Chen Tong, Cheng Xiaoming, Liu Xudong, Zhang Huifeng, Wang Shengzhang
Academy for Engineering and Technology, Fudan University, Shanghai, China.
Department of Aeronautics and Astronautics, Fudan University, Shanghai, China.
Front Cardiovasc Med. 2024 Mar 25;11:1377765. doi: 10.3389/fcvm.2024.1377765. eCollection 2024.
Patients with single-ventricle physiologies continue to experience insufficient circulatory power after undergoing palliative surgeries. This paper proposed a right heart assist device equipped with flexible blades to provide circulatory assistance for these patients. The optimal elastic modulus of the flexible blades was investigated through numerical simulation.
A one-way fluid-structure interaction (FSI) simulation was employed to study the deformation of flexible blades during rotation and its impact on device performance. The process began with a computational fluid dynamics (CFD) simulation to calculate the blood pressure rise and the pressure on the blades' surface. Subsequently, these pressure data were exported for finite element analysis (FEA) to compute the deformation of the blades. The fluid domain was then recreated based on the deformed blades' shape. Iterative CFD and FEA simulations were performed until both the blood pressure rise and the blades' shape stabilized. The blood pressure rise, hemolysis risk, and thrombosis risk corresponding to blades with different elastic moduli were exhaustively evaluated to determine the optimal elastic modulus.
Except for the case at 8,000 rpm with a blade elastic modulus of 40 MPa, the pressure rise associated with flexible blades within the studied range (rotational speeds of 4,000 rpm and 8,000 rpm, elastic modulus between 10 MPa and 200 MPa) was lower than that of rigid blades. It was observed that the pressure rise corresponding to flexible blades increased as the elastic modulus increased. Additionally, no significant difference was found in the hemolysis risk and thrombus risk between flexible blades of various elastic moduli and rigid blades.
Except for one specific case, deformation of the flexible blades within the studied range led to a decrease in the impeller's functionality. Notably, rotational speed had a more significant impact on hemolysis risk and thrombus risk compared to blade deformation. After a comprehensive analysis of blade compressibility, blood pressure rise, hemolysis risk, and thrombus risk, the optimal elastic modulus for the flexible blades was determined to be between 40 MPa and 50 MPa.
单心室生理结构的患者在接受姑息性手术后，循环动力仍然不足。本文提出了一种配备柔性叶片的右心辅助装置，为这些患者提供循环辅助。通过数值模拟研究了柔性叶片的最佳弹性模量。
采用单向流固耦合（FSI）模拟研究柔性叶片在旋转过程中的变形及其对装置性能的影响。该过程首先通过计算流体动力学（CFD）模拟来计算血压升高和叶片表面的压力。随后，导出这些压力数据进行有限元分析（FEA）以计算叶片的变形。然后根据变形叶片的形状重新创建流体域。进行迭代的CFD和FEA模拟，直到血压升高和叶片形状都稳定下来。详尽评估了不同弹性模量叶片对应的血压升高、溶血风险和血栓形成风险，以确定最佳弹性模量。
在所研究的范围内（转速为4000转/分钟和8000转/分钟，弹性模量在10兆帕至200兆帕之间），除了叶片弹性模量为40兆帕、转速为8000转/分钟的情况外，柔性叶片相关的压力升高低于刚性叶片。观察到柔性叶片对应的压力升高随着弹性模量的增加而增加。此外，不同弹性模量的柔性叶片与刚性叶片在溶血风险和血栓风险方面没有发现显著差异。
除了一种特定情况外，在所研究的范围内柔性叶片的变形导致叶轮功能下降。值得注意的是，与叶片变形相比，转速对溶血风险和血栓风险的影响更大。在对叶片可压缩性、血压升高、溶血风险和血栓风险进行综合分析后，确定柔性叶片的最佳弹性模量在40兆帕至50兆帕之间。
