Sex Differences in Patients Presenting With ST-Segment Elevation Myocardial Infarction and Nonobstructive Coronary Arteries

Background

Sex differences in ST-segment elevation myocardial infarction (STEMI) due to obstructive coronary artery disease (CAD) are well-established, but limited research exists on sex differences in STEMI patients with nonobstructive coronary arteries (MINOCA) and MINOCA mimickers.

Methods

We analyzed 8560 consecutive STEMI patients, enrolled in the Midwest STEMI Consortium from 2003 to 2020. Patients with non-obstructive CAD were classified into MINOCA (defined as < 50% coronary artery stenosis and confirmed or suspected coronary artery plaque disruption, epicardial coronary spasm, or coronary embolism/thrombosis) and MINOCA mimickers (takotsubo cardiomyopathy, myocarditis, or non-ischemic cardiomyopathy). The primary outcome was 5-year all-cause mortality.

Results

Of the 8560 patients, 409 (4.8%) had non-obstructive CAD, including 120 (1.4%) MINOCA and 289 (3.4%) MINOCA mimickers. Females were more likely to have MINOCA and MINOCA mimickers (49.2% and 56.4%, respectively). There were no significant sex differences in in-hospital or 5-year mortality in MINOCA, but females with MINOCA mimickers had higher unadjusted 5-year mortality (HR 2.90, 95% CI 1.53−5.53). After adjusting for age and comorbidities, the long-term mortality risk was similar between sexes (adjusted HR 1.16, 95% CI: 0.61−2.24). Females with obstructive CAD had higher 5-year mortality in unadjusted models (HR 1.66, 95% CI 1.48, 1.86), but the difference was not significant after adjustment (adjusted HR 1.1, 95% CI: 0.98−1.24).

Conclusions

Our findings highlight important sex-based differences in the prevalence, treatment, and long-term outcomes of STEMI patients with MINOCA, MINOCA mimickers, and obstructive CAD. Despite clinical disparities, mortality risks were similar across sexes after adjusting for comorbidities.