Ultrasonic Measurement of Transient Change in Stress–Strain Property of Radial Arterial Wall Caused by Endothelium-Dependent Vasodilation
Ultrasonic Measurement of Transient Change in Stress–Strain Property of Radial Arterial Wall Caused by Endothelium-Dependent Vasodilation
复制标题
内皮依赖性血管舒张引起的桡动脉壁应力应变特性瞬态变化的超声测量
DOI：
10.1143/jjap.47.4165
复制
发表时间：
2008
影响因子：
1.5
通讯作者：
H. Kanai
中科院分区：
文献类型：
--
作者：
K. Ikeshita;H. Hasegawa;H. Kanai
内皮功能障碍被认为是动脉粥样硬化的起始步骤。此外，据报道，构成动脉中膜的平滑肌由于动脉粥样硬化而改变其特性。因此，有必要建立一种评价局部血管内皮功能和血管壁力学特性的方法。有一种常规的技术，用于测量在无血管化释放后由血流介导的扩张（FMD）引起的肱动脉直径的瞬时变化。为了更敏感和区域性的评估，我们开发了一种测量FMD引起的桡动脉弹性变化的方法。在这项研究中，动脉壁的机械性能的瞬态变化进一步揭示了通过测量在每次心跳的应力-应变关系。在一个心动周期中，桡动脉壁的厚度（应变）的微小变化是通过相位跟踪方法测量的，同时用脉搏计在桡动脉处连续测量血压波形。从测量的壁厚和血压的变化获得心动周期期间应力-应变关系的瞬时变化，以显示瞬时粘弹性的瞬时变化。从体内实验结果来看，应力-应变关系呈现滞后回线。由于FMD，环的斜率减小，这表明弹性模量减小，并且当假定Voigt模型时，环的增加面积取决于损耗模量（取决于粘度）与弹性模量的比率。这些结果显示了潜在的所提出的方法的粘弹性的瞬态变化，由于FMD的彻底分析。
The endothelial dysfunction is considered to be an initial step of atherosclerosis. Additionally, it was reported that the smooth muscle, which constructs the media of the artery, changes its characteristics owing to atherosclerosis. Therefore, it is essential to develop a method for assessing the regional endothelial function and mechanical property of the arterial wall. There is a conventional technique of measuring the transient change in the diameter of the brachial artery caused by flow-mediated dilation (FMD) after the release of avascularization. For more sensitive and regional evaluation, we developed a method of measuring the change in the elasticity of the radial artery due to FMD. In this study, the transient change in the mechanical property of the arterial wall was further revealed by measuring the stress–strain relationship during each heartbeat. The minute change in the thickness (strain) of the radial arterial wall during a cardiac cycle was measured by the phased tracking method, together with the waveform of blood pressure which was continuously measured with a sphygmometer at the radial artery. The transient change in stress–strain relationship during a cardiac cycle was obtained from the measured changes in wall thickness and blood pressure to show the transient change in instantaneous viscoelasticity. From the in vivo experimental results, the stress–strain relationship shows the hysteresis loop. The slope of the loop decreased owing to FMD, which shows that the elastic modulus decreased, and the increasing area of the loop depends on the ratio of the loss modulus (depends on viscosity) to the elastic modulus when the Voigt model is assumed. These results show a potential of the proposed method for the thorough analysis of the transient change in viscoelasticity due to FMD.