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Description
Atherosclerosis is a lipid-driven chronic inflammatory disease representing a leading cause of death globally, with plaques preferentially forming in regions of complex blood flow patterns, such as arterial bifurcations, bends, and branches. The role of local hemodynamics in atherosclerosis at the carotid bifurcation has been the subject of study by computational fluid dynamics (CFD) simulations for over three decades. However, the underlying assumption of rigid arterial walls is still a source of debate, with the growing interest around personalized, predictive in silico cardiovascular modelling. The complex interplay between blood flow and arterial wall mechanics can be modelled through fluid–structure interaction (FSI) approaches, nominally simulating more realistically the arterial biomechanical environment. However, its benefits must be carefully weighed against the increased computational cost, workload, and associated uncertainty.
In this study, ten subject-specific carotid bifurcations with ostensibly normal lumen geometries were analyzed using both rigid-wall CFD and two-way fully coupled FSI simulations. The FSI models incorporated an anisotropic fiber-reinforced hyperelastic arterial wall [1], estimation of the diastolic tensional state[2], viscoelastic support from surrounding tissue [3], and measurement-derived patient-specific inflow/outflow boundary conditions. Simulations were conducted using the monolithic finite-element based solver svFSI (SimVascular package [4]), based on the Arbitrary Lagrangian–Eulerian formulation (ALE) to model fluid-solid interaction. Qualitative and quantitative comparative analyses of wall shear stress-based metrics (including topological features) and intravascular flow patterns showed small to moderate differences between FSI and CFD simulations, suggesting that rigid-wall CFD simulations are generally sufficient to capture hemodynamic features of biological and clinical relevance. Nevertheless, the value of FSI for evaluating structural quantities that cannot be obtained through rigid-wall simulations, and for exploring their interaction with hemodynamic stresses on the endothelium, should not be overlooked.
[1]Holzapfel et al.,J Elast,2000
[2]Hsu et al.,Finite Elem Anal Des,2011
[3]Bäumler et al.,Biomech Model Mechanobiol,2020
[4]Zhu et al.,J Open Source Softw,2022