From the Department of Neurosurgery (N.V., W.C., D.Z., Y.F., Q.H., J.L.), Changhai Hospital, Second Military Medical University, Shanghai, China.
National Scientific and Technical Research Council of Argentina (I.L.), Buenos Aires, Argentina.
AJNR Am J Neuroradiol. 2018 Jan;39(1):118-122. doi: 10.3174/ajnr.A5452. Epub 2017 Nov 2.
The multiple stent placement technique has largely improved the long-term outcomes of intracranial fusiform aneurysms, but the hemodynamic mechanisms remain unclear. In this study, we analyzed the hemodynamic changes caused by different stent-placement strategies in patient-specific models using the computational fluid dynamics technique, aiming to provide evidence for clinical decision-making.
Ten vertebral artery fusiform aneurysms were included, and their patient-specific computational fluid dynamics models were reconstructed. A fast virtual stent placement technique was used to simulate sequential multiple stent placements (from a single stent to triple stents) in the vertebral artery fusiform aneurysm models. Hemodynamic parameters, including wall shear stress, pressure, oscillatory shear index, relative residence time, and flow pattern, were calculated and compared among groups with different numbers of stents.
Virtual stents were deployed in all 10 cases successfully, consistent with the real stent configuration. Wall shear stress decreased progressively by 7.2%, 20.6%, and 25.8% as the number of stents increased. Meanwhile, relative residence time and pressure increased on average by 11.3%, 15.4%, and 45.0% and by 15.7%, 21.5%, and 28.2%. The oscillatory shear index showed no stable variation trend. Flow patterns improved by weakening the intensity of the vortices and displacing the vortex center from the aneurysmal wall.
Stent placement modifies hemodynamic patterns in vertebral artery fusiform aneurysms, which might favor thrombosis formation in the aneurysmal sac. This effect is amplified with the number of stents deployed. However, a potential risk of rupture or recanalization exists and should be considered when planning to use the multiple stent placement technique in vertebral artery fusiform aneurysms.
多支架置入技术在很大程度上改善了颅内梭形动脉瘤的长期预后，但血流动力学机制仍不清楚。本研究旨在通过计算流体动力学技术分析特定患者模型中不同支架置入策略引起的血流动力学变化，为临床决策提供依据。
纳入 10 例椎动脉梭形动脉瘤患者，重建其个体化计算流体动力学模型。采用快速虚拟支架置入技术模拟椎动脉梭形动脉瘤模型中连续的多支架置入（从单支架到三支架）。计算并比较了不同支架数量组的血流动力学参数，包括壁面切应力、压力、振荡剪切指数、相对停留时间和流型。
10 例患者的虚拟支架均成功置入，与真实支架构型一致。随着支架数量的增加，壁面切应力逐渐降低 7.2%、20.6%和 25.8%。同时，相对停留时间和压力平均增加 11.3%、15.4%和 45.0%以及 15.7%、21.5%和 28.2%。振荡剪切指数没有稳定的变化趋势。流型通过减弱涡流强度和将涡流中心从动脉瘤壁上移来改善。
支架置入改变了椎动脉梭形动脉瘤的血流动力学模式，可能有利于动脉瘤腔内血栓形成。这种效果随着支架数量的增加而放大。然而，存在破裂或再通的潜在风险，在计划使用椎动脉梭形动脉瘤的多支架置入技术时应考虑这一风险。
