Three‐dimensional distribution of wall shear stress and its gradient in red cell‐resolved computational modeling of blood flow in in vivo‐like microvascular networks

Using a high‐fidelity, 3D computational model of blood flow in microvascular networks, we provide the full 3D distribution of wall shear stress ( WSS ), and its gradient ( WSSG ), and quantify the influence of red blood cells ( RBC s) on WSS and WSSG . The deformation and flow dynamics of the individual RBC s are accurately resolved in the model, while physiologically realistic microvascular networks comprised of multiple bifurcations, convergences, and tortuous vessels are considered. A strong heterogeneity in WSS and WSSG is predicted across the networks, with the highest WSS occurring in precapillary bifurcations and capillary vessels. 3D variations of WSS and WSSG are shown to occur due to both network morphology and the influence of RBC s. The RBC s increase the WSS by as much as three times compared to that when no RBC s are present, and the highest increase is observed in venules. WSSG also increases significantly, and high WSSG s occur over wider regions in the presence of RBC s. In most vessels, the circumferential component of WSSG is observed to be greater than the axial component in the presence of RBC s, while the opposite trend is observed when RBC s are not considered. These results underscore the important role of RBC s on WSS and WSSG that cannot be predicted by widely used 1D models of network blood flow. Furthermore, the subendothelium‐scale variations of WSS and WSSG predicted by the present model have implications in terms of endothelial cell functions in the microvasculature.