Coronary microvascular dysfunction: a narrative review

Abstract

Coronary microvascular dysfunction (CMD) describes pathology within the microcirculation of the coronary arterial tree. Patients with this condition present similarly to macrovascular coronary disease, and it remains challenging to diagnose using invasive coronary angiography (ICA) alone. CMD is a cause of frequent hospital separations, and due to limitations in existing diagnostic techniques goes under-diagnosed. There is increasing interest amongst specialists, as reflected in recent American, European, and Japanese guidelines. This review seeks to present a thorough overview of recent research on CMD, outlining its pathophysiology, diagnostic insights, prognosis, available treatment options, and future directions of research and management. A systematic search of PubMed [1990-2024] was conducted, including English-language original research, reviews, and consensus documents. Articles were selected independently by two reviewers. The incidence of CMD is increasing due to greater recognition and improved availability of coronary physiological assessment. CMD should be considered in patients with symptoms of angina without obstructive coronary artery disease (CAD) identified on ICA or computed tomography (CT). In addition to existing invasive techniques, non-invasive methods of diagnosis are emerging. There is a substantial body of evidence linking CMD with inflammatory conditions, potentially making this pathway a novel therapeutic target. Previously thought to bear no mortality effect, registry data is showing reduction in not only quality of life metrics but elevated risk of cardiovascular events in this cohort. Medical options are limited, with variable patient response. CMD is a heterogeneous condition presenting diagnostic challenges, refractory symptoms, and evolving recognition of its prognostic significance. Emerging research focuses on non-invasive diagnostics and novel therapies to bridge treatment gaps. Large-scale trials are needed to assess their impact on clinical outcomes.