Myocardial ischemia in nonobstructive coronary arteries: A review of diagnostic dilemmas, current perspectives, and emerging therapeutic innovations

Table 1 Classification of myocardial infarction with nonobstructive coronary arteries based on pathophysiological mechanisms

Category	Mechanism	Description
Atherosclerotic causes	Plaque erosion	Partial thrombus formation without significant luminal obstruction due to endothelial dysfunction and inflammation
	Coronary microembolization	Small emboli from an atherosclerotic plaque cause transient ischemia without visible stenosis
	Coronary microvascular dysfunction	Endothelial dysfunction and increased arterial stiffness impair myocardial perfusion
Non-atherosclerotic causes	Coronary vasospasm	Transient epicardial or microvascular constriction triggered by endothelial dysfunction, sympathetic activation, or vasoconstrictive agents leading to ischemia
	Spontaneous coronary artery dissection	Intimal tear or intramural hematoma causes lumen compression and ischemia. It is often associated with fibromuscular dysplasia and peripartum changes
	Myocardial oxygen supply-demand mismatch	Increased myocardial oxygen demand in conditions like anemia, tachyarrhythmias, hypertensive crises, and sepsis