Comparative study of warfarin versus antiplatelet therapy in patients with a St. Jude Medical valve in the aortic position.

To determine the necessity of long-term warfarin anticoagulation after St. Jude Medical aortic valve replacement in adults, we evaluated the risks of thromboembolism, valve thrombosis, anticoagulant hemorrhage, and sudden cardiac death in two groups of patients. Group I consisted of 41 patients treated with conventional long-term warfarin therapy. Forty-two patients in Group II were treated primarily with antiplatelet therapy (aspirin, dipyridamole, or both); 17 of these patients received warfarin for a short time postoperatively and seven others received it intermittently during the study period. The groups were similar with respect to age, sex, associated cardiovascular disease, and length of follow-up (mean 29 months per patient). In the warfarin-treated group, three late sudden deaths occurred, one of which was preceded by a cerebrovascular accident, for a cardiac mortality of 2.7% per patient-year. There were eight major nonfatal complications (7.3% per patient-year), of which four were hemorrhagic and four embolic. In Group II, there was one sudden cardiac death (1.1% per patient-year) and four major complications occurred (3.2% per patient-year). Two of the complications were embolic and two were episodes of valve thrombosis, both necessitating reoperation. Although the incidence of serious morbidity in the warfarin-treated group was twice that of patients treated with antiplatelet therapy, there were no statistically significant differences in the rates of sudden death or major complications. These data suggest that antiplatelet therapy may be as effective as warfarin in preventing embolism from the St. Jude Medical valve in the aortic position. Valve thrombosis occurred in two patients, both receiving antiplatelet therapy (2.2% per patient-year). Whether this type of valve failure can be prevented by warfarin remains in question.