Abstract 4141054: Management of Severe Non-Rheumatic Mitral Stenosis in Pregnancy

Introduction: Physiologic changes in pregnancy can accentuate valvular pathologies. The modified WHO pregnancy risk classification categorizes severe mitral stenosis (MS) as mWHO Risk Class IV in which pregnancy is contraindicated. Literature on the management of MS in pregnancy is limited to rheumatic heart disease. Those that are non-rheumatic in nature are therefore difficult to characterize. To better understand these differences in management, we present a case of MS from pannus-overgrowth 10 years after bioprosthetic valve placement. Our Case: A 29-year-old primigravid female, with a history of traumatic rupture of the posterior papillary muscle managed by a 25mm Carpentier-Edwards bioprosthetic mitral valve was seen at 13-weeks. A multidisciplinary (MDC) meeting was held with maternal-fetal medicine (MFM) and cardiothoracic surgery. A TEE confirmed severe MS [MVA 1.3cm 2 , mean gradient 19.5 mmHg, and peak velocity of 2.6 m/s] as the result of pannus-overgrowth limiting mobility in 1/3 leaflets. She was not a candidate for balloon valvuloplasty given her bioprosthetic valve, or valve replacement due to the risks cardiopulmonary bypass. She opted to continue pregnancy with medical management. As expected, in the mid-second trimester blood pressure reached its nadir, and her heart rate increased; therefore, metoprolol was started. Exposure to β-blockers is associated with fetal growth restriction (FGR) and the MFM team performed serial growth ultrasounds for close monitoring. At 28-weeks, she developed dyspnea, and the β-blocker dose was titrated. At 32-weeks these symptoms worsened, and furosemide was started. She experienced palpitations, but remote cardiac monitoring was reassuring. The pregnancy was complicated by non-severe FGR and so the MDC decided to pursue a medically indicated planned vaginal delivery in the intensive care unit (ICU) at 35-weeks. Delivery was accomplished via assisted second stage of labor to avoid maternal Valsalva. The postpartum course was uncomplicated. As she desired future childbearing, she underwent successful mechanical valve replacement after 3-months. Discussion: For pregnant patients with MS, heart rate and volume optimization are of critical importance. β-blockers and diuretics are safe and effective in pregnancy and providers should initiate these therapies as needed. We highlight the importance of an MDC approach in patients with MS and confirm that pregnancy and vaginal delivery can be safe.