Operative mortality after conventional versus coronary revascularization without cardiopulmonary bypass.

OBJECTIVE: Off-pump coronary artery bypass (CABG) is a safe revascularization option with comparable or superior results to the conventional on-pump CABG. However, comparative analysis of the type of surgical approach on the mortality rate is largely unknown. This study sought to investigate whether CABG without cardiopulmonary bypass (off-pump CABG) is associated with lower operative mortality than the conventional on-cardiopulmonary bypass (on-pump) approach.

METHODS: From October 1998 to June 2001, off-pump CABG was performed on 2477 patients and on-pump CABG was performed on 3077 patients. The patients undergoing off-pump CABG were randomly matched to on-pump patients via propensity score. Seventy-four percent of the off-pump CABG patients were matched with on-pump patients via propensity scores. A logistic regression model was used to test the difference in the postoperative mortality rate between off-pump CABG and on-pump CABG, controlling the correlation between matched sets. A multiple logistic regression model predicting the risk of mortality adjusted by risk factors of mortality and operation type was computed.

RESULTS: Results from the general estimating equation showed that patients who had on-pump CABG were 1.6 (95% confidence intervals (CI)=1.2-2.0, P<0.01) times more likely to die during the first 30 days after surgery than patients who had off-pump CABG. Independent predictors of 30-day mortality identified from the multiple logistic model included on-pump CABG (versus off-pump CABG), advanced age, female gender, carotid artery disease, chronic renal failure, depressed ejection fraction, reoperative CABG, preoperative intraaortic balloon counterpulsation, and recent myocardial infarction.

CONCLUSION: Excellent clinical results and a lower operative mortality rate can be achieved with the off-pump CABG technique compared with the conventional on-pump approach.