Development of a Noninvasive Marker of Wall Shear Stress Effects in Discrete Subaortic Stenosis

Abstract

The precise etiology of discrete subaortic stenosis is unknown. It has been suggested that shear forces play a role in its initiation and progression. Because shear stress and its derivatives cannot be directly measured in vivo, we designed this study to define a clinical index of the wall shear stress and its spatial derivative using Doppler echocardiography. Using a computational model, we tested the hypothesis that a modification of the Dean number, a dimensionless index that describes shear rates in curved vessels, may yield a correlate of shear stresses in the region of interest. This would enable verification of our proposed etiology and may yield a noninvasive method to predict the development of subaortic stenosis. With the results from the computational model, we determined an index based on modifications to the Dean number that linearly correlates with the magnitude and the spatial derivative of shear stress.