- BACKGROUND: The authors sought to examine in-hospital and one-year outcomes of off-pump coronary artery bypass grafting (CABG) and to determine the subgroups of patients most likely to benefit from the off-pump procedure in a regular surgical practice. METHODS: From March 2001 to December 2002, 1657 consecutive patients were treated with off-pump CABG and 1693 consecutive patients were treated with on-pump CABG. Propensity score modelling was performed to control for treatment and selection bias. A propensity-matched analysis was performed to identify factors associated with survival benefit from the off-pump procedure. RESULTS: The mortality was similar postoperatively and at one year after surgery. The rate of stroke was decreased in the off-pump group postoperatively (OR=0.49, 95% CI 0.23 to 1.06) and significantly at one year after surgery (OR=0.49, 95% CI 0.27 to 0.90). A significant reduction in acute renal dialysis and a significant increase in myocardial infarction rates were seen in off-pump patients during the initial hospitalization but these differences disappeared during the follow-up period. The number of grafts completed was significantly lower in off-pump CABG than in on-pump CABG (2.62+/-1.00 versus 3.36+/-0.92, respectively; P<0.001). Hospital length of stay and the percentage of patients who required mechanical ventilation were significantly lower in the off-pump group than in the on-pump group. At one year after surgery, the adjusted rate of coronary angiogram and revascularization was similar between the two groups, and the adjusted rate of self-reported angina and memory status was significantly better in the off-pump CABG group. Almost all subgroups of patients had a neutral effect or a survival benefit with the off-pump technique. CONCLUSIONS: The results from a Canada-wide multicentre registry showed the safety and effectiveness of off-pump CABG in most subgroups of patients in a regular surgical practice.