Petrou Anastasios, Lee Jongseok, Dual Seraina, Ochsner Gregor, Meboldt Mirko, Schmid Daners Marianne
Department of Mechanical and Process Engineering, Product Development Group Zurich, ETH Zurich, Zurich, Switzerland.
Artif Organs. 2018 Mar;42(3):E29-E42. doi: 10.1111/aor.12999. Epub 2017 Nov 2.
Various physiological controllers for left ventricular assist devices (LVADs) have been developed to prevent flow conditions that may lead to left ventricular (LV) suction and overload. In the current study, we selected and implemented six of the most promising physiological controllers presented in literature. We tuned the controllers for the same objectives by using the loop-shaping method from control theory. The in vitro experiments were derived from literature and included different preload, afterload, and contractility variations. All experiments were repeated with an increased or decreased contractility from the baseline pathological circulation and with simulated sensor drift. The controller performances were compared with an LVAD operated at constant speed (CS) and a physiological circulation. During preload variations, all controllers resulted in a pump flow change that resembled the cardiac output response of the physiological circulation. For afterload variations, the response varied among the controllers, whereas some of them presented a high sensitivity to contractility or sensor drift, leading to LV suction and overload. In such cases, the need for recalibration of the controllers or the sensor is indicated. Preload-based physiological controllers showed their clinical significance by outperforming the CS operation and promise many benefits for the LVAD therapy. However, their clinical implementation in the near future for long-term use is highly dependent on the sensor technology and its reliability.
已经开发了各种用于左心室辅助装置（LVAD）的生理控制器，以防止可能导致左心室（LV）抽吸和过载的血流状况。在当前研究中，我们选择并实现了文献中提出的六种最有前景的生理控制器。我们使用控制理论中的回路成形方法针对相同目标对控制器进行了调整。体外实验源自文献，包括不同的前负荷、后负荷和收缩性变化。所有实验均在基线病理循环的收缩性增加或降低以及模拟传感器漂移的情况下重复进行。将控制器的性能与以恒定速度（CS）运行的LVAD和生理循环进行了比较。在前负荷变化期间，所有控制器导致的泵流量变化类似于生理循环的心输出量反应。在后负荷变化时，各控制器的反应有所不同，其中一些对收缩性或传感器漂移表现出高敏感性，导致左心室抽吸和过载。在这种情况下，表明需要重新校准控制器或传感器。基于前负荷的生理控制器通过优于CS操作显示出其临床意义，并有望为LVAD治疗带来诸多益处。然而，它们在不久的将来用于长期使用的临床实施高度依赖于传感器技术及其可靠性。
