Clinical trials evaluating platelet-modifying drugs in patients with atherosclerotic cardiovascular disease and thrombosis.

Aspirin has been convincingly shown to reduce stroke and death in men with transient ischemic attacks (it may possibly be beneficial to women also), myocardial infarction and death in patients with unstable angina, thromboembolic complications associated with artificial heart valves in patients receiving oral anticoagulants (although gastrointestinal bleeding is prohibitive with this combination), and thrombotic occlusion of silicone rubber arteriovenous cannulae in uremic patients undergoing hemodialysis. In addition, aspirin may possibly decrease occlusion of saphenous vein aortocoronary grafts and venous thrombosis in men after hip replacement, although these reports require confirmation. Aspirin is ineffective in the secondary prevention of stroke and has unproven benefit in the secondary prevention of myocardial infarction. Dipyridamole in combination with oral anticoagulation decreases the thromboembolic complications associated with mechanical heart valves. The combination of aspirin and dipyridamole prevents both early and late occlusion of saphenous vein aortocoronary bypass grafts and protects renal function in patients with membranoproliferative glomerulonephritis. The relative importance of combining aspirin and dipyridamole compared with either agent used singly remains to be established. Sulfinpyrazone reduces the thrombotic occlusion of arteriovenous cannulae and early occlusion of saphenous vein aortocoronary grafts. The reported benefit in the secondary prevention of myocardial infarction is controversial.