Hydoro-dynamic analysis for effect of cannula shapes on the diseased aorta during extracorporeal circulation.-Basic and clinical study-

目的：本研究旨在阐明动脉插管射流对老年病变主动脉的流体动力学效应。本研究的最终目标是开发更复杂的插管形状，以衰减主动脉壁上的剪切应力。材料和方法：本研究由两个基础和一个临床调查。第一个基础研究是使用正常和病变主动脉的模拟玻璃模型进行的。应用粒子图像速度法测量了正常和病变（主动脉弓瘤）主动脉模型的剪切应力和剪切速度，并对流线进行了分析。根据模型实验数据，建立了数学模型，并对扭曲简化的主动脉模型进行了数值模拟分析。应用彩色多普勒超声及彩色标测技术，对体外循环中的血流速度及矢量进行了分析。 关于我们 姐在正常和病变主动脉模型上分析了不同类型主动脉插管的流型特征：弯曲端孔插管、分散插管、SELECT 3D插管和Soft-Flow插管。每种套管产生不同形式的大涡和螺旋流。端孔插管中的流速较高，对主动脉弓产生了较大的应变;分散插管中的流速降低了主动脉弓外曲的应变; Soft-Flow插管中的流速和应变进一步降低。在Select 3D插管中，观察到沿着主动脉弓的内弯有较高的应变。2.在简化的数学模型中，采用端孔插管作为动脉灌注插管。结论：端孔插管不应用于动脉粥样硬化性主动脉瘤的治疗。根据这一结果，应特别注意插管和插管部位的选择。少

Objectives :This study was conducted to elucidate the fluid dynamic effect of jet flow from the arterial cannulae on the aged, diseased aorta. The final goal for this study is to develop more sophisticated cannula shape to attenuate shear stress on the aortic wall.Materials and methods :This study was composed of two basic and one clinical investigation. The first basic investigation is performed using mocked glass model of the normal and diseased aorta. Particle image velocity method was used to measure shear stress and shear velocity and to analyze stream line in the normal and diseased (arch aneurysm) aortic model. Based on data obtained from the model experiment, mathematic model was constructed and computed simulation of the flow in the twisted, simplified aortic model was analyzed. In clinical study, flow velocity and vector analysis during cardiopulmonary bypass were performed using epi-aortic and trans-esophageal duplex and color mapping scan.Results :1.Mocked glass model analy … More sis. The characteristics of flow pattern in different types of aortic cannulae were analyzed in normal and diseased aortic models: curved end-hole cannula, dispersion cannula, SELECT 3D cannula and Soft-Flow cannula. Different patterns of large vortices and helical flow were made by each cannula. The high velocity flow was observed in end-hole cannula, causing high strain on the aortic arch. The flow from dispersion cannula brought about decreased strain on the outer curvature of the aortic arch. In Soft-Flow cannula, further decreased flow velocity and strain were observed. In Select 3D cannula, high strain was observed along the inner curvature of the aortic arch.2.In simplified mathematic model, end-hole cannula was used as arterial perfusion cannula. Flow vector and stream line analysis showed similar pattern with glass model.3.Clinical investigation revealed essentially the same result obtained in glass model analysis.Conclusions :The end-hole cannula should not be used in atherosclerotic aorta. Particular attention should be paid both for selection of cannulae and cannulation site based on this result. Less