Factors Affecting Coronary Flow Reserve: Measured by Transthoracic Doppler Echocardiography

Background and Objectives:Coronary flow reserve (CFR) is considered an important index of the functional significance of coronary artery stenosis, but is influenced by several factors, such as left ventricle hypertrophy (LVH), diabetes mellitus (DM), hyperlipidemia and smoking. Measurement of the coronary flow velocity of the left anterior descending coronary artery (LAD) by transthoracic Doppler echocardiography (TTDE) is feasible, and provides reliable information. The purpose of this study was to investigate the relationship between CFR and LVH, DM, hyperlipidemia and hypertension in patients with or without coronary artery disease, and to assess the prominent factors influencing CFR. Subjects and Methods:Coronary angiographies were performed in 38 patients to evaluate chest pain. The distal LAD flow velocity was measured by TTDE, and the CFR calculated as a ratio of the hyperemic and baseline mean diastolic velocities. The CFR was compared with clinical, echocardiographic and angiographic parameters. Results:The CFR was similar in patients both with and without hypertension, DM, high LDL-cholesterol levels and low ejection fraction (<40%). The mean CFR was lower in patients with (50% LAD stenosis than in patients with no significant stenosis. The CFR of patients with a left ventricle wall thickness of (12mm was lower than in those without LVH. The multivariate analysis of the aforementioned factors showed that LVH was the factor most influencing to the CFR (p<0.05). Conclusion:When using CFR as a functional parameter of LAD stenosis, one should consider LVH as one of the factors attributed to CFR modification. (Korean Circulation J 2002; 32(11):958-964)