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New Assessment of Endothelium-Dependent Flow-Mediated Vasodilation to Characterize Endothelium Dysfunction

Craiem, Damian MSc1,*; Chironi, Gilles MD2; Simon, Alain MD2; Levenson, Jaime MD2

American Journal of Therapeutics: July-August 2008 - Volume 15 - Issue 4 - p 340-344
doi: 10.1097/MJT.0b013e318164c6f0
Proceedings: Fifth Latin American Congress on Hypertension

The vascular endothelium plays an important role in the regulation of vascular tone, cell growth, inflammation, and thrombogenicity. Endothelium dysfunction, then, is considered to promote several disorders that initiate the atherosclerosis process. Vascular tone dysfunction can be determined by high-resolution ultrasonographic imaging of the brachial artery, enabling one to assess endothelium-dependent flow-mediated dilation (FMD). It is based on the principle that an increase in blood flow, specifically in shear stress, provokes the release of nitric oxide and then a vasodilation that can be quantified. In this study, brachial artery diameter evolution was continuously followed during baseline and hyperemia after forearm occlusion using a custom designed software. Some techniques used to measure FMD are limited by operator dependence. We present a new, automated, and versatile method of FMD quantification based on B-mode echographic images and edge detection algorithms. Edges for each image in the acquired sequences are recognized as interfaces based on the grey-level profiles of the averaged pixel values. Within-reading and within-subject FMD% coefficients of variation were 7% and 10%, respectively. This technique largely improves manual measurements and was shown to be appropriate for wide clinical use.

1Universidad Favaloro, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina; and 2AP-HP, Hôpital Européen Georges Pompidou (site Broussais), Centre de Médecine Préventive Cardiovasculaire, Université René Descartes-Faculté de Médecine Paris 5, Paris, France.

*Address for correspondence: Centre de Médecine Préventive Cardiovasculaire, Hôpital Broussais, 96 rue Didot, F-75674 Paris, France. E-mail: jaime.levenson@brs.ap-hop-paris.fr

© 2008 Lippincott Williams & Wilkins, Inc.