Sex-related differences in suspected MINOCA: a multicentre national registry analysis

Abstract Background Myocardial infarction with nonobstructive coronary arteries (MINOCA) is defined by clinical symptoms compatible with acute myocardial infarction (AMI) but without significant stenosis in a major epicardial artery. Sex differences in MINOCA are not fully understood. Purpose To establish sex-differences in Portuguese patients with a working diagnosis of MINOCA. Material and methods Retrospective multicentre analysis of MINOCA patients included in the Portuguese Registry on Acute Coronary Syndromes between 2010 and 2022. Two cohorts were defined according to sex. Baseline characteristics/findings, treatment and a composite of in-hospital major adverse cardiac events (MACE - death, stroke or AMI) were compared. Multivariate analysis assessed predictors of in-hospital MACE. Results From a total of 33686 patients included in the registry, 3668 patients had clinically suspected MINOCA (15% of AMI). The mean age was 66 ± 13 years, with 35% being female. Female patients were significantly older (p< 0.001) and had a higher prevalence of high blood pressure (p<0.001), previous angina (p<0.001), ischemic stroke (p=0.004), valvular heart disease (p < 0.001), and family history of coronary artery disease (p=0.009). Regarding presentation, women exhibited more atypical symptoms, but the severity of presentation was similar between sexes. While ST-segment elevation myocardial infarction was a more frequent admission diagnosis among men (p<0.001), women had a higher percentage of normal electrocardiograms (p=0.003) or negative T-waves at admission (p<0.001). Several differences in medications were observed, both in outpatient and inpatient settings. The composite of in-hospital MACE occurred in 10% of the patients and was significantly higher among women. However, after multivariate analysis, only age over 75 years (OR 2.889, 95% CI 1.131-7.378, p=0.027), Killip class above 1 (OR 3.920, 95% CI 1.59-9.66, p=0.003), and diuretics (OR 11.119, 95% CI 4.280-28.884, p<0.001) remained as independent predictors of in-hospital MACE. Conclusions This study describes sex differences in Portuguese MINOCA patients. Women represented only 35% of MINOCA cases, probably related to the underrepresentation of this group, which is in accordance with previous studies. Although women had a higher prevalence of adverse events, sex was not an independent predictor of the composite endpoint after adjusting for confounders. Addressing these disparities may significantly enhance our understanding of MINOCA, leading to more targeted interventions and improved outcomes.