14 Oct

Antithrombotic Therapy in Mechanical and Biological Prosthetic Heart Valves and Saphenous Vein Bypass Grafts: Mechanical Bioprosthetic Valves

When antiplatelet agents were administered with anticoagulants, advantageous effects were shown (Table 2). Dipyridamole, 400 mg/day, in combination with warfarin, was shown in a (level I) prospective randomized trial to significantly reduce the incidence of thromboembolism compared with prophylactic treatment with warfarin alone. Also, a prospective randomized trial (level II) in patients with various types of mechanical prosthetic valves indicated a trend in the reduction of thromboembolism with warfarin plus dipyridamole compared with warfarin alone or warfarin plus aspirin. Other prospective randomized trials (level II) also showed advantageous effects of warfarin in combination with dipyridamole. A 1-3-year follow-up showed that only 5% (2 of 40) of patients who received combination therapy suffered a thromboembolic event, whereas 21% (8 of 39) of patients receiving anticoagulants alone suffered a thromboembolic event. this

Others, in a 1-2-year follow-up, showed only 4% (3 of 78) of patients treated with anticoagulants plus dipyridamole suffered a thromboembolic event, whereas 13% (11 of 87) of patients treated with anticoagulants alone had a thromboembolic episode. A 1-year collaborative study, however, with 290 randomized patients showed only a trend in favor of combined therapy. Thromboembolic events occurred in 3% of patients treated with combined therapy and in 5% treated with anticoagulants alone. Aspirin 1 g/day in combination with warfarin (level I study) was shown in a randomized trial to be associated with fewer thromboembolic complications than warfarin alone, irrespective of whether the patients were in sinus rhythm or AF. A comparable experience has been shown by others as well (level I). Warfarin plus aspirin, however, resulted in excessive bleeding.

Categories: Antithrombotic Therapy
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