Fluid-dynamic optimal design of helical vascular graft for stenotic disturbed flow

Although a helical configuration of a prosthetic vascular graft appears to be clinically beneficial in suppressing thrombosis and intimal hyperplasia, an optimization of a helical design has yet to be achieved because of the lack of a detailed understanding on hemodynamic features in helical grafts and their fluid dynamic influences. In the present study, the swirling flow in a helical graft was hypothesized to have beneficial influences on a disturbed flow structure such as stenotic flow. The characteristics of swirling flows generated by helical tubes with various helical pitches and curvatures were investigated to prove the hypothesis. The fluid dynamic influences of these helical tubes on stenotic flow were quantitatively analysed by using a particle image velocimetry technique. Results showed that the swirling intensity and helicity of the swirling flow have a linear relation with a modified Germano number (Gn*) of the helical pipe. In addition, the swirling flow generated a benefi...尽管人工血管移植物（prosthetic vascular graft）采用螺旋构型，虽可在抑制血栓形成与内膜增生方面展现临床获益，但由于目前对螺旋移植物内的血流动力学特征及其流体动力学影响缺乏深入认知，螺旋设计的优化仍未达成。本研究提出假说：螺旋移植物内部的旋流（swirling flow）对狭窄流（stenotic flow）等紊乱流结构具有有益作用。为验证该假说，本研究针对不同螺旋节距与曲率的螺旋管所产生的旋流特性展开了系统探究；随后采用粒子图像测速法（Particle Image Velocimetry）对这些螺旋管对狭窄流的流体动力学影响进行了定量分析。结果显示，旋流的涡旋强度与螺旋度与螺旋管的修正格尔马诺数（modified Germano number, Gn*）呈线性相关。此外，该旋流所产生的有益……