Sex differences in the diagnostic yield of CMR timing in patients with acute coronary syndromes and non-obstructive coronary arteries

Abstract Background Cardiovascular magnetic resonance imaging holds a Class I indication for the evaluation of suspected myocardial infarction with non-obstructive coronary arteries (MINOCA). Although the timing of CMR significantly influences its diagnostic yield, the extent to which this relationship is modulated by sex remains unclear. Current guidelines provide universal timing recommendations without considering potential sex-specific effects. Purpose To evaluate sex-specific timing interactions on CMR diagnostic probability in suspected MINOCA patients. Methods A total of 888 consecutive patients presenting with acute coronary syndrome and non-obstructed coronary arteries underwent comprehensive 1.5T CMR (51% female, mean age 57 ± 15.9 years), at a median of 20 days (IQR 6, 55 days). Based on CMR findings, patients were categorised into five diagnostic groups: myocardial infarction, myocarditis, cardiomyopathy, Takotsubo syndrome, and normal CMR. Logistic regression incorporating restricted cubic splines was used to model nonlinear interactions between sex and CMR timing in relation to diagnostic probability. Model performance was evaluated using the Akaike Information Criterion (AIC) and the concordance index (C-index). Results CMR identified underlying causes in 75.7% of patients (27.4% myocardial infarction, 24.4% myocarditis, 13.0% Takotsubo, 10.9% cardiomyopathy). Sex-specific diagnostic patterns were observed: males exhibited a significantly higher prevalence of myocarditis and cardiomyopathy compared to females (37.2% vs. 12.1%, respectively 15.4% vs. 6.6%), whereas females demonstrated significantly greater rates of Takotsubo syndrome and normal CMR findings (23.6% vs. 1.8%, respectively 29.1% vs. 19.3%, all p