Some studies have indicated that women have less access to cardiac procedures or poorer outcomes after myocardial infarction than men. King and colleagues investigated sex differences in survival after catheterization, with separate analyses stratified by degree of risk, type of intervention, and time.
This study used data from a previous study on gender differences in access to care, the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease. Patients were followed for long-term outcomes after cardiac care using 18 clinical risk variables. The indication for catheterization was recorded, as were the extent of coronary artery disease and left ventricular ejection fraction, and occurrence of revascularization procedures. The primary outcome was all-cause mortality.
Of 37,401 patients, 30 percent were women. As a group, women were significantly older and had more comorbidities than men but fewer myocardial infarctions and previous cardiac interventions. They also had a higher left ventricular ejection fraction and lower-risk coronary artery anatomy. Women had a higher one-year mortality rate than men (5.6 percent versus 4.6 percent). The latter finding applied particularly in the early period after catheterization. Stratification analysis showed that women with high-risk coronary anatomy had a higher mortality rate than men. In addition, there was a marked increase in women’s mortality risk one day after coronary artery bypass graft (CABG; relative risk [RR], 3.49) and percutaneous coronary intervention (PCI; RR, 2.38); the risk eventually declined to a level equal to that in men.
Mortality and risk profiles in the “no revascularization” group were similar in women and men. Results also were similar after adjustment for time between catheterization and interventional procedure. Finally, the authors sought to determine whether the procedures themselves increased mortality risk or if death was associated with high-risk coronary anatomy. The women who were more likely to be triaged to revascularization (driven by high-risk anatomy), had a higher mortality risk.
This study found notable sex differences in outcomes in the time immediately following PCI and CABG, but the underlying mechanisms are unknown. It may be that the worse outcomes occurred because of the higher incidence of comorbidities in women undergoing catheterization.