Does low-dose aspirin prevent aortocoronary vein bypass graft occlusion? The Spanish Group for Aortocoronary Bypass Follow-up (GESIC Study).

Although the importance of antiplatelet treatment in preventing early bypass occlusion has been clearly recognized, questions regarding the optimal drug regimen remain. To study the efficacy of low-dose aspirin, alone or in combination with dipyridamole, 927 consecutive patients were enrolled in a multicenter, randomized, double-blind, placebo-controlled trial comparing aspirin, 50 mg t.i.d., aspirin, 50 mg t.i.d. plus dipyridamole, 75 mg t.i.d., and placebo. Both aspirin and aspirin plus dipyridamole reduced the occlusion rate of distal anastomoses, but only aspirin plus dipyridamole reduced the number of patients with at least one occluded graft. Logistic regression analysis identified distal vessel diameter, bypassed artery, graft type, and postoperative antiplatelet treatment as independent predictors of graft patency.