May-Newman Karen
From the Bioengineering Program, Department of Mechanical Engineering, San Diego State University, San Diego, California.
ASAIO J. 2023 Mar 1;69(3):284-289. doi: 10.1097/MAT.0000000000001771. Epub 2022 Jul 6.
Constant speed control of rotary LVADs attenuates vascular pulsatility, which has been linked to clinical complications such as thrombus formation, bleeding, and valvular dysfunction. Speed modulation can improve pulsatility and washout, but optimization requires coordination with the native heartbeat. A simple mathematical model of the left ventricle-left ventricular assist device (LV-LVAD) flow interaction was developed that sums the individual contributions of the native LV and the HeartMate3 artificial pulse (AP) to predict the total systemic flow. The model flow and pulsatility predictions results were in good agreement with experimental data from a mock circulatory loop measured for full bypass support conditions. The model was used to evaluate three schemes for optimizing the synchronization of the AP with the native heart. The optimized interaction occurred when the AP speed increase occurred during contraction, resulting in a doubling of flow pulsatility, and corresponded to an increase in the area enclosed by the dynamic pressure-flow relation. The model provides a simple tool for exploring the optimization of LVAD speed modulation that can reduce the time and expense of mock loop studies during the development process.
旋转式左心室辅助装置（LVAD）的恒速控制可减弱血管搏动性，而血管搏动性与血栓形成、出血和瓣膜功能障碍等临床并发症有关。速度调节可改善搏动性和冲洗效果，但优化需要与自身心跳相协调。建立了一个左心室-左心室辅助装置（LV-LVAD）血流相互作用的简单数学模型，该模型将自身左心室和HeartMate3人工脉冲（AP）的各自贡献相加，以预测总全身血流。模型的血流和搏动性预测结果与在全旁路支持条件下测量的模拟循环回路的实验数据高度吻合。该模型用于评估三种优化AP与自身心脏同步的方案。当AP速度在收缩期增加时会出现优化的相互作用，导致血流搏动性加倍，并且对应于动压-血流关系所包围面积的增加。该模型为探索LVAD速度调节的优化提供了一个简单工具，可减少开发过程中模拟回路研究的时间和费用。
