Document Type



Medicine and Health Sciences




The survival difference between off-pump and on-pump coronary artery bypass graft (CABG) surgery for follow-up longer than 5 years is not well understood. The objective of this study is to examine the difference in 7-year mortality after these two procedures.

Methods and Results

New York State’s Cardiac Surgery Reporting System was used to identify the 2,640 off-pump and 5,940 on-pump isolated CABG patients discharged from July through December, 2000. The National Death Index was used to ascertain patients’ vital statuses through 2007. A logistic regression model was fit to predict the probability of receiving an off-pump procedure using baseline patient characteristics. Off-pump and on-pump patients were matched with a 1:1 ratio based on the probability of receiving an off-pump procedure. Kaplan-Meier survival curves for the 2 procedures were compared using the propensity-matched data, and the hazard ratio for death for off-pump in comparison to on-pump procedures was obtained. In subgroup analyses, the significance of interactions between type of surgery and baseline risk factors was tested. In this study, 2,631 pairs of off-pump and on-pump patients were propensity matched. The 7-year Kaplan-Meier survival rates were 71.2% and 73.4% (P=0.07) for off-pump and on-pump surgery, respectively. The hazard ratio for death (off-pump vs. on-pump) was 1.10 (95% confidence interval: 0.99-1.21, P=0.07). No statistical significance was detected for the interaction terms between type of surgery and a number of different baseline risk factors.


The difference in long-term morality between on-pump and off-pump CABG surgery is not statistically significant.


Circ Cardiovasc Qual Outcomes. Author manuscript; available in PMC 2013 January 10. Published in final edited form as: Circ Cardiovasc Qual Outcomes. 2012 January 1; 5(1): 76–84. Published online 2012 January 10. doi: 10.1161/CIRCOUTCOMES.111.963124 PMCID: PMC3277259 NIHMSID: NIHMS349285