However, the clotting disorders and platelet dysfunction induced by cardiopulmo- nary bypass may actually have desirable effects by protecting anastomosis patency and preventing graft thrombosis. Several reports have documented the existence of a relative hyperco- agulable state after off-pump surgery, associated with higher levels of postoperative platelet activity and a decrease in plate- let sensitivity to aspirin after OPCAB.52 60 Moreover, in some early studies of graft patency after OPCAB, vein graft occlu- sion was noticeably higher both early and late after OPCAB compared with conventional CABG.53,61 Questions were therefore raised about whether antiplatelet therapy with aspi- rin alone would be sufficient for patients after OPCAB, and as early as 2003, leading off-pump centers instituted policy changes to treat all OPCAB patients with both clopidogrel and aspirin after surgery for a duration of 3 months.62 Although dual antiplatelet therapy developed into the stan- dard of care after OPCAB, data confirming the merits of com- bined aspirin and clopidogrel after off-pump surgery have been fairly limited. Some benefits were noted in terms of improved and clinical outcomes64 in single-center obser- vational studies. In a small, randomized trial comparing the combination of clopidogrel 75 mg and aspirin 150 mg daily with aspirin 150 mg alone, Nielsen et al65 noted that patients who received dual antiplatelet therapy achieved greater plate- let inhibition as determined by thromboelastography studies 30 days after OPCAB. Most recently, Mannacio et al66 performed a single-center, prospective, randomized trial to evaluate the impact of clopidogrel on graft patency after off-pump surgery. Three hundred OPCAB patients without a history of diabetes mellitus were randomized to receive either aspirin 100 mg plus clopidogrel 75 mg daily or aspirin 100 mg daily for 1 year after surgery. 