Abstract
BACKGROUND: Flow-mediated dilation (FMD) is the established parameter of endothelial function but requires skill and specialized equipment. This study aimed to investigate whether changes in carotid artery ultrasound parameters during passive leg raising (PLR) could reflect FMD values. METHODS AND RESULTS: Thirty-six adult males underwent standard FMD measurement. After 15 min of rest, a carotid artery ultrasound was performed to measure the maximal common carotid artery (CCA) diameter and stiffness parameter β. The PLR maneuver was then performed, and the change in these parameters (∆CCA(PLR) and ∆β(PLR)) was calculated. There were 6 participants with decreased FMD value (<4%). While the maximal CCA diameter remained unchanged during PLR (P=0.54), the stiffness parameter β significantly decreased during PLR compared with baseline (P=0.014). Among several carotid artery ultrasound parameters, ∆β(PLR) correlated most strongly with FMD (r=-0.70; P<0.001). Receiver operating characteristic analysis showed that ∆β(PLR) predicted decreased FMD with an area under the curve of 0.89, sensitivity of 87%, and specificity of 83% at an optimal cut-off of 4.7%. CONCLUSIONS: Change in carotid arterial stiffness parameter β during the PLR maneuver correlated with FMD, suggesting it may serve as an alternative indicator for endothelial function.