Modeling the effect of blood viscosity on hemodynamic factors in a small bifurcated artery
Modeling the effect of blood viscosity on hemodynamic factors in a small bifurcated artery
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DOI：
10.1016/j.ces.2011.12.015
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发表时间：
2012-03-26
影响因子：
4.7
通讯作者：
Paras, S. V.
中科院分区：
文献类型：
--
作者：
Kanaris, A. G.;Anastasiou, A. D.;Paras, S. V.
许多研究将高粘滞血症与心血管疾病、高血压和脑梗塞联系起来，因此血流动力学因素的研究对于理解、预测和治疗此类疾病非常重要。在这项工作中，数值研究了血液粘度对小口径分叉动脉（母动脉：600μm，子动脉：470μm）中壁剪切应力（WSS）、壁剪切应力梯度（WSSG）、血流速率和压降等几个血流动力学因素的影响。模拟中使用了 CFD 代码，该代码已通过本实验室获得的相关实验数据进行了验证。为了模拟血液的脉动流，施加了速度波动（U 平均值=0.080-0.105 m/s）作为入口边界条件。由于血液是非牛顿流体，其粘度是使用卡森模型计算的。结果表明，当血液粘度增加时，心脏也必须增加其泵血功率（高达126%）才能保持心输出量不变。另一方面，如果假设心脏的泵血功率固定，则血流速率会相应衰减（对于所研究的最高血细胞比容，衰减 64%）。对于所有研究的病例，发现分叉外壁处的 WSS 值低于动脉壁其余部分的值。在分叉顶点计算的高 WSS 和 WSSG 值（分别为 10 Pa 和 4 x 10(4) Pa/m，H-t=45%）表明该位置容易发生内皮损伤。这些发现可能有助于理解与高粘滞血症引起的血管损伤相关的机制。 (C) 2011 Elsevier Ltd. 保留所有权利。
Many studies link hyperviscosity to cardiovascular diseases, hypertension and cerebral infraction, rendering the study of hemodynamic factors very important for understanding, predicting and treating this type of disorders. In this work the effect of blood viscosity on several hemodynamic factors, such as wall shear stress (WSS), wall shear stress gradient (WSSG), blood flow rate and pressure drop in a small-caliber bifurcated artery (parent: 600 mu m, daughters: 470 mu m) was numerically studied. A CFD code, validated by relevant experimental data acquired in this Lab, was used for the simulations. In order to simulate the pulsatile flow of blood a velocity fluctuation has been imposed (U-mean=0.080-0.105 m/s) as inlet boundary condition. As blood is a non-Newtonian fluid, its viscosity was calculated using the Casson model. The results showed that, when blood viscosity increases, the heart must also increase its pumping power (up to 126%) in order to keep cardiac output unchanged. On the other hand, and if it is assumed that the pumping power of the heart is fixed, the blood flow rate is attenuated accordingly (by 64% for the highest hematocrit studied). For all cases studied it was found that at the outer wall of the bifurcation WSS values are lower than those on the rest of the arterial wall. The high WSS and WSSG values calculated at the apex of the bifurcation (10 Pa and 4 x 10(4) Pa/m, respectively, for H-t=45%) indicate that this location is predisposed to endothelium damages. These findings could aid in the comprehension of the mechanisms related to vascular damages caused by hyperviscosity. (C) 2011 Elsevier Ltd. All rights reserved.