LONDON – The mortality risk for pregnant women with moderate or severe aortic stenosis is close to zero in contemporary practice, according to data from the large, international ROPAC registry.
That being said, more than one-third of women with severe aortic stenosis will require hospitalization for cardiac reasons during their pregnancy, with heart failure the number-one cause for admission, Dr. Stefan Orwat reported at the annual congress of the European Society of Cardiology.
Dr. Stefan Orwat
Severe fetal complications are rare. However, preterm birth, small for gestational age, and neonatal Apgar scores below 7 are quite common in pregnancies involving severe aortic stenosis, as defined by a prepregnancy transaortic peak gradient of 64 mm Hg or more, according to Dr. Orwat of University Hospital in Muenster, Germany.
ROPAC (the Registry on Pregnancy and Cardiac disease) is a unique ongoing, global, prospective, observational registry created in order to advance understanding of the risks of pregnancy in the setting of structural heart disease. Prior reports from other sources have often provided conflicting guidance because of relatively small patient sample sizes. That’s been especially true with regard to aortic stenosis (AS), the cardiologist said.
Out of 2,966 pregnancies in women with various forms of structural heart disease in ROPAC, Dr. Orwat focused on the 99 pregnancies in 96 women with moderate or severe AS, 21 of whom had a prosthetic heart valve in place prior to pregnancy; 65 of the women had moderate AS as evidenced by an echocardiographic prepregnancy peak gradient of 36-63 mm Hg.
No maternal deaths occurred during pregnancy or within 1 week afterward. However, 13% of women with moderate AS and 35% with severe AS were hospitalized for cardiac reasons during their pregnancy. Most of the admissions were for new or worsening heart failure, which occurred at a median of 28 weeks’ gestation.
The risk of heart failure hospitalization during pregnancy was quite low – in the 6%-8% range – among women with baseline prepregnancy asymptomatic or symptomatic moderate AS or asymptomatic severe AS. In contrast, the rate shot up to 26% in women with symptomatic and severe AS prior to pregnancy.
There were a couple of hospitalizations for arrhythmias and one for endocarditis. Unlike in some prior reports by other research groups, there were no cases of pulmonary embolism, valve thrombosis, cerebrovascular events, or deep vein thrombosis. The presence of a mechanical valve with its required rigorous anticoagulation wasn’t related to worse outcomes in this series, unlike in some others.
The heart failure was generally manageable medically. Only two patients required intervention. One developed endocarditis, then underwent balloon aortic valvuloplasty and aortic valve replacement with a mechanical valve 4 months into pregnancy, with subsequent vaginal delivery at 38 weeks. The other patient, who was unaware she had AS prior to pregnancy, presented with severe AS and a depressed left ventricular ejection fraction at 20 weeks’ gestation. She responded well to valvuloplasty, had an uneventful vaginal delivery at 38 weeks, then underwent aortic valve replacement.
In a multivariate analysis, only two independent predictors of maternal hospitalization during pregnancy were identified: the presence of symptoms prior to pregnancy, and the prepregnancy hemodynamic severity of AS.
Preterm birth prior to 37 weeks occurred in 16% of pregnancies involving moderate and 36% of those featuring severe AS. An Apgar score below 7 occurred in 5% of cases of moderate and 16% of severe AS. The small for gestational age rate was 3% with moderate AS and ballooned to 21% with severe AS. The only independent predictor of fetal complications was the degree of elevation in peak aortic gradient prior to pregnancy.
Audience questions focused on challenging scenarios. Would you allow a pregnancy to continue, Dr. Orwat was asked, if a woman with AS developed an aortic gradient of 90 mm Hg during the first trimester?
“It depends on whether she was asymptomatic prior to pregnancy. If so, I think it’s a low-risk situation, and you can carry on with the pregnancy,” he replied. Remember, he added, it’s the baseline gradient that’s important. Cardiac output goes up during the first trimester as a matter of course, and so will the gradient.
Dr. Orwat emphasized that symptomatic severe AS is an indication for aortic valve replacement, and he would advise an affected patient to undergo the surgery prior to pregnancy.
Audience member Dr. Fiona Walker rose to advocate ordering a prepregnancy treadmill exercise test in all patients with asymptomatic severe AS in order to learn whether they are likely to remain asymptomatic during the stresses of pregnancy. In a patient with severe AS who remains asymptomatic with exercise, it’s probably safer to go through pregnancy without prior valve replacement than to put in a mechanical valve.