Because arterial graft patency rates are high even in the absence of antiplatelet therapy, the administration of such therapy has not shown an improvement. Aspirin administration before CABG offers no improvement in subsequent SVG patency compared with its early postoperative initiation.535 Prospective controlled trials have demonstrated a graft patency benefit when aspirin was started 1, 7, or 24 hours after operation103,537; in contrast, the benefit of postoperative aspirin on SVG patency was lost when it was initiated 48 hours after surgery.538 Dosing regimens ranging from 100 mg daily to 325 mg 3 times daily appear to be efficacious.539 As the grafted recipient s coronary arterial luminal diameter increases, SVG patency rates improve, and the relative advantage of aspirin over placebo is reduced.540 Although aspirin doses of 100 mg daily have been used for prevention of adverse events in patients with CAD, they may be less efficacious than higher doses in optimizing SVG patency.541 Enteric-coated aspirin, 75 mg, has been associated with suboptimal inhibition of platelet aggregation in 44% of patients with stable cardiovascular disease, suggesting that soluble aspirin may be preferred if low-dose aspirin is used.542 When given within 48 hours after CABG, aspirin has been shown to reduce subsequent rates of mortality, MI, stroke, renal failure, and bowel infarction.519 Although ticlopidine is efficacious at inhibiting platelet aggregation, it offers no advantage over aspirin except as an alternative in the truly aspirin-allergic patient.543 In addition, its use may be associated with potentially life-threatening neutropenia, a rare adverse effect, such that white blood cell counts should be monitored repetitively after initiating it. Dipyridamole and warfarin add nothing to the effect of aspirin on SVG patency,544,545 and use of the latter may be associated with an increased risk for bleeding compared with Clopidogrel is associated with fewer adverse effects than ticlopidine. 