Ghasemi Pour Mohammad Javad, Hassani Kamran, Khayat Morteza, Etemadi Haghighi Shahram
Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Perfusion. 2022 May;37(4):367-376. doi: 10.1177/0267659121998549. Epub 2021 Mar 3.
Fluid structure interaction (FSI) is defined as interaction of the structures with contacting fluids. The aortic valve experiences the interaction with blood flow in systolic phase. In this study, we have tried to predict the hemodynamics of blood flow through a normal and stenotic aortic valve in two relaxation and exercise conditions using a three-dimensional FSI method.
The aorta valve was modeled as a three-dimensional geometry including a normal model and two others with 25% and 50% stenosis. The geometry of the aortic valve was extracted from CT images and the models were generated by MMIMCS software and then they were implemented in ANSYS software. The pulsatile flow rate was used for all cases and the numerical simulations were conducted based on a time-dependent domain.
The obtained results including the velocity, pressure, and shear stress contours in different systolic time sequences were explained and discussed. The maximum blood flow velocity in relaxation phase was obtained 1.62 m/s (normal valve), 3.78 m/s (25% stenosed valve), and 4.73 m/s (50% stenosed valve). In exercise condition, the maximum velocities are 2.86, 4.32, and 5.42 m/s respectively. The maximum blood pressure in relaxation phase was calculated 111.45 mmHg (normal), 148.66 mmHg (25% stenosed), and 164.21 mmHg (50% stenosed). However, the calculated values in exercise situation were 129.57, 163.58, and 191.26 mmHg.The validation of the predicted results was also conducted using existing literature.
We believe that such model are useful tools for biomechanical experts. The further studies should be done using experimental data and the data are implemented on the boundary conditions for better comparison of the results.
流固相互作用（FSI）被定义为结构与接触流体之间的相互作用。主动脉瓣在收缩期会经历与血流的相互作用。在本研究中，我们试图使用三维FSI方法预测在两种静息和运动状态下通过正常和狭窄主动脉瓣的血流动力学。
将主动脉瓣建模为三维几何结构，包括一个正常模型和另外两个分别有25%和50%狭窄的模型。从CT图像中提取主动脉瓣的几何结构，通过MMIMCS软件生成模型，然后在ANSYS软件中实现。所有病例均使用脉动流速，并基于时间相关域进行数值模拟。
对不同收缩期时间序列中获得的结果，包括速度、压力和剪应力等值线进行了解释和讨论。静息期的最大血流速度分别为1.62米/秒（正常瓣膜）、3.78米/秒（25%狭窄瓣膜）和4.73米/秒（50%狭窄瓣膜）。在运动状态下，最大速度分别为2.86、4.32和5.42米/秒。静息期的最大血压计算值分别为111.45毫米汞柱（正常）、148.66毫米汞柱（25%狭窄）和164.21毫米汞柱（50%狭窄）。然而，运动状态下的计算值分别为129.57、163.58和191.26毫米汞柱。还使用现有文献对预测结果进行了验证。
我们认为这样的模型对生物力学专家是有用的工具。应使用实验数据进行进一步研究，并将数据应用于边界条件以更好地比较结果。
