Acute mechanical valve thrombosis of the St. Jude medical prosthesis

From 1986 to 1996, 2585 patients underwent Valve replacement with the St. J ude medical prosthesis. Sixty experienced mechanical valve thrombosis. Seve nteen of 60 patients (28.3%) had isolated aortic valve replacements, 33 had isolated mitral valve replacements (55%), and 10 had double valve replacem ents (16.7%) (aortic and mitral valve replacement). All patients who underw ent reoperation for mechanical valve thrombosis were functional Class III o r IV. Against medical advice, systemic anticoagulation with warfarin sodium had been discontinued or used only intermittently. Thus, anticoagulant act ivity was not adequate. The diagnosis of thrombosis was made by clinical ex amination, laboratory findings, and echocardiography and cineradiography. O f the 60 patients, 9 patients died early after surgery or before discharge. Most of the deaths were attributed to low cardiac output. The overall hosp ital mortality was 15%. The overall 10-year actuarial survival rate was 82. 8 +/- 1.6%. In our study, reoperation for thrombosed mechanical prosthesis was not an independent parameter determining mortality. Age was the only st atistically important hospital mortality predictor. Of this group, 90% suff ered mechanical valve obstruction within the first 5 years after operation. These results suggest that valve re-replacement appears to be a suitable s urgical treatment for thrombosis of mechanical prosthetic valves, especiall y in the young. In these patients subsequent anticoagulation management is necessary.