregnancy as class

I or II have a good prognosis and a minimal risk of complications

or death Even if uncorrected, uncomplicated coarctation has

historically carried with it a risk of maternal mortality of only

3 – 4% [58] These unrepaired patients should be considered for

repair of their coarctation after the postpartum period is

con-cluded and before contemplation of a next pregnancy Those

pregnant women who have uncontrolled symptomatic

hyperten-sion attributable to coarctation despite maximal medical therapy

should have a stent placed at the coarctation site This procedure

is 90% successful with < 20 mmHg residual gradient The risk of

fetal irradiation is low compared to the high maternal risk of

death from heart failure, arrhythmia, dissection, stroke, and

myo-cardial infarction The fetal risk can further be reduced by

involv-ing a radiation physicist from the hospital who can help calculate

the radiation dose based on the distance of the X - ray tube from

the mother ’ s abdomen, by shielding the mother ’ s abdomen with

lead (both anterior and posterior), and by performing the

proce-dure after the second trimester Surgical intervention for

coarcta-tion of the aorta in a pregnant woman is not ideal

For those with previously surgically repaired coarctation of the

aorta, the maternal outcome appears good [63,65] Surgical

repair of the coarctation, often accomplished in early childhood,

usually results in long - term normalization of blood pressure

However, those who have surgeries done at an early age require

ongoing surveillance since the site of surgical intervention does

not typically “ grow ” with the child and further intervention may

be necessary for redevelopment of hypertension, aneurysm at the

site of the surgical repair, or other issues related to the repair

Percutaneous catheter - based interventional techniques for

treat-ment of coarctation are also being widely used as well, for

man-agement of both children and older patients Weakness in the

aortic wall, both proximal and distal to the repair, is histologically

similar (cystic medial necrosis) to the aortic weakness exhibited

in Marfan syndrome and bicuspid aortic valve This abnormality

can be amplifi ed during pregnancy For women who have

unre-paired coarctation of the aorta, who have residual coarctation

after surgical or interventional therapy, or who have a residual

gradient, β- blockade therapy seems reasonable, although

For those in whom the diagnosis is established, both maternal outcome and pregnancy is generally well tolerated with NYHA class I or II symptoms [70] It is still diffi cult to quantify RV function due to the lack of a suitable control group for compari-son, and because of the dependence on shape assumptions and loading conditions of the commonly used systolic indices Nevertheless, those with severe AV valve regurgitation or severely depressed morphologic RV function should be counseled against pregnancy regardless of functional class Lessons being learned from those who have had atrial switch operations for D - TGA (see below) and similar systemic arterial RV functional issues may be

of help in this group of patients

D - transposition ( D - TGA )

D - transposition or complete transposition of the great vessels is incompatible with prolonged life after birth In this condition, the transposed aorta is connected to the RV and the pulmonary artery to the LV The atria and ventricles are not transposed so that systemic venous return to the RV is ejected into the aorta This defect requires urgent surgical palliation and then subse-quent complete repair The fi rst complete repair involved the “ atrial switch ” operation Both the Mustard and Senning opera-tions in the late 1950s and early 1960s revolutionized the manage-ment of babies with D - TGA and became the treatmanage-ment of choice

In this operation, the systemic venous fl ow from the RA is redi-rected into the LV and PA, while the systemic arterial fl ow is redirected from the pulmonary veins into the morphologic RV

to the aorta Since the morphologic RV serves as the systemic arterial ventricle, similar issues arise to those seen with L - TGA, and the key to long - term outcome is the fate of the RV In addi-tion, because of the extensive surgical intervention to the atria in redirection of fl ow, signifi cant arrhythmias have been described

in both types of surgeries This procedure has been largely aban-doned in favor of the arterial switch begun in the 1980s [71] because of these concerns This procedure appears to reduce the late morbidity rates that have been described with the atrial repairs [72,73] Women that have had successful arterial switch procedures are now entering reproductive ages The arterial switch procedure is done within days of birth Both great arteries are transected and reanastomosed above the sinuses of Valsalva, and the coronary arteries are translocated The native pulmonary valve becomes the systemic outfl ow valve, and the anatomic pul-monary root is subjected to systemic blood pressure The native valves are not touched Short - and midterm follow - up of these patients have shown coronary artery narrowing, pulmonary artery stenosis, neoaortic valve aortic insuffi ciency, and neoaortic root dilation [74,75]

