Left ventricular outflow tract obstruction after bioprosthetic mitral valve replacement with posterior mitral leaflet preservation.

We present a case of transient left ventricular outflow tract obstruction after mitral valve replacement with a high-profile bioprosthesis; only the posterior native mitral valve leaflet was preserved. A 76-year-old woman was admitted to our institution with pulmonary edema. Two weeks earlier, she had undergone mitral valve replacement at our hospital due to severe mitral stenosis and 2+ mitral regurgitation complicated by cardiac failure and atrial fibrillation. The patient was taking digoxin, furosemide, and warfarin at the time of readmission. Echocardiography showed a narrowed left ventricular outflow tract. Doppler echocardiography revealed a peak 64-mmHg gradient between the septum and the strut of the bioprosthesis. The patient was successfully treated medically. This case indicates that the risk of left ventricular outflow tract obstruction after bioprosthetic mitral valve replacement is not always eliminated by removal of the anterior mitral valve leaflet when the posterior mitral leaflet is preserved.