Off-pump versus on-pump coronary bypass in high-risk subgroups

Background. Cardiopulmonary bypass (CPB) has pathophysiologic sequelae that may be more severe in high-risk subsets. We wanted to determine whether off-pump coronary bypass (OPCAB) could optimize outcomes. Methods. Our database of 242 OPCAB patients undergoing complete revascularization was compared to a base of 483 CABG patients undergoing CPB. Results were compared for the overall series and in the following high-risk subsets: 80 years of age or older, ventricular dysfunction (ejection fraction (EF) ≤ 0.25), prior neurologic event or renal failure, chronic obstructive pulmonary disease (COPD), and reoperation. Results. In the overall series, OPCAB significantly reduced the incidence of intraoperative transfusion requirements and showed a trend toward reduced morbidity in terms of postoperative neurologic and renal complications, prolonged ventilator requirement greater than 3 days, and bleeding requiring reexploration. Mortality was less in the OPCAB group (0.4% versus 2.7%, p = not significant). Similar results were achieved in the following high-risk subgroups (n = off-pump/on-pump): 80 years of age or older (n = 28/58), EF less than or equal to 25% (n = 13/26), preoperative neurologic event (n = 25/36), preoperative renal failure (n = 27/46), COPD (n = 33/43), and reoperation (n = 28/76). OPCAB decreased the incidence of prolonged ventilation in COPD patients (0/33 [0%] versus 4/43 [9.3%] p = not significant) and decreased the incidence of renal complications in the elderly (1/28 [3.6%] versus 9/58 [15.5%] p = not significant). Off-pump coronary bypass reduced but did not eliminate neurologic events in the elderly (2/28 [7.1%] versus 8/58 [13.8%] p = not significant). Conclusion: Off-pump coronary bypass significantly reduced the incidence of transfusion requirement compared to the CPB counterparts and had a consistent trend in reducing morbidity and mortality overall and in all high-risk subsets. Neurologic events are not eliminated in OPCAB.