体外反搏下局部狭窄动脉内血液脉动流的一个数学模型

Instant hemodynamics circumstance study in arterial stenosis under math modeling of external counterpulsation

目的研究体外反搏对局部狭窄动脉内血流动力学环境的影响,进而探讨体外反搏对动脉粥样硬化斑块的干预作用。方法设计了一个基于流体动力学理论的数学模型,在特定的空间坐标系下推导了描述血液脉动流的控制方程,给出了合适的边界条件,并设计了数值算法对模型进行求解。以雄性乳猪的颈动脉为对象,在体测量了动脉的几何参数及反搏前后心动周期内连续的流率、动脉内压和心电。通过将反搏前后的实测数据分别应用到文中建立的数学模型中进行求解。结果得到了反搏前后心动周期里动脉模型内的多种重要的血流动力学量,包括血液流场、速度分布、壁面切应力(WSS)分布等。结论体外反搏能有效提高心动周期内动脉的血流量、提高心动周期内尤其是舒张期的动脉内壁切应力水平及压力梯度、增加动脉局部狭窄段后端回流区的血液回流速度。这些改变对于动脉粥样硬化斑块的发生及发展都有良好的干预作用。

Objective To study the hemodynamics circumstance in arterial stenoses under enhanced external eounterpulsation（EECP） and to explore the effect of EECP on atherosclerotic plaque. Methods A finite difference numerical solving system was developed and constructed. And the real-time blood flow rate and pressure of a cardiac cycle in a pig＇s carotid artery were, measureed in vivo pre-EECP, and during EECP and inputted to the solving system as boundary and inilial conditions. Results The hemodynamics circumstance changed a lot during EECP. Hemodynamic data were. obtained. Conclusion Changes caused by EECP may restrict the appearance and development of the atherosclerotic plaque to some extent.