From the Departments of Radiology (M.S., E.R., P.K.N.)
Neurology (M.S., H.R.).
AJNR Am J Neuroradiol. 2018 Dec;39(12):2278-2283. doi: 10.3174/ajnr.A5874. Epub 2018 Nov 15.
Flow diversion is being increasingly used to treat bifurcation aneurysms. Empiric approaches have generally led to encouraging results, and a growing body of animal and ex vivo literature addresses the fate of target aneurysms and covered branches. Our prior investigations highlighted the dynamic nature of metal coverage provided by the Pipeline Embolization Device and suggested strategies for creating optimal single and multidevice constructs. We now address the geometric and hemodynamic aspects of jailing branch vessels and neighboring target aneurysms.
Fundamental electric and fluid dynamics principles were applied to generate equations describing the relationships between changes in flow and the degree of vessel coverage in settings of variable collateral support to the jailed territory. Given the high complexity of baseline and posttreatment fluid dynamics, in vivo, we studied a simplified hypothetic system with minimum assumptions to generate the most conservative outcomes.
In the acute setting, Pipeline Embolization Devices modify flow in covered branches, principally dependent on the amount of coverage, the efficiency of collateral support, and intrinsic resistance of the covered parenchymal territory. Up to 30% metal coverage of any branch territory is very likely to be well-tolerated regardless of device or artery size or the availability of immediate collateral support, provided, however, that no acute thrombus forms to further reduce jailed territory perfusion.
Basic hemodynamic principles support the safety of branch coverage during aneurysm treatment with the Pipeline Embolization Device. Rational strategies to build bifurcation constructs are feasible.
血流导向装置越来越多地用于治疗分叉部动脉瘤。经验性方法通常会取得令人鼓舞的结果,越来越多的动物和离体文献探讨了目标动脉瘤和覆盖分支的命运。我们之前的研究强调了 Pipeline 栓塞装置提供的金属覆盖的动态特性,并提出了创建最佳单器械和多器械结构的策略。现在,我们研究了监禁分支血管和邻近目标动脉瘤的几何和血液动力学方面。
应用基本的电路和流体动力学原理,生成了描述在可变侧支支持的情况下,血流变化与血管覆盖程度之间关系的方程。鉴于体内基线和治疗后血流动力学的高度复杂性,我们研究了一个简化的假设系统,该系统假设最少,以产生最保守的结果。
在急性情况下,血流导向装置会改变覆盖分支的血流,主要取决于覆盖程度、侧支支持的效率以及覆盖实质区域的固有阻力。任何分支区域高达 30%的金属覆盖率很可能是可以耐受的,无论设备或动脉的大小如何,或者是否有即时的侧支支持,只要没有急性血栓形成进一步降低监禁区域的灌注。
基本血液动力学原理支持在使用 Pipeline 栓塞装置治疗动脉瘤时对分支进行覆盖的安全性。构建分叉结构的合理策略是可行的。