title: Safety and efficacy outcomes of preoperative aspirin in patients undergoing coronary artery bypass grafting: a systematic review and meta-analysis.
abstract: BACKGROUND
  The administration of aspirin is traditionally discontinued prior to coronary artery bypass grafting (CABG), given a potential risk of excessive postoperative bleeding. Few studies have previously suggested the benefits of continuing aspirin until the time of surgery. The primary aim of this review is to evaluate the effects of preoperative aspirin therapy on several clinically important outcomes in patients undergoing CABG.
  
  
  METHODS
  A meta-analysis of eligible studies of patients undergoing CABG, reporting preoperative aspirin in comparison with no aspirin/placebo and our outcomes, was carried out. 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.
  
  
  RESULTS
  In 8 randomized controlled trials (RCTs; n = 1538), preoperative aspirin increased postoperative bleeding (difference in means = 132.30 mL; 95 % confidence interval [CI] 47.10-217.51; P = .002), PRBC transfusion requirements (difference in means = 0.67 units; 95% CI 0.10-1.24; P = .02), and reoperation for bleeding (odds ratio [OR] = 1.76; 95% CI 1.05-2.93; P = .03). In 19 observational studies (n = 19551), preoperative aspirin increased postoperative bleeding (difference in means = 132.74 mL; 95% CI 45.77-219.72; P = .003) and PRBC transfusion requirements (difference in means = 0.19 units; 95% CI 0.02-0.35; P = .02) but not reoperation for bleeding (OR = 1.13; 95% CI 0.91-1.42; P = .27). Subgroup analyses for RCTs demonstrated that aspirin given at doses ≤ 100 mg/d might not increase the postoperative bleeding, and the dose of 325 mg/d might not be a cutoff value that has clinical and statistical significance. No statistically significant differences in the rate of perioperative MI, CVAs, or mortality were seen between the 2 groups.
  
  
  CONCLUSIONS
  Preoperative aspirin therapy is associated with increased postoperative bleeding, PRBC transfusion requirements, and reoperation for bleeding in patients undergoing CABG. Doses lower than 100 mg/d may minimize the risk of bleeding. Additional RCTs are needed to assess the effects of preoperative aspirin on the safety and efficacy outcomes in patients undergoing CABG.
authors.affiliation: 1Shandong University School of Medicine, Jinan, Shandong, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Ma
authors.forename: Chi
authors.initials: C
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Yun
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xia
authors.initials: X
authors.lastname: Zheng
mesh_terms: D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001026:Coronary Artery Bypass / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D019106:Postoperative Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D011292:Premedication; D016032:Randomized Controlled Trials as Topic; D012086:Reoperation / Q000706:statistics & numerical data; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin
keywords: aspirin; coronary artery bypass graft; efficacy; safety