Coronary Flow Reserve Measurement by Transthoracic Doppler Echocardiography

Introduction Coronary flow reserve (CFR) is defined as a ratio of maximal (stimulated) to baseline (resting) coronary blood flow. CFR evaluation is important for the understanding of the pathophysiology of coronary circulation. CFR measurement is used both to assess epicardial coronary stenoses and to examine the integrity of microvascular circulation. An appreciation of coronary physiology is an integral part of clinical decision-making for cardiologists treating patients with coronary artery disease. In the absence of stenosis in epicardial coronary artery, the CFR may be decreased when coronary microvascular circulation is compromised by arterial hypertension with or without left ventricular hypertrophy, diabetes mellitus, hypercholesterolemia, syndrome X, hypertrophic cardiomyopathy or other diseases [1].