Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy.
Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, Pavia, Italy.
Interact Cardiovasc Thorac Surg. 2021 Apr 8;32(3):408-416. doi: 10.1093/icvts/ivaa288.
Transcatheter aortic root repair (TARR) consists of the simultaneous endovascular replacement of the aortic valve, the root and the proximal ascending aorta. The aim of the study is to set-up a computational model of TARR to explore the impact of the endovascular procedure on the coronary circulation supported by chimney grafts.
Computed tomography of a patient with dilated ascending aorta was segmented to obtain a 3-dimensional representation of the proximal thoracic aorta, including aortic root and supra-aortic branches. Computed assisted design tools were used to modify the geometry to create the post-procedural TARR configuration featuring the main aortic endograft integrated with 2 chimney grafts for coronary circulation. Computational Fluid Dynamics simulations were run in both pre- and post-procedural configurations using a pulsatile inflow and lumped parameter models at the outflows to simulate peripheral aortic and coronary circulation. Differences in coronary flow and pressure along the cardiac cycle were evaluated.
After the virtual implant of the TARR device with coronary grafts, the flow became more organized and less recirculation was seen in the ascending aorta. Coronary perfusion was guaranteed with negligible flow differences between pre- and post-procedural configurations. However, despite being well perfused by chimney grafts, the procedure induces an increase of the pressure drop between the coronary ostia and the ascending aorta of 8 mmHg.
The proposed numerical simulations, in the specific case under investigation, suggest that the TARR technique maintains coronary perfusion through the chimney grafts. This study calls for experimental validation and further analyses of the impact of TARR on cardiac afterload, decrease of aortic compliance and local pressure drop induced by the coronary chimney grafts.
经导管主动脉根部修复术（TARR）包括同时经血管内置换主动脉瓣、根部和升主动脉近端。本研究的目的是建立 TARR 的计算模型，以探讨血管内手术对烟囱移植物支持的冠状动脉循环的影响。
对一名升主动脉扩张的患者进行 CT 扫描，以获得近端胸主动脉的三维表示，包括主动脉根部和升主动脉分支。使用计算辅助设计工具修改几何形状，以创建 TARR 后处理配置，其中包括主要主动脉内移植物与 2 个用于冠状动脉循环的烟囱移植物集成。在术前和术后配置中使用脉动流入和流出端集总参数模型进行计算流体动力学模拟，以模拟外周主动脉和冠状动脉循环。评估了心脏周期中冠状动脉血流和压力的差异。
在虚拟植入带有冠状动脉移植物的 TARR 装置后，血流变得更加有序，升主动脉中的再循环减少。冠状动脉灌注通过烟囱移植物得到保证，术前和术后配置之间的流量差异可以忽略不计。然而，尽管烟囱移植物能够很好地灌注，但该手术会导致冠状动脉口和升主动脉之间的压力降增加 8mmHg。
在具体案例中，所提出的数值模拟表明 TARR 技术通过烟囱移植物维持冠状动脉灌注。本研究呼吁对 TARR 对心脏后负荷、主动脉顺应性降低和冠状动脉烟囱移植物引起的局部压力降的影响进行实验验证和进一步分析。
