The Role of Sex in Multiarterial Coronary Artery Bypass Grafting: A Landmark and Risk Factor analysis

Objective Bilateral internal thoracic artery (BITA) grafting is associated with superior long-term outcomes in coronary artery bypass grafting (CABG), yet sex-based disparities persist, with women facing greater early morbidity and mortality. Methods This retrospective, single-center cohort study included 2010 patients undergoing CABG with BITA grafts between 2005 and 2024, stratified by biological sex. The primary outcome was a composite of death and repeat coronary revascularization. Analyses included weighted survival curves, landmark analyses excluding early events, competing risk regression by sex, and random survival forests to characterize sex-specific risk profiles. Results Of 3872 patients undergoing total CABG and 2010 patients undergoing BITA-CABG, 268 (13.3%) were female. Women were older (68.0 vs 65.0 years, P < .001), had smaller graft diameters (left internal thoracic artery and right internal thoracic artery both P < .001), greater perioperative risk (European System for Cardiac Operative Risk Evaluation 1.40 vs 0.99, P < .001), and smoked less (26% vs 44%, P < .001). Postoperative mortality (23% vs 15%, P = .003) and reintervention (15% vs 11%, P = .049) rates were greater for women. After adjustment, the composite outcome disparity was minimized (log-rank P = .051); long-term survival and revascularization rates were similar in the 30-day landmark-analysis ( P = .139). In women, outcomes were most strongly influenced by New York Heart Association class, pulmonary hypertension, and graft flow; whereas in men, the main predictors were smoking, previous infarction, and peripheral artery disease. Conclusions Early outcome disparities after BITA-CABG are driven by anatomical and clinical factors in women, including smaller conduit and vessel size and greater perioperative risk, particularly in the immediate postoperative period. Long-term outcomes are similar between sexes once this phase is overcome. Distinct risk profiles underscore the need for individualized, sex-specific management in contemporary CABG care.