Critical Rheumatic Mitral Stenosis Unmasked During Pregnancy Complicated by Preeclampsia With Severe Features and Managed With Urgent Balloon Mitral Valvuloplasty.

Pregnancy imposes significant hemodynamic changes that can unmask previously undiagnosed cardiovascular disease and complicate management when concurrent obstetric conditions are present. We present the case of a 32-year-old immigrant woman at 21 weeks' gestation with a limited medical history due to a significant language barrier, who presented with hypertensive crisis and was diagnosed with preeclampsia with severe features. During her evaluation, she developed worsening dyspnea and acute respiratory decompensation. Further cardiac assessment revealed critical rheumatic mitral stenosis, accompanied by severe left atrial enlargement and markedly elevated transmitral gradients. The coexistence of preeclampsia with severe features and critical mitral stenosis posed a complex hemodynamic challenge, leading to flash pulmonary edema and progressive maternal instability. Given the high maternal and fetal risk associated with continued deterioration, a multidisciplinary team involving maternal-fetal medicine, cardiology, interventional cardiology, cardiac anesthesia, and critical care was assembled to determine the optimal treatment strategy. The patient underwent urgent balloon mitral valvuloplasty with atrial septostomy, resulting in marked hemodynamic improvement and resolution of pulmonary edema. Following the procedure, her clinical status stabilized, and she was discharged with close cardiology follow-up. This report highlights the importance of maintaining a high index of suspicion for underlying structural heart disease in pregnant patients presenting with pulmonary edema, particularly when symptoms appear disproportionate to the severity of preeclampsia. It also demonstrates the critical role of multidisciplinary collaboration and timely percutaneous intervention in achieving favorable maternal outcomes in the setting of severe rheumatic mitral stenosis during pregnancy.