Simulated bioprosthetic heart valve deformation under quasi-static loading
Simulated bioprosthetic heart valve deformation under quasi-static loading
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DOI：
10.1115/1.2049337
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发表时间：
2005-11-01
影响因子：
1.7
通讯作者：
Sacks, MS
中科院分区：
文献类型：
--
作者：
Sun, W;Abad, A;Sacks, MS
40多年来，用人工设备替换患病的天然心脏瓣膜极大地延长了全球数百万患者的生命质量和生命长度。然而，由于组织耐久性差和设计错误，生物人工心脏瓣膜(BHV)由于结构故障而继续失效。显然，深入了解BHV在组织和功能假体水平的生物力学行为对于改进BHV设计和降低失败率至关重要。在本研究中，我们模拟了40、80和120毫米汞柱准静态跨瓣膜压力下的准静态BHV瓣叶变形。采用冯氏弹性材料模型，结合实际小叶双轴试验得到的材料参数和轴线，测量小叶的胶原纤维结构。为了验证模型的结果，对预测的小叶应变场进行了严格的实验验证。有限元计算结果与实验测量结果之间的最大误差为2.36%，表明计算的主要主应变与测量的主应变具有很好的一致性。对所有三个传单使用一个传单的材料参数集进行参数研究，导致传单的应力和应变分布有很大差异。这一结果表明，利用实际的叶片材料属性对于准确的BHV有限元模拟是至关重要的。本研究还强调了在模拟BHV、功能和设计时需要严格的实验和准确的本构模型。
For more than 40 years, the replacement of diseased natural heart valves with prosthetic devices has dramatically extended the quality and length of the lives of millions of patients worldwide. However, bioprosthetic heart valves (BHV) continue to fail due to structural failure, resulting from poor tissue durability and faulty design. Clearly, an in-depth understanding of the biomechanical behavior of BHV at both the tissue and,functional prosthesis levels is essential to improving BHV design and to reduce rates of failure. hi this study, we simulated quasi-static BHV leaflet deformation under 40, 80, and 120 mm Hg quasi-static transvalvular pressures. A Fung-elastic material model was used that incorporated material parameters and axes derived from actual leaflet biaxial tests and measured leaflet collagen fiber Structure. Rigorous experimental validation of predicted leaflet strain field was used to validate the model results. An overall maximum discrepancy of 2.36% strain between the finite element (FE) results and experiment measurements was obtained, indicating good agreement between computed and measured major principal strains. Parametric studies utilizing the material parameter set from one leaflet for all three leaflets resulted in substantial variations in leaflet stress and strain distributions. This result suggests that utilization of actual leaflet material properties is essential for accurate BHV FE Simulations. The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV,function and design.