However, vein graft patency was significantly improved in the combined treatment group compared with the isolated aspirin treatment group (85.7% versus 91.6%, aspirin versus aspirin and clopidogrel; P=0.04). Although dual antiplatelet therapy improved vein graft patency in this study, providing low-dose aspirin (100 mg) to the control subjects may have resulted in undertreat- ment of these patients, biasing the results in favor of those who received combination therapy. Using a higher dose of aspirin, the Clopidogrel After Surgery For Coronary Artery Disease (CASCADE) trial was a randomized, double-blind, placebo-controlled trial of 113 patients comparing aspirin 162 mg daily with aspirin 162 mg plus clopidogrel 75 mg daily. The majority of patients (96%) underwent on-pump CABG in this study. Patients underwent conventional coronary angiography 1 year after surgery, and each patient underwent intravascular ultrasound assessment of Kulik et al Secondary Prevention After CABG 931 1 randomly selected vein graft to evaluate the extent of graft intimal hyperplasia. The combination of aspirin plus clopido- grel did not significantly reduce the development of vein graft intimal hyperplasia as indicated by intravascular ultrasound 1 year after CABG compared with aspirin. Overall graft patency (95.2% versus 95.5%, aspirin and clopidogrel versus aspirin; P=0.90) and vein graft patency (94.3% versus 93.2%, aspi- rin and clopidogrel versus aspirin; P=0.69) were not different between the groups at 1 year.42 Most recently, investigators from the Randomized On/ Off Bypass (ROOBY) on-pump and off-pump CABG trial performed an observational study to evaluate the impact of clopidogrel use on graft patency 1 year after surgery. The authors noted similar graft patency between patients who received clopidogrel after surgery (86.5%) and those who To summarize the published data, 3 meta-analyses have assessed the potential benefits of dual antiplatelet therapy after CABG, presenting mixed results. 