Roszelle Breigh N, Nair Priya, Gonzalez L Fernando, Haithem Babiker M, Ryan Justin, Frakes David
J Biomech Eng. 2014 Feb;136(2):021013. doi: 10.1115/1.4026257.
Whether treated surgically or with endovascular techniques, large and giant cerebral aneurysms are particularly difficult to treat. Nevertheless, high porosity stents can be used to accomplish stent-assisted coiling and even standalone stent-based treatments that have been shown to improve the occlusion of such aneurysms. Further, stent assisted coiling can reduce the incidence of complications that sometimes result from embolic coiling (e.g., neck remnants and thromboembolism). However, in treating cerebral aneurysms at bifurcation termini, it remains unclear which configuration of high porosity stents will result in the most advantageous hemodynamic environment. The goal of this study was to compare how three different stent configurations affected fluid dynamics in a large patient-specific aneurysm model. Three common stent configurations were deployed into the model: a half-Y, a full-Y, and a crossbar configuration. Particle image velocimetry was used to examine post-treatment flow patterns and quantify root-mean-squared velocity magnitude (VRMS) within the aneurysmal sac. While each configuration did reduce VRMS within the aneurysm, the full-Y configuration resulted in the greatest reduction across all flow conditions (an average of 56% with respect to the untreated case). The experimental results agreed well with clinical follow up after treatment with the full-Y configuration; there was evidence of thrombosis within the sac from the stents alone before coil embolization was performed. A computational simulation of the full-Y configuration aligned well with the experimental and in vivo findings, indicating potential for clinically useful prediction of post-treatment hemodynamics. This study found that applying different stent configurations resulted in considerably different fluid dynamics in an anatomically accurate aneurysm model and that the full-Y configuration performed best. The study indicates that knowledge of how stent configurations will affect post-treatment hemodynamics could be important in interventional planning and demonstrates the capability for such planning based on novel computational tools.
无论是采用手术治疗还是血管内技术治疗，大型和巨大型脑动脉瘤都特别难以治疗。然而，高孔隙率支架可用于完成支架辅助弹簧圈栓塞术，甚至是基于支架的独立治疗，这些治疗已被证明可改善此类动脉瘤的闭塞情况。此外，支架辅助弹簧圈栓塞术可降低有时由栓塞性弹簧圈栓塞引起的并发症发生率（例如，瘤颈残留和血栓栓塞）。然而，在治疗分叉末端的脑动脉瘤时，哪种高孔隙率支架配置会导致最有利的血流动力学环境仍不清楚。本研究的目的是比较三种不同的支架配置如何影响大型患者特异性动脉瘤模型中的流体动力学。三种常见的支架配置被部署到模型中：半Y形、全Y形和横杆配置。使用粒子图像测速技术检查治疗后的血流模式，并量化动脉瘤腔内的均方根速度大小（VRMS）。虽然每种配置确实都降低了动脉瘤内的VRMS，但全Y形配置在所有血流条件下导致的降低幅度最大（相对于未治疗的情况平均降低56%）。实验结果与采用全Y形配置治疗后的临床随访结果非常吻合；在进行弹簧圈栓塞之前，仅从支架就有动脉瘤腔内血栓形成的证据。全Y形配置的计算模拟与实验和体内研究结果吻合良好，表明对治疗后血流动力学进行临床有用预测的潜力。本研究发现，应用不同的支架配置在解剖学精确的动脉瘤模型中会导致显著不同的流体动力学，并且全Y形配置表现最佳。该研究表明，了解支架配置如何影响治疗后的血流动力学在介入规划中可能很重要，并展示了基于新型计算工具进行此类规划的能力。
