P2.07: Validation of a Novel Method to Assess Endothelial Function

Objectives Assessment of pulse wave velocity (PWV) is normally used as a measure of arterial stiffness. However, measurement of change in PWV before and after a period of reactive hyperaemia may enable the technique to be harnessed as a measure of endothelial function as flow-mediated slowing (FMS). The aim of this study was to validate this approach as a novel method of endothelial function assessment. Methods FMS and flow-mediated dilatation (FMD) of the brachio-radial arterial tract was assessed in 25 young healthy subjects on two separate occasions to assess reproducibility. To assess the ability of the technique to investigate acute vascular dysfunction FMS and FMD was assessed before and after a 20-minute period of ischaemia-reperfusion (IR) in 15 healthy subjects. Finally, 12 Familial Hypercholesterolaemia patients undergoing lipo-protein apheresis had FMS assessed pre and post treatment. Results Reproducibility -Baseline PWV and FMS% showed good reproducibility (CV 3.3% & 7.2% respectively). There was no correlation between baseline brachial artery diameter and PWV visit 1 r = 0.325 p = 0.113 visit 2 r = 0.335 p = 0.192 or FMD and FMS visit 1 r = 0.27 p = 0.192 visit 2 r = −0.425 p = 0.053. Ischaemia Reperfusion — There was a significant decrease in FMD following IR (-28.5% p = 0.04). The trend to a reduction in FMS post-IR was not significant (-13.2% p = 0.112). Following lipoprotein apheresis there was a 28.2% increase in FMS (from 18.8% to 24.1% p = 0.006). Conclusions FMS is a reproducible technique. The ability of the method to detect changes in endothelial function shows considerable promise but requires further investigation.