计算机模拟支架植入后载瘤动脉位移对动脉瘤复发的流体力学影响

Stent–assisted embolization has become the first line therapy for almost bifurcation aneurysms. Due to intracranial distal bifurcation aneurysms are located in the subarachnoid space, parent arteries shape change significantly after Stent–assisted deployment leading to local hemodynamics obviously change and affect the biological features of the aneurysms. Computational flow dynamics (CFD) has been used in studying the intracranial aneurysms, but as for these aspects study has no reports about hemodynamics changes of parent arteries after stent deployment for these bifurcation aneurysms in the subarachnoid space..This study first use the 3D rigid vascular wall models, various intracranial stent models and coil porosity medium model, adopt modified finite element method simulation release of the stents technique. Combining the effect factors of the hydromechanics parameters determined by the stent struts, we study the local hydromechanics parameters changes determined by the angle alteration on the neck of parent artery at stent pre-implanted, post and follow up. Comparative study corresponding cases adopt the coiling technique is to find the discrepancy the recurrence arte via the long–term follow up in order to seek the hydromechanics characteristic parameters influencing the growth and recurrence of aneurysms for treatment of the distal bifurcation affording the theoretical foundation.

支架辅助栓塞成为多数分叉部宽颈动脉瘤的首选治疗方法。颅内远端分叉部动脉瘤游离于蛛网膜下腔，支架释放后载瘤动脉变形明显，局部流体力学可能发生明显改变，进而影响动脉瘤的生物学特性。计算机模拟流体力学已被应用于颅内动脉瘤治疗的研究，但对游离于蛛网膜下腔的分叉部动脉瘤支架后载瘤动脉成角重塑后流体力学变化的研究尚未见报道。.本研究首次利用三维血管刚性壁模型、各种颅内支架模型及弹簧圈多孔介质模型，采用优化版有限元法模拟支架释放技术，结合支架网孔对流体力学参数的影响因素，研究支架释放前后及栓塞后的载瘤动脉瘤颈处成角重塑引起的局部流体力学参数变化；对比研究相应病例单纯栓塞的局部流体力学参数，通过长期随访单纯栓塞与支架辅助病例的复发概率有无差异，寻找支架影响动脉瘤生长和栓塞后复发的流体力学特征性参数，为支架辅助栓塞远端分叉部动脉瘤方案设计提供理论依据。

背景：颅内分叉部动脉瘤形成及破裂与载瘤动脉分叉成角有关，同时支架植入后具有拉直载瘤动脉效应。.主要研究内容：与单纯弹簧圈栓塞比较，长期随访颅内分支动脉瘤支架辅助栓塞的安全性及有效性，并比较常用支架的拉直效应；应用有限元方法模拟不同弹簧圈及支架，建立支架、弹簧圈模型数据库；有限元方法验证支架的拉直效应的流体力学效果；运用有限元方法比较不同支架的拉直效应与支架网孔的流体力学效果；比较支架辅助栓塞与单纯弹簧圈栓塞的流体力学效果；评估支架的拉直效应是否可产生不利的流体力学效果；评估Y形支架的流体力学效果；探寻颅内分叉动脉瘤复发的特征性流体力学参数。.重要成果:支架拉直效应可降低动脉瘤的复发率；闭环支架Solitaire的拉直效应明显优于开环支架Neuroform，且复发率明显低于Neuroform支架；成功模拟并建立不同支架、弹簧圈的有限元模型数据库, 并揭示支架的拉直效应的流体力学效果；三种支架的拉直效应均优于支架网孔的流体力学效果；证实了支架辅助栓塞的流体力学效果明显优于单纯弹簧圈栓塞；对于瘤颈偏向一侧分支的动脉瘤，支架的拉直效应可产生即刻的不利的流体力学效果；单支架产生的流体力学效果可优于Y形支架；瘤颈高流速流入道（>0.3m/s）面积可预测动脉瘤复发。.科学意义：支架的拉直效应可引起载瘤动脉血流重塑，从而可明显降低动脉瘤复发率；有限元方法计算机模拟可为术前制定个性化的精准栓塞策略。