Myocardial infarction with non-obstructive coronary arteries: what is the prognosis?

Myocardial infarction in the absence of obstructive coronary stenosis (MINOCA) is a syndrome with several causes, characterized by clinical evidence of myocardial infarction and coronary angiographically normal or almost normal (stenosis ≤50%). MINOCAs represent about 10% of acute coronary syndromes. The causes of MINOCA are manifold and can be classified on the basis of the mechanism in epicardial (unstable plaque not manifested by angiography, epicardial spasm and coronary dissection) or microvascular. The latter in turn can be divided into intrinsic (microvascular spasm, Takotsubo syndrome and coronary embolization) and extrinsic (myocarditis). In the former, the dysfunctional microcirculation causes myocardial necrosis due to reduction of the lumen due to vasoconstriction and / or obstruction, while in the latter, the compression of the lumen occurs ab extrinsic due to myocardial edema. Note that the prognosis of MINOCA is extremely variable and depends on the underlying cause with high risk clinical subsets. A correct diagnostic procedure includes first level tests (clinical / anamnestic examination, ECG, myocardial necrosis enzyme dosage, trans-thoracic echocardiogram, coronary angiography, ventriculogram) and second level tests (intracoronary imaging, coronary vasomotor test, cardiac nuclear magnetic resonance and trans-esophageal or contrast ultrasound). Through this process, it is possible to identify the cause of MINOCA, fundamental for targeting therapy on the disease mechanism, thus constituting a typical example of precision medicine.