Cardiac Complications in Pregnant Women With Isolated Mitral Stenosis and Their Association With Echocardiographic Changes During Pregnancy

In women with mitral stenosis (MS), mitral valve gradients and right ventricular systolic pressure (RVSP) can increase in response to the physiologic stress of pregnancy. The prognostic significance of these echocardiographic changes has not been well studied. Pregnancy outcomes and serial echocardiograms were collected in women with MS prospectively recruited as part of a larger study on pregnancy outcomes. Third trimester echocardiograms were compared with baseline echocardiograms. Changes in mitral valve area (MVA), transmitral mean gradient (MG), and RVSP during pregnancy and their relationship to adverse cardiac events (CE) were examined. Fifty-six pregnancies in 47 women with MS were included. The MVA did not change during pregnancy (1.6 ± 0.6 cm2 at baseline vs 1.7 ± 0.6 cm2 in the third trimester, p = 0.46). There was an increase in the MG (8 ± 3 vs 11 ± 6 mm Hg, p <0.001) and the RVSP (39 ± 14 vs 47 ± 20 mm Hg, p <0.001) during the third trimester. Adverse CE occurred in 45% (25/56) of pregnancies. CE were associated with baseline MG>10 mm Hg, baseline RVSP >40 mm Hg, third-trimester MG>10 mm Hg, and RVSP >40 mm Hg. Women with mitral valve MG ≤10 mm Hg who had a normal RVSP at baseline and in the third trimester were at lowest risk for CE (11%) with a negative predictive value of 89%. In conclusion, baseline echocardiographic assessment of MS severity as well as changing echocardiographic parameters during pregnancy can help identify women at risk for cardiac complications during pregnancy.