Role of cardiac magnetic resonance imaging in identifying infarct related artery and non-ischemic pathogenesis in patients presenting with non ST elevation myocardial infarction

Identifying an Infarct-related artery (IRA)in Non-STEMI is sometimes tricky. Besides, myocardial infarction with non-obstructive coronary arteries (MINOCA) mimickers are often labeled as myocardial infarction. Late Gadolinium enhancement (LGE) on cardiac MRI can help in identifying IRA besides MINOCA mimickers. To study the role of LGE on cardiac MRI(CMR) in NSTEMI. It was a prospective observational, double-blinded study. 70 NSTEMI patients were prospectively enrolled over two years. CMR was done before coronary angiography (CAG) during the index hospitalization. Matching was done between IRA selected by CAG and IRA as determined by LGE on MRI. Mean age was 58 ± 15 years. CAG could not identify IRA in 38.6% (n = 27) patients. In this patient group, LGE-CMR identified IRA in 48.1% (n = 13) & a new non-CAD diagnosis was identified in 18.5% (n = 5) patients. IRA was identified in 61.4% (n = 43) by CAG & in this patient group, LGE-CMR identified a different IRA in 6.9% (n = 3) patients. LGE-CMR also identified a new non-CAD diagnosis in 11.6% (n = 5) of patients from this group. Overall, LGE-CMR led to a new IRA diagnosis in 23% (n = 16) patients & a diagnosis of non-ischemic pathogenesis in 14% (n = 10) patients. Non-Ischemic diagnosis on CMR included stress cardiomyopathy in 3, myocarditis in 6, and infiltrative disorder in 1 patient. CMR leads to new IRA diagnoses or non-ischemic pathogenesis in one-third of the cohort.