Prognostic value of CMR-derived extracellular volume in myocardial infarction with non-obstructive coronary arteries

Cardiac magnetic resonance (CMR) is crucial for diagnosing myocardial infarction with non-obstructive coronary arteries (MINOCA) and is recommended by current guidelines for its diagnostic and prognostic capabilities. However, the prognostic value of CMR parameters, particularly extracellular volume (ECV), in predicting major adverse cardiovascular events (MACE) among MINOCA remains unclear. This study analyzes ECV distribution across different MINOCA etiologies and its predictive value for MACE in "true" MINOCA.

Consecutive patients with a working diagnosis of MINOCA who underwent CMR were included. We investigated the relationships between CMR parameters and MACE in "true" MINOCA. Cox regression and ROC curve analyses were used to assess ECV in predicting MACE. "True" MINOCA was defined by evidence of ischemia or infarction on CMR.

Among 275 patients with a working diagnosis of MINOCA (median 4 days to CMR), 96 were diagnosed with "true" MINOCA, 66 with myocarditis, 31 with Takotsubo syndrome (TS), 34 with cardiomyopathies, and 48 had normal findings. "True" MINOCA had higher ECV compared to other etiologies (29.10 % vs. 26.00 %, P < 0.001). During a median follow-up of 26.6 months, 29.2 % of "true" MINOCA patients experienced MACE. In the adjusted Cox model, ECV (HR 1.063, 95 % CI 1.019-1.108, P = 0.004) was an independent predictor of MACE in patients with "true" MINOCA. According to optimal cut-off values from ROC, patients with ECV >28.94 % had a significantly higher MACE risk (log-rank P < 0.001).

CMR-derived ECV varies by MINOCA etiology, with higher levels in "true" MINOCA. Elevated ECV independently predicts increased MACE risk in "true" MINOCA patients.

ClinicalTrials.gov (ID: NCT06502899).