Safety and Efficacy Outcomes of Preoperative Aspirin in Patients Undergoing Coronary Artery Bypass Grafting: A Systematic Review and Meta-Analysis

Study Questions:

What is the benefit of preoperative aspirin on the outcome of patients undergoing coronary artery bypass grafting (CABG)?


The authors performed a meta-analysis of randomized controlled trials as well as observational studies investigating aspirin among patients undergoing CABG. The safety outcomes included postoperative bleeding, packed red blood cell (PRBC) transfusion requirements, and reoperation for bleeding. The efficacy outcomes included perioperative myocardial infarction (MI), cerebrovascular accidents (CVAs), and mortality.


In eight randomized controlled trials (RCTs; n = 1,538), preoperative aspirin increased postoperative bleeding (difference in means 132 ml; 95% confidence interval [CI], 47-217; p = 0.002), PRBC transfusion requirement units (difference in means 0.67 units; 95% CI, 0.10-1.24; p = 0.02), and reoperation for bleeding (odds ratio, 1.76; 95% CI, 1.05-2.93; p = 0 .03). In 19 observational studies (n = 19,551), preoperative aspirin increased postoperative bleeding and PRBC transfusion requirements, but not reoperation for bleeding. Subgroup analyses for RCTs demonstrated that aspirin given at doses of ≤100 mg/d might not increase the postoperative bleeding. No statistically significant differences in the rate of perioperative MI, CVAs, or mortality were seen between the two groups.


The authors concluded that use of aspirin prior to CABG increases the risk of bleeding complications without any demonstrated reduction in ischemic events.


This meta-analysis corroborates the findings of prior work (Sun JC, et al., Eur Heart J 2008;29:1057-71), which has demonstrated an increase in bleeding complications without a reduction in ischemic complications in patients treated with aspirin prior to undergoing CABG. Given the conflicting results from prior observational studies and small randomized controlled trials, a large adequately powered randomized controlled trial is warranted in this population to assess the appropriate antiplatelet regimen for patients undergoing CABG.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention

Keywords: Postoperative Hemorrhage, Risk, Myocardial Infarction, Stroke, Safety, Platelet Aggregation Inhibitors, Cardiovascular Diseases, Coronary Artery Bypass, Hemorrhage

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