The influence of flow, vessel diameter, and non-Newtonian blood viscosity on the wall shear stress in a carotid bifurcation model for unsteady flow
The influence of flow, vessel diameter, and non-Newtonian blood viscosity on the wall shear stress in a carotid bifurcation model for unsteady flow
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DOI：
10.1097/01.rli.0000160550.95547.22
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发表时间：
2005-05-01
影响因子：
6.7
通讯作者：
Reiber, JHC
中科院分区：
文献类型：
--
作者：
Box, FMA;van der Geest, RJ;Reiber, JHC
目的：动脉粥样硬化过程与局部壁面切应力（WSS）密切相关。斑块发展特别发生在有再循环的区域（即WSS振荡的区域）。我们研究了非牛顿的血液粘度，流速的变化，血管直径的影响，在颈动脉分叉model.Materials和方法的壁现象：通过模型的颈动脉分叉的流动模拟通过有限元方法。全血粘度是剪切速率的函数，并且通过Carreau-Yasuda（CY）模型建模。通过磁共振成像评估流速和血管形态。在49名健康志愿者中测量流速、血液粘度和红细胞压积水平（Hct）。我们提出了一个适应的CY模型，以便在Hct的差异可以被纳入;此外，血浆粘度是不同的CY model.Results：从我们的模型的数据表明，流量的增加有一个更大的影响WSS比预测一个简单的抛物面模型。血浆粘度低时，Hct对WSS的影响更大。低血浆粘度与低WSS相关，这意味着矛盾，因为高WSS和低血浆粘度都被认为是健康系统的指标。最大WSS振荡被发现在边缘的回流regions.Conclusions：流量和直径的变化有显着的影响，对壁面剪切应力值的粘度也是如此，但在较小的程度上。
Objectives: The atherosclerotic process in arteries is correlated with the local wall shear stress (WSS). Plaque development particularly occurs in regions with recirculation (ie, where the WSS oscillates). We investigated the effects of non-Newtonian blood viscosity, variations in flow rate, and vessel diameter on wall phenomena in a carotid bifurcation model.Materials and Methods: The flow through a model of a carotid artery bifurcation was simulated by means of the finite element method. The whole-blood viscosity is a function of shear rate, and was modeled by the Carreau-Yasuda (CY) model. Flow rate and vessel morphology were assessed with magnetic resonance imaging. Flow rate, blood viscosity, and hematocrit levels (Hct) were measured in 49 healthy volunteers. We propose an adaptation of the CY model so that differences in Hct can be incorporated; furthermore, plasma viscosity was varied in the CY model.Results: The data from our model indicate that flow increases have a larger effect on the WSS than predicted with a simple paraboloid model. Hct had more influence on the WSS when the plasma viscosity was low. Low plasma viscosity was associated with a low WSS, which implies a contradiction, because both high WSS and low plasma viscosity are thought to be indicators for a healthy system. Maximum WSS oscillations were found at the edges of the recirculation region.Conclusions: Flow and diameter changes have significant influence on wall shear stress values; the same is true for the viscosity, but to a lesser extent.