Prosthetic valve obstruction: Thrombolysis versus operation

An acute obstruction is a life-threatening complication of mechanical valve prostheses, and is caused by the formation of fresh clot or fibrous tissue overgrowth, or both. Accurate selection of the most appropriate treatment far a particular patient is mandatory. From January 1991 to July 1992, 28 e ases of prosthetic thrombosis were managed. Twenty patients underwent surgi cal treatment, with one operative death, and 8 patients were treated with t hrombolysis using recombinant tissue-type plasminogen activator (rt-PA). Th e criteria for using thrombolysis were (1) the recent onset of symptoms, (2 ) transesophageal echocardiographic evidence of clots on the valve or cardi ac chambers, and (3) preserved disc excursions. All patients who underwent thrombolysis had mechanical valves (two bileaflets, four tilting discs, and two bah valves); seven valves were in the mitral position and one was in t he aortic. Symptoms of obstruction consisted of cardiac failure in 6 cases or thromboembolism in 5, or both. The mean interval between the onset of sy mptoms and the initiation of thrombolysis was 81 +/- 65 hours. After infusi on of the rt-PA, normal valve function was restored in all patients, as doc umented by transesophageal echocardiography. No deaths or neurologic compli cations occurred; there was one episode of minor peripheral embolism. Throm bolysis using rt-PA maybe the appropriate treatment in patients with primar y thrombosis of mechanical valves, thereby avoiding the operation-related r isks.