Misleading noninvasive signs of Bjork--Shiley mitral valve dysfunction

Three months after receiving a Bjork--Shiley mitral valve prosthesis, a patient experienced acute gastronintestinal bleeding associated with heavy alcohol intake and poor compliance with oral anticoagulation therapy. As a result of the gastrointestinal bleeding, treatment with warfarin was discontinued. Ten months later, the patient presented with symptoms of transient cerebral ischemia. Despite demonstrated loss by phonocardiography of the previously well-recorded opening click and echocardiographic suggestion of a thrombosed prosthetic mitral valve, no thrombosis or dysfunction of the prosthetic mitral valve was revealed at reoperation.