The risk of pregnancy in patients with D - transposition who have had the Mustard or Senning procedure is related to the severity of any heart failure present, the degree of AV valve regur-gitation, the degree of resultant pulmonary hypertension and the presence of arrhythmias A series of pregnant patients who were followed subsequent to the Mustard (atrial switch) operation reported 12 of 15 live births and no maternal deaths [76] In a

with a 30% fetal mortality due to hypoxia [66,69] In patients

with uncorrected VSD and right ventricular outfl ow tract

obstruc-tion or pulmonic stenosis, the decline in SVR that accompanies

pregnancy can lead to worsening of the right to left shunt This

condition can be aggravated further by systemic hypotension as

a result of peripartum blood loss A poor prognosis for successful

pregnancy has been related to several prepregnancy parameters,

including a hemoglobin exceeding 20 g/dL, a history of syncope

or congestive failure, electrocardiographic evidence of right

ven-tricular strain, cardiomegaly, right venven-tricular pressure in excess

of 120 mmHg, and peripheral oxygen saturation below 85%

Women who present with a palliative shunt procedure only from

childhood may be cyanotic and/or have pulmonary hypertension

with the same attendant problems as outlined in the section on

pulmonary hypertension/Eisenmenger ’ s syndrome If they are

found to have this problem they should be discouraged from

attempting or continuing pregnancy

Transposition of the g reat v essels

Transposition of the great vessels consists of two types:

• L - transposition; the so - called congenitally corrected

transposi-tion of the great arteries

• D - transposition: the complete transposition

L - transposition ( L - TGA )

In L - transposition, or congenitally corrected transposition, the

great arteries are transposed This accounts for less than 1% of all

congenital cardiac defects In this defect, the atria and ventricles

are also transposed Hence there is a double discordance of the

atrial - ventricular and ventricular - arterial connections The right

ventricle is attached to the aorta and acts as the systemic arterial

ventricle receiving oxygenated blood from the lungs and left

atrium The morphologic left ventricle is attached to the

pulmo-nary artery and acts as the systemic venous ventricle receiving

venous blood from the right atrium, IVC and SVC Although the

morphologic right ventricle is not designed to accommodate

sys-temic arterial pressures, it may accommodate this pressure well

for years Ventricular dysfunction and AV valve regurgitation are

recognized and important complications of patients with L - TGA

but this may present slowly and insidiously and does not happen

in all L - TGA patients Although RV dilation is common, few

develop evidence of symptomatic heart failure Serial studies do

not indicate that there is an inevitable progressive downward and

progressive deterioration of function with time Heart failure

symptoms are typical, as one would expect, with pulmonary

edema, increasing pulmonary pressures and decreased forward

systemic arterial output This condition is detected later in life

usually when the morphologic right ventricle can no longer

accommodate systemic arterial pressures or the AV valve becomes

regurgitant and symptoms of shortness of breath, palpitations,

and arrhythmia become manifest Disconcertingly, the diagnostic

anatomic features of this congenital defect may be missed on

echocardiography by adult cardiologists not trained in congenital

heart disease

Functional s ingle v entricle and Fontan p rocedure

Some of the anomalies described as a functional single ventricle that will ultimately undergo staged reconstructive procedures resulting in a “ Fontan circulation ” are tricuspid atresia, hypoplas-tic left heart, double - inlet left ventricle, and some variations of double - outlet right ventricle Given the variety of lesions and the infrequency of this procedure, data on pregnancy outcomes after Fontan operation are limited [82,83] In the small numbers reported in the United States, no maternal deaths have occurred Pregnancies in these patients have been associated with an increased incidence of spontaneous abortions, however In a small survey from the Netherlands, 10 pregnancies in 6 women were associated with a 50% miscarriage rate and one aborted ectopic pregnancy In the four live births, NYHA class deteriora-tion, atrial fi brillation and premature delivery were reported There were no maternal deaths Thus, at this early stage, although maternal death does not appear to be prominent in patients who have undergone a Fontan repair with their specifi c underlying congenital lesion and who have elected to proceed with preg-nancy, there appears to be a substantial risk for spontaneous abortion, as well as other signifi cant obstetric and cardiac issues

Fetal c onsiderations

Perinatal outcome in patients with cyanotic congenital cardiac disease correlates best with hematocrit; successful outcome in patients with a hematocrit exceeding 65% or hemoglobin exceed-ing 20 g/dL is unlikely Presbitero and associates [13] described outcome in 96 pregnancies complicated by cyanotic congenital heart disease Patients with Eisenmenger ’ s syndrome were excluded from this analysis Although only one maternal death was seen (from endocarditis 2 months postpartum), the preg-nancy loss rate was 51% Functional class III or IV, hemoglobin greater than 20 g/dL, and a prepregnancy oxygen saturation less than 85% all were associated with a high risk for poor pregnancy outcome Such patients have an increased risk of spontaneous abortion, intrauterine growth restriction, and stillbirth Maternal

