Kerl Hans U, Boll Hanne, Fiebig Teresa, Figueiredo Giovanna, Förster Alex, Nölte Ingo S, Nonn Andrea, Groden Christoph, Brockmann Marc A
*University of Heidelberg, Medical Faculty Mannheim, Department of Neuroradiology, Mannheim, Germany; ‡University Hospital of the RWTH Aachen, Department of Diagnostic and Interventional Neuroradiology, Aachen, Germany.
Neurosurgery. 2014 Mar;74(3):321-34; discussion 334. doi: 10.1227/NEU.0000000000000253.
Flow-diverting stent (FDS) implantation is an endovascular treatment option for intracranial aneurysms. However, little is known about the hemodynamic effects.
To assess the effect of stent compression on FDS porosity, to evaluate the influence of single and overlapping implantation of FDS on intra-aneurysmal flow profiles, and to correlate stent porosity with changes in static mean intra-aneurysmal pressure.
Intra-aneurysmal time-density curves were recorded in a pulsatile in vitro flow model before and after implantation of FDSs (Pipeline Embolization Device; ev3) in 7 different types of aneurysm models. Reductions in the maximum contrast inflow and time to maximum intra-aneurysmal contrast were calculated. Micro--computed tomography was performed, and compression-related FDS porosity was measured. The influence of FDS placement on mean static intra-aneurysmal pressure was measured.
FDS compression resulted in an almost linear reduction in stent porosity. Stent porosity (struts per 1 mm) correlated significantly with the reduction of aneurysm contrast inflow (R = 0.81, P < .001) and delay until maximum contrast (R = 0.34, P = .001). Circulating intra-aneurysmal high-velocity flow was terminated in all sidewall models after implantation of a single stent. Superimposition of 2 stents reduced maximum intra-aneurysmal contrast by 69.1 ± 3.1% (mean ± SD) in narrow-necked sidewall aneurysm models, whereas no substantial reduction in maximum intra-aneurysmal contrast was observed in wide-necked sidewall aneurysm models. Intra-aneurysmal mean static pressure did not correlate with FDS porosity or number of implanted stents.
Implantation of FDS effectively reduces aneurysm inflow in a porosity-dependent way without relevantly affecting static mean intra-aneurysmal pressure.
FDS, flow-diverting stentMAP, mean arterial pressurePED, Pipeline Embolization Device.
血流导向支架（FDS）植入术是颅内动脉瘤的一种血管内治疗选择。然而，对其血流动力学影响知之甚少。
评估支架压缩对FDS孔隙率的影响，评价FDS单枚及重叠植入对动脉瘤内血流分布的影响，并将支架孔隙率与动脉瘤内静态平均压力的变化相关联。
在7种不同类型的动脉瘤模型中，于植入FDS（Pipeline栓塞装置；ev3）前后，在体外脉动血流模型中记录动脉瘤内时间-密度曲线。计算最大对比剂流入量的减少以及达到最大动脉瘤内对比剂的时间。进行微型计算机断层扫描，并测量与压缩相关的FDS孔隙率。测量FDS放置对动脉瘤内静态平均压力的影响。
FDS压缩导致支架孔隙率几乎呈线性降低。支架孔隙率（每1 mm的金属丝）与动脉瘤对比剂流入量的减少显著相关（R = 0.81，P <.001），与达到最大对比剂的延迟时间也显著相关（R = 0.34，P =.001）。在所有侧壁模型中，植入单枚支架后，动脉瘤内循环的高速血流均终止。在窄颈侧壁动脉瘤模型中，两枚支架重叠使最大动脉瘤内对比剂减少69.1±3.1%（平均值±标准差），而在宽颈侧壁动脉瘤模型中，未观察到最大动脉瘤内对比剂有实质性减少。动脉瘤内静态平均压力与FDS孔隙率或植入支架数量无关。
FDS植入术以依赖孔隙率的方式有效减少动脉瘤血流，而对动脉瘤内静态平均压力无显著影响。
FDS，血流导向支架；MAP，平均动脉压；PED，Pipeline栓塞装置
