title: Off-pump coronary artery surgery for reducing mortality and morbidity: meta-analysis of randomized and observational studies.
abstract: OBJECTIVE
  The purpose of this study was to assess the effects of off-pump coronary bypass surgery (OPCAB) on mortality and morbidity.
  
  
  BACKGROUND
  Despite its potential for reducing morbidity and mortality, OPCAB's role in clinical practice remains controversial.
  
  
  METHODS
  A meta-analysis of 37 randomized controlled trials (RCTs) (n = 3,449) and 22 risk-adjusted (logistic regression or propensity-score) observational studies (n = 293,617) was performed. Two reviewers performed literature searches (MEDLINE, EMBASE, PubMed, reference lists), quality assessment, and data extraction. Treatment effects were calculated as odds ratios (ORs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  In RCTs, OPCAB was associated with reduced atrial fibrillation (OR 0.59; 95% CI 0.46 to 0.77) and trends toward reduced 30-day mortality (OR 0.91 95% CI 0.45 to 1.83), stroke (OR 0.52; 95% CI 0.25 to 1.05), and myocardial infarction (OR 0.79; 95% CI 0.50 to 1.25). Observational studies showed OPCAB to be associated with reduced 30-day mortality (OR 0.72; 95% CI 0.66 to 0.78), stroke (OR 0.62; 95% CI 0.55 to 0.69), infarction (OR 0.66; 95% CI 0.50 to 0.88), and atrial fibrillation (OR 0.78; 95% CI 0.74 to 0.82). At one to two years, OPCAB was associated with trends toward reduced mortality, but also increased repeat revascularization (RCT: OR 1.75, 95% CI 0.78 to 3.94; Observational: OR 1.35, 95% CI 0.76 to 2.39).
  
  
  CONCLUSIONS
  Randomized controlled trials did not find, aside from atrial fibrillation, the statistically significant reductions in short-term mortality and morbidity demonstrated by observational studies. These discrepancies might be due to differing patient-selection and study methodology. Future studies must focus on improving research methodology, recruiting high-risk patients, and collecting long-term data.
authors.affiliation: Department of Anesthesia, Toronto General Hospital, Toronto, Ontario, Canada. duminda.wijeysundera@uhn.on.ca
authors.forename: Duminda N
authors.initials: DN
authors.lastname: Wijeysundera
authors.forename: W Scott
authors.initials: WS
authors.lastname: Beattie
authors.forename: George
authors.initials: G
authors.lastname: Djaiani
authors.forename: Vivek
authors.initials: V
authors.lastname: Rao
authors.forename: Michael A
authors.initials: MA
authors.lastname: Borger
authors.forename: Keyvan
authors.initials: K
authors.lastname: Karkouti
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Cusimano
mesh_terms: D058186:Acute Kidney Injury / Q000517:prevention & control; D001281:Atrial Fibrillation / Q000517:prevention & control; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects / Q000401:mortality; D003327:Coronary Disease / Q000601:surgery*; D006801:Humans; D009203:Myocardial Infarction / Q000517:prevention & control; D019370:Observation; D016032:Randomized Controlled Trials as Topic; D020379:Risk Adjustment; D018570:Risk Assessment; D020521:Stroke / Q000517:prevention & control; D016896:Treatment Outcome