Cardiac magnetic resonance imaging features prognostic information in patients with suspected myocardial infarction with non-obstructed coronary arteries

Background: To assess the prognostic implications of cardiac magnetic resonance imaging (CMR) in patients with clinical suspicion of myocardial infarction with non-obstructed coronary arteries (MINOCA).

Methods: A total of 145 patients (58 ± 15 years, 97 men) were retrospectively enrolled in this single-center, longitudinal observational study. All patients underwent CMR including cine, edema-sensitive, and late gadolinium enhancement acquisitions, within a median of 3 days after cardiac catheterization. Follow-up was performed by medical records chart review and phone interviews; the median follow-up time was 4.2 years. The primary endpoint was defined as a combination of death, stroke, new onset of congestive heart failure, recurrent hospitalization, or the need for an invasive cardiac procedure.

Results: In 143 (98.6%) cases, CMR revealed the following cardiac pathologies: myocarditis (n = 48, 33.1%), structural cardiomyopathies (n = 40, 27.6%), "true" myocardial infarction (n = 22, 15.1%), hypertensive heart disease (n = 19, 13.1%), and Tako-Tsubo cardiomyopathy (n = 14, 9.7%). Only two patients (1.4%) had a normal CMR examination. There were significant prognostic differences between different etiologies, e.g. myocarditis and Tako-Tsubo cardiomyopathy had a more favorable prognosis then structural cardiomyopathies. Age, end-diastolic volume index and time-to-CMR showed significant association with the primary endpoint in multi-variate Cox regression.

Conclusions: CMR performed early after the onset of clinical symptoms allows discrimination between acute myocardial injury from "true" MINOCA in patients presenting with chest pain and elevated cardiac biomarkers, thereby helping to identify the underlying pathology in suspected MINOCA and allowing risk stratification based on the established diagnosis. Furthermore, CMR parameters allow for improved prediction of adverse events compared to clinical and laboratory parameters.