Operative mortality after conventional versus coronary revascularization without cardiopulmonary bypass

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.

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 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.

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.