Validation of semi-automated flow mediated dilation measurement in healthy volunteers

Dobbie, L. J., Mackin, S. T., Hogarth, K., Lonergan, F., Kannenkeril, D., Brooksbank, K. and Delles, C. (2020) Validation of semi-automated flow mediated dilation measurement in healthy volunteers. Blood Pressure Monitoring, 25(4), pp. 216-223. (doi: 10.1097/MBP.0000000000000448) (PMID:32304385) (PMCID:PMC7331823)

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Background: Flow-mediated dilation (FMD) is a non-invasive imaging modality used to measure endothelial function but has significant intra- and inter-observer variability. The use of semi-automated FMD devices could overcome this limitation. We assessed the reproducibility of same-day semi-automated FMD measurements by investigators who received basic training on the correct use of the device. Methods: Forty-three healthy volunteers had two brachial artery FMD measurements performed 20 minutes apart using the UNEX EF 38G device, and automated outputs were produced. Images were also manually analysed using edge-detection software. The reproducibility of repeat FMD measurements within individuals was compared for automated and manual readings, and the correlation between analytical techniques was calculated. Results: Twenty-five percent of scans were of non-diagnostic quality (n = 32). Automated analyses demonstrated sub-optimal reproducibility and measurement variability [intraclass correlation coefficient (ICCC) = 0.334, coefficient of variation (CV) = 45.87%]. In contrast, manually analysed scans had excellent reproducibility and low measurement variance (ICCC = 0.815, CV = 11.40%). FMD values obtained from automated and manual analysis correlated poorly (r = 0.164), whereas resting (r = 0.955) and maximal brachial artery diameters demonstrated excellent correlation (r = 0.867). Conclusion: Manually evaluated serial UNEX EF readings have good reproducibility and therefore, the optimal FMD workflow involves manual analyses prior to independent automated interrogation. The high non-diagnostic scan rate is most likely the result of insufficient training and indicates that semi-automatic devices such as UNEX EF should be used by experienced investigators to achieve optimal results.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Mackin, Dr Sharon and Brooksbank, Dr Katriona and Delles, Professor Christian
Authors: Dobbie, L. J., Mackin, S. T., Hogarth, K., Lonergan, F., Kannenkeril, D., Brooksbank, K., and Delles, C.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Blood Pressure Monitoring
Publisher:Lippincott, Williams & Wilkins
ISSN (Online):1473-5725
Published Online:15 April 2020
Copyright Holders:Copyright © 2020 The Author(s)
First Published:First published in Blood Pressure Monitoring 25(4): 216-223
Publisher Policy:Reproduced under a Creative Commons license

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
190814BHF centre of excellenceRhian TouyzBritish Heart Foundation (BHF)RE/13/5/30177Institute of Cardiovascular & Medical Sciences
303944BHF Centre of ExcellenceRhian TouyzBritish Heart Foundation (BHF)RE/18/6/34217CAMS - Cardiovascular Science