Tran Kenneth, Feliciano K Brennan, Yang Weiguang, Schwarz Erica L, Marsden Alison L, Dalman Ronald L, Lee Jason T
Division of Vascular Surgery, Stanford University School of Medicine, Stanford, CA.
Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
JVS Vasc Sci. 2022 Apr 21;3:219-231. doi: 10.1016/j.jvssci.2022.04.002. eCollection 2022.
The durability of fenestrated endovascular aneurysm repair (fEVAR) has been threatened by thrombotic complications. In the present study, we used patient-specific computational fluid dynamic (CFD) simulation to investigate the effect of the endograft diameter on hemodynamics after fEVAR and explore the hypothesis that diameter-dependent alterations in aortic hemodynamics can predict for thrombotic events.
A single-institutional retrospective study was performed of patients who had undergone fEVAR for juxtarenal aortic aneurysms. The patients were stratified into large diameter (34-36 mm) and small diameter (24-26 mm) endograft groups. Patient-specific CFD simulations were performed using three-dimensional paravisceral aortic models created from computed tomographic images with allometrically scaled boundary conditions. Aortic time-averaged wall shear stress (TAWSS) and residence time (RT) were computed and correlated with future thrombotic complications (eg, renal stent occlusion, development of significant intraluminal graft thrombus).
A total of 36 patients (14 with a small endograft and 22 with a large endograft) were included in the present study. The patients treated with large endografts had experienced a higher incidence of thrombotic complications compared with small endografts (45.5% vs 7.1%; = .016). Large endografts were associated with a lower postoperative aortic TAWSS (1.45 ± 0.76 dynes/cm vs 3.16 ± 1.24 dynes/cm; < .001) and longer aortic RT (0.78 ± 0.30 second vs 0.34 ± 0.08 second; < .001). In the large endograft group, a reduction >0.39 dynes/cm in aortic TAWSS demonstrated discriminatory power for thrombotic complications (area under the receiver operating characteristic curve, 0.77). An increased aortic RT of ≥0.05 second had similar accuracy for predicting thrombotic complications (area under the receiver operating characteristic curve, 0.78). The odds of thrombotic complications were significantly higher if patients had met the hemodynamic threshold changes in aortic TAWSS (odds ratio, 7.0; 95% confidence interval, 1.1-45.9) and RT (odds ratio, 8.0; 95% confidence interval, 1.13-56.8).
Patient-specific CFD simulation of fEVAR in juxtarenal aortic aneurysms demonstrated significant endograft diameter-dependent differences in aortic hemodynamics. A postoperative reduction in TAWSS and an increased RT correlated with future thrombotic events after large-diameter endograft implantation. Patient-specific simulation of hemodynamics provides a novel method for thrombotic risk stratification after fEVAR.
开窗式血管腔内动脉瘤修复术（fEVAR）的耐久性受到血栓形成并发症的威胁。在本研究中，我们使用个体化计算流体动力学（CFD）模拟来研究移植物直径对fEVAR术后血流动力学的影响，并探讨主动脉血流动力学的直径依赖性改变可预测血栓形成事件的假说。
对接受fEVAR治疗近肾主动脉瘤的患者进行单中心回顾性研究。患者被分为大直径（34 - 36mm）和小直径（24 - 26mm）移植物组。使用从计算机断层扫描图像创建的三维内脏主动脉模型并采用异速生长缩放边界条件进行个体化CFD模拟。计算主动脉时间平均壁面切应力（TAWSS）和停留时间（RT），并将其与未来的血栓形成并发症（如肾支架闭塞、显著的腔内移植物血栓形成）相关联。
本研究共纳入36例患者（14例使用小移植物，22例使用大移植物）。与小移植物相比，接受大移植物治疗的患者血栓形成并发症发生率更高（45.5%对7.1%；P = 0.016）。大移植物与术后较低的主动脉TAWSS（1.45±0.76达因/厘米对3.16±1.24达因/厘米；P < 0.001）和较长的主动脉RT（0.78±0.30秒对0.34±0.08秒；P < 0.001）相关。在大移植物组中，主动脉TAWSS降低>0.39达因/厘米对血栓形成并发症具有鉴别能力（受试者操作特征曲线下面积，0.77）。主动脉RT增加≥0.05秒对预测血栓形成并发症具有相似的准确性（受试者操作特征曲线下面积，0.78）。如果患者达到主动脉TAWSS（优势比，7.0；95%置信区间，1.1 - 45.9）和RT（优势比，8.0；95%置信区间，1.13 - 56.8）的血流动力学阈值变化，则血栓形成并发症的几率显著更高。
对近肾主动脉瘤进行fEVAR的个体化CFD模拟显示，主动脉血流动力学存在显著的移植物直径依赖性差异。大直径移植物植入术后TAWSS降低和RT增加与未来血栓形成事件相关。血流动力学的个体化模拟为fEVAR术后血栓形成风险分层提供了一种新方法。
