Sex differences following percutaneous coronary intervention or coronary artery bypass surgery for acute myocardial infarction

Background: Women have been underrepresented in the literature; the effects of female sex on outcomes in patients with acute myocardial infarction (AMI) remain unclear. Objectives: This study compares the real-world outcomes of women and men with AMI who have undergone revascularization via percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). Methods: This is a retrospective cohort study utilizing data from the Taiwan National Health Insurance database. We identified patients who were admitted for AMI and who underwent coronary revascularization during the index admission period between January 1, 2001, and December 31, 2013. Patients were then categorized based on the treatment received into PCI and CABG groups. In-hospital and long-term outcomes were compared between women and men in each group. Interaction tests were then performed to determine whether the differences between sexes were modified by the mode of revascularization. Analyses were repeated after propensity score matching between women and men in each group to minimize possible confounders. We also conducted subgroup analyses, stratifying by the presence of diabetes mellitus, congestive heart failure, and chronic kidney disease. Results: We enrolled 67,534 patients who met the inclusion criteria in the analysis; 60,207 patients had undergone PCI (13,514 female and 46,693 male), while 7327 patients had received CABG (1762 female and 5565 male). Prior to matching, enrolled female patients were older on average, with more comorbidities. In-hospital and long-term outcomes were worse in women, particularly in the PCI group. After matching, the incidence of hospitalization for heart failure (HHF) was higher in women (10.4% vs 8.0%, OR 1.32, 95% CI 1.22–1.43), with fewer repeat revascularizations (28.1% vs 32.4%, OR 0.84, 95% CI 0.81–0.88). Both observations were more pronounced in the PCI group (HHF: P for interaction = 0.0496; repeat revascularization: P for interaction = 0.021). Conclusions: Women presenting with AMI exhibited worse in-hospital and long-term outcomes than men, especially among women who received PCI as the initial mode of revascularization. Women who underwent PCI were more likely to be admitted for heart failure during follow-up. Possible socioeconomic inequalities or a distinct pathobiology of cardiac ischemia between sexes may underlie these results; thus, further investigation is needed.