title: Aspirin and coronary artery surgery: a systematic review and meta-analysis.
abstract: BACKGROUND
  Aspirin administration before cardiac surgery represents a balance between preventing perioperative thrombotic events and promoting surgical bleeding. Clear evidence to guide the preoperative use of aspirin in patients undergoing cardiac surgery is lacking.This systematic review and meta-analysis was performed to evaluate the efficacy and safety of preoperative aspirin, in patients undergoing coronary artery surgery.
  
  
  METHODS
  We conducted a systematic review and meta-analysis of randomized trials involving patients undergoing coronary artery surgery assigned to preoperative aspirin therapy or no aspirin/placebo. The MEDLINE and EMBASE databases and Cochrane Central Register of Controlled Trials were searched up to March 2014 without language restrictions. Two reviewers performed independent quality review and data extraction. Efficacy outcomes of myocardial infarction (MI) and mortality, and safety outcomes of blood loss, red cell transfusion, and surgical re-exploration were compared.
  
  
  RESULTS
  In 13 trials (n=2399), preoperative aspirin therapy reduced the risk of MI (OR, 0.56; 95% CI, 0.33-0.96; P=0.03), without a reduction in mortality (OR, 1.16; 95% CI, 0.42-3.22; P=0.77). Preoperative aspirin increased postoperative chest tube drainage (mean difference 168 ml; 95% CI, 39-297 ml; P=0.01), red cell transfusion (mean difference 141 ml; 95% CI, 55-226; P=0.001) and need for surgical re-exploration (OR, 1.85, 95% CI, 1.15-2.96; P=0.01). Studies were of low methodological quality, with significant heterogeneity identified.
  
  
  CONCLUSIONS
  In patients undergoing coronary artery surgery, preoperative aspirin reduces perioperative MI, but at a cost of increased bleeding, blood transfusion, and surgical re-exploration.
authors.affiliation: Department of Anaesthesia and Perioperative Medicine, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia s.hastings@alfred.org.au.
authors.forename: S
authors.initials: S
authors.lastname: Hastings
authors.affiliation: Department of Anaesthesia and Perioperative Medicine, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia Department of Anaesthesia and Perioperative Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Myles
authors.affiliation: Department of Anaesthesia and Perioperative Medicine, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia Department of Anaesthesia and Perioperative Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: D
authors.initials: D
authors.lastname: McIlroy
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology*; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data; D001803:Blood Transfusion / Q000706:statistics & numerical data; D006348:Cardiac Surgical Procedures; D003331:Coronary Vessels / Q000601:surgery*; D006801:Humans; D009203:Myocardial Infarction / Q000517:prevention & control; D019106:Postoperative Hemorrhage / Q000139:chemically induced; D011300:Preoperative Care / Q000379:methods*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin
keywords: aspirin; blood transfusion; coronary artery bypass; myocardial infarction