Objective To evaluate off-pump versus on-pump coronary artery bypass grafting (CABG) in patients with three-vessel disease and a high-risk operative profile.

Design A randomised clinical trial.

Setting Rigshospitalet, University Hospital, Copenhagen, Denmark.

Participants 341 patients with three-vessel disease and a EuroSCORE of 5 or greater. Main exclusion criteria were previous heart surgery, poor left ventricular function (ejection fraction <30%), or unstable preoperative condition.

Intervention CABG performed with versus without cardiopulmonary bypass.

Main outcome measure The primary outcome was a composite of major adverse cardiac and cerebrovascular events (MACCE) including all-cause mortality, acute myocardial infarction, cardiac arrest with successful resuscitation, low cardiac output syndrome/cardiogenic shock, stroke and coronary reintervention.

Results MACCE occurred in 69 (40%) patients allocated to off-pump versus 54 (33%) patients allocated to on-pump CABG during the median 3.7 years of follow-up (HR 1.22; 95% CI 0.86 to 1.75; p=0.26). All-cause mortality was significantly increased in the off-pump group (24% vs 15%; HR 1.66, 95% CI 1.02 to 2.73; p=0.04), but cardiac-related death was not significantly different (10% vs 7%; HR 1.30, 95% CI 0.64 to 2.66; p=0.47). An insignificant trend towards a reduction in myocardial infarction after off-pump CABG was observed (7% vs 14%; HR 0.53, 95% CI: 0.27 to 1.04; p=0.06).

Conclusions No significant difference in the primary outcome of MACCE was found between off-pump and on-pump CABG. However, mortality seemed higher after off-pump CABG.

Trial registration http://clinicaltrials.gov/ number, NCT00120991.