Purpose

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.

Methods

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.

Results

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.

Conclusion

In conclusion, the development of realistic and accurate FSI patient-specific models can be used as a support for clinical decisions before the implantation.

中文翻译：

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关于患者特异性经导管主动脉瓣置换术的建模：一种流体-结构相互作用方法。

目的

经导管主动脉瓣置换术 (TAVR) 是一种针对高危主动脉疾病患者的微创治疗。尽管它的使用越来越多，但仍有许多影响因素有待了解，需要不断调查。能够再现瓣膜力学和血液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特定于患者的 FSI 方法，能够模拟植入阶段以及心动周期中的瓣膜工作条件。

方法

包括主动脉根部、自体瓣膜和钙化在内的患者特定区域是根据 CT 图像重建的，而设备、金属框架和心包的 CAD 模型则来自文献数据。源自患者数据的心室和主动脉压力波形被用作边界条件。所提出的方法应用于两个真实的临床病例，在瓣周漏 (PVL) 方面呈现不同的结果，PVL 是 TAVR 后的主要并发症。

结果

结果证实了轻度和中度 PVL 的临床预后与反流体积和有效反流口面积的相关值。此外，该装置的最终释放配置和速度场与术后 CT 扫描和多普勒轨迹进行了比较，显示出良好的定性和定量匹配。

结论

总之，开发逼真且准确的 FSI 患者特定模型可以用作植入前临床决策的支持。