RESUMO
This study sought to identify parameters that could guide towards an ischemic origin in patients hospitalized for myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA). MINOCA is challenging in clinical practice, as the pathophysiology is multifaceted. A total of 135 patients with MINOCA who underwent cardiovascular magnetic resonance imaging (CMR) in a single tertiary University Hospital, were retrospectively included. The study cohort was classified into 4 groups according to the CMR diagnosis (i.e., myocarditis, myocardial infarction, Takotsubo cardiomyopathy, normal or uncommon diagnosis). According to the CMR, 62% had myocarditis, 14.1% myocardial infarction, 4.4% of Takotsubo and 19.3% showed a normal CMR or uncommon diagnoses. In the multivariate analysis, three criteria were independently correlated with the underlying diagnosis of myocardial infarction: (1) the absence of inflammatory response (HR: 5.71 IC95% [1.79-18.28]; p = 0.002), (2) the presence of coronary atheroma in invasive coronary angiography (HR: 6.56 IC95% [2.27-18.92]; p = 0.001) and (3) a peak of troponin ratio elevated than normal levels of 150 (HR: 4.12 IC95% [1.45-11.65]; p = 0.01). The prevalence of myocardial infarction in MINOCA was 4.9% in the absence of these three criteria, 3.4% with one of the criteria present, 34.5% with two criteria present and 71.4% with all three criteria. The negative predictive value for MI was 96% in the presence of at least two criteria. Our study shows that the absence of inflammatory response, a high troponin and the presence of angiographic coronary atheroma are independently correlated with a myocardial infarction underlying cause of MINOCA.