Comparing Long-term Survival Between Patients Undergoing Off-pump and On-pump Coronary Artery Bypass Graft Operations

Background: As the population of the United States and Western Europe ages, the number of patients undergoing isolated coronary artery bypass grafting (CABG) for revascularization can be expected to increase. This study investigated long-term survival in patients undergoing off-pump vs on-pump CABG.

Methods: Survival was assessed in 8081 consecutive patients who underwent isolated CABG (732 received off-pump) between January 1, 1997, and December 31, 2008. A propensity-adjusted model controlling for preoperative risk factors identified by the Society of Thoracic Surgeons and other preoperative clinical and nonclinical details was used to assess adjusted long-term mortality differences between off-pump and on-pump CABG.

Results: Ten-year unadjusted survival was 54.7% (95% confidence interval, 47.2% to 61.6%) in off-pump CABG patients and 62.3% (95% confidence interval 60.9% to 63.8%) in on-pump CABG patients. The log-rank test (p=0.012) indicated a significantly higher risk of death in off-pump CABG patients. After adjustment, the risk of death remained significantly higher in the off-pump CABG patients (hazard ratio, 1.18; 95% confidence interval, 1.02 to 1.38). The adjusted association regarding off-pump learning curve and survival was assessed separately and was not statistically significant (p=0.774), further validating our findings regarding off-pump CABG.

Conclusions: After controlling for preoperative severity of disease and other possible confounders, the risk of long-term mortality in patients undergoing off-pump CABG is significantly higher than in those undergoing on-pump CABG. For multivessel coronary disease, on-pump CABG might be preferable to off-pump CABG given that it may achieve a more complete and durable revascularization.