Soulis Johannes V, Fytanidis Dimitrios K, Lampri Olga P, Giannoglou George D
Department of Civil Engineering, Fluid Mechanics Division, School of Engineering, Demokrition University of Thrace, Vas. Sofias 12, 67100 Xanthi, Greece; These authors contributed equally to this work.
The 1st Cardiology Department, Cardiovascular Engineering and Atherosclerosis Laboratory, AHEPA University Hospital, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Kiriakidi 1, 54621 Thessaloniki, Greece; These authors contributed equally to this work.
Cardiol Res. 2016 Apr;7(2):66-79. doi: 10.14740/cr467w. Epub 2016 May 4.
The temporal variation of the hemodynamic mechanical parameters during cardiac pulse wave is considered as an important atherogenic factor. Applying non-Newtonian blood molecular viscosity simulation is crucial for hemodynamic analysis. Understanding low density lipoprotein (LDL) distribution in relation to flow parameters will possibly spot the prone to atherosclerosis aorta regions.
The biomechanical parameters tested were averaged wall shear stress (AWSS), oscillatory shear index (OSI) and relative residence time (RRT) in relation to the LDL concentration. Four non-Newtonian molecular viscosity models and the Newtonian one were tested for the normal human aorta under oscillating flow. The analysis was performed via computational fluid dynamic.
Tested viscosity blood flow models for the biomechanical parameters yield a consistent aorta pattern. High OSI and low AWSS develop at the concave aorta regions. This is most noticeable in downstream flow region of the left subclavian artery and at concave ascending aorta. Concave aorta regions exhibit high RRT and elevated LDL. For the concave aorta site, the peak LDL value is 35.0% higher than its entrance value. For the convex site, it is 18.0%. High LDL endothelium regions located at the aorta concave site are well predicted with high RRT.
We are in favor of using the non-Newtonian power law model for analysis. It satisfactorily approximates the molecular viscosity, WSS, OSI, RRT and LDL distribution. Concave regions are mostly prone to atherosclerosis. The flow biomechanical factor RRT is a relatively useful tool for identifying the localization of the atheromatic plaques of the normal human aorta.
心脏脉搏波期间血液动力学力学参数的时间变化被认为是一个重要的动脉粥样硬化形成因素。应用非牛顿血液分子粘度模拟对于血液动力学分析至关重要。了解低密度脂蛋白（LDL）与血流参数相关的分布情况可能会发现易发生动脉粥样硬化的主动脉区域。
测试的生物力学参数是平均壁面剪应力（AWSS）、振荡剪切指数（OSI）和相对于LDL浓度的相对停留时间（RRT）。在振荡流条件下，对四种非牛顿分子粘度模型和牛顿模型在正常人体主动脉上进行了测试。通过计算流体动力学进行分析。
针对生物力学参数测试的粘度血流模型得出了一致的主动脉模式。高OSI和低AWSS出现在主动脉凹面区域。这在左锁骨下动脉下游血流区域和升主动脉凹面最为明显。主动脉凹面区域表现出高RRT和升高的LDL。对于主动脉凹面部位，LDL峰值比其入口值高35.0%。对于凸面部位，高18.0%。高RRT能很好地预测位于主动脉凹面部位的高LDL内皮区域。
我们支持使用非牛顿幂律模型进行分析。它能令人满意地近似分子粘度、壁面剪应力、OSI、RRT和LDL分布。凹面区域最易发生动脉粥样硬化。血流生物力学因素RRT是识别正常人体主动脉动脉粥样硬化斑块定位的一个相对有用的工具。
