Haese Collin E, Dubey Vijay, Mathur Mrudang, Pouch Alison M, Timek Tomasz A, Rausch Manuel K
Department of Mechanical Engineering, The University of Texas at Austin, 204 E. Dean Keeton Street, Austin, TX, 78712, USA.
Department of Cardiothoracic Surgery, Stanford University, 870 Quarry Rd Extension, Palo Alto, CA, 94304, USA.
J Mech Behav Biomed Mater. 2025 Mar;163:106879. doi: 10.1016/j.jmbbm.2024.106879. Epub 2024 Dec 22.
Transcatheter edge-to-edge repair (TEER) simulations may provide insight into this novel therapeutic technology and help optimize its use. However, because of the relatively short history and technical complexity of TEER simulations, important questions remain unanswered. For example, there is no consensus on how to handle the annular boundary conditions in these simulations. In this short communication, we tested the sensitivity of such simulations to the choice of annular boundary conditions using a high-fidelity finite element model of a human tricuspid valve. Therein, we embedded the annulus among elastic springs to simulate the compliance of the perivalvular myocardium. Next, we varied the spring stiffness parametrically and explored the impact on two key measures of valve function: coaptation area and leaflet stress. Additionally, we compared our results to simulations with a pinned annulus. We found that a compliant annular boundary condition led to a TEER-induced "annuloplasty effect," i.e., annular remodeling, as observed clinically. Moreover, softer springs led to a larger coaptation area and smaller leaflet stresses. On the other hand, pinned annular boundary conditions led to unrealistically high stresses and no "annuloplasty effect." Furthermore, we found that the impact of the boundary conditions depended on the clip position. Our findings in this case study emphasize the importance of the annular boundary condition in tricuspid TEER simulations. Thus, we recommend that care be taken when choosing annular boundary conditions and that results from simulations using pinned boundaries should be interpreted with caution.
经导管缘对缘修复（TEER）模拟可以为这种新型治疗技术提供见解，并有助于优化其使用。然而，由于TEER模拟的历史相对较短且技术复杂，一些重要问题仍未得到解答。例如，在这些模拟中如何处理瓣环边界条件尚无共识。在这篇简短的通讯中，我们使用人类三尖瓣的高保真有限元模型测试了此类模拟对瓣环边界条件选择的敏感性。在该模型中，我们将瓣环嵌入弹性弹簧之间以模拟瓣周心肌的顺应性。接下来，我们参数化地改变弹簧刚度，并探讨其对瓣膜功能的两个关键指标的影响：贴合面积和瓣叶应力。此外，我们将我们的结果与固定瓣环的模拟结果进行了比较。我们发现，顺应性瓣环边界条件会导致TEER诱导的“瓣环成形术效应”，即瓣环重塑，这在临床上也有观察到。此外，较软的弹簧会导致更大的贴合面积和更小的瓣叶应力。另一方面，固定瓣环边界条件会导致不切实际的高应力，且没有“瓣环成形术效应”。此外，我们发现边界条件的影响取决于夹子的位置。我们在这个案例研究中的发现强调了瓣环边界条件在三尖瓣TEER模拟中的重要性。因此，我们建议在选择瓣环边界条件时要谨慎，并且对使用固定边界的模拟结果应谨慎解释。
