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

目的：研究动脉导管射流对老年病变主动脉的流体动力学影响。本研究的最终目标是开发更复杂的套管形状，以减轻对主动脉壁的剪切应力。材料与方法：本研究由两项基础研究和一项临床研究组成。第一次基本调查是使用正常和病变主动脉的模拟玻璃模型进行的。采用粒子图像速度法测量正常和病变（拱形动脉瘤）主动脉模型的剪切应力和剪切速度，并分析血流线。在模型实验数据的基础上，建立了扭曲主动脉模型的数学模型，并对扭曲主动脉模型简化后的血流进行了计算模拟分析。在临床研究中，采用经主动脉和经食管双工和彩色映射扫描对体外循环进行流速和矢量分析。结果:1。仿玻璃模型分析…分析不同类型主动脉插管在正常和病变主动脉模型中的血流模式特点：弯曲端孔插管、弥散型插管、SELECT 3D插管和软流插管。不同的套管形成不同的大涡流和螺旋流。在端孔插管中观察到高速血流，对主动脉弓造成高应变。弥散性导管的流动使主动脉弓外弯曲的应变减小。在软流插管中，流速和应变进一步降低。在选择的3D插管中，沿主动脉弓内曲率观察到高应变。在简化的数学模型中，采用端孔插管作为动脉灌注插管。流矢量和流线分析结果与玻璃模型相似。临床研究结果与玻璃模型分析基本相同。结论：端孔插管不宜用于动脉粥样硬化主动脉。根据这一结果，应特别注意导管的选择和导管的位置。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