Clinical outcomes of nonelective coronary revascularization with and without cardiopulmonary bypass

Background: Patients who undergo emergent coronary artery bypass grafting pose a greater challenge in terms of intraoperative and postoperative mortality and morbidity compared to elective coronary artery bypass. Coronary artery bypass without cardiopulmonary bypass (off-pump coronary artery bypass) might benefit these high-risk patients by eliminating the cardiopulmonary bypass and therefore decreasing the systemic inflammatory response associated with it. The aim of this study was to compare the early clinical outcome after nonelective off-pump coronary artery bypass with a matched set of patients undergoing coronary artery bypass with cardiopulmonary bypass (on pump). Methods: Between January 2000 and October 2003, 2273 patients underwent nonelective (urgent or emergent) off-pump coronary artery bypass and were compared with a contemporaneous control group of 3487 patients undergoing on-pump coronary artery bypass. Logistic regression analysis was used to compare operative mortality, postoperative stroke, length of stay, postoperative placement of intra-aortic balloon pump, postoperative renal failure, and hemorrhage-related re-exploration between the groups, controlling for preoperative risk factors. The patients undergoing off-pump coronary artery bypass were matched to patients undergoing on-pump bypass by propensity scores. Results: Patients undergoing off-pump coronary artery bypass had comparable operative mortality (odds ratio, 0.8; 95% confidence interval, 0.57-1.15; P =.24) and stroke rate (odds ratio, 0.6; 95% confidence interval, 0.33-1.08; P =.09) with the patients undergoing on-pump coronary artery bypass after controlling for preoperative risk factors through matching. Off-pump coronary artery bypass was associated with an abbreviated length of stay (odds ratio, 0.5; 95% confidence interval, 0.47-0.64; P < .01), lower rate of postoperative renal failure (odds ratio, 0.5; 95% confidence interval, 0.37-0.72; P < .01), intra-aortic balloon pump placement (odds ratio, 0.5; 95% confidence interval, 0.3-0.71; P < .01), and hemorrhage-related re-exploration rate (odds ratio, 0.70; 95% confidence interval, 0.5-1.0; P =.5) compared with on-pump coronary artery bypass after matching by propensity scores. Conclusions: Nonelective coronary revascularization without cardiopulmonary bypass is associated with comparable operative mortality and stroke and abbreviated length of stay. Off-pump coronary artery bypass might also decrease the need for intra-aortic balloon pump placement and lower the rate of postoperative renal failure and hemorrhage-related re-exploration compared with that of conventional on-pump coronary artery bypass in this subset of patients.