School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing 100037, China.
Comput Methods Programs Biomed. 2023 Nov;241:107741. doi: 10.1016/j.cmpb.2023.107741. Epub 2023 Jul 31.
Parallel (chimney and periscope) graft technique is an effective approach for left subclavian artery (LSA) reconstruction in patients treated by thoracic endovascular aortic repair (TEVAR) for the inadequate landing zone. However, certain stent graft (SG) configurations may promote thrombosis and reduce distal blood flow, increasing risks of cerebral infarction and reintervention.
In this paper, we first attempt to systematically evaluate the hemodynamic performances of different parallel graft techniques as potential determinants of complication risks. Based on the patient-specific 3D aortic geometry undergoing parallel graft technique, fifteen models in total for five kinds of LSA branched SG configurations (Forward, Backward, Extended, Elliptical and Periscopic) were designed virtually, and the hemodynamic discrepancies between them were analyzed by computational fluid dynamics.
Results show that flow rate of patients undergoing periscope technique reduces by half compared with chimney technique, suggesting that periscope SG may cause more serious flow obstruction to LSA, leading to stroke. For chimney stent structure, the extension length 0has little influence on energy loss and other parameters. Conversely, hemodynamic differences between the retrograde curvature and the antegrade curvature are significant (time average WSS: 47.07%), so the retrograde curvature might prompt SG displacement. Furthermore, the flatter chimney SG induces more aggressive hemodynamic forces, among which the difference of the maximum WSS between the flatter SG and nearly round SG reaches 65.56%, leading to the greater risk of vascular wall damage.
Results obtained might provide suggestions for physicians to formulate appropriate parallel graft technique schemes in TEVAR.
在接受胸主动脉腔内修复术（TEVAR）治疗的患者中，由于左锁骨下动脉（LSA）的着陆区不足，平行（烟囱和潜望镜）移植技术是重建左锁骨下动脉的有效方法。然而，某些支架移植物（SG）的构型可能会促进血栓形成并减少远端血流，增加脑梗死和再介入的风险。
本文首先尝试系统地评估不同平行移植技术的血流动力学性能，作为并发症风险的潜在决定因素。基于接受平行移植技术的患者特定的 3D 主动脉几何形状，总共设计了 15 个模型，用于 5 种 LSA 分支 SG 构型（前向、后向、扩展、椭圆形和潜望镜），通过计算流体动力学分析它们之间的血流动力学差异。
结果表明，与烟囱技术相比，接受潜望镜技术的患者的血流速度降低了一半，这表明潜望镜 SG 可能会对 LSA 造成更严重的血流阻塞，导致中风。对于烟囱支架结构，延长长度 0 对能量损失和其他参数几乎没有影响。相反，逆行曲率和前向曲率之间的血流动力学差异非常显著（时间平均壁面切应力：47.07%），因此逆行曲率可能会促使 SG 移位。此外，更平坦的烟囱 SG 会引起更具侵略性的血流动力，其中更平坦的 SG 和几乎圆形的 SG 之间的最大壁面切应力差异达到 65.56%，导致血管壁损伤的风险更大。
所得结果可能为医生在 TEVAR 中制定适当的平行移植技术方案提供建议。
