Evaluation of antiplatelet agents in the prevention of aorto-coronary bypass occlusion.

The cumulative occlusion rates of aorto-coronary artery venous bypass grafts average from 16 to 26% per distal anastomosis within 12 months and about 2% per following year. The potential benefit of oral anticoagulants and platelet inhibitor drugs has been tested to prevent graft occlusion and to retard the atherosclerotic process. Oral anticoagulants started on the third postoperative day do not significantly reduce graft occlusion after 6 months. Among the platelet inhibitor drugs, dipyridamole started before surgery, followed by dipyridamole and aspirin soon after surgery, was the drug regimen with the best results. More randomised double-blind clinical trials are highly desirable to confirm these findings and to resolve the question of relative efficacy and safety for the various drugs reported to have shown benefit when used in combination.