Interrelationship Between Noninvasive Predictors of Atherosclerosis: Transthoracic Coronary Flow Reserve, Flow-Mediated Dilation, Carotid Intima-Media Thickness, Aortic Stiffness, Aortic Distensibility, Elastic Modulus, and Brachial Artery Diameter

Background: In this study, we searched for a correlation between transthoracic coronary flow reserve (CFR) and well‐established surrogates of coronary atherosclerosis. Methods: The study was conducted on 136 healthy subjects (mean age: 39.9 ± 7.3 years) who were free of coronary risk factors. Transthoracic echocardiography was used to measure the aortic stiffness index (AoSI), aortic distensibility (AoD), and aortic elastic modulus (AoEM). High‐resolution ultrasound was used to measure brachial artery endothelium‐dependent and independent vasomotion and carotid intima‐media thickness (IMT). In addition, transthoracic second harmonic Doppler echocardiography was used to measure CFR. Results: All of the parameters significantly correlated with each other except brachial endothelium‐independent dilation. CFR correlated significantly with brachial endothelium‐dependent dilation (EDD) (r = 0.302, P < 0.01), carotid IMT (r =−0.388, P < 0.01), brachial artery diameter (r = 0.340, P < 0.01), AoD (r = 0.275, P < 0.01), AoS (r =−0.299, P < 0.01), and AoEM (r =−0.30,7 P < 0.01). Carotid IMT correlated significantly with brachial EDD and modestly with brachial artery diameter, AoD, AoS, and AoEM. In multivariate analysis, carotid IMT (β=−0.323, P < 0.0001) and brachial artery diameter (β=−0.259, P = 0.001) were significant independent predictors of CFR. The left ventricular mass index (β= 0.371, P < 0.0001), brachial EDD (β=−0.232, P = 0.002), and CFR (β=−0.228, P = 0.003) were significant predictors for IMT. Conclusion: Transthoracic CFR correlated significantly with well‐established noninvasive predictors of atherosclerosis, and we suggest that it can be used as a surrogate for coronary atherosclerosis.