Effect of dipyridamole and aspirin on vein graft patency after coronary bypass operations.

Antiplatelet therapy with dipyridamole, 100 mg q.i.d., starting 2 days before surgery, followed by aspirin, 325 mg t.i.d. plus dipyridamole, 75 mg t.i.d., 7 hours after surgery was assessed in the prevention of saphenous vein bypass graft occlusion. Early (less than or equal to 1 month) and late (1 year) occlusions were reduced both on a per patient and a per distal anastomosis basis. Bleeding complications were not increased. Graft occlusion in high-risk situations (low-flow grafts and endarterectomy) was reduced, but not eliminated, by this antiplatelet regimen. The authors recommend this combination of dipyridamole before surgery, adding aspirin after surgery, to prevent coronary artery bypass graft occlusion.