Sex differences after coronary artery bypass grafting with a second arterial conduit

Objectives — Double arterial conduit use during coronary artery bypass grafting is associated with improved clinical outcomes compared with single arterial conduits in the general population. However, the sex-specific outcomes of this strategy remain unknown and are needed to inform sex-specific revascularization guidelines.

Methods — We conducted a population-based, retrospective cohort study of all Ontarians who underwent primary isolated coronary artery bypass grafting with single arterial conduits or double arterial conduits between October 2008 and September 2017. The primary outcome was all-cause mortality. Secondary outcomes included major adverse cardiac and cerebrovascular events, defined as a composite of myocardial infarction, heart failure hospitalization, repeat revascularization, and stroke. We used inverse probability of treatment weighting to account for group imbalances.

Results — A total of 9135 women and 36,748 men underwent coronary artery bypass grafting. At 30 days, there was no between-group difference in mortality or major adverse cardiac and cerebrovascular events in men. However, among women, a double arterial conduit was associated with an increased rate of 30-day death (hazard ratio, 1.48; 95% confidence interval, 1.23-1.79) and major adverse cardiac and cerebrovascular events (hazard ratio, 1.32; 95% confidence interval, 1.14-1.51). The risk of medium-term mortality with double arterial conduits was less in men (hazard ratio, 0.88; 95% confidence interval, 0.84-0.92) and women (hazard ratio, 0.87; 95% confidence interval, 0.81-0.94), as was the medium-term risk of major adverse cardiac and cerebrovascular events (hazard ratio, 0.91; 95% confidence interval, 0.87-0.94) [men]; hazard ratio, 0.91; 95% confidence interval, 0.86-0.97) [women]). The incremental improvement in 9-year survival was 4.0% in women with a double arterial conduit and 0.9% in men.

Conclusions — Double arterial conduit is associated with better medium-term survival and cardiovascular outcomes in both sexes. Double arterial conduits are associated with increased perioperative risk in women, but the medium-term benefit is greater than in men.