Outcomes in off-pump vs. on-pump coronary artery bypass grafting stratified by pre-operative risk profile: an assessment using propensity score

Abstract: Aims To assess the benefit of off-pump coronary surgery stratified by the pre-operative risk profile. Methods and results Prospective and multicentric cohort study. All consecutive patients undergoing a first coronary bypass procedure between November 2001 and November 2003 were potentially eligible. Pre-operative EuroSCORE and in-hospital outcomes were prospectively collected using strictly standardized criteria. To ensure optimal adjustment, a propensity score was constructed using clinically relevant variables and incorporating individual centres. Of 1602 patients who underwent a first coronary bypass, EuroSCORE could be calculated in 1585: 787 were of moderate/high pre-operative risk profile (EuroSCORE > 3), of which 347 underwent off-pump procedures, and 798 were of low pre-operative risk profile (EuroSCORE <= 3), of which 349 underwent off-pump procedures. After risk adjusting for propensity score, off-pump patients had less major events (post-operative death, myocardial infarction, and need for reoperation). This benefit was higher in the low-risk stratum (OR ranged between 0.27 and 0.4; P=0.02-0.07) than in the high-risk stratum (OR between 0.4 and 0.7; P, not significant). Conclusion In real-life conditions, off-pump coronary surgery may be more effective than on-pump surgery. In contrast with previous reports, our results suggest that this benefit may be higher in patients with low pre-operative risk