Choosing Between On-Pump and Off-Pump Coronary Artery Bypass Grafting

On-pump (ONCAB) and off-pump coronary artery bypass grafting (OPCAB) remain established approaches to surgical myocardial revascularization, but contemporary evidence does not support a universal preference for either technique. The clinically relevant question is which patient and operative setting are most likely to benefit from each strategy. We performed a contemporary narrative evidence synthesis of landmark randomized trials, long-term follow-up studies, systematic reviews and meta-analyses, observational cohorts, graft-patency studies, and major coronary revascularization guidelines. MEDLINE/PubMed, Embase, the Cochrane Library, and Web of Science were searched for studies published from 2009 through 2025. Evidence was organized around perioperative neurologic, renal, bleeding, and respiratory outcomes; completeness of revascularization; graft patency; conversion to cardiopulmonary bypass; surgical experience; and long-term survival. No de novo meta-analysis was performed, and all pooled estimates reported in this review are explicitly attributed to previously published evidence syntheses. Randomized evidence indicates broadly similar long-term mortality between OPCAB and ONCAB, whereas OPCAB may reduce selected perioperative complications, particularly stroke, transfusion, acute kidney injury, and respiratory morbidity in appropriately selected patients. Conversely, complex coronary anatomy may favor ONCAB because a stable operative field can facilitate complete revascularization. Conversion from OPCAB to cardiopulmonary bypass is consistently associated with worse outcomes, underscoring the importance of surgeon and institutional experience. Graft-patency differences are most evident for saphenous vein grafts and technically challenging territories. Anaortic or no-touch OPCAB may be particularly valuable in patients with extensive ascending-aortic atherosclerosis. ONCAB and OPCAB should therefore be viewed as complementary strategies. Selection should integrate aortic pathology, ventricular function, renal and bleeding risk, coronary complexity, the probability of complete revascularization, and local OPCAB expertise. A patient-tailored framework can help translate heterogeneous comparative evidence into practical clinical decision-making.