动力性主动脉瓣瓣架的改进研究

作对先前的动力性主动脉瓣的瓣架进行了改进。用悬臂式支架代替笼式支架,瓣架由端环、悬臂、悬臂轴、支架梁、尾环等部分组成。悬臂轴由端环的中心伸出,通过位于顶端的垂直悬壁与端环相连接以保持其工作位置。轴尾悬空。无支撑点。悬臂轴借滑动轴承支承“转子一叶轮”体。为降低摩擦消耗,轴表面由耐磨材料制成。端环与普通机械瓣的瓣环相似,其外周嵌入编织的缝合环,植入时与主动脉瓣环缝合固定。从端环的周边与悬臂轴平行的方向等距离伸出支架梁并在尾端与尾环相连。支架梁和尾环与主动脉内壁紧贴,支撑动脉壁以防止其与“转子一叶轮”体接触。输入电压为7V时,动力瓣迅速启动,两端容器中液平面开始出现位差并逐步加大。至50mmH2O时趋于平衡。提高输入电压,液面位差稍有增加,但在16V～25V区间内变化不大。结果显示改进后的动力瓣性能大幅度提高,表明悬臂式动力瓣的瓣架结构比笼式支架结构更趋合理。揭示了动力瓣探索的一个重要方向。

Improvement of the Support Cage for a Dynamic Aortic Valve

Dynamic aortic valve, a novel constituent of left ventricular assist device, was improved by substituting the basket cage with a cantilever cage. The surface of cantilever shaft was made of abrasion -resistant alloy for reducing friction. The shaft supported the rotor - impeller with a sliding bearing mechanism. The top ring was similar to the orifice ring of a mechanical valve prosthesis and its margin was embedded by a sewing ring of textile cuff attaching to the aortic annulus during implantation. The support arms and end ring clinged the aortic intima and supported the aortic wall, permitting the rotor - impeller rotation freely without contact to the aortic wall. The dynamic aortic valve actuated rapidly when the input voltage reached 7 volts and resulted in a fluid potential difference increasing gradually, but tended to get equilibrium at 50mmH2O. The fluid potential difference increased slightly as the input voltage elevating, but there was no distinct change between 16V and 25V. The results showed that the performance of the novel dynamic aortic valve improved significantly and the cantilever structure was more efficient than that of the basket cage. This study also reveals a new way for exploring the dynamic aortic valve.