Abstract 2775: The Performance of a New Automated Device for Brachial Artery Flow Mediated Vasodilation Measurement
Background: Operator-dependence of most measurement methods of brachial artery flow-mediated vasodilation (FMD) is a limitation for research and clinical applications.
Methods: We developed a new fully automated device for FMD measurement based on robotized manipulation of the probe and computerized analysis of the ultrasound scan. Beat-to-beat diastolic baseline diameter (bD) and hyperemic diameter (hD) (Figure⇓) allowed FMD calculation ((hD-bD)*100/bD). Hyperemic shear rate (hSR) was calculated as 4V/bD, V being the mean centerline blood velocity during the 15 first seconds of reactive hyperaemia. One scan of each subject was read twice by 2 observers in 26 subjects (within reading variability), and 2 scans per subject were measured by the same operator 1 hour apart in 21 subjects (within subject variability).
Results: Coefficients of variation (CV) and standard deviations (SD) of within reading and within subject FMD, bD and hSR are shown in Table⇓. Correlations existed between repeated readings and repeated measurements 1 hour apart for FMD (p<0.001, p<0.01) and dB (p<0.001).
Conclusion: This automated device provides FMD variability of about 1/4 that obtained with conventional manual methods. However, within patient FMD variability remains high, because of shear rate variations between measurements.