Simultaneous measurement of wall shear stress and arterial distension in FMD studies

In Flow-mediated dilation (FMD) studies, blood flow in the brachial artery is restricted for about 5 minutes by a cuff. When the restriction is removed, the subsequent increase in wall shear rate (WSR) stimulates the release of nitric oxide, a vasodilator, from the endothelial cells into the smooth muscle. Impaired FMD responses, which are considered independent predictors of possible cardiovascular events, should be reliably detected. While several efforts have been so far dedicated to measure the diameter change, the source of this change, i.e., the WSR increase, has not been measured so far. In this paper, first results of the simultaneous measurement of WSR and diameter performed during FMD studies in the brachial arteries of 15 volunteers are reported. All measurements were obtained through the ULtrasound Advanced Open Platform (ULA-OP).