A reoperation of thrombosed On-X valve detected by multidetector-row computed tomography.

A 62-year-old female patient underwent mitral valve replacement with a 31/33-mm On-X valve for ischemic mitral valve regurgitation. Three months later, transthoracic echocardiography incidentally showed a blocked leaflet with 6 mmHg of mean pressure gradient and 2.4 cm(2) of mitral valve orifice area. Transesophageal echocardiography could not detect thrombus. Electrocardiographically gated multidetector-row computed tomography (MDCT) clearly demonstrated a blocked leaflet in the close position and thrombus (2 cm in length, 0.4 cm(2) in area) attached onto the atrial aspect of the leaflet. These findings observed by MDCT were confirmed at reoperation. MDCT was useful diagnostic method for visualizing prosthetic valve thrombosis.