Pregnancy Complicated by Prosthetic Valve Thrombosis

A 19-year-old woman presents with signs and symptoms of heart failure (HF) at 33 weeks gestation of her first pregnancy. The patient was born with truncus arteriosus and underwent ventricular septal defect closure, right ventricle-to-pulmonary artery conduit placement in infancy, with subsequent conduit and mechanical aortic valve replacement as an adolescent. Due to the pregnancy, she was switched from warfarin 10 mg daily to low-molecular-weight heparin at week 6 of gestation. Four months prior to this presentation, while on heparin but with variable compliance, she was hospitalized with a deep venous thrombosis of the right common femoral vein. This was managed conservatively. On this current presentation, she reports 3 weeks of progressive dyspnea on exertion, fatigue, and lower extremity edema that limit her activity. She reports no chest pain, presyncope, syncope, or palpitations. Vital signs are within normal limits. The exam is notable for mild lower extremity edema, a harsh IV/VI systolic ejection murmur at the cardiac base, and a I/IV high-pitched decrescendo diastolic murmur at the apex. Significant laboratory results include 95,000 platelets, B-type natriuretic peptide 273pg/mL, and anti-Xa level 0.62 (goal 0.8-1.2 units/mL). Figures 1 and 2 below are from the transthoracic echocardiogram. Previous baseline aortic valve velocity was 3.8 m/s. A cine clip from aortic valve fluoroscopy is shown in Video 1.

Figure 1: Color Doppler Across the Aortic Valve

Figure 1

Figure 2: Doppler Echocardiography Across the Aortic Valve

Figure 2

Video 1: Aortic Valve Fluoroscopy

What is the next step in this patient's management?

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