Maternal and Fetal Outcomes in Pregnant Patients With Mechanical and Bioprosthetic Heart Valves

Abstract

Background Guidelines for choice of prosthetic heart valve in people of reproductive age are not well established. Although biologic heart valves (BHVs) have risk of deterioration, mechanical heart valves (MHVs) require lifelong anticoagulation. This study aimed to characterize the association of prosthetic valve type with maternal and fetal outcomes in pregnant patients. Methods and Results Using the 2008 to 2019 National Inpatient Sample, we identified all adult patients hospitalized for delivery with prior heart valve implantation. Multivariable regressions were used to analyze the primary outcome, major adverse cardiovascular events, and secondary outcomes, including maternal and fetal complications, length of stay, and costs. Among 39 871 862 birth hospitalizations, 4152 had MHVs and 874 had BHVs. Age, comorbidities, and cesarean birth rates were similar between patients with MHVs and BHVs. The presence of a prosthetic valve was associated with over 22-fold increase in likelihood of major adverse cardiovascular events (MHV: adjusted odds ratio, 22.1 [95% CI, 17.3-28.2]; BHV: adjusted odds ratio, 22.5 [95% CI, 13.9-36.5]) as well as increased duration of stay and hospitalization costs. However, patients with MHVs and BHVs had no significant difference in the odds of any maternal outcome, including major adverse cardiovascular events, hypertensive disease of pregnancy, and ante/postpartum hemorrhage. Similarly, fetal complications were more likely in patients with valve prostheses, including a 4-fold increase in odds of stillbirth, but remained comparable between MHVs and BHVs. Conclusions Patients hospitalized for delivery with prior valve replacement carry substantial risk of adverse maternal and fetal events, regardless of valve type. Our findings reveal comparable outcomes between MHVs and BHVs.

Keywords: anticoagulation; heart valve prostheses; pregnancy; thrombosis; valvular heart disease.

Figure 1. Flow chart of patient inclusion.

Using the 2008 to 2019 National Inpatient Sample (NIS) database, an estimated 39 871 862 birth hospitalizations were identified, including 5026 (0.01%) with a prosthetic heart valve. Of pregnant patients with prostheses, 4152 (82.6%) had mechanical and 874 (17.4%) had bioprosthetic valves.

Figure 2. Adjusted maternal and fetal outcomes in pregnancies with valve prostheses.

Adjusted odds ratios accounted for valve type, age, race, year of hospitalization, elective admission, cesarean birth, comorbidities as in Table 3, income quartile, payer status, hospital teaching status, and region. Outcomes of patients with mechanical and bioprosthetic valves were assessed relative to patients with no prosthetic valve. Pregnancies with valve prostheses had increased odds of maternal complications, such as ante/postpartum hemorrhage and requiring blood transfusion, as well as fetal complications, such as preterm birth and stillbirth. HDP indicates hypertensive disease of pregnancy; and PPROM, preterm premature rupture of membranes. *P<0.05.

Figure 3. Adjusted maternal and fetal outcomes in bioprosthetic vs mechanical valve patients.

Adjusted odds ratios accounted for valve type, age, race, year of hospitalization, elective admission, cesarean birth, comorbidities as in Table 3, income quartile, payer status, hospital teaching status, and region. Outcomes of patients with bioprosthetic valves were assessed relative to patients with mechanical valves. There were no significant differences in both maternal and fetal outcomes between valve types. HDP indicates hypertensive disease of pregnancy; MACE, major adverse cardiovascular events; and PPROM, preterm premature rupture of membranes.

Figure 4. Study summary.

MACE indicates major adverse cardiovascular events.