CMR reclassifies patients with suspected myocardial infarction with non-obstructive coronary arteries (MINOCA)

Abstract Funding Acknowledgements Type of funding sources: None. Objectives This study sought to assess the role of cardiac magnetic resonance (CMR) in investigating patients presenting with suspected acute coronary syndrome (ACS) and non-obstructed coronary arteries. Methods Consecutive patients presenting to a tertiary cardiology centre with suspected ACS and non-obstructed coronary arteries and referred for CMR were retrospectively identified. A comprehensive imaging protocol was performed to include cines, T2-weighted, and late gadolinium enhancement (LGE) sequences. Final CMR diagnosis was based on established patterns of tissue characterisation from myocardial oedema and LGE imaging, with patients grouped into five: myocardial infarction, myocarditis, Takotsubo syndrome, cardiomyopathy, and a normal CMR. Results A total of 888 patients were identified. The mean age across the cohort was 57 years (SD ±15.9 years) with 51% female patients. Median time to CMR from acute presentation was 21 days (Figure 1). Aetiology of presentation was uncertain in more than half of patients referred for CMR (483, 54.1%). Of patients with an initial uncertain aetiology, CMR was able to identify an underlying diagnosis in 74.9%. Diagnosis across the whole cohort was reclassified in 691 patients (77.8%), with overall diagnostic yield (CMR identified underlying aetiology for presentation) of 75.6%. (Figure 2). Conclusions In a large single-centre cohort of patients presenting with suspected ACS and non-obstructed coronary arteries, diagnostic yield with CMR was high at 76%. CMR reclassified nearly 80% of patients. Our results highlight the importance of CMR in the diagnostic pathway of suspected ACS and potential implications on clinical management.