Objective: A promising treatment for congestive heart failure is the implementation of a left ventricular assist device (LVAD) that works as a mechanical pump. Modern LVADs work with adjustable constant rotor speed and provide therefore continuous blood flow; however, recently undertaken efforts try to mimic pulsatile blood flow by oscillating the pump speed. This work proposes an algorithmic framework to construct and evaluate optimal pump speed policies. Methods: We use a model that captures the atrioventricular plane displacement, which is a physiological indicator for heart failure. We employ mathematical optimization to adapt this model to patient specific data and to find optimal pump speed policies with respect to ventricular unloading and aortic valve opening. To this end, we reformulate the cardiovascular dynamics into a switched system and thereby reduce nonlinearities. We consider system switches that stem from varying the constant pump speed and that are state dependent such as valve opening or closing. Results: As a proof of concept study, we personalize the model to a selected patient with respect to ventricular pressure. The model fitting results in a root-mean-square deviation of about 6 mmHg. Optimized constant and piecewise constant rotor speed profiles improve the default initialized solution by 31% and 68% respectively. Conclusion: These in silico findings demonstrate the potential of personalized hemodynamical optimization for the LVAD therapy. Significance: LVADs and their optimal configuration are active research fields. Mathematical optimization enhances our understanding of how LVADs should provide pulsatility.

中文翻译：

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基于房室平面位移的心室辅助设备最优控制的个性化开关系统方法

目的：对于充血性心力衰竭的一种有前途的治疗方法是实施作为机械泵的左心室辅助装置（LVAD）。现代LVAD的转子转速可调，因此可提供连续的血流。然而，最近进行的努力试图通过振荡泵的速度来模拟脉动血流。这项工作提出了构建和评估最佳泵速策略的算法框架。方法：我们使用捕获房室平面位移的模型，该模型是心力衰竭的生理指标。我们采用数学优化方法使该模型适应患者的具体数据，并针对心室卸载和主动脉瓣打开找到最佳泵速策略。为此，我们将心血管动力学重构为一个切换系统，从而减少非线性。我们考虑系统开关，这些开关源于恒定泵速的变化，并且取决于状态，例如阀门的打开或关闭。结果：作为概念研究的证明，我们针对选定的心室压患者对模型进行个性化设置。模型拟合得出的均方根偏差约为6 mmHg。优化的恒定和分段恒定转子速度曲线分别将默认初始化解决方案分别提高了31％和68％。结论：这些计算机研究结果表明，个性化血流动力学优化可用于LVAD治疗。启示：LVAD及其最佳配置是活跃的研究领域。