Off-pump techniques disproportionately benefit women and narrow the gender disparity in outcomes after coronary artery bypass surgery

BACKGROUND - Women experience greater morbidity and mortality than men after conventional coronary artery bypass grafting (CABG) on cardiopulmonary bypass (CPB). The objective of this study was to determine whether off-pump CABG (OPCAB) alters this gender-based disparity. METHODS AND RESULTS - Retrospective review of risk factors and clinical outcomes for 11 413 consecutive patients having isolated CABG between January 1, 1997, and May 31, 2005, at a US academic center. Interventions were OPCAB or CABG/CPB, performed at the discretion of 14 faculty surgeons. Main outcome measures included in-hospital death, stroke, myocardial infarction or combined major adverse cardiac events (MACE=death or stroke or myocardial infarction). Odds ratios of adverse events, adjusted for 31 risk factors, were compared between women and men who had OPCAB versus CABG/CPB. Covariates included Propensity Score, Society of Thoracic Surgeons' Predicted Risk, surgeon and body habitus. Female patients (n=3248) and those treated with OPCAB (n=4492) were older, had more comorbidities and higher predicted risk than male patients (n=8165) and those treated with conventional CABG/CPB (n=6921), respectively. Women treated with CABG/CPB had a risk-adjusted odds ratio of 1.60 for death (P=0.01), 1.71 for stroke (P=0.007), 2.26 for myocardial infarction (P=0.008) and 1.71 for MACE (P<0.001) compared with men who had CABG/CPB. In contrast, women treated with OPCAB had outcomes statistically similar to men who had either OPCAB or CABG/CPB. Among women, OPCAB was associated with a significant reduction in death (OR 0.39, P=0.001), stroke (OR 0.43, P=0.002) and MACE (OR 0.43, P<0.001). CONCLUSIONS - OPCAB is associated with fewer major adverse cardiac events and benefits women disproportionately, thereby narrowing the gender disparity in clinical outcomes after CABG.