P a O 2 below 70 mmHg results in decreased fetal oxygen saturation; thus, P a O 2 should be kept above this level during pregnancy, labor, and delivery In the presence of maternal cardiovascular disease, the growth - restricted fetus is especially sensitive to intra-partum hypoxia, and fetal decompensation may occur more rapidly [7,84] During the antepartum period, serial antepartum sonography for the detection of growth restriction and antepar-tum fetal heart rate testing are recommended in any patient with signifi cant cardiac disease Fetal activity counting also may be of value in patients with severe disease [85] In a series of six patients with cyanotic cardiac disease, every pregnancy was eventually delivered secondary to fetal, rather than maternal, deterioration [86]

Of equal concern in patients with congenital heart disease is the risk of fetal congenital cardiac anomalies This risk appears to

be of the order of 5%, although one older study suggested that

similar series of seven patients with transposition having

under-gone the Mustard procedure, no maternal deaths were reported

[77] In one case, however, pregnancy termination was necessary

due to maternal deterioration In the largest series described thus

far, using a retrospective nationwide registry in the Netherlands,

outcomes of 70 women with D - transposition and Mustard or

Senning operations were reported [78] Forty - two were childless

of whom 35 wished to bear children in the future Of the 28

patients who completed 49 pregnancies, all were in NYHA class

I or II before pregnancy There was clinical deterioration in

NYHA in one - third of pregnancies and development of clinically

signifi cant arrhythmias in 20% of these pregnancies No maternal

deaths occurred The cardiac issues were manageable However,

there was a high incidence of obstetric complications The authors

indicated that in contrast to what is generally assumed, pregnancy

is not always well tolerated in these patients They also estimate

that approximately 4500 women with this congenital lesion and

surgical procedure will enter childbearing age in the USA over

the next few years

Women who have had the Jatene (arterial switch) procedure

are only now entering their childbearing years There has been a

case report, cited frequently, of a successful pregnancy and

deliv-ery in a patient with D - transposition and arterial switch [79]

Pulmonic s tenosis

Pulmonic stenosis is a common congenital defect Although

obstruction can be valvular, supravalvular, or subvalvular, the

degree of obstruction, rather than its site, is the principal

deter-minant of clinical performance [8] Maternal well - being is rarely

signifi cantly affected by pulmonic stenosis Even 30 years ago, a

compilation (totaling 106 pregnancies) of three series of patients

with pulmonic stenosis revealed no maternal deaths [25 – 27]

With severe stenosis, right heart failure can occur; fortunately,

this is usually less clinically severe than is the left heart failure

associated with mitral or aortic valve lesions Symptoms of

dyspnea, angina, syncope or presyncope can occur in those with

markedly stentotic lesions Severe pulmonic stenosis is defi ned by

a peak valvular gradient of more than 80 mmHg Because this

degree of obstruction imposes a signifi cant load on the right

ventricle, patients with severe pulmonic stenosis usually benefi t

from balloon valvuloplasty even in the absence of symptoms In

these women with severe pulmonic stenosis, pregnancy may be

associated with increased risk during labor, delivery, and the

puerperium The fi rst balloon valvuloplast was performed in

1982 Balloon valvuloplasty in pregnancy has since been

per-formed successfully and with relatively low complication rates

[80] The incidence of fetal congenital heart disease in patients

with pulmonic valve stenosis appears to be approximately 20%,

with a 55% concordance rate [81]

Aortic s tenosis

Congenital and rheumatic aortic valvular disease are important

causes of aortic stenosis The impact of aortic stenosis on

preg-nancy will be discussed in Acquired cardiac lesions

and pedal edema mimic the symptoms of valvular heart disease making the clinical diagnosis diffi cult Jugular venous distention, brisk and collapsing pulses, and a diffuse and laterally displaced left ventricular impulse, all normal physiologic adaptations to pregnancy, further confound the clinical assessment On auscul-tation of the normal heart during pregnancy, it is not unusual to hear an accentuated fi rst heart sound (S1) or a systolic fl ow murmur that peaks in midsystole and is best appreciated along the left sternal border A third heart sound (S3), a fourth heart sound (S4), or a diastolic murmur are uncommon in normal pregnancy and require an echocardiographic assessment Doppler echocardiography in normal pregnancy refl ects the physiologic consequences of the increased intravascular volume and blood fl ow on the cardiac chambers and valves There is an increase in the left ventricular end - diastolic dimension and a decrease in the left ventricular end - systolic dimension represent-ing an increase in both the stroke volume and ejection fraction The aortic root dimension, as well as the mitral and tricuspid annuli, are slightly increased The left ventricular mass increases

