Su Chengxuan, Li Shulei, Gui Xingmin, Jin Donghai, Liu Guangmao
School of Energy and Power Engineering, Beihang University, Beijing, China.
Fuwai Hospital State Key Laboratory of Cardiovascular Disease, Beijing, China.
Int J Artif Organs. 2024 Dec;47(12):908-919. doi: 10.1177/03913988241291678. Epub 2024 Oct 27.
Most of the modeling of the Left Ventricular Assist Devices (LVADs) coupled with the cardiovascular system is based on the assumption of constant rotational speed. Compared with the traditional inertial model, the validated hysteresis model can take into account the unsteady characteristics of LVADs, but it fails to work under the condition of variable speed modulation.
This study takes into consideration the impact of speed variations on the unsteady hysteresis effects. The time constant in the hysteresis model is treated as a time-varying parameter, thereby developing a new model applicable to variable speed modulation. Under sinusoidal speed modulation at various phases, a comparative analysis was undertaken among the steady-state model, inertial model, and the new model. Transient Computational Fluid Dynamics (CFD) simulations and existing experimental results are used for validation.
The new model provides a more accurate method for the predicting the characteristics of LVAD in the coupled model under varying pump speeds, and exhibits higher linearity in the work done by the left ventricle and the blood pump, and , which is aligning closely with the experimental results. This enhancement renders it applicable for proactive control predictions and passive control validations.
大多数左心室辅助装置（LVAD）与心血管系统耦合的建模是基于恒定转速的假设。与传统的惯性模型相比，经过验证的滞后模型可以考虑LVAD的非稳态特性，但在变速调节条件下无法工作。
本研究考虑了速度变化对非稳态滞后效应的影响。将滞后模型中的时间常数视为时变参数，从而开发出一种适用于变速调节的新模型。在不同相位的正弦速度调制下，对稳态模型、惯性模型和新模型进行了对比分析。使用瞬态计算流体动力学（CFD）模拟和现有实验结果进行验证。
新模型为预测耦合模型中不同泵速下LVAD的特性提供了更准确的方法，并且在左心室和血泵所做的功方面表现出更高的线性度，与实验结果密切吻合。这种改进使其适用于主动控制预测和被动控制验证。
