人工心脏泵辅助水平对左心室血流动力学影响的数值研究

发布时间：2018-03-04 16:11

本文选题：人工心脏泵　切入点：辅助水平　出处：《北京工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：心室辅助会改变左心室血流动力学特性，但其机理目前却并不明确。本论文的目标是阐明人工心脏泵辅助水平对左心室血流动力学特性的影响规律。为此本论文展开如下的研究：利用有限元仿真软件ADINA实施在健康、心衰以及人工心脏泵不同辅助水平下的左心室及内部血液的流固耦合数值仿真并对结果进行分析。本论文的研究结果获得如下结论：第一，人工心脏泵辅助改变了心室内压力。20%和55%辅助水平下的左心室压力高于心衰时的左心室压力，在辅助水平为75%、80%以及95%时，左心室压力低于心衰时的左心室压，整体上，随着辅助水平增加，左心室压力呈现递减趋势，高辅助水平可以改善心室卸载；第二，人工心脏泵辅助改变了心室内流量。在充盈期，随着辅助水平增加，，二尖瓣入口处体积流速持续增加；在射血期，随着辅助水平增加，主动脉瓣出口体积流速持续减小，射血时间延长，泵血量增加，人工心脏泵辅助可以改善器官灌注；第三，人工心脏泵辅助改变了左心室壁面切应力。随着辅助水平增加，壁面切应力持续降低，此外，在高辅助水平下，赤道面至心尖区域壁面无壁面切应力分布；第四，人工心脏泵辅助改变了心室内漩涡。在健康状态下，二尖瓣入口处产生两个漩涡，从正面观察，上侧漩涡顺时针转动，下侧漩涡逆时针转动，充盈结束时，漩涡有最大面积，健康状态下，漩涡存在时间最长，在充盈结束时漩涡运动至心尖位置，提高心尖处血流流动，降低血栓产生的可能性；在低辅助水平时（20%和55%），存在两个漩涡，但是漩涡不能运动至心尖位置，导致心尖存在血液停滞区；在高辅助水平时（85%和95%），由于主动脉瓣提前打开，上侧的漩涡在运动过程中受到出口处血流影响，漩涡的形状受到影响，同时漩涡不能运动至心尖位置，使得心尖处存在血液停滞区；在75%辅助水平时，漩涡的运动和健康时类似，它在充盈末期能运动至心尖，保证了心尖处血流流动。
[Abstract]:Ventricular assist changes left ventricular hemodynamics, But the mechanism is not clear at present. The aim of this thesis is to clarify the influence of the auxiliary level of artificial heart pump on left ventricular hemodynamics. Finite element simulation software ADINA was used to simulate the fluid-solid coupling of left ventricle and internal blood at different levels of health, heart failure and artificial heart pump, and the results were analyzed. The research results of this thesis are as follows:. First, the artificial heart pump adjuvant changes the left ventricular pressure at 20% and 55% auxiliary levels, which is higher than the left ventricular pressure at heart failure. At the auxiliary level of 75% or 80% and 95%, the left ventricular pressure is lower than the left ventricular pressure at heart failure as a whole. With the increase of auxiliary level, the pressure of left ventricle decreased, and high auxiliary level could improve the unloading of ventricle. Second, the artificial heart pump adjusts the flow in the ventricle. During the filling period, with the increase of the auxiliary level, the volume velocity of the mitral valve inlet continues to increase, and during the ejection period, with the increase of the auxiliary level, The volume velocity of aortic valve outlet continuously decreased, the ejection time prolonged, the pump blood volume increased, the artificial heart pump can improve the organ perfusion. Thirdly, the wall shear stress of the left ventricular wall was changed by the artificial heart pump. With the increase of the auxiliary level, the wall shear stress continued to decrease, in addition, there was no wall shear stress distribution from the equator to the apical region at the high auxiliary level. In 4th, the artificial heart pump helped change the swirl in the ventricle. In a healthy state, two swirls occur at the entrance of the mitral valve, viewed from the front, turning clockwise on the upper side, turning counterclockwise on the lower side, and turning at the end of the filling. The whirlpool has the largest area. In healthy condition, the vortex exists for the longest time. At the end of filling, the vortex moves to the apical position, increases the flow of blood flow at the apex, and reduces the possibility of thrombosis. At the low auxiliary level, there are two whirlpools, 20% and 5550%. However, the vortex can not move to the apical position, leading to the existence of a blood stagnation area at the apical point. At the high auxiliary level, 85% and 95% of the aortic valve opens ahead, and the upper vortex is affected by the blood flow at the outlet during the course of movement. The shape of the vortex is affected, and the vortex is unable to move to the apical position, resulting in a blood stagnation zone at the apical point; at the 75% auxiliary level, the vortex moves like a healthy one, moving to the apex at the end of filling. The blood flow at the apex is guaranteed.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R318.11

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