Clinical and cardiac magnetic resonance imaging features for differentiation between acute myocardial infarction with and without obstructive coronary arteries.

Background: Misdiagnosis often occurs in patients with myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) and MI with obstructive coronary arteries (MIOCA). This study explored the clinical and imaging characteristics of patients with MINOCA and MIOCA. Methods: Patients with acute MI (AMI) who underwent cardiac magnetic resonance (CMR) imaging and coronary angiography (CAG) were evaluated. According to coronary stenosis degree (>50%), patients with AMI (n=147) were divided into the MINOCA and MIOCA groups. The cardiac function and CMR characteristics of the two subgroups were emphasized in analysis. Results: The MINOCA group had a lower proportion of patients with hypertension (29.4% vs. 55.2%), hyperlipoproteinemia (9.8% vs. 16.7%), diabetes (19.6% vs. 37.5%), wall motion abnormalities (39.3% vs. 75%), complex (both epicardial and subendocardial infarction) infarct type (19.6% vs. 29.2%), and multiple infarct territories (58.8% vs. 77.1%) than did the MIOCA group. Compared with the MIOCA group, the MINOCA group had a smaller left ventricular (LV) infarct size and a lower infarct size rate. The MINOCA group had a higher LV ejection fraction (LVEF) and global peak strain (GPS) in the three directions compared with the MIOCA group. The GPS in three directions were inversely associated with increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, a greater LV infarct extent, and decreased LVEF in patients with AMI. NT-proBNP level was shown to be an independent determinant of the global longitudinal peak strain (GLPS) in patients with MINOCA and GPS in three directions in patients with MIOCA. Infarct size was an independent determinant of GPS in three directions in the MINOCA and MIOCA groups. Conclusions: MINOCA had a specific etiology, and patients with MINOCA had better myocardial function than those with MIOCA. Strain, infarct size on CMR imaging, and NT-proBNP level are reliable for monitoring cardiac dysfunction in patients with MINOCA. GLPS and global circumferential peak strain are useful early biomarkers of subclinical impairment in MINOCA.