Resident Université de Montréal Montreal, Quebec, Canada
Background: Pregnancy induces many physiologic hemodynamic adaptations, such as increased cardiac output, decreased systemic vascular resistance, and increased heart rate. The impact of pregnancy on disease penetrance and severity of HCM in females with disease-causing sarcomeric variants is not well established. Risk factors associated with adverse HCM outcomes in pregnancy are also scarcely described.
METHODS AND RESULTS: This retrospective multicentric study based on the HiRO-HCM database aims to determine if pregnancy is associated with increased HCM disease penetrance and severity in women with sarcomeric variants and to identify risk factors of cardiovascular events during pregnancy and postpartum in patients with HCM, incorporating cardiovascular risk scores used for pregnancy such as mWHO, CARPREG, CARPREG II, ZAHARA. We included 668 female patients with either a clinical diagnosis of HCM and/or carrying an HCM-causing sarcomeric gene variant, and with available clinical, genetic and imaging data. Cardiovascular events are defined as heart failure hospitalizations, sustained atrial or ventricular arrhythmias, stroke, resuscitated cardiac arrest, heart transplant, or cardiovascular death. Among the 247 women with sarcomeric variants, patients with or without history of pregnancy had a similar prevalence of clinical HCM (73.4% vs 59.0%, p=0.137), left ventricle outflow tract (LVOT) gradient (9.00 (0.00-25.00) mm Hg vs 0.00 (0.00-10.50) mm Hg, p= 0.106), maximal interventricular septum thickness (17.00 (13.00-22.00) mm vs 16.00 (10.00-21.00) mm, p= 0.307), and cardiovascular events (36.7% vs 29.5%, p=0.277) adjusted for age. Among the 56 patients with pregnancies after or within a year of their diagnosis of HCM, with or without sarcomeric variants, 7 (12.5%) experienced cardiovascular events during pregnancy or within 6 months postpartum. Presence of LVOT obstruction before pregnancy (71.4% vs 8.2%, p< 0.001), prior cardiovascular events before pregnancy (42.9% vs 8.2%, p=0.009), atrial fibrillation or atrial flutter (28.6% vs 0%, p< 0.001), and scores of mWHO (p < 0.001), CARPREG (1 vs 0, p< 0.001), CARPREG II (3 vs 0, p< 0.001), ZAHARA (4 vs 0, p< 0.001) are significantly higher in patients who experienced cardiovascular events during pregnancy or postpartum compared to those without events.
Conclusion: Pregnancy is not associated with increased disease penetrance or severity in women with HCM-causing sarcomeric variants. Elevated mWHO, CARPREG, CARPREG II, and ZAHARA risk scores are associated with an increased risk of cardiovascular events during pregnancy or postpartum in patients with HCM.
