Thrombosis of a Mechanical Mitral Valve
Kevin Christopher Harris, M.D., M.H.Sc., and Andrew I.M. Campbell, M.D.
N Engl J Med 2011; 365:e45December 15, 2011
An 8-year-old girl with a history of congenital mitral stenosis and mitral-valve replacement presented after 1 week of dyspnea on exertion, fatigue, and orthopnea. The patient had not been monitoring her international normalized ratio regularly during the period before presentation. On examination, she had tachypnea, a heart rate of 130 beats per minute, and oxygen saturation of 85 to 87% while she was breathing ambient air. The jugular venous pressure was elevated 4 cm above the sternal angle. She had a faint mechanical S1, a narrowly split S2, and both a grade 2/6 holosystolic murmur and a grade 2/6 diastolic murmur, heard at the apex. A chest radiograph, obtained with the patient in a sitting position, showed interstitial thickening, pulmonary edema, and pleural fluid (Panel A). Echocardiography revealed a dilated left atrium, markedly increased inflow velocity across the mitral valve, mitral regurgitation, and abnormal excursion of the mechanical mitral valve. Fluoroscopy confirmed that one leaflet of the mechanical valve was fixed and the other leaflet had reduced mobility (Panel B [arrows indicate the positions of open leaflets in a normally functioning mechanical valve] and videos). In the operating room, extensive clot and pannus were found on the mechanical valve. The patient underwent replacement of the mechanical mitral valve and recovered uneventfully.