Off-pump Versus On-pump Coronary Artery Bypass Grafting: a Systematic Review and Meta-analysis of Propensity Score Analyses

Objective: Despite numerous randomized and nonrandomized trials on off- and on-pump coronary artery bypass grafting, it remains open which method is superior. Patient selection and small sample sizes limit the evidence from randomized trials; lack of randomization limits the evidence from nonrandomized trials. Propensity score analyses are expected to improve on at least some of these problems. We aimed to systematically review all propensity score analyses comparing off- and on-pump coronary artery bypass grafting.

Methods: Propensity score analyses comparing off- and on-pump surgery were identified from 8 bibliographic databases, citation tracking, and a free web search. Two independent reviewers abstracted data on 11 binary short-term outcomes.

Results: A total of 35 of 58 initially retrieved propensity score analyses were included, accounting for a total of 123,137 patients. The estimated overall odds ratio was less than 1 for all outcomes, favoring off-pump surgery. This benefit was statistically significant for mortality (odds ratio, 0.69; 95% confidence interval, 0.60-0.75), stroke, renal failure, red blood cell transfusion (P < .0001), wound infection (P < .001), prolonged ventilation (P < .01), inotropic support (P = .02), and intraaortic balloon pump support (P = .05). The odds ratios for myocardial infarction, atrial fibrillation, and reoperation for bleeding were not significant.

Conclusions: Our systematic review and meta-analysis of propensity score analyses finds off-pump surgery superior to on-pump surgery in all of the assessed short-term outcomes. This advantage was statistically significant and clinically relevant for most outcomes, especially for mortality, the most valid criterion. These results agree with previous systematic reviews of randomized and nonrandomized trials.