Myocardial infarction with non-obstructive coronary arteries: A comprehensive review and future research directions

Table 1 Myocardial infarction with non-obstructive coronary arteries classification, management overview, prevalence and suggested therapy

Mechanism	Diagnosis	Prevalence in coronary syndromes	Therapy
Epicardial causes
Coronary artery disease	IVUS/OCT, FFR/iFR	5%-20% of MI	Antiplatelet therapy, statins, ACEi/ARB, beta-blockers
Coronary dissection	IVUS/OCT	25% of MI in women under 50 yr of age	Beta-blocker and simple antiplatelet therapy
Coronary artery spasm	Intracoronary nitrates, intracoronary Ach or ergonovine test by experienced teams	3%–95% of MI depending on the registry	Calcium antagonists, nitrates
Microvascular causes
Microvascular coronary spasm	Objective evidence of ischaemia (ECG, LV wall motion abnormalities, PET). Impaired microvascular function (CFR, intracoronary Ach test, abnormal CMR, slow coronary flow)	As high as 25% depending on the registry	Beta-blockers and nitrates, calcium antagonist, possibly ranolazine
Takotsubo syndrome	Ventriculography, echocardiography, troponin, B-natriuretic peptide, CMR	1%-3% of general STEMI, 5%-6% women with STEMI, concomitant CAD 10%-29%	Heart failure treatment, mechanical support in cardiogenic shock
Myocarditis	CMR, EMB, viral serologies, high c-reactive protein	33% of MINOCA when determined by CMR	Heart failure treatment if complication, autoimmune therapy in autoimmune forms
Coronary embolism	History of potential thromboembolic sources, thrombophilia screen, TTE, TOE, bubble contrast echography	2.9% MI	Antiplatelet therapy, anticoagulation, transcatheter closure or surgical repair

MINOCA: Myocardial infarction with non-obstructive coronary arteries; MI: Myocardial infarction; CAD: Coronary artery disease; IVUS: Intravascular ultrasound; OCT: Optical coherence tomography; CMR: Cardiac magnetic resonance; STEMI: ST segment elevation myocardial infarction; PET: Positron emission tomography; FFR: Fractional flow reserve; ECG: Electrocardiogram; iFR: Instantaneous wave-free ratio; EMB: Endomyocardial biopsies; ACEi: Angiotensin-converting-enzyme inhibitors.