Luraghi Giulia, Migliavacca Francesco, García-González Alberto, Chiastra Claudio, Rossi Alexia, Cao Davide, Stefanini Giulio, Rodriguez Matas Jose Felix
Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Piazza L. da Vinci 32, 20133, Milan, Italy.
Laboratori de Càlcul Numèric (LaCàN), E.T.S. de Ingenieros de Caminos, Canales y Puertos, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034, Barcelona, Spain.
Cardiovasc Eng Technol. 2019 Sep;10(3):437-455. doi: 10.1007/s13239-019-00427-0. Epub 2019 Jul 15.
Transcatheter aortic valve replacement (TAVR) is a minimally invasive treatment for high-risk patients with aortic diseases. Despite its increasing use, many influential factors are still to be understood and require continuous investigation. The best numerical approach capable of reproducing both the valves mechanics and the hemodynamics is the fluid-structure interaction (FSI) modeling. The aim of this work is the development of a patient-specific FSI methodology able to model the implantation phase as well as the valve working conditions during cardiac cycles.
The patient-specific domain, which included the aortic root, native valve and calcifications, was reconstructed from CT images, while the CAD model of the device, metallic frame and pericardium, was drawn from literature data. Ventricular and aortic pressure waveforms, derived from the patient's data, were used as boundary conditions. The proposed method was applied to two real clinical cases, which presented different outcomes in terms of paravalvular leakage (PVL), the main complication after TAVR.
The results confirmed the clinical prognosis of mild and moderate PVL with coherent values of regurgitant volume and effective regurgitant orifice area. Moreover, the final release configuration of the device and the velocity field were compared with postoperative CT scans and Doppler traces showing a good qualitative and quantitative matching.
In conclusion, the development of realistic and accurate FSI patient-specific models can be used as a support for clinical decisions before the implantation.
经导管主动脉瓣置换术（TAVR）是针对高危主动脉疾病患者的一种微创治疗方法。尽管其应用越来越广泛，但仍有许多影响因素有待了解，需要持续研究。能够再现瓣膜力学和血流动力学的最佳数值方法是流固耦合（FSI）建模。这项工作的目的是开发一种针对患者的FSI方法，能够对植入阶段以及心动周期中的瓣膜工作状态进行建模。
从CT图像重建包括主动脉根部、天然瓣膜和钙化在内的患者特异性区域，而装置、金属框架和心包的CAD模型则从文献数据中提取。从患者数据中得出的心室和主动脉压力波形用作边界条件。所提出的方法应用于两个真实临床病例，这两个病例在TAVR术后主要并发症——瓣周漏（PVL）方面呈现出不同的结果。
结果证实了轻度和中度PVL的临床预后，反流体积和有效反流口面积值一致。此外，将装置的最终释放构型和速度场与术后CT扫描及多普勒追踪结果进行比较，显示出良好的定性和定量匹配。
总之，开发逼真且准确的针对患者的FSI模型可用于在植入前为临床决策提供支持。
