Patient selection and current practice strategy for off-pump coronary artery bypass surgery

Objective - Previous studies comparing off-pump coronary artery bypass surgery (OPCABG) to conventional techniques utilizing cardiopulmonary bypass (CABG-CPB) have failed to provide patient selection guidelines. We sought to determine guidelines, attempting to rectify the limitations of previous studies. Methods and Results - A retrospective analysis of prospectively collected data from the Society of Thoracic Surgeons National Database, from January 1999 through December 2000, identified 204 602 multivessel coronary artery bypass (CABG) patients. Unadjusted and risk-adjusted odds ratios (OR) were calculated to compare OPCABG and CABG-CPB morbidity and mortality. A propensity model was developed to identify factors associated with selection for OPCABG. All off-pump patients were pair-matched with on-pump patients based on their propensity to receive an off-pump procedure. Off-pump patients, 8.8% of the total, had significantly different patient characteristics than the on-pump group. Characteristics associated with OPCABG selection included fewer diseased vessels, absence of left main disease, fewer bypass grafts, no previous CABG, older age, chronic lung disease, and renal failure. Unadjusted and risk-adjusted odds ratios indicate a significant off-pump survival benefit and decreased morbidity including stroke and renal failure in the overall group. Propensity matching also showed a significant OPCABG survival benefit [OR (95% CI) 0.83 (0.72, 0.96)]. Subgroup analysis of propensity-matched groups identified off-pump survival benefits in patients with previous CABG (OR=0.53), diabetics (OR=0.66), LVEF between 30% to 50% (OR=0.75), females (OR=0.79), and age 66 to 75 years (OR=0.80). Conclusion - OPCABG imparts some survival benefit to most patient subgroups. Higher risk patients including those undergoing reoperative CABG, diabetics, and the elderly may gain the most benefit.