Letters To The Editor Proper “normalization ” of flow-mediated dilation for shear

leagues (1), the measurement of brachial artery flow-mediated dilation (FMD) is the most used noninvasive assessment of endothelial function. In an effort to standardize the FMD measurement among researchers, guidelines for the ultrasonic assessment of brachial artery FMD (2) were published in 2002. Since then, additional work has been conducted to create an even more reliable and accurate measurement of endothelial function. The shear produced by hyperemic blood flow is proposed to be the most important mechanical stimuli that evokes the vasodilatory response (4). Given that the magnitude of the shear stimulus generated with reactive hyperemia is influenced by several factors and may vary among subjects, correcting (normalizing) the FMD for shear is imperative. Recently, Pyke and Tschakovsky (5) investigated the independent contribu