Effect of Timing of Chronic Preoperative Aspirin Discontinuation on Morbidity and Mortality in Coronary Artery Bypass Surgery

BACKGROUND: Aspirin (ASA) has been shown to reduce postoperative coronary artery bypass grafting (CABG) mortality and ischemic events; however, the timing of chronic ASA discontinuation before surgery is controversial because of concern about postoperative bleeding. We evaluated the effect of the timing of ASA discontinuation before CABG on major adverse cardiovascular outcomes and postoperative bleeding using the Cleveland Clinic Cardiovascular Information Registry database. METHODS AND RESULTS: At the Cleveland Clinic between January 1, 2002, and January 31, 2008, 4143 patients undergoing CABG were taking preoperative chronic ASA. Of these, 2298 discontinued ASA 6 or more days before surgery (early discontinuation), and 1845 took ASA within 5 days of the surgery (late use). Because of substantial differences between these 2 groups, propensity score analysis, and matching based on 31 variables were used for fair comparison of outcomes. This resulted in 1519 well-matched pairs of patients (73%). There was no significant difference between those with early discontinuation and late ASA use with regard to the composite outcome of in-hospital mortality, myocardial infarction, and stroke (1.7% versus 1.8%, P=0.80). Late use was associated with more intraoperative transfusions (23% versus 20%, P=0.03) and postoperative transfusions (30% versus 26%, P=0.009) but a similar number of reoperations for bleeding (3.4% versus 2.4% P=0.10). CONCLUSIONS: Among patients undergoing isolated CABG, late discontinuation of ASA resulted in no difference in postoperative cardiovascular outcomes; however, there was an increased transfusion requirement. Thus, we recommend weighing the risks and benefits of late ASA use in these patients.