Considerations for analysis of endothelial shear stress and strain in FSI models of atherosclerosis
Considerations for analysis of endothelial shear stress and strain in FSI models of atherosclerosis
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DOI：
10.1016/j.jbiomech.2021.110720
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发表时间：
2021-09-02
影响因子：
2.4
通讯作者：
Krams, Rob
中科院分区：
文献类型：
--
作者：
Patel, Miten;Savvopoulos, Fotios;Krams, Rob
动脉粥样硬化是一种脂质驱动的慢性炎症性疾病，其特征在于在好发部位形成斑块。这些好发部位（侧支、弯曲段和分叉）通常与受干扰的剪应力分布有关。然而，除了剪切应力，内皮细胞也经历动脉壁应变，这可能有助于动脉粥样硬化的进展。在这里，我们描述了一种方法来准确地获得这些剪切应力和应变分布。我们开发了一个流体-结构相互作用（FSI）框架，用于在一个商用软件包（Abaqus，版本6.12）中对动脉进行建模，该软件包包括已知的预应力（周向，轴向和压力相关）。此外，我们将3D组织学与来自胆固醇喂养的ApoE-/-小鼠的动脉粥样硬化颈动脉的micro-CT衍生3D重建共同配准，以包括受试者特定模型内脂质的空间分布。FSI模型还结合了非线性超弹性材料模型，该模型具有区分健康血管壁和斑块的区域变化特性。FSI预测的剪切应力低于CFD（-12%），但具有较软属性的斑块区域的进一步降低（-24%）取决于用于在动脉壁中实施预应力的方法。当实施我们的新的混合方法（零预应力区域的脂质沉积），有显着的异质性，在动脉粥样硬化动脉的内皮剪切应力，由于刚度的变化，反过来，壁应变。总之，在获得病变动脉中的内皮剪切应力和应变时，仔细考虑预应力是必要的。本文提供了一种实现它们的方法。
Atherosclerosis is a lipid driven chronic inflammatory disease that is characterized by the formation of plaques at predilection sites. These predilection sites (side branches, curved segments, and bifurcations) have often been associated with disturbed shear stress profiles. However, in addition to shear stress, endothelial cells also experience artery wall strain that could contribute to atherosclerosis progression. Herein, we describe a method to accurately obtain these shear stress and strain profiles. We developed a fluid-structure interaction (FSI) framework for modelling arteries within a commercially available package (Abaqus, version 6.12) that included known prestresses (circumferential, axial and pressure associated). In addition, we co-registered 3D histology to a micro-CT-derived 3D reconstruction of an atherosclerotic carotid artery from a cholesterol-fed ApoE-/-mouse to include the spatial distribution of lipids within a subject-specific model. The FSI model also incorporated a nonlinear hyperelastic material model with regionally varying properties that distinguished between healthy vessel wall and plaque. FSI predicted a lower shear stress than CFD (--12%), but further decreases in plaque regions with softer properties (--24%) were dependent on the approach used to implement the prestresses in the artery wall. When implemented with our new hybrid approach (zero prestresses in regions of lipid deposition), there was significant heterogeneity in endothelial shear stress in the atherosclerotic artery due to variations in stiffness and, in turn, wall strain. In conclusion, when obtaining endothelial shear stress and strain in diseased arteries, a careful consideration of prestresses is necessary. This paper offers a way to implement them.