Zhang T, Guo H B, Li W H, Li W, Zhang X M, Li Q L, Zhang X M
Department of Vascular Surgery, Peking University People's Hospital, Beijing 100044, China.
Zhonghua Yi Xue Za Zhi. 2019 Jan 8;99(2):142-147. doi: 10.3760/cma.j.issn.0376-2491.2019.02.013.
To construct computational fluid model of type B aortic dissection using patient-specific reverse engineering and fluid-structure interaction, and evaluate the application of computational fluid model on aortic remodeling of type B aortic dissection. Consecutive computed tomographic angiograph data was acquired from a patient with type B aortic dissection at initial diagnosis, 1 week and 6 years after endovascular repair of primary tear entry and 3 months after endovascular repair of distal tear erosion. Three-dimensional model of aortic dissection was reversely reconstructed by Mimics, and then the model was smoothened by Geomagic. Computational fluid dynamic numerical simulation was performed in ANSYS by the means of two-way fluid-structure interaction, and the relation between blood dynamic characteristic and thrombosed remodeling of type B aortic dissection was evaluated. The computational fluid model of type B aortic dissection using patient-specific reverse engineering and fluid-structure interaction method was successfully constructed. Local peak of blood pressure on the convex surface of junction at aortic arch and descending aorta was found. The wall stress was much higher at the false lumen than that at the true lumen, and the peak of wall stress converged on the edge and tear entry of false lumen. After the exclusion of proximal tear entry, the blood streamline was decreased significantly and flowed reversely. Blood flow in the remaining false lumen was retrograded from the entry at left iliac artery and formed turbulence at the top of false lumen, which was benefit for dissection thrombus remodeling. The higher pressure at the false lumen was associated with the new formation of aortic aneurysm at the distal tear. The computational fluid model of aortic dissection based on patient-specific reverse engineering and fluid-structure interaction method can successfully reveal the relatively truly blood dynamic and wall pressure characteristic of type B aortic dissection.
利用患者特异性逆向工程和流固耦合构建B型主动脉夹层的计算流体模型，并评估计算流体模型在B型主动脉夹层主动脉重塑中的应用。连续采集一名B型主动脉夹层患者在初始诊断时、原发破口血管腔内修复术后1周和6年以及远端破口侵蚀血管腔内修复术后3个月的计算机断层血管造影数据。通过Mimics对主动脉夹层的三维模型进行逆向重建，然后用Geomagic对模型进行平滑处理。在ANSYS中通过双向流固耦合进行计算流体动力学数值模拟，评估B型主动脉夹层血液动力学特征与血栓形成重塑之间的关系。成功构建了采用患者特异性逆向工程和流固耦合方法的B型主动脉夹层计算流体模型。发现主动脉弓与降主动脉交界处凸面的局部血压峰值。假腔处的壁面应力远高于真腔，壁面应力峰值集中在假腔边缘和破口处。排除近端破口后，血流流线明显减少并出现反向流动。剩余假腔内的血流从左髂动脉入口逆行，在假腔顶部形成湍流，这有利于夹层血栓重塑。假腔内较高的压力与远端破口处主动脉瘤的新形成有关。基于患者特异性逆向工程和流固耦合方法的主动脉夹层计算流体模型能够成功揭示B型主动脉夹层相对真实的血液动力学和壁面压力特征。
