Fluid-Structure Interaction Study of Transcatheter Aortic Valve Dynamics Using Smoothed Particle Hydrodynamics.
Fluid-Structure Interaction Study of Transcatheter Aortic Valve Dynamics Using Smoothed Particle Hydrodynamics.
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DOI：
10.1007/s13239-016-0285-7
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发表时间：
2016-12
影响因子：
1.8
通讯作者：
Sun W
中科院分区：
文献类型：
--
作者：
Mao W;Li K;Sun W
结合流体动力学和瓣膜结构响应的心脏瓣膜动力学的计算建模一直具有挑战性。在这项研究中，我们开发了一种新的完全耦合的流体-结构相互作用（FSI）模型，采用光滑粒子流体动力学（SPH）。利用先前开发的经导管主动脉瓣（TAV）非线性有限元（FE）模型与SPH耦合，模拟整个心动周期的瓣叶动力学。进行了比较模拟，以研究在TAV模拟中使用仅FE模型与FSI模型以及各向同性与各向异性瓣叶材料模型的影响。从结果来看，仅FE和FSI模型之间的瓣叶运动学存在实质性差异，FSI模型可以捕获真实的瓣叶动态变形，因为其施加在瓣叶上的更准确的空间和时间载荷条件。有限元和流固耦合模拟的应力和应变分布相似。然而，由于在FSI模型中的流动惯性在关闭阶段引起的水锤效应，峰值应力是不同的，这导致仅FE模型中的峰值应力比FSI模型的峰值应力低13%-28%。模拟结果还表明，组织各向异性对瓣膜的血液动力学影响较小。然而，瓣叶径向上较低的组织刚度可能会降低水锤效应引起的瓣叶峰值应力。希望所开发的FSI模型可以作为更好地评估瓣膜动力学和优化下一代TAV设计的有效工具。
Computational modeling of heart valve dynamics incorporating both fluid dynamics and valve structural responses has been challenging. In this study, we developed a novel fully-coupled fluid-structure interaction (FSI) model using smoothed particle hydrodynamics (SPH). A previously developed nonlinear finite element (FE) model of transcatheter aortic valves (TAV) was utilized to couple with SPH to simulate valve leaflet dynamics throughout the entire cardiac cycle. Comparative simulations were performed to investigate the impact of using FE-only models versus FSI models, as well as an isotropic versus an anisotropic leaflet material model in TAV simulations. From the results, substantial differences in leaflet kinematics between FE-only and FSI models were observed, and the FSI model could capture the realistic leaflet dynamic deformation due to its more accurate spatial and temporal loading conditions imposed on the leaflets. The stress and the strain distributions were similar between the FE and FSI simulations. However, the peak stresses were different due to the water hammer effect induced by the flow inertia in the FSI model during the closing phase, which led to 13%–28% lower peak stresses in the FE-only model compared to that of the FSI model. The simulation results also indicated that tissue anisotropy had a minor impact on hemodynamics of the valve. However, a lower tissue stiffness in the radial direction of the leaflets could reduce the leaflet peak stress caused by the water hammer effect. It is hoped that the developed FSI models can serve as an effective tool to better assess valve dynamics and optimize next generation TAV designs.