Abstract
The coronary microvascular system accounts for 95% of the total coronary arterial bed and plays a crucial role in regulating blood flow to meet the changing metabolic demands of the myocardium. Coronary microvascular dysfunction (CMD) refers to the impairment of this regulatory mechanism resulting in reduced coronary blood flow. The pathophysiology of CMD is complex and involves both structural abnormalities such as microvascular spasm, reduced vascular density, and perivascular fibrosis, as well as functional abnormalities including endothelial dysfunction, vascular smooth muscle dysfunction, and autonomic imbalance.
CMD is frequently observed in patients with cardiovascular risk factors such as diabetes mellitus (T2DM), hypertension, dyslipidemia, obesity, and metabolic syndrome. Clinically, CMD is prevalent in both obstructive coronary artery disease (CAD) and nonobstructive CAD as well as in non-atherosclerotic cardiovascular diseases or conditions where atherosclerosis plays a minor role in pathogenesis.
In most of these clinical scenarios, CMD has been shown to be an independent prognostic factor associated with an increased risk of major adverse cardiovascular events (MACE). Early recognition, a comprehensive understanding of its pathophysiology, and identification of its clinical presentations are essential for developing effective therapeutic strategies and improving the management of cardiovascular diseases.