Adverse events in coronary artery bypass graft (CABG) trials: a systematic review and analysis

Objectives: To quantify the incidence of major adverse events (AEs) occurring in hospital or within 30 days after surgery in patients undergoing coronary artery bypass graft (CABG) surgery and to identify risk factors for these AEs. Methods: Systematic review and analysis of studies published in English since 1990. Studies of isolated standard CABG reporting postoperative incidence of myocardial infarction (MI), stroke, gastrointestinal bleeding, renal failure, or death in hospital or within 30 days were eligible for inclusion. Incidence of these events was calculated overall and for selected patient groups defined by all elective CABG versus mixed (some non-elective); mean ejection fraction less than or equal to50% versus >50%; mean age less than or equal to60 versus >60 years; primary CABG versus some reoperations; randomised controlled trials versus cohort studies; and single centre versus multicentre studies. Odds ratios of selected AEs were computed according to group risk factors. Results: 176 studies (205717 patients) met all inclusion criteria. The average incidence of major AEs occurring in-hospital was death (1.7%); non-fatal MI (2.4%); non-fatal stroke (1.3%); gastrointestinal bleeding (1.5%); and renal failure (0.8%). Thirty day mortality was 2.1%. Meta-analyses show that age >70, female sex, low ejection fraction, history of stroke, MI, or heart surgery, and presence of diabetes or hypertension are all associated with increased 30 day mortality after CABG. Conclusion: The incidence of major AEs in patients after CABG varies widely across studies and patient populations, and this heterogeneity must be controlled when using the literature to benchmark safety.