Abstract Body (Do not enter title and authors here): Background: Measurement of flow-mediated vasodilation (FMD) in the brachial artery by using ultrasound is a well-established technique for evaluating endothelial function. To make the measurement quicker and easier than the measurements of conventional ultrasound FMD (uFMD), we have developed a novel noninvasive method, plethysmographic FMD (pFMD), to assess vascular response to reactive hyperemia in the brachial artery. The aim of this study was to determine the accuracy of measurement of pFMD in comparison to that of measurement of conventional uFMD.
Methods and results: This study was a multi-center, cross-sectional study. We compared pFMD by a new device using cuff pressure and volume with conventional uFMD using ultrasound in 50 men (mean age, 41±9 years). pFMD significantly correlated with conventional uFMD (β=0.59, P<0.001). In Bland-Altman plot analysis of pFMD and conventional uFMD, the mean difference of pFMD and conventional uFMD was 0.78%, and limits of agreement (mean difference ±2 standard deviations of the difference) ranged from -4.53% to 6.11%.
Conclusions: We demonstrated validity of the new method for measurement of pFMD, which has the capability to automate the assessment of endothelial function in a short period of time. Measurement of pFMD is easier than measurement of conventional uFMD and may have less artificial bias compared to that of conventional uFMD measurement.