Hemodynamic evaluation of embolic trajectory in an arterial bifurcation - An in-vitro experimental model
Hemodynamic evaluation of embolic trajectory in an arterial bifurcation - An in-vitro experimental model
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DOI：
10.1161/01.str.0000190097.08862.9a
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发表时间：
2005-12-01
期刊：
影响因子：
8.3
通讯作者：
Tanne, D
中科院分区：
文献类型：
--
作者：
Bushi, D;Grad, Y;Tanne, D
背景和目的-尽管栓塞作为脑梗死的主要原因很重要，但对于大栓子倾向于遵循的血流动力学因素知之甚少。我们的目的是在体外测试，在y形分支模型中，除分支之间的流量比外，其他血流动力学参数是否会影响栓塞颗粒的分布，该模型用于模拟动脉分支。方法：体外实验使用水-甘油混合物中的球形颗粒悬浮液（0.6,1.6和3.2 mm），在y形分叉模型中使用稳定和脉动的层流模式(相同的分支角[θ (1) = θ(2) = 45度]，其中一个子分支直径比另一个更宽[D-1 = 6 mm, D-2 = 4 mm]；平均雷诺数500)。结果-在稳定流动条件和四种出口流量比下使用自然浮力颗粒的实验表明，小（0.6 mm）和中型（1.6 mm）颗粒非优先进入较窄或较宽的分岔子分支，与流量比成比例。然而，大颗粒（3.2 mm）优先进入较宽的子分支。此外，随着流量比的增加，这种现象也会增强。进一步的实验表明，在脉动流动和颗粒与流体的密度比下，更宽的子分支对高颗粒与分支直径比的偏好进一步增加。结论：除了出口流量比之外，分支中的颗粒分布还受到颗粒与分支直径比的影响。在脉动流动条件下，大颗粒优先进入流量比以外的更宽分叉分支的趋势增强，并受颗粒与流体密度比的影响。这些发现可能对理解大栓子形成轨迹的血流动力学机制具有重要意义。
Background and Purpose - Despite the importance of embolism as a major cause of brain infarction, little is known about the hemodynamic factors governing the path large emboli tend to follow. Our aim was to test in vitro, whether hemodynamic parameters other than flow ratios between bifurcation branches may affect the distribution of embolic particles in a Y-shaped bifurcation model, used as an analogue to an arterial bifurcation.Methods - In vitro experiments were conducted using suspensions of sphere-shaped particles (0.6, 1.6, and 3.2 mm) in water-glycerin mixture, using steady and pulsatile laminar flow regimes in a Y-shaped bifurcation model (identical branching angles [theta(1) = theta(2) = 45 degrees] with one daughter branch diameter wider than the other [D-1 = 6 mm, D-2 = 4 mm]; average Reynolds number 500).Results - Experiments using naturally buoyant particles under steady flow conditions and four outlet-flow ratios revealed that small (0.6 mm) and mid-sized (1.6 mm) particles entered into either the narrower or wider bifurcation daughter branch nonpreferentially, proportionally to the flow ratios. Large particles (3.2 mm), however, preferentially entered the wider daughter branch. Moreover, as the flow ratio increases this phenomenon was augmented. Further experiments revealed that the preference of the wider daughter branch for high particle-to-branch diameter-ratios further increases under pulsatile flow and by the density ratio between particles and fluid.Conclusion - Particles' distribution in a bifurcation is affected, beyond its outlets-flow-ratios, by the particle-to-branch diameter-ratio. The tendency of large particles to preferentially enter the wider bifurcation branch, beyond the flow ratio, is augmented under pulsatile flow conditions and is affected by particle-to-fluid density-ratio. These findings may have important implications for understanding the hemodynamic mechanisms underlying the trajectory of large emboli.