Thrombotic occlusion of a Bjork-Shiley mitral valve

Thrombosis of a mechanical cardiac valve is a complication potentially preventable by adequate anticoagulation. A patient is described who discontinued anticoagulant therapy, with resultant near-fatal thrombosis of a mitral Bjork-Shiley valve. The literature is reviewed concerning the incidence of thrombotic prosthetic valve occlusion in the various anatomical sites and potential factors contributing to its occurrence.