Mechanical Mitral Valve Thrombosis in a Patient With Prior Nonbacterial Thrombotic Endocarditis

A 54-year-old woman with a mechanical mitral valve replacement presented with recurrent admissions for pneumonia and pulmonary edema. Multimodality imaging revealed mobile masses on the prosthesis and discrepant point of care and inpatient international normalized ratio levels owing to antiphospholipid antibody cross-reactivity on the outpatient assay. The prosthetic valve thromboses resolved with therapeutic anticoagulation. (Level of Difficulty: Beginner.)