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 cuffbased, 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.