P2.04 ASSESSMENT OF BRACHIAL ARTERY REACTIVITY USING THE ENDOCHECK: REPEATABILITY, REPRODUCIBILITY AND PRELIMINARY COMPARISON WITH ULTRASOUND

Abstract

Objective: The Endocheck, embedded within the Vicorder device, uses cuff-based, pulse volume (PV) displacement to record brachial PV waveforms at baseline, and during reactive hyperaemia. The aim of this study was to assess the utility of the Endocheck method. Methods: The study consisted of two parts. Part 1: Healthy volunteers (n=9) were studied twice, separated by 24hours. Each visit consisted of two studies, 30min apart, where, after 10min supine rest, brachial BP was assessed and PV waveforms recorded for 10sec (baseline). A cuff placed distally around the forearm was then inflated to 200mmHg for 5min. Following cuff-release, PV waveforms were recorded for 3min. The square root of the ratio of peak:baseline PV during hyperaemia (√V2/V1) was calculated. Part 2: Healthy volunteers (n=16) were studied once. Brachial artery responses were assessed simultaneously in both arms, using ultrasound (right arm) and Endocheck (left arm), following a similar protocol as above. Results: Part 1: An average change in PV of 74±82% was detected in response to forearm ischaemia (P=0.003). Within-visit repeatability was acceptable, with a mean (±SD) difference in √V2/V1 of 0.03±0.25 (P=0.6), and a high correlation between studies (r=0.64; P=0.004). Between-visit reproducibility was high, with a mean difference of 0.004±0.17 (P=0.9) and a strong correlation between readings (r=0.81; P<0.0001; Figure 1). Part 2: There was a modest association (r=0.14, P=NS) between hyperaemic responses assessed using the different methods. Conclusion: The Endocheck can reliably assess changes in brachial PV during hyperaemia. Further studies are required to determine whether the observed changes reflect endothelial function.