Interaction of Elastic Vessel Wall and Arterial Blood Flow

弹性血管壁与动脉血流的相互作用

基本信息

批准号：
02670618
负责人：
SEKI Junji
金额：
$ 1.41万
依托单位：
National Cardiovascular Center Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02670618/
关键词：
Pulsatile flow Elastic tube flow Vessel wall elasticity Laser-Doppler anemometer Pulse propagation Propagation velocity Microvascular network Spontaneously hypertensive rat 乱流遷移脈波レイノルズ数ウォマ-スリ数

项目摘要

Effects of the elasticity of the vessel walls on the blood flow characteristics are studied in vitro and In vivo using laser-Doppler anemometers (LDA).In in vitro experiments, a flow apparatus was devised to produce a fully developed pulsatile flow of which Reynolds number and frequency parameter can be vaded for the ranges corresponding to those of the blood flow In the human large arteries. The flow tube was chosen to be 15 mm In diameter and 4.3 m long to produce the developed flow for the Reynolds number up to 5000. The pulsatile flow with non zero mean flow rate is generated by a rotating sheath and a slit put at the outlet of the flow tube. The flow velocity was measured by a 2-dimensional LDA system and the velocity profiles over the cross-section of the tube are obtained by traversing the LDA system. The velocity profile obtained under a steady flow condition was well represented by the Poiseuille velocity profile corresponding to the flow rate measured by an electromagnetic fl … More ow meter, which shows the flow was fully developed. The velocity profiles under a pulsatile flow condition showed a flow reversal near the tube wall in the phases of minimum flow although the total flow rate was always positiv during the pulsation period. Inflection points were also observed In the velocity profiles at the acceleration phases. These features of the pulsatile velocity profiles agree well with the theoretical expectations for the unsteady flow of an incompressible fluid through a straight circular cylinder. Elastic tube highly transparent for the measurement with LDA was made from polyurethane and the velocity measurement inside the elastic tube is in progress.In in vivo experiments, pulsation of the blood flow was studied in microvessels of the mesente ry of rats (SHR and WKY) by a fiber-optic laser-Doppler anemometer microscope (FLDAM) in relation to the rheology and the network topology of the microvessels. The phase lag of the microvascular flow relative to the carotid arterial pressure increased with decreasing diameter of arterioles in SHR mesentery, while there was little correlation between them In WKY. The propagation of the flow pulse In arterioles was theoretically treated by a porous tapered elastic tube model simulating the microvascular tree and the experimental results were analyzed based on this model. It was suggested from the model that the difference observed in the flow pulsation between SHR and WKY might be due to the longer arteriolar length and the fewer branch points in the SHR microvasculature than WKY. The velocity of the propagation of the flow pulse was also measured in arterioles with diameters from 10 to 30 mum to estimate the elastic property of single vessels. The propagation velocity was in the order of 10 cm/s and increased with the increasing vessel diameter, which is also consistent with the prediction derived from the porous tapered elastic tube model. Less

使用激光多普勒风速计（LDA）在体外和体内研究了血管壁弹性对血流特性的影响。在体外实验中，设计了一种流动装置来产生完全发展的脉动流，其雷诺数和频率参数可适用于与人体大动脉中的血流相对应的范围。选择直径为 15 mm、长为 4.3 m 的流量管以产生雷诺兹的开发流量。数量高达 5000。通过旋转护套和流量管出口处的狭缝产生非零平均流量的脉动流。流速由二维 LDA 系统测量，并测量流速分布。管的横截面是通过遍历 LDA 系统获得的。在稳定流动条件下获得的速度分布可以通过与电磁流测量的流速相对应的泊肃叶速度分布来很好地表示。流量计显示，脉动流条件下的速度分布显示，在最小流量阶段，管壁附近出现流动反转，尽管在脉动期间总流量始终为正值，但也观察到了拐点。在加速阶段的速度分布中，脉动速度分布的这些特征与不可压缩流体通过直圆柱体的不稳定流动的理论预期非常吻合，用于使用 LDA 进行测量。在体内实验中，通过光纤激光多普勒风速计显微镜研究了大鼠（SHR 和 WKY）肠系膜微血管中的血流脉动（ FLDAM）与微血管的流变学和网络拓扑的关系微血管血流相对于颈动脉压力的相位滞后随着微血管直径的减小而增加。 SHR肠系膜中的小动脉之间存在相关性，而WKY中的小动脉中的血流脉冲传播是通过模拟微血管树的多孔锥形弹性管模型进行理论上处理的，并基于该模型对实验结果进行了分析。从模型中可以看出，SHR 和 WKY 之间观察到的血流脉动差异可能是由于 SHR 微脉管系统比 WKY 更长的小动脉长度和更少的分支点所致。还测量了直径为 10 至 30 μm 的小动脉中的流脉冲传播速度，以估计单个血管的弹性特性。传播速度约为 10 cm/s，并随着血管直径的增加而增加。也与多孔锥形弹性管模型的预测一致。