Role of Microvascular Dysfunction in Non-Obstructive Coronary Artery Disease: A Literature Review

Abstract

Introduction: A substantial proportion of patients with angina-like symptoms have no obstructive coronary artery disease on angiography, suggesting alternative mechanisms such as coronary microvascular dysfunction (CMD). CMD is linked to adverse outcomes, yet remains underrecognized.
Methods: A systematic search of PubMed, Scopus, and Web of Science (2010–2023) was conducted using terms “coronary microvascular dysfunction,” “non-obstructive CAD,” and “angina.” Inclusion criteria: original studies and reviews assessing CMD via invasive or non-invasive methods. Exclusion: obstructive CAD >50% stenosis. Quality was assessed using Newcastle-Ottawa Scale.
Results: Of 1,240 articles, 42 met inclusion. Prevalence of CMD in symptomatic non-obstructive CAD ranged 45–70%. Impaired coronary flow reserve (CFR <2.5) correlated with worse major adverse cardiovascular events (MACE; HR 2.3, 95%CI 1.5–3.6). Women were disproportionately affected (67% of cases). Endothelial-independent microvascular spasm was seen in 30%.
Discussion: CMD contributes to myocardial ischemia through vasodilatory dysfunction and increased vasoconstrictor tone. The high prevalence in women suggests sex-specific pathophysiology, possibly related to hormonal and inflammatory factors. Limitations include heterogeneity in CMD definitions and diagnostic cutoffs.
Conclusions: Coronary microvascular dysfunction is common in non-obstructive CAD and independently predicts MACE. Standardized diagnostic criteria and targeted therapies (e.g., statins, lifestyle modification) are urgently needed.