Managing asymptomatic severe rheumatic mitral stenosis in pregnancy: a case report

Rheumatic heart disease (RHD) is a disease of disparity most prevalent in developing countries and among immigrant populations. Mitral stenosis (MS) is a common sequalae of RHD and affects females disproportionately more than males. Rheumatic MS remains a significant management challenge as severe MS is usually poorly tolerated in pregnancy due to haemodynamic changes and increased cardiovascular demands of progressing pregnancy. Pregnancy remains contraindicated in current management guidelines based on expert consensus, due to a paucity of evidence-based literature.

A 28-year-old aboriginal woman with known severe MS was found to be pregnant during routine health review, despite contraceptive efforts. Echocardiography demonstrated mean mitral valve (MV) gradient 14 mmHg; stress echocardiography demonstrated increased MV gradient 28-32 mmHg at peak exercise and post-exercise pulmonary artery pressure 56 + 3 mmHg with marked dynamic D-shaped septal flattening. Left ventricular systolic function remained preserved. She remained remarkably asymptomatic and underwent successful elective induction of labour at 34 weeks. Postpartum, she remained euvolaemic despite worsening MV gradients and new atrial fibrillation (AF). She subsequently underwent balloon mitral valvuloplasty with good result.

Severe rheumatic MS in pregnancy carries significant morbidity and mortality, due to an already fragile predisposition towards heart failure development compounded by altered haemodynamics. Pregnancy avoidance and valvular intervention prior to conception or in the second trimester remain the mainstay of MS management; however, we present an encouraging case of successful near-term pregnancy with minimal complications in a medically managed asymptomatic patient with critical MS, who subsequently underwent valvular intervention post-partum.