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.

动脉粥样硬化是一种脂质驱动的慢性炎症性疾病，其特征是在好发部位形成斑块。这些偏好部位（侧枝、弯曲段和分叉）通常与受干扰的剪切应力分布有关。然而，除了剪切应力外，内皮细胞还会经历可能导致动脉粥样硬化进展的动脉壁应变。在这里，我们描述了一种准确获得这些剪切应力和应变分布的方法。

我们开发了一种流固耦合 (FSI) 框架，用于在商业可用的软件包（Abaqus，版本 6.12）中对动脉进行建模，其中包括已知的预应力（周向、轴向和压力相关）。此外，我们将 3D 组织学与来自喂食胆固醇的 ApoE ^-/-小鼠的动脉粥样硬化颈动脉的 micro-CT 衍生 3D 重建共同注册，以包括特定对象模型中脂质的空间分布。FSI 模型还结合了非线性超弹性材料模型，该模型具有区域变化的特性，可区分健康血管壁和斑块。

FSI 预测的剪切应力低于 CFD (~-12%)，但具有较软特性的斑块区域的进一步减少 (~-24%) 取决于用于在动脉壁中实施预应力的方法。当使用我们的新混合方法（脂质沉积区域的零预应力）实施时，由于刚度的变化以及壁应变的变化，动脉粥样硬化动脉中的内皮剪切应力存在显着的异质性。

总之，在获得病变动脉的内皮剪切应力和应变时，需要仔细考虑预应力。本文提供了一种实现它们的方法。