Does off-pump coronary artery bypass graft surgery have a beneficial effect on long-term mortality and morbidity compared with on-pump coronary artery bypass graft surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether off-pump coronary artery bypass grafting (CABG) surgery offered superior long-term outcomes compared with on-pump CABG surgery. Best evidence papers were considered to be those that had a follow-up period of ≥5 years, had >50 patients in either cohort, did not utilize concomitant interventions nor comprised low-risk, high-risk or sub-population groups. Where potential duplicate data sets from the same institution were likely, the more credible and recently published study was included. Two hundred and fifty-six papers were found as a result of the reported search, of which 16 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The 16 studies comprised 4 prospective randomized controlled trials (RCTs), with the remaining 12 retrospective, of which 8 were propensity-score matched. All 4 RCTs contained fewer than 450 participants. Two studies concluded with a survival advantage towards on-pump CABG: one, a large registry-based study, the Veterans Affairs, with >25 000 patients, and another, a propensity-matched retrospective study involving almost 8000 patients. The remaining 14 studies all provided evidence to suggest comparable long-term survival. In addition, all other long-term outcomes mentioned within these studies including angina recurrence, myocardial infarction heart failure, need for revascularization, stroke, graft patency, cognitive and quality of life showed similar results between the two groups. We conclude that off-pump CABG surgery may have similar or slightly reduced long-term survival compared with on-pump CABG surgery. Other long-term indicators such as cardiovascular or cerebrovascular events or neuro-psychological outcomes were similar between the two groups. Despite these conclusions, the evidence is limited by substantial variability in patient selection and study methods. The CORONARY (coronary artery bypass surgery off- or on-pump revascularization study) trial recently presented results, which showed no significant differences in composite outcomes at 1 year; it will be interesting to observe whether these comparable outcomes are maintained for a much longer time frame.