Baráth Krisztina, Cassot Francis, Fasel Jean H D, Ohta Makoto, Rüfenacht Daniel A
Department of Radiology, University Hospital of Geneva, Geneva, Switzerland.
Neurol Res. 2005;27 Suppl 1:S120-8. doi: 10.1179/016164105X35477.
Stent implantation across the neck of cerebral aneurysms may induce intra-aneurysmal flow reduction, and consequently saccular thrombosis and vessel wall repair. To analyse the influence of different stent parameters on such flow reduction, we studied the flow changes in vascular models, induced by a series of stents.
Two different neck-sized elastic sidewall aneurysm models were connected to a circulatory loop. Twenty different stents were introduced in both models to analyse the effect of their parameters, such as porosity, filament diameter and permeability. Flow patterns were visualized by using glass particles and laser sheet translumination. The digitally recorded data were transferred for computer analysis. The changes of the vortex velocity for each stent model combination were investigated and statistically evaluated.
Intra-aneurysmal flow analysis showed dispersion of the vortices of a variable degree, and velocity reduction of 30% mean in model 1 and 49% mean in model 2. By statistical analysis three groups of stents ('best', 'medium', 'worst') were identified, according to their haemodynamic efficacy. No correlations were observed between the haemodynamic performance of the stents and the porosity, filament diameter and permeability values separately. The stent effects were on average more important in the large-necked than in the small-necked aneurysm model.
Stent implantation induces intra-aneurysmal loss of vortex coherence and flow reduction. The analysed stent parameters show complex interrelationship, including also stent 'design'. The difference in the haemodynamic efficacy of the individual stents between the two models raises the question of 'stent positioning effects'.
在脑动脉瘤颈部植入支架可能会导致动脉瘤内血流减少，进而引起囊状血栓形成和血管壁修复。为分析不同支架参数对这种血流减少的影响，我们研究了一系列支架在血管模型中引起的血流变化。
将两种不同颈部尺寸的弹性侧壁动脉瘤模型连接到一个循环回路中。在两个模型中分别植入20种不同的支架，以分析其参数（如孔隙率、丝径和渗透率）的影响。使用玻璃颗粒和激光片透射法观察血流模式。将数字记录的数据传输进行计算机分析。研究并统计评估每种支架模型组合的涡旋速度变化。
动脉瘤内血流分析显示涡旋有不同程度的分散，模型1中平均流速降低30%，模型2中平均流速降低49%。通过统计分析，根据血流动力学效果确定了三组支架（“最佳”、“中等”、“最差”）。未观察到支架的血流动力学性能与孔隙率、丝径和渗透率值之间分别存在相关性。在大颈动脉瘤模型中，支架的影响平均比小颈动脉瘤模型更显著。
支架植入会导致动脉瘤内涡旋连贯性丧失和血流减少。所分析的支架参数显示出复杂的相互关系，其中还包括支架“设计”。两种模型中各个支架血流动力学效果的差异提出了“支架定位效应”的问题。