by as much as 30% with minimal changes in wall thickness [91] Flow velocities across the aortic valve are minimally increased but rarely exceed 1.5 m/s by Doppler assessment Campos et al [92] studied 18 pregnant women longitudinally throughout preg-nancy utilizing Doppler echocardiogram Mild valvular regurgi-tation was detected consistently throughout pregnancy Aortic regurgitation was rarely detected; however, mitral (0 – 28%) tricuspid (39 – 94%), and pulmonic regurgitation (22 – 94%) were found to increase substantially from early to late gestation Table 20.7 reviews the effect of pregnancy on the clinical and echocar-diographic fi ndings associated with cardiac valvular abnormali-ties [81]

Acquired valvular lesions generally are rheumatic in origin, although endocarditis secondary to intravenous drug abuse may

the actual risk may be as high as 10%, or even higher in women

whose congenital lesion involves ventricular outfl ow obstruction

[13,81,87,88] (see Figure 20.3 ) In such patients, fetal

echocar-diography is indicated for prenatal diagnosis of congenital cardiac

defects [89] Of special interest is that affected fetuses appear to

be concordant for the maternal lesion in approximately 50% of

cases The genetics and embryologic development of congenital

cardiac defects have been reviewed by Clark [90]

Acquired c ardiac l esions

Many common complaints associated with normal pregnancy

including dyspnea, fatigue, orthopnea, palpitations, presyncope

Figure 20.3 Echocardiographic image of a fetus at 19 weeks in a mother with

a ventricular septal defect (VSD) A similar VSD is demonstrated in this fetus

Table 20.7 The effect of pregnancy on the clinical and echocardiographic fi ndings associated with cardiac valvular abnormalities

Aortic stenosis (AS) Diminished or single S2 –

unchanged

Increase in intensity and duration Systolic ejection click unchanged Increase in Doppler gradient;

AVA unchanged Aortic insuffi ciency (AI) Diminished S2 – unchanged Decreased or unchanged Wide pulse pressure – increased

or unchanged

LV dimensions may increase secondary to pregnancy not AI Mitral stenosis (MS) Loud 1 – increased; P2 –

increased

Increased decrease or unchanged S2 – OS interval gradient, decrease

in pressure half - time and increase in calculated MVA

Increase in Doppler

Mitral regurgitation (MR) Diminished S1 – unchanged Decreased or unchanged S3 – unchanged to pregnancy not

MR

LV dimensions may increase secondary

Pulmonic stenosis (PS) Diminished P2 – unchanged Increase in intensity and duration Systolic ejection click unchanged Increase in Doppler gradient Pulmonic insuffi ciency (PI) Diminished P2 – unchanged Decreased or unchanged N/A secondary to pregnancy not

PI

RV dimensions may increase Tricuspid stenosis (TS) N/A Increased N/A N/A

Tricuspid regurgitation (TR) N/A unchanged Decreased or secondary to

pregnancy not TR

N/A RV dimensions may increase

AVA, arteriovenous anastomosis; LV, left ventricle; MVA, mitral valve anastomosis; RV, right ventricle

diagnosis of mitral stenosis will be discovered for the fi rst time during pregnancy, illustrating what is frequently referred to as “ occult ” mitral stenosis The hemodynamic changes accompany-ing normal pregnancy may represent the fi rst time the patient ’ s cardiovascular system has been signifi cantly stressed These patients may present with “ acute ” pulmonary edema and/or atrial

fi brillation as the initial diagnostic clue to the presence of mitral stenosis When clinical symptoms persist despite attentive medical management, interventional therapy may be prudent Percutaneous balloon mitral valvuloplasty during pregnancy has become increasingly prevalent More than 100 pregnant women have undergone percutaneous balloon mitral valvuloplasty without periprocedural maternal or fetal mortality Multiple case reports [95 – 97] and case series [98 – 105] support the relative safety of this procedure during pregnancy Procedural complica-tions include cardiac tamponade, maternal arrhythmias, tran-sient uterine contractions, and systemic thromboembolism Transesophageal echocardiography can be used as the sole imaging modality, thereby eliminating the undesired radiation exposure associated with fl uoroscopy

