Refining the diagnosis of myocardial infarction with nonobstructive coronary arteries

The condition referred to as myocardial infarction with nonobstructive coronary arteries (MINOCA) has attracted considerable attention in recent years, with many studies addressing the clinical features and prognosis of these patients. In this issue of the Coronary Artery Disease, Montenegro Sá et al. 1 added to this discussion by evaluating patients presenting with an apparent acute myocardial infarction (AMI) and comparing those with/without obstructive coronary artery disease. Using the approach described in the European Society of Cardiology MINOCA Position Paper 2 [including cardiac magnetic resonance imaging (MRI) in almost 80% of the MINOCA patients], the authors attributed the apparent AMI clinical presentation to takotsubo cardiomyopathy (20%), myocarditis (18%), atrial fibrillation-associated coronary embolism (10%), microvascular dysfunction (6%), severe valvular disease (5%), hypertrophic cardiomyopathy (4%), coronary spasm (3%), thrombophilia disorders (1%) and unknown causes (32%). The authors further detailed the clinical determinants of this heterogeneous study group, which included female sex, younger age, atrial fibrillation, the absence of tobacco use, ST-segment elevation and absence of previous history of myocardial infarction. In considering whether these findings are broadly representative, interpretation should take into account (a) the retrospective nature of the study, (b) the single-centre recruitment, (c) the small sample size, (d) patient exclusion criteria (e.g. pulmonary embolism) and (e) the limited testing for coronary vasomotor disorders. More importantly, this study highlights the need to refine the nomenclature for the diagnosis of MINOCA.