发表机构
University of Texas at Austin; Iowa State University（德克萨斯大学奥斯汀分校; 爱荷华州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出浸没几何流固耦合框架，结合参数化重建与罚函数修复模型，模拟二尖瓣TEER手术，并验证网格收敛性，量化术前术后血流动力学变化。
AI 中文摘要
经导管缘对缘修复（TEER）通过一个夹子抓住并贴合二尖瓣（MV）瓣叶来治疗二尖瓣反流。预测其疗效需要解析血流与完整二尖瓣装置之间的相互作用，其中高度可变形瓣叶和腱索经历大变形和复杂接触。本文提出一种浸没几何流固耦合（FSI）公式，其中瓣膜组件、周围血流与修复之间的耦合被弱化施加，无需一致离散化。开发了一个完全参数化的重建流程，将分割图像转换为可直接用于分析的等几何网格。瓣叶和腱索分别建模为Kirchhoff-Love壳和缆索，壳公式被修改以包含一个体内预应变张量，该张量考虑了成像几何中已存在的载荷。我们提出一种子单元方法，改进了界面约束的求积，并消除了为防止通过瓣叶的非物理泄漏而本需的过度细化。二尖瓣修复通过一个罚函数公式建模，该公式在指定区域强制瓣叶对合，允许在不重新网格化或建模装置的情况下改变夹子数量和位置。左心室流出道处的集总参数模型施加与流量相关的压力，而非预设波形，从而使前向血流与反流的分流符合生理行为。我们针对分割成像数据验证了重建，证明了所提公式的网格收敛性，并将该框架应用于一个脱垂二尖瓣及其单夹和双夹修复，以量化术前和术后瓣膜动力学及左心血流动力学的变化。
英文摘要
Transcatheter edge-to-edge repair (TEER) treats mitral regurgitation with a clip that grasps and coapts the mitral valve (MV) leaflets. Predicting its outcome requires resolving the interaction between the blood flow and the complete MV apparatus, in which highly deformable leaflets and chordae tendineae undergo large deformation and complex contact. In this work, we introduce an immersogeometric fluid-structure interaction (FSI) formulation in which the coupling among the valvular components, the surrounding flow, and the repair is enforced weakly, without requiring conforming discretizations. A fully parameterized reconstruction pipeline is developed to convert segmented images into analysis-ready isogeometric meshes. The leaflets and chordae are modeled as Kirchhoff-Love shells and cables, and the shell formulation is modified to include an in-vivo prestrain tensor that accounts for the loading already present in the imaged geometry. We propose a subcell approach that improves the quadrature for the interfacial constraint and eliminates the over-refinement otherwise needed to prevent unphysical leakage through the leaflets. The MV repair is modeled by a penalty formulation that enforces leaflet coaptation over a prescribed region, allowing clip number and placement to be varied without remeshing or modeling the device. A lumped-parameter model at the outflow tract of the left heart imposes a flow-dependent pressure rather than a prescribed waveform, so that the split between forward and regurgitant flow matches physiological behavior. We validate the reconstruction against the segmented imaging data, demonstrate mesh convergence of the proposed formulations, and apply the framework to a prolapsed MV and its single- and double-clip repairs to quantify pre- and post-operative changes in valve dynamics and left-heart hemodynamics.
