Epicardial Adipose Tissue and Long-Term Outcomes in CMR-Confirmed MINOCA.

BACKGROUND: Cardiac magnetic resonance (CMR) serves as a pivotal diagnostic tool for myocardial infarction with nonobstructive coronary arteries (MINOCA) and enables the precise quantification of epicardial adipose tissue (EAT). OBJECTIVES: This study aimed to evaluate the predictive value of EAT for long-term major adverse cardiovascular events (MACE) in CMR-confirmed MINOCA and to determine whether EAT provides incremental prognostic utility. METHODS: This single-center retrospective study enrolled 117 patients with a working diagnosis of MINOCA who demonstrated an ischemic myocardial injury pattern on CMR after exclusion of nonischemic mimics or normal CMR findings. EAT volume was divided by body surface area to yield the EAT volume index (EATVi). RESULTS: During a median follow-up of 48 months (IQR: 39-63), MACE occurred in 28 of 117 patients (23.9%; 95% CI: 17.1%-32.4%). In multivariable Firth penalized Cox regression adjusting for age, global longitudinal strain, infarct size, and N-terminal pro-B-type natriuretic peptide, each 10 mL/m2 increase in EATVi was associated with a higher risk of MACE (HR = 1.35, 95% CI: 1.01-1.76, P = 0.040). The Harrell C-index increased from 0.728 (95% CI: 0.637-0.812) for the base model to 0.751 (95% CI: 0.653-0.839) after the addition of EATVi. Kaplan-Meier analysis demonstrated lower MACE-free survival among patients with EATVi >43.21 mL/m2 (selection-adjusted P = 0.002). CONCLUSIONS: Among patients with CMR-confirmed MINOCA, higher EATVi was associated with an increased long-term risk of MACE. Given the potential influence of metabolic factors and residual confounding, these findings require validation in larger external cohorts.