Management of Valvular Heart Failure Due To Mechanical Mitral Valve Thrombosis During Pregnancy

Abstract

Background Mechanical heart valves may pose hemodynamic challenges leading to significant heart failure during pregnancy, especially if thrombosis or stenosis occurs. On the other hand, warfarin can have teratogenic effects, and expectant mothers may try to avoid it during pregnancy. Case A 38-year-old woman with 30-week pregnancy complained of progressive dyspnea on minimal exertion. She had a history of congenital mitral valve abnormality for which had undergone mechanical valve replacement 21 years prior, with subsequent mechanical valve thrombosis after she held her warfarin for several days during a previous pregnancy which was treated successfully with tissue plasminogen activator (tPA). The patient's anticoagulation had been changed to enoxaparin from weeks 7 to 12 to decrease the risk of teratogenesis. Her international normalized ratio (INR) remained therapeutic afterwards, so her mildly elevated mean mitral gradient (MMG) was initially attributed to increased cardiac output of pregnancy. However, as her dyspnea worsened, concerns for thrombosis increased. She underwent transthoracic echocardiography (TTE) which evidenced that her MMG had increased from 12 to 20-22 mmHg over the last 3 months prior to presentation, with no decrease in her right or left ventricular systolic functions. Fluoroscopy and transesophageal echocardiography (TEE) showed no anterior leaflet mobility. She was admitted to the cardiovascular critical care unit where she received tPA infusion for 24 hours with subsequent TTE evaluation. Although the MMG normalized, there was still residual leaflet restriction. Fibrinolytics were continued for a total of 48 hours, and she was bridged to warfarin with heparin (goal partial thromboplastin time [PTT] 2-2.5 of control range). Her INR goal range was increased to 3-4. She underwent cesarean section and tubal ligation at 34 weeks of pregnancy. Neither she nor her baby had complications. Conclusion This case supports the cautious use of fibrinolysis in pregnant patients presenting with progressive heart failure secondary to mechanical valve thrombosis under intensive, multi-disciplinary monitoring by cardiologist and maternofetal medicine specialists.