Coronary Microvascular Dysfunction

Abstract

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed “ischemia with non-obstructive coronary artery disease” (INOCA) and for a small proportion of “myocardial infarction with non-obstructive coronary artery disease” (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

3D Imaging and Quantitative Characterization of Mouse Capillary Coronary Network Architecture

“…Exchanges between blood and cardiac tissue take place in the capillary network. Structural or functional alterations of the coronary microvascularization are referred as coronary microvascular diseases (CMDs) [ 1 ]. These CMDs are associated with the development of cardiac pathologies, including angina and heart failure [ 2 ].…”

“…Historically, most of the studies that intended to analyze human and animal coronary capillary networks have been done in 2D. In humans, the coronary microcirculation is hardly detectable by standard imaging techniques [ 1 ]. 2D angiography has been used to measure the large coronary vessel diameters, but not microvessels [ 3 ].…”

Ox-LDL induced endothelial progenitor cells oxidative stress via p38/Keap1/Nrf2 pathway

“…Endothelial cells usually work as the rst defensive line in vessels against harmful substances in the blood. However, when vascular endothelial cells are exposed to excessive external stimulus, their structure and function become impaired (18). EPCs with the inherent capacity to differentiate into mature endothelial cells play a critical role in postischemic vascular repair (19).…”

Evaluation of Microcirculation, Cytokine Profile, and Local Antioxidant Protection Indices in Periodontal Health, and Stage II, Stage III Periodontitis

“…In the circulatory system, the microvasculature is the link between arterial and venous vessels and depends on a large number of factors acting at the tissue level [ 25 ]. The study of the vascular system of the periodontium is important since the microvascular bed is the terminal site where the transport function of the cardiovascular system is realized and transcapillary metabolism is provided, which determines periodontal tissue metabolism.…”