Numerical investigation of the effect of carotid bifurcation stenosis degree on pulsatility characteristics

Chao Liu; Gao Wu; Jianxin Xu; Qingtai Xiao; Hua Wang

doi:10.3389/fphys.2023.1169198

July 6, 2023Frontiers in PhysiologyOpen Access

Numerical investigation of the effect of carotid bifurcation stenosis degree on pulsatility characteristics

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Why the study?

Arterial bifurcations are susceptible to hemodynamic effects and thrombus formation, prompting evaluation of pulsation dynamics and heat transfer at different degrees of stenosis.

Does the degree of carotid bifurcation stenosis affect pulsatility characteristics, wall shear stress, and heat transfer in a computational model?

Structured PICO

Does the degree of carotid bifurcation stenosis affect pulsatility characteristics, wall shear stress, and heat transfer in a computational model?

P

Population

Simplified 3D computational model of a human carotid arterial bifurcation (based on the Y-AHCB model) with varying degrees of stenosis (0.5 mm to 1.5 mm).

I

Intervention

Simulated arterial stenosis (0.5 mm, 1.0 mm, and 1.5 mm) at the carotid bifurcation.

C

Comparator

Normal carotid artery bifurcation model (0 mm stenosis).

O

Outcome

Hemodynamic effects including pressure drop, wall shear stress, heat transfer coefficient, and absolute vorticity during the pulsation cycle.surrogate

Computational fluid dynamics modeling demonstrates that increasing carotid bifurcation stenosis significantly elevates peak pulsatile pressure drop and mean wall shear stress, providing biomechanical insights into thrombosis risk.

Implication

May heighten carotid thrombosis risk via shear stress; hypothesis-generating for human pulsatility assessment.

Abstract

Arterial bifurcations are regions that are susceptible to hemodynamic effects and thrombus formation. In the current study, the hemodynamic effects of a simplified 3D model of an arterial bifurcation were simulated using the commercial computational fluid dynamics software FLUENT. The non-Newtonian properties of blood were modeled using the Carreau model, and the pulsation dynamics and heat transfer characteristics of blood at different degrees of stenosis in the arterial bifurcation were analyzed. The results indicate that arterial stenosis caused by a thrombus when the pulsation velocity reaches its peak has an essential impact on blood transport. The stenosis of the bifurcation increases the peak pulsatile flow pressure drop, and each 0.5 mm stenosis of the arterial bifurcation increases the mean wall shear stress of the bifurcated segment by approximately 0.25 Pa. From the heat transfer perspective, arterial stenosis has little effect on the heat transfer coefficient. The heat transfer coefficient measured inside the bifurcation is much larger than that measured outside the bifurcation. The stenosis of the arterial bifurcation causes an increase in the mean velocity of the arterial cross-section, and the volume-averaged absolute vorticity is introduced to quantify the secondary flow effect during the pulsation cycle, where the arterial stenosis causes an increase in the mean absolute vorticity at pulsation velocity and accelerates the decay of the vorticity at uniform velocity. In this paper, the hemodynamics of carotid bifurcation pulsation is analyzed in conjunction with flow field properties to reveal the flow field dynamics factors and heat transfer characteristics of local stenosis of the carotid bifurcation and to conduct an exploratory study for the diagnosis and treatment of carotid bifurcation thrombosis.