Measurement of coronary vasomotor function: getting to the heart of the matter in cardiovascular research

Abstract

Measurement of endothelial function in patients has emerged as a useful tool for cardiovascular research. Although no gold standard for the measurement of endothelial function exists, the measurement of flow-mediated dilation in the brachial artery, assessed with Doppler ultrasonography, is the most studied method. However, the assumption that endothelial dysfunction detected in brachial arteries is a manifestation of systemic endothelial dysfunction including the coronary circulation may not be entirely valid. Brachial and myocardial circulations differ in terms of the microvascular architecture, the pattern of blood flow and vascular resistance (e.g. shunt vessels occur in the hand but not in the myocardium), their metabolic regulation, type of receptors that contribute to humoral regulation and the pathways that are activated to induce hyperaemia. In this context, measuring coronary vasomotor function may be more useful than brachial artery measures to predict and assess potential myocardial damage related to limited vascular responsiveness. This review aims to provide an overview of the basic concept of coronary flow reserve and its different modalities of measurement, as well as its utility in cardiovascular research.

Coronary Vasomotor Function Is Abnormal in First-Degree Relatives of Patients With Type 2 Diabetes

“…The abnormal FMD could not be explained by confounding variables including age, sex, ethnicity, obesity, lipids, blood pressure, glycemia, or insulin resistance (5). However, endothelial dysfunction detected in brachial arteries may not reflect the condition of the coronary vasculature, as brachial and coronary circulations differ in terms of the microvascular architecture, pattern of blood flow, their metabolic regulation, and the pathways that are activated to induce hyperemia (6). Coronary flow reserve measurement has been considered to be a useful physiologic index for coronary circulation (6).…”

“…However, endothelial dysfunction detected in brachial arteries may not reflect the condition of the coronary vasculature, as brachial and coronary circulations differ in terms of the microvascular architecture, pattern of blood flow, their metabolic regulation, and the pathways that are activated to induce hyperemia (6). Coronary flow reserve measurement has been considered to be a useful physiologic index for coronary circulation (6). In this study, we report for the first time impaired coronary flow reserve in young nonobese normoglycemic first-degree relatives compared with healthy control subjects.…”

Altered coronary vasomotor function in young patients with systemic lupus erythematosus

“…Brachial artery endothelial dysfunction has been reported in young patients with SLE (2). However, the assumption that endothelial dysfunction detected in brachial arteries is a manifestation of coronary vascular dysfunction may not be entirely valid (3,4). Brachial and myocardial circulation differ in terms of the microvascular architecture, pattern of blood flow, and the pathways that are activated to induce hyperemia.…”

“…Brachial and myocardial circulation differ in terms of the microvascular architecture, pattern of blood flow, and the pathways that are activated to induce hyperemia. Measurements of coronary vasomotor function may therefore provide more relevant information with which to predict and assess potential cardiovascular damage related to limited vascular responsiveness (3,4). Importantly, several studies have demonstrated that the extent of coronary vasomotor dysfunction is an independent reflection of the magnitude of future risk of adverse cardiovascular events (5).…”

Impaired Coronary Flow Reserve as a Marker of Microvascular Dysfunction to Predict Long-Term Cardiovascular Outcomes, Acute Coronary Syndrome and the Development of Heart Failure

“…Therefore, impaired CFR reflects the presence of microvascular dysfunction in the absence of obstructive coronary artery narrowing. 1 Advances in transthoracic Doppler echocardiography (TTDE) allow non-invasive, physiological assessment of CFR in the left anterior descending (LAD) artery. 2, 3 Previous TTDE investigations have reported that a CFR of less than 2.0 is associated with cardiac death and acute coronary syndrome (ACS) events in patients with coronary artery disease (CAD).…”