主动脉瓣狭窄对左心室血流特性的影响

Effect of aortic stenosis on blood flow characteristics in the left ventricle

基于CT断层扫描数据,对心脏左心室进行三维重构和模型优化。结合心肌壁面的运动特性,建立左心室几何模型过流边界运动的数学模型。通过水力半径表征主动脉瓣的狭窄程度,采用动网格技术研究主动脉瓣狭窄对左心室血液流动的影响。研究发现不同程度主动脉瓣狭窄时,水力半径与主动脉瓣狭窄程度负相关,出口面积减小,收缩期出口处速度与压力升高,剪切应力增加。舒张期,速度与压力出现先增大后减小的规律。当水力半径较小时,左心室瓣膜处剪切应力较大,收缩初期剪切应力最大为0.81 Pa。通过动态模拟对心脏的仿真研究,为后续心脏的研究提供重要的参考价值。

The 3D model of the left ventricle is reconstructed and optimized based on CT scan data.In combination with the motion characteristics of myocardium wall,the mathematical models of left ventricular wall motions are established.The degree of aortic stenosis is characterized by hydraulic radius,and the moving grid technique is used to explore the effect of aortic stenosis on left ventricular blood flow.It is found that hydraulic radius is negatively correlated with the degree of aortic stenosis.The decreased outlet area results in higher velocity and pressure at the outlet in systole and increasing shear stress.During diastole,the velocity and pressure increase first and then decrease.With small hydraulic radius,the shear stress at the left ventricular valve is larger,and the maximum shear stress at the initial stage of contraction is 0.81 Pa.The dynamic simulation of the heart provides significant reference for the subsequent research on the heart.