Abstract 18409: Long-Term Mortality Following On- and Off-Pump Coronary Artery Bypass Graft Surgery

Abstract

Background: There are limited data on the relative survival following on- and off-pump coronary artery bypass graft (CABG) surgery during follow-up periods longer than 5 years. Objectives: To examine the difference in 7-year mortality after on- and off-pump isolated CABG surgery. Methods: A total of 5,940 on-pump and 2,640 off-pump isolated CABG patients discharged between October 1 and December 31, 2000 were identified using the New York State's Cardiac Surgery Reporting System. The patients' vital statuses through the end of 2007 were determined by matching to the National Death Index. We fit a logistic regression model that used the baseline patient characteristics to predict the probability (propensity) of receiving off-pump procedure. Using a 1:1 ratio, we then matched on- and off-pump CABG patients based on the propensity of receiving off-pump procedure. We compared the Kaplan-Meier survival curves for on- and off-pump CABG using the matched data, and fit a Cox proportional hazards model to obtain the hazard ratio for death for off-pump in comparison to on-pump procedures. We also conducted subgroup analysis and tested the significances of interactions between treatment (on- or off-pump) and a number of baseline risk factors. Results: A total of 2,634 off-pump patients were matched to on-pump patients. During the follow-up until the end of 2007, 727 on-pump and 780 off-pump patients died. The respective 7-year survival rates for off- and on-pump were 71.3% and 73.1% (P=0.09), and the hazard ratio for death (off- vs. on-pump) was 1.11 (95% confidence interval: 1.00 to 1.24, P=0.06). In addition, there were no differences in 7-year mortality between off- and on-pump CABG surgery in the subgroups of patients defined by age, sex, the number of diseased coronary arteries, left main coronary disease, ejection fraction, history of myocardial infarction, and comorbidities such as cerebrovascular disease, peripheral vascular disease, congestive heart failure, and diabetes. Conclusions: There was no difference in long-term morality between on- and off-pump CABG surgery.