Influence of pulsatile blood flow on allometry of aortic wall shear stress

G Croizat , A Kehren , H Roux de Bézieux , A. Barakat (1)

1 laboratoire de génétique humaine

Shear stress plays an important role in the creation and evolution of atherosclerosis. A key element for in-vivo measurements and extrapolations is the dependence of shear stress on body mass. In the case of a Poiseuille modeling of the blood flow, P. Weinberg and C. Ethier [2] have shown that shear stress on the aortic endothelium varied like body mass to the power − 3 8 , and was therefore 20-fold higher in mice than in men. However, by considering a more physiological oscillating Poiseuille-Womersley combinated flow in the aorta, we show that results differ notably: at larger masses (M > 10 kg) shear stress varies as body mass to the power − 1 8 and modifies the man to mouse ratio to 1:8. The allometry and value of temporal gradient of shear stress also change: ∂τ /∂t varies as M −3/8 instead of M −5/8 at larger masses, and the 1:150 ratio from man to mouse becomes 1:61. Lastly, we show that the unsteady component of blood flow does not influence the constant allometry of peak velocity on body mass: umax ∝ M 0. This work extends our knowledge on the dependence of hemodynamic parameters on body mass and paves the way for a more precise extrapolation of in-vivo measurements to humans and bigger mammals.

Domaines: Biomécanique [physics.med-ph]; Mécanique des fluides [physics.class-ph]

G Croizat, A Kehren, H Roux de Bézieux, A. Barakat. Influence of pulsatile blood flow on allometry of aortic wall shear stress. 2018. ⟨hal-02410685⟩