Cardiac output in patients with mitral stenosis is largely depen-dent on two factors First, these patients are dependepen-dent on ade-quate diastolic fi lling time Thus, while in most patients tachycardia is a clinical sign of underlying hemodynamic instabil-ity, in patients with mitral stenosis, the tachycardia itself, regard-less of etiology, may contribute signifi cantly to hemodynamic decompensation During labor, such tachycardia may accompany the exertion of pushing or be secondary to pain or anxiety Such

a patient may exhibit a rapid and dramatic fall in cardiac output and BP in response to tachycardia This fall compromises mater-nal as well as fetal well - being To avoid hazardous tachycardia, the physician should consider intravenous β - blocker therapy for any patient with severe mitral stenosis who enters labor with a pulse exceeding 90 – 100 bpm A short acting β - blocker, such as esmolol, is ideal in that minute - to - minute heart rate control can

be achieved without the undesired prolonged beat - blockade that

is associated with more conventional agents such as propranolol Another consideration is use of intravenous calcium channel blocking agents such as diltiazem with which the cardiologists and nursing personnel are generally familiar and for which administration is easier In patients who are not initially tachy-cardic, acute control of tachycardia with an intravenous β blocking agent is only rarely necessary [42]

A second important consideration in patients with mitral ste-nosis is left ventricular preload In the presence of mitral steste-nosis, pulmonary capillary wedge pressure is not an accurate refl ection

of left ventricular fi lling pressures Such patients often require high - normal or elevated pulmonary capillary wedge pressures to maintain adequate ventricular fi lling pressure and cardiac output Any preload manipulation (i.e diuresis), therefore, must be undertaken with extreme caution and careful attention to main-tenance of cardiac output

Potentially dangerous intrapartum fl uctuations in cardiac output can be minimized by using epidural anesthesia [106] ;

occasionally occur, especially with right heart lesions During

pregnancy, maternal morbidity and mortality with such lesions

result from congestive failure with pulmonary edema or

arrhyth-mias Szekely et al [93] found the risk of pulmonary edema in

pregnant patients with rheumatic heart disease to increase with

increasing age and with increasing length of gestation The onset

of atrial fi brillation during pregnancy carries with it a higher risk

of right and left ventricular failure (63%) than does fi brillation

with onset before gestation (22%) In addition, the risk of

sys-temic embolization after the onset of atrial fi brillation during

pregnancy appears to exceed that associated with onset in the

non - pregnant state In counseling the patient with severe

rheu-matic cardiac disease on the advisability of initiating or

continu-ing pregnancy, the physician must also consider the long - term

prognosis of the underlying disease Chesley [94] followed 134

women who had functionally severe rheumatic heart disease and

who had completed pregnancy for up to 44 years He reported a

mortality of 6.3% per year but concluded that in patients who

survived the gestation, maternal life expectancy was not

short-ened by pregnancy Thus, in general, pregnancy does not appear

to introduce long - term sequelae for patients who survive the

pregnancy [44]

Pulmonic and t ricuspid l esions

Isolated right - sided valvular lesions of rheumatic origin are

uncommon; however, such lesions are seen with increased

fre-quency in intravenous drug abusers, where they are secondary to

valvular endocarditis Pregnancy - associated hypervolemia is far

less likely to be symptomatic with right - sided lesions than with

those involving the mitral or aortic valves In a review of 77

maternal cardiac deaths, Hibbard [27] reported no deaths

associ-ated with isolassoci-ated right - sided lesions In a more recent review,

congestive heart failure occurred in only 2.8% of women with

pulmonic stenosis [87] Even following complete tricuspid

val-vectomy for endocarditis, pregnancy, labor, and delivery are

gen-erally well tolerated Cautious fl uid administration is the mainstay

of labor and delivery management in such patients In general,

invasive hemodynamic monitoring during labor and delivery is

not necessary

Mitral s tenosis

Mitral stenosis is the most common rheumatic valvular lesion

encountered during pregnancy [42] It can occur as an isolated

lesion or in conjunction with aortic or right - sided lesions When

mitral stenosis is signifi cant (valve area < 1.0 cm 2 ) the principal

hemodynamic aberration involves a left ventricular diastolic

fi lling obstruction, resulting in a relatively fi xed cardiac output

Marked increases in cardiac output accompany normal

preg-nancy, labor, and delivery If the pregnant patient is unable to

accommodate such volume fl uctuations, atrial arrhythmias and/

or pulmonary edema may result

Ideally it is best to treat signifi cant mitral stenosis before

preg-nancy with balloon and/or surgical commissurotomy Often the