Risk of Pregnancy with Heart Disease
ABSTRACT & COMMENTARY
Synopsis: Pregnant women with heart disease have a low mortality rate, but these women also have considerable morbidity that can be predicted by maternal baseline characteristics.
Source: Sui SC, et al. Circulation 1997;96:2789-2794.
More children with heart disease are surviving into the reproductive age groups. Recommendations regarding the risks of pregnancy are based upon older studies predating current diagnostic and therapeutic advances. Thus, Sui and colleagues evaluated outcomes in 221 women with heart disease who underwent 276 pregnancies from 1986 to 1994. Twenty-four had miscarriages, and 252 completed pregnancy. The majority of patients had no previous pregnancy, were NYHA class I or II, and were on no cardiac medications. A few women were on heparin because of mechanical values (n = 9), and 10 patients were cyanotic. Only cyanosis and NYHA class III predicted miscarriages (P < 0.01). Maternal heart failure, symptomatic brady- or tachy-arrhythmias, and stroke or TIA occurred in 45 completed pregnancies (18%). There were no deaths. Multivariate analysis identified five predictors of maternal cardiac events: 1) prior cardiac events; 2) prior arrhythmia; 3) NYHA class III or cyanosis; 4) left heart obstruction; and 5) myocardial dysfunction.
Assigning a point to each of these predictors resulted in a 0-5 scale, but the highest score in this study was 3. The frequency of cardiac events was 3% for a score of zero, 30% for 1, and 66% for 2. Neonatal complications occurred in 42 pregnancies (17%) and included: death (2), respiratory distress syndrome (16), intraventricular hemorrhage (92), premature birth (35), and low birthweight (14). Only poor maternal functional class and cyanosis predicted neonatal complications. Postpartum hemorrhage (18) was also predicted by maternal functional class and cyanosis. Pregnancy induced hypertension (10) was associated with maternal aortic coarctation. Sui et al conclude that pregnant women with heart disease and their neonates have a low mortality rate, but these women also have considerable morbidity that can be predicted by maternal baseline characteristics.
COMMENT BY MICHAEL H. CRAWFORD, MD
The value of this observational study is that it is a contemporary series with comprehensive maternal care at a single large referral center, which would more closely reflect current practice. Remarkably, there were no maternal deaths. Undoubtedly, previous experience with certain conditions occasionally discouraged some pregnant patients. For example, there were no Eisenmenger patients in this series, but eight patients had moderate pulmonary hypertension (systolic pressures, 53-99 mmHg). Also, only 10 patients had low ejection fractions, and no patient was in NYHA class IV. Of the 10 patients with low ejection fraction, seven had cardiomyopathy. Of these seven patients, two had heart failure peripartum, two had ventricular tachycardia, and one had a premature birth. The three patients with low ejection fraction due to other causes all did well. Thus, patients with severe pulmonary hypertension, cardiomyopathy, and cyanosis and elevated NYHA class should be discouraged from pregnancy.
Overall, 28% of completed pregnancies had a maternal or neonatal complication. Most of the complications were antepartum and involved heart failure or arrhythmias (89%). There was one embolic stroke through an AV defect. One patient thrombosed a mechanical mitral valve. Two patients had severe heart failure requiring valvuloplasty (aortic and mitral). Complications were predicted by five baseline maternal characteristics, and the more of these characteristics the patient had, the more likely there would be a complication. There was no relation to parity, twinning, or prior heart surgery. However, other characteristics may not have been identified because they were infrequent. For example, pregnancy-induced hypertension only occurred in those post coarctation repair, despite lack of obstruction on echo. Also, the patients with Marfan’s syndrome did well, but all the patients had normal aortas and were on beta blockers. Thus, the authors’ point system is a general guide, but the risk of less common entities should be specifically evaluated .
The most important risk characteristics were cyanosis and elevated NYHA functional class. These two factors are interrelated, and, so, they were combined in the point score system. These characteristics identified a high risk of miscarriage as well as other complications of pregnancy.
Since the presence of any risk characteristic predicts a 30% complication rate, serious concerns about the advisability of pregnancy in any of these patients should be discussed. However, given the very low mortality rate of this carefully managed cohort, the risks of pregnancy in women with heart disease seem lower than previously believed. Thus, women with heart disease who are determined to reproduce can be reassured that with specialized care, pregnancy can be successfully completed in most.
Maternal cardiac events during pregnancy can be predicted by:
a. cyanosis.
b. left heart obstruction.
c. myocardial dysfunction.
d. all of the above.
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