Myocardial Infarction with Non-Obstructive Coronary Artery Disease: The Labyrinth of Investigations. Case Report and Review of the Literature.

Myocardial infarction with non-obstructive coronary artery disease (MINOCA) accounts for approximately 5-15% of acute myocardial infarctions (MI). This infarction type raises a series of questions about the underlying mechanism of myocardial damage, the diagnostic pathway, optimal therapy, and the outcomes of these patients when compared to MI associated with obstructive coronary artery disease. We present the case of a 60-year-old patient with multiple cardiovascular risk factors and comorbidities who is admitted in an emergency setting. The patient is known with a conservatively treated inferior myocardial infarction which occurred 3 months prior, with reduced left ventricular ejection fraction. Emergency coronary angiography revealed normal epicardial coronary arteries, which led to further investigations of the underlying cause. Considering the absence of epicardial and microvascular spasm, CMR (cardiac magnetic resonance) confirmation of two transmural myocardial infarctions in the territories tributary to coronary arteries, and a high index of myocardial resistance in culprit arteries, we concluded the diagnosis of MINOCA due to the microvascular endothelial dysfunction. Although the concept of MINOCA was devised almost a decade ago, and these patients are an important part of MI presentations, it still represents a diagnostic challenge with multiple explorations required to establish the precise etiology.