Sex-specific differences in mortality after first time, isolated coronary artery bypass graft surgery: a systematic review and meta-analysis of randomized controlled trials

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Evidence quantifying sex-specific differences in cardiac surgical outcomes is scant. PURPOSE The purpose of this review was to determine whether contemporary evidence indicates Coronary Artery Bypass Graft Surgery (CABGS) is differentially efficacious than alternative procedures by sex on mortality outcomes. METHODS EMBASE, CINAHL, Medline and Cochrane Library databases were searched (January 2010-April 2020). English language, randomized controlled trials, comparing isolated CABGS to an alternative revascularization strategy in adults, with analyses comparing sex-specific differences in mortality were included. Analyses of incidence data was performed using Mantel-Haenszel fixed-effects modelling, Cochrane RoB2 tool and CONSORT checklist. PROSPERO Registration ID: CRD42020181673. RESULTS The search yielded 4459 citations, with 29 articles for full-text review revealing 9 eligible studies with variability in time to follow-up. In contrast to men, mortality risk for women was lower in pooled analyses (RR 0.95, 95% CI 0.85-1.05, p = 0.33) but higher in sensitivity analyses excluding ‘high-risk’ patients (RR 1.18, 95% CI 0.99-1.40, p = 0.07). At 30-days and 10 years, women had an 18% (RR 0.82, 95% CI 0.66-1.02, p = 0.08) and 19% (RR 0.81, 95% CI 0.69-0.95, p = 0.01) mortality risk reduction. At 1-2 years women had a 7% (RR 1.07, 95% CI 0.69-1.64, p = 0.77), and at 2-5 years a 25% increase in risk of mortality compared to men (RR 1.25, 95% CI 1.03-1.53, p = 0.03). Women were increasingly under represented (23.2%) over time, comprising 29% (30-days) to 16% (10 years) of the pooled population. CONCLUSION Trials with sex-specific stratification are required to ensure appropriate treatment options for coronary revascularization.