Myocardial Infarction With Non-obstructive Coronary Arteries: Italian Study

Acute coronary syndromes have been extensively studied in recent decades, focusing mainly on myocardial infarctions with obstructive coronary artery disease and early revascularisation strategies. However, the extensive use of highly sensitive troponin tests and coronary angiography has revealed a substantial group of patients with myocardial infarction without significant coronary stenosis (≥50%). This group is referred to as myocardial infarction with non-obstructive coronary arteries (MINOCA). MINOCA are defined by evidence of a myocardial infarction with normal or near-normal coronary arteries on angiography, in the absence of an alternative diagnosis specific to the clinical presentation (e.g. sepsis, myocarditis, pulmonary embolism). MINOCA may present with different aetiologies, including coronary plaque rupture/erosion, epicardial or microvascular spasm and coronary embolism. Therefore, the diagnosis of MINOCA must be considered a 'working diagnosis', which not only requires but warrants further investigation to determine the underlying cause. In fact, the investigation of MINOCA is conducted on two levels, first by excluding disorders that mimic myocardial infarction and then by identifying the cause responsible for MINOCA. In order to identify the various underlying causes of MINOCA, a cardiac MRI and/or coronary vascular imaging approach with OCT or intravascular ultrasound (IVUS) and a coronary functional assessment of microvascular function, as well as the provocation of coronary spasms by acetylcholine testing are recommended. Moreover, the clear definition of the aetiology is of great importance considering the role they play in the most appropriate therapeutic choice.

Therefore, the creation of an Italian national database could implement not only the knowledge of this clinical condition but also its management and consequent prognosis.