School of Electrical Engineering, Shandong University, Jinan, PR China.
Comput Methods Biomech Biomed Engin. 2021 Jul;24(9):956-972. doi: 10.1080/10255842.2020.1861601. Epub 2020 Dec 21.
Continuous-flow left ventricular assist devices (CFLVADs) routinely operate at a constant speed for the support of a failing heart, which decreases the pulsatility in the arteries. Some late complications could be related to a long-term lack of pulsatility. Modulating the CFLVAD speed is a solution to enhance the pulsatility. The purpose of this study is to modulate multiple varying speed patterns and investigate their effects on the ventricle and vascular system. A cardiovascular coupling numerical model is developed to provide a simulation platform for testing the varying speed patterns. The varying speed patterns are modulated by combining the shape, amplitude, frequency, phase shift, and pulsatile duty cycle of the speed profile. The influence of varying speed support is examined by analyzing the indexes of pulsatility, indexes of ventricular unloading, and hemodynamic variables. The results show that the synchronous counterpulsation pattern can effectively reduce the ventricular unloading indexes, whereas the low-frequency asynchronous pattern can effectively increase the vascular pulsatility indexes. Also, the hemodynamics with synchronous varying speed support is more physiological than that with asynchronous varying speed support. This study provides valuable insight for further optimization of varying speed modulation by weighing vascular pulsatility, ventricular unloading, and hemodynamics.
连续流动左心室辅助装置（CFLVAD）通常以恒定速度运行，以支持衰竭的心脏，从而降低动脉的脉动性。一些晚期并发症可能与长期缺乏脉动性有关。调节 CFLVAD 速度是增强脉动性的一种解决方案。本研究的目的是调节多种变化的速度模式，并研究它们对心室和血管系统的影响。开发了一个心血管耦合数值模型，为测试变速模式提供了一个模拟平台。变速模式通过组合速度曲线的形状、幅度、频率、相移和脉动占空比来调节。通过分析脉动性指标、心室卸载指标和血液动力学变量来检查变速支持的影响。结果表明，同步反搏模式可以有效降低心室卸载指标，而低频异步模式可以有效增加血管脉动性指标。此外，同步变速支持的血液动力学更接近生理状态，而异步变速支持的血液动力学则更接近生理状态。本研究通过权衡血管脉动性、心室卸载和血液动力学，为进一步优化变速调制提供了有价值的见解。
