Professor, Surgery Population Health Research Institute Hamilton, Ontario, Canada
Background: The CABG Off or On Pump Revascularization Study (CORONARY) was a landmark randomized controlled trial comparing off-pump with on-pump coronary artery bypass grafting (CABG) in 4,752 patients. There were no significant differences between the off-pump and on-pump groups in the rate of the primary composite outcome at 30 days, 1 year and 5 years. Although both strategies were demonstrated to be safe and effective, their benefits and risks varied across geographic regions.
METHODS AND RESULTS: We conducted a post hoc analysis of 822 CORONARY trial patients randomized to receive off-pump or on-pump CABG at 10 Canadian centres. The primary outcome was a composite of cardiovascular death, stroke, myocardial infarction, or new renal failure requiring dialysis at 30 days, 1 year, and 5 years. The mean age of the cohort was 69 years, 83% were men, 40% had diabetes, and the mean follow-up was 5.0 ± 1.7 years. Overlap weighting was applied using covariates such as age, sex, previous myocardial infarction, stroke, renal failure, peripheral artery disease, smoking status, and diabetes. Baseline characteristics were similar between off-pump and on-pump groups after weighting. The risk of the primary outcome was reduced after off-pump compared with on-pump CABG at 30 days (weighted hazard ratio [HR], 0.59; 95% CI, 0.39-0.91), 1 year (weighted HR, 0.66; 95% CI, 0.44-0.99) and 5 years (weighted HR, 0.69; 95% CI, 0.49-0.95).
Conclusion: In this post hoc analysis of Canadian patients from the CORONARY trial, off-pump CABG was associated with a lower risk of major adverse events over 5 years when performed by Canadian surgeons.
