Computer modeling for the prediction of thoracic aortic stent graft collapse
Computer modeling for the prediction of thoracic aortic stent graft collapse
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DOI：
10.1016/j.jvs.2012.09.063
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发表时间：
2013-05-01
影响因子：
4.3
通讯作者：
Vorp, David A.
中科院分区：
文献类型：
--
作者：
Pasta, Salvatore;Cho, Jae-Sung;Vorp, David A.
目的：通过模拟结构载荷和量化胸主动脉支架壁突出延伸至模型弓的流体动力学，评估支架过度突出至主动脉弓与胸主动脉支架（TASG）塌陷的生物力学意义。方法：采用单向耦合的流固相互作用分析方法，对一例外伤性胸主动脉损伤修复术后重建的主动脉壁和TASG近端突出部位施加的血流动力学和结构载荷进行研究。Gore TAG胸内假体（W. L. Gore and Assoc, Flagstaff, arizona）的力学性能通过实验性径向压缩测试进行评估，并纳入计算模型。TASG壁突出的几何特征是突出延伸（PE）和TASG与主动脉小曲率之间的角度（theta）。在PE固定于1.1 cm的情况下，采用theta = 10°、20°、30°和40°四种模型探讨theta的作用。采用4个模型评价PE的效果，分别为：PE = 1.1 cm、1.4 cm、1.7 cm和2.0 cm， theta固定为10度。结果：TASG壁突入主动脉弓导致内移植物近端腔面形成旋涡状、复杂的血流区。高PE值（PE = 2.0 cm）导致左锁骨下血流速率明显降低（0.27 L/min），收缩期灌注压降低（98 mm Hg），收缩期TASG峰值直径减小（2 mm）。当PE = 2.0 cm, θ = 10°时，跨壁压力负荷最大；当PE = 1.1 cm, θ = 40°时，跨壁压力负荷为11.6 mm Hg。结论：本研究的结果表明，PE升高会增加远端器官灌注不良和近端高血压的明显风险，PE和θ的升高都会导致TASG壁跨壁压力显著增加，这种负荷预示着TASG塌陷。患者特异性计算模型可以识别TASG崩溃的高风险患者，并指导预防性干预。[J] .中华外科杂志，2013;57:1353-61。
Objective: To assess the biomechanical implications of excessive stent protrusion into the aortic arch in relation to thoracic aortic stent graft (TASG) collapse by simulating the structural load and quantifying the fluid dynamics on the TASG wall protrusion extended into a model arch.Methods: One-way coupled fluid-solid interaction analyses were performed to investigate the flow-induced hemodynamic and structural loads exerted on the proximal protrusion of the TASG and aortic wall reconstructed from a patient who underwent traumatic thoracic aortic injury repair. Mechanical properties of a Gore TAG thoracic endoprosthesis (W. L. Gore and Assoc, Flagstaff, Ariz) were assessed via experimental radial compression testing and incorporated into the computational modeling. The TASG wall protrusion geometry was characterized by the protrusion extension (PE) and by the angle (theta) between the TASG and the lesser curvature of the aorta. The effect of theta was explored with the following four models with PE fixed at 1.1 cm: theta = 10 degrees, 20 degrees, 30 degrees, and 40 degrees. The effect of PE was evaluated with the following four models with theta fixed at 10 degrees: PE = 1.1 cm, 1.4 cm, 1.7 cm and 2.0 cm.Results: The presence of TASG wall protrusion into the aortic arch resulted in the formation of swirling, complex flow regions in the proximal luminal surface of the endograft. High PE values (PE = 2.0 cm) led to a markedly reduced left subclavian flow rate (0.27 L/min), low systolic perfusion pressure (98 mm Hg), and peak systolic TASG diameter reduction (2 mm). The transmural pressure load across the TASG was maximum for the model with the highest PE and theta, 15.2 mm Hg for the model with PE = 2.0 cm and theta = 10 degrees, and 11.6 mm Hg for PE = 1.1 cm and theta = 40 degrees.Conclusions: The findings of this study suggest that increased PE imparts an apparent risk of distal end-organ malperfusion and proximal hypertension and that both increased PE and theta lead to a markedly increased transmural pressure across the TASG wall, a load that would portend TASG collapse. Patient-specific computational modeling may allow for identification of patients with high risk of TASG collapse and guide preventive intervention. (J Vasc Surg 2013;57:1353-61.)