Study on Guide System Based on the Blood Flow Force for Intravascular Catheter

通常很难将导管安全地引导到血管内。为了控制导管穿过内径2- 6mm的动脉血管时的前进方向，我们设计了一种基于血管流体力的导向系统。该系统由一个直径1毫米、长1.5毫米、壁厚20微米的圆柱形拖带、两个支撑腿和一个20微米的灯丝组成。拖缆的运动可以通过调整导线的长度来控制。通过流体力的数值分析研究了圆柱流线的行为，并利用脉动血流模拟器（雷诺数范围：71 ~ 930，动态粘度：1 ~ 6 mm2/s）实验研究了模型系统的特性。得到了攻角与无量纲升力、无量纲阻力和无量纲升力的关系，设计了原型导向系统，成功地对模拟器分支船进行了导向。为了简化流线位置和角度的控制，设计了一种新型的偏心薄硅橡胶管液压螺旋变形作动器，并在实验中证明了它的实用性。还发明了一种用于激光血管内治疗的安全分离方法。我们将该机构连接到导管末端，并通过兔子实验证实了其有效性。

It is usually difficult to guide a catheter safely inside blood vessels. We have devised a guide system based on the fluid force of blood vessel in order to control the direction of advance of a catheter being passed through artery blood vessels with 2-6 mm inner diameter. This system consists of a cylindrical streamer with a 1 mm diameter, 1.5 mm long and 20mum wall thickness, two supporting legs and one filament of 20 mum. Movement of the streamer can be controlled by adjusting the length of the wire. We studied the behavior of the cylindrical streamer by numerical analysis of fluid force, and investigated the cahracteristics of a model system by experiment using a simulator of pulsating blood flow (range of Reynolds number : 71-930, dynamic viscosity : 1-6 mm2/s). We obtained relation between attack angle and dimensionless lift, dimensionless drag and dimensionless lift, and then designed a prototype guide system and succeeded to guide branched vessels of the simulator.A new type of actuator which consists of an eccentric thin silicon rubber tube and deforms spirally by hydraulic pressure was invented to simplify the control of a position and an angle of the streamer, and showed its usefulness in experiment.Also a safety detaching method for endovascular treatment with laser light was invented. We attached the mechanism to the end of a catheter and confirmed its usefulness by experiments on rabbits.