Wall stress and flow dynamics in abdominal aortic aneurysms: finite element analysis vs. fluid-structure interaction
Wall stress and flow dynamics in abdominal aortic aneurysms: finite element analysis vs. fluid-structure interaction
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DOI：
10.1080/10255840701827412
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发表时间：
2008-06-01
影响因子：
1.6
通讯作者：
Finol, Ender A.
中科院分区：
文献类型：
--
作者：
Scotti, Christine M.;Jimenez, Jorge;Finol, Ender A.
腹主动脉瘤(AAA)破裂是诱导力超过动脉壁强度所提供的阻力的临床表现。这种力通常被认为是沿病变壁面作用的均匀管腔压力的产物。然而，流体动力学是AAA发病机制的已知因素，血流和动脉壁的动态相互作用代表了宏观尺度上的体内环境。本研究的主要目的是评估与流固耦合(FSI)分析所产生的不均匀压力相比，假设动脉瘤囊内任意估计的峰值流体压力对于评估AAA壁力学的意义。此外，使用有限元方法估计了非对称性和壁厚对10个理想化的AAA模型和1个非动脉瘤对照的壁应力和流体动力学的影响。使用了五个不对称度，壁厚均匀且可变。每一种都是在静态压力-变形分析和瞬时FSI下建模的。结果表明，流体流动的包裹体产生的最大AAA壁应力比假设峰值管腔压力为117 mm Hg的静态壁应力高出20%。可变壁厚模型的最大壁应力几乎是均匀壁厚的四倍，并且在两种情况下都随着不对称而增大。在计算区域加入轴向拉伸和外部压力后，壁面应力降低了17%。
Abdominal aortic aneurysm (AAA) rupture is the clinical manifestation of an induced force exceeding the resistance provided by the strength of the arterial wall. This force is most frequently assumed to be the product of a uniform luminal pressure acting along the diseased wall. However fluid dynamics is a known contributor to the pathogenesis of AAAs, and the dynamic interaction of blood flow and the arterial wall represents the in vivo environment at the macro-scale. The primary objective of this investigation is to assess the significance of assuming an arbitrary estimated peak fluid pressure inside the aneurysm sac for the evaluation of AAA wall mechanics, as compared with the non-uniform pressure resulting from a coupled fluid-structure interaction (FSI) analysis. In addition, a finite element approach is utilised to estimate the effects of asymmetry and wall thickness on the wall stress and fluid dynamics of ten idealised AAA models and one non-aneurysmal control. Five degrees of asymmetry with uniform and variable wall thickness are used. Each was modelled under a static pressure-deformation analysis, as well as a transient FSI. The results show that the inclusion of fluid flow yields a maximum AAA wall stress up to 20% higher compared to that obtained with a static wall stress analysis with an assumed peak luminal pressure of 117 mmHg. The variable wall models have a maximum wall stress nearly four times that of a uniform wall thickness, and also increasing with asymmetry in both instances. The inclusion of an axial stretch and external pressure to the computational domain decreases the wall stress by 17%.