Left atrial clot in patients with mitral prostheses: increased rate of detection after recent systemic embolism

We studied 70 patients with mitral valvar replacements by both transthoracic and transoesophageal echocardiography. Fifteen subjects had recently suffered a suspected embolic episode. The remainder (55) were studied for other clinical reasons. Transthoracic echocardiography demonstrated thrombus in only 1 of the 70 patients. By contrast, transoesophageal examination revealed thrombus in 8 out of 15 patients with recent suspected embolism and 3 out of 55 without. Thrombus was most commonly seen in patients with biological valvar prostheses whose anticoagulation had been discontinued. When patients with prosthetic mitral valves present with a suspected embolic episode, transoesophageal echocardiography is strongly recommended. This study also suggests that transoesophageal echocardiography may be useful for evaluating patients with biological valves if anticoagulation is withdrawn so as to identify formation of thrombus at the earliest possible stage.