Comparison of new measures of vascular function to flow mediated dilatation as a measure of cardiovascular risk factors.

Although flow-mediated dilatation (FMD) is widely used, the ideal vascular parameter for the measurement of cardiovascular risk is not clear. Recently, it has been proposed that shear stress and blood velocity during hyperemia (VRH) may provide stronger correlations with cardiovascular risk factors than FMD. The aim of this study was to evaluate the relations of VRH and shear stress during reactive hyperemia (SSRH) to FMD and the association of these measures to cardiovascular risk factors in 1,477 men without cardiovascular disease. SSRH and VRH showed weak correlations with FMD in bivariate analysis (r = 0.239, p <0.001, and r = 0.108, p <0.001, respectively). The only cardiovascular risk factor independently associated with FMD was systolic blood pressure (beta = -0.073, p <0.01). In contrast, as the dependent variable, SSRH (R2 for model = 0.107) was independently associated with age, systolic blood pressure, low-density lipoprotein cholesterol, and body mass index. As the dependent variable, VRH was associated with the same risk factors with a slightly weaker R2 value of 0.095. In conclusion, SSRH and simply calculated VRH have stronger associations with cardiovascular risk factors than FMD. This may reflect greater sensitivity of these measures to detect early abnormalities associated with risk factors in a relatively young and healthy population.