Aspirin and clopidogrel use in the early postoperative period following on-pump and off-pump coronary artery bypass grafting

Objective Preoperative use of clopidogrel increases the risk of bleeding, but its postoperative use has not been studied. We studied early postoperative clopidogrel use in on-pump and off-pump coronary artery bypass grafting. Methods Data were obtained from the University HealthSystem Consortium database. We conducted a retrospective analysis of data of 15,067 adults who had coronary artery bypass grafting between 2003 and 2006 and received perioperative aspirin alone or in combination with clopidogrel, with the latter administered within 2 days after coronary artery bypass grafting. Logistic regression was used to analyze in-hospital mortality, 30-day readmission, ischemic or thrombotic events, and bleeding events, with propensity score adjustment for clopidogrel treatment. Results Combined aspirin and clopidogrel were used in 3268 patients (22%). Compared with aspirin alone, aspirin plus clopidogrel was associated with reductions of in-hospital mortality (0.95% vs 1.78%; adjusted odds ratio: 0.50; 95% confidence interval: 0.25, 0.99) and bleeding events (4.19% vs 5.17%; adjusted odds ratio: 0.70; 95% confidence interval: 0.51, 0.97). Ischemic or thrombotic events were not significantly different (1.29% vs 1.53%; adjusted odds ratio, 0.99; 95% confidence interval: 0.59, 1.64). The relative effect of combined treatment did not differ between on-pump and off-pump coronary artery bypass grafting. Conclusions Early postoperative clopidogrel combined with aspirin may be safe and beneficial compared with perioperative aspirin treatment alone, in both on-pump and off-pump coronary artery bypass grafting. However, a possibility of selection bias calls for randomized controlled trials to confirm our findings.