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

Study Questions:

Does timing of aspirin discontinuation prior to coronary artery bypass grafting (CABG) affect outcomes?


At the Cleveland Clinic, 2,298 chronic aspirin (ASA) users discontinued ASA 6 or more days before CABG (early discontinuation), and 1,845 took ASA within 5 days of the surgery (late use). Propensity score analysis to better match groups based on 31 variables resulted in 1,519 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% vs. 1.8%, p = 0.80). Late use was associated with more intraoperative transfusions (23% vs. 20%, p = 0.03) and postoperative transfusions (30% vs. 26%, p = 0.009), but a similar number of reoperations for bleeding (3.4% vs. 2.4%, p = 0.10).


The authors concluded that among patients undergoing CABG, late discontinuation of ASA resulted in no difference in postoperative cardiovascular outcomes; however, there was an increased transfusion requirement.


Guidelines regarding discontinuation of ASA prior to CABG vary widely. While continuation of aspirin may increase bleeding risk, aspirin use may reduce perioperative thrombotic vascular complications. Although the current study was nonrandomized and retrospective, the authors used propensity analysis in attempts to compare two ‘matched’ groups that discontinued ASA within 5 or greater than 6 days prior to CABG. Considering variability in the response to ASA, these groups may not be that different; however, increased bleeding was noted in the group of patients with late ASA discontinuation without evidence of benefit. It would be interesting to compare a group that continues ASA up to the day of CABG, as benefits may outweigh risks in this setting. A randomized, controlled trial is needed to address this important issue.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention

Keywords: Blood Transfusion, Myocardial Infarction, Stroke, Reoperation, Hospital Mortality, Coronary Artery Bypass

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