Author + information
- Jasmine Grewal, MD,
- Samuel C. Siu, MD,
- Heather J. Ross, MD,
- Jack M. Colman, MD and
- Candice K. Silversides, MD⁎ ()
- ↵⁎University of Toronto, Pregnancy and Heart Disease Research Program, Toronto General Hospital, 585 University Avenue, 5N-521, Toronto, Ontario M5G 2N2, Canada
We thank Dr. van den Berg and colleagues for their interest in our paper (1), and agree that in addition to the increased hemodynamic load imposed by pregnancy, discontinuation of cardiac medications can contribute to cardiac decompensation in pregnant women with a dilated cardiomyopathy. We acknowledged this as a limitation in our ability to determine accurately the direct role of pregnancy on outcomes in this population.
Angiotensin-converting enzyme inhibitors are associated with an increased fetal risk of major congenital malformations, and therefore are not used in pregnancy (2,3). Because there is a potential for reduction in intravascular volume with diuretics and an effect on uteroplacental perfusion, we typically use only diuretics to treat congestive symptoms (4,5). We agree, however, that treatment with beta-blockers throughout pregnancy would be optimal, and our current practice is to encourage continued use of beta-blockers. However, beta-blocker therapy for heart failure was not used as routinely in the early 1990s at the beginning of our cohort recruitment. Furthermore, some women referred to our center already had stopped medications on the advice of the referring physician and others elected to stop when the fetal risk of beta-blockers was discussed (6,7). Thus, there were many reasons that the use of beta-blocker therapy was low in this study.
We were unable to compare outcomes adequately among women who continued versus discontinued medications primarily because of the small sample size. First, all women stopped taking angiotensin-converting enzyme inhibitors after the initial assessment. There were only 7 women undergoing diuretic therapy at the first antenatal visit, and diuretics were continued in only 5 women. Beta-blocker therapy was continued in all women (n = 13) who were taking it at our first assessment. The adverse cardiac event rate during pregnancy for women taking beta-blockers was 38% (5 of 13) compared with 39% (9 of 23) in women not taking a beta-blocker.
Finally, in our series there were 5 women with doxorubicin-induced dilated cardiomyopathy. We did not observe an increase in the event rates among women with doxorubicin-induced cardiomyopathy compared with those with idiopathic dilated cardiomyopathy. It is possible that oxidative stress during pregnancy may play a role in cardiac decompensation. However, a larger sample of women would be needed to answer this question.
- American College of Cardiology Foundation
- Grewal J.,
- Siu S.C.,
- Ross H.J.,
- et al.
- Briggs G.G.,
- Freeman R.K.,
- Yaffe S.J.
- Magee L.A.,
- Duley L.