Early-onset MINOCA: Prognostic implications and considerations for practice

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is common in clinical practice and accounts for about 10% of all patients presenting with myocardial infarction (MI) [ ]. The absence of significant coronary stenosis should not be regarded as a benign feature. Patients with MINOCA are at increased risk of recurrent infarction and mortality [ , ] and should not be dismissed as having a ‘false-positive’ diagnosis of MI. Prompt recognition of MINOCA is relevant because secondary prevention strategies can improve patients' prognosis [ , ]. However, this entity remains difficult to clinically distinguish from other nonischemic conditions that manifest with similar symptoms and troponin elevation [ ]. Based on the consensus of international societies, a diagnosis of MINOCA should be reserved for patients with MI – according to the fourth universal definition – who also present no stenosis ≥50% in any major epicardial artery on coronary angiography (Table 1) [ , ]. Noteworthy, MINOCA is a working diagnosis and should be confirmed only after carefully excluding nonischemic etiologies of myocardial injury (i.e., myocarditis), inadvertently overlooked coronary obstruction (i.e., occlusion of small/distal vessels), and other possible causes of troponin elevation (i.e., pulmonary embolism). Once these alternatives have been considered and discarded, a diagnosis of MINOCA can be made [ , ]. Early investigation (i.e., within 7–14 days) by cardiac magnetic resonance (CMR) with late gadolinium enhancement is helpful to assess cardiac anatomy and differentiate infarct patterns (i.e., subendocardial/transmural) from nonischemic patterns (i.e., subepicardial/mid-wall). When CMR reveals a myocardial injury that is consistent with an ischemic etiology, a systematic search of the potential causes of MINOCA is necessary to uncover underlying mechanisms [ ]. The presence of plaque rupture/erosion is often reported in MINOCA and can be recognized by intravascular imaging (i.e., optical coherence tomography [OCT]). Coronary artery vasospasm may cause persistent ischemia and MINOCA; provocative tests to detect vasomotor abnormalities are safe and informative when adequately performed, although they are used rarely in daily practice [ , ]. Spontaneous coronary artery dissection represents an uncommon cause of MINOCA, except in young females [ ]. Coronary microvascular disease is often responsible for MINOCA and could account for about 20% of all cases [ ]. Identifying the precise mechanisms of MINOCA remains key to assist clinicians in defining optimal follow-up and treatment strategies in individual patients.