Damage Analysis by Elongation of Blood Vessels

该装置旨在分析在超出其生理极限的情况下对血管的损害。它由步进电机、脉冲发生器、板簧和数据传输组成。拉伸速度由恒定或加速控制。使用非创伤性抓钳固定血管两端。为了均匀样本的数据采集，将兔主动脉的矩形材料（10 × 4 mm）沿其纵向或水平方向修剪，并设置和拉扯。在血管伸长过程中，应变-应力曲线表现出一定的模式，尽管它们看起来有很大程度的分散。开始延伸后，应力值缓慢升高（第一阶段），随后应力值急剧升高（第二阶段）。在达到峰值后，应力值下降（第三阶段）。第一阶段表现为正常血管的伸展和收缩的正常生理阶段，第二阶段表现为各血管各自的特点。第三阶段是破坏性的。剔除不合适材料后，对纵向和水平方向材料的应力应变值进行统计比较。在固定速度（40mm/mm）和加速度（0.000467m/s^2）下，也有类似的趋势。在本研究中，我们建立了如何分析^*大动脉在拉长时的破坏，但对于中等大小的动脉，如椎动脉，需要进一步改进抓握工具。

The device was designed to analyze the damages to blood vessels while elongating beyond its physiological limits. It consists of a stepping motor, pulse generator, leaf spring and data transmission. Elongating speed is controlled by either constant or accelerated. A non-traumatic grasping forceps was used to fix at each end of a vessel. For purpose of data collections of uniform samples, rectangular materials (10 x 4 mm) of aorta of rabbits were trimmed with the longitudinal or horizontal direction of it, and set and pulled. Strain-stress curves during vessel elongations showed a certain pattern even though they appeared to have a large degree of dispersions. The values of stress increased slowly after starting elongation (the first stage), and then increases of stress raised sharply (the second stage). After reaching a peak, the values of stress decreased (the third stage). The first stage would show the normal physiological phase of extension and shrinkage that normal vessels have, and the second stage would show own characteristics of each vessel. And the third stage was destructive one. After improper materials were eliminated, the values of stress and strain were statistically compared between materials of longitudinal and horizontal direction. The similar tendency was obtained from a fixed speed (40mm/mm) and an acceleration (0.000467m/s^2). In this study, we established how to analyze disruption of the ^*large-sized arteries while elongating, however, in case of the median-sized arteries like vertebral arteries, further improvement of the grasping pars is needed.