Coronary Microvascular Dysfunction and Vasospastic Angina-Pathophysiology, Diagnosis and Management Strategies

Coronary artery disease is one of the leading public health problems in the world in terms of mortality and economic burden from the disease. Traditionally, the focus of research and clinical pathways leading to the diagnosis and treatment of coronary artery disease was on the more common variant of the disease resulting from atherosclerosis in the epicardial coronary arteries. However, coronary microvasculature, representing the vast majority of the total heart circulation, has the greatest influence on overall coronary resistance and, therefore, blood flow. Coronary microvascular dysfunction (CMD), characterized by structural or functional abnormalities in the microvasculature, significantly impacts myocardial perfusion. Endothelial dysfunction results in inadequate coronary dilation during exercise or spontaneous spasm in the microvasculature or epicardial arteries. A significant proportion of people presenting for coronary angiography in the context of angina have unobstructed epicardial coronary arteries yet are falsely reassured about the benign nature of their condition. Meanwhile, increasing evidence indicates that patients diagnosed with CMD as well as vasospastic angina (VSA) face an increased risk of Major Adverse Cardiovascular Events (MACEs), including death. The aim of this review is to outline the current practice with regard to invasive and non-invasive methods of CMD and VSA diagnosis and assess the evidence supporting the existing treatment strategies. These include endotype-specific pharmacological therapies, a holistic approach to lifestyle modifications and risk factor management and novel non-pharmacological therapies. Furthermore, the review highlights critical gaps in research and suggests potential areas for future investigation, to improve understanding and management of these conditions.