Ando Masahiko, Nishimura Takashi, Takewa Yoshiaki, Ogawa Daisuke, Yamazaki Kenji, Kashiwa Koichi, Kyo Shunei, Ono Minoru, Taenaka Yoshiyuki, Tatsumi Eisuke
Department of Artificial Organ, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka, 565-8565, Japan.
J Artif Organs. 2011 Mar;14(1):74-9. doi: 10.1007/s10047-010-0544-6. Epub 2011 Jan 18.
Recent developments in adjunct therapeutic options for end-stage heart failure have enabled us to remove implanted left ventricular assist devices (LVADs) from more patients than before. However, a safe and proper protocol for pump-off trials is yet to be established, because diastolic backward flow in a pump circuit turns up when it is driven at low-flow conditions. We have developed a novel drive mode of centrifugal pumps that can change its rotational speed in synchronization with the cardiac cycle of the native heart. The purpose of this study was to test-drive this novel system of a centrifugal pump in a mock circulation and to evaluate the effect of the counterpulse mode, which increases pump speed just in diastole, on the amount of this nonphysiological intracircuit retrograde flow. A rotary pump (EVAHEART, Sun Medical Technology Research Corporation) was connected to the mock circulation by left ventricular uptake and ascending aortic return. We drove it in the following four conditions: (A) continuous mode at 1500 rpm, (B) counterpulse mode (systolic 1500 rpm, diastolic 2500 rpm), (C) continuous mode at 2000 rpm, and (D) counterpulse mode (systolic 2000 rpm, diastolic 2500 rpm). Data concerning the rotation speed, pump flow, left ventricular pressure, aortic pressure, and pressure head (i.e., aortic pressure-left ventricular pressure) in each condition were collected. After data collection, we analyzed pump flow, and calculated its forward and backward flow. Counterpulse mode decreased the amounts of pump backward flow compared with the continuous mode [mean backward flow, -4, -1, -0.5, 0 l/min, in (A), (B), (C), and (D) conditions, respectively]. The actual amounts of mean backward flow can be different from those in clinical situations; however, this novel drive mode for rotary pumps can relatively decrease pump backward flow during pump weaning and can be beneficial for safe and proper pump-off trials. Further investigations in in vivo settings are currently ongoing.
终末期心力衰竭辅助治疗方案的最新进展使我们能够比以往更多地为患者移除植入的左心室辅助装置（LVAD）。然而，由于泵回路在低流量条件下驱动时会出现舒张期逆流，因此尚未建立安全且合适的泵关闭试验方案。我们开发了一种新型离心泵驱动模式，它可以与天然心脏的心动周期同步改变其转速。本研究的目的是在模拟循环中对这种新型离心泵系统进行试驾，并评估反搏模式（仅在舒张期提高泵速）对这种非生理性回路逆行血流量的影响。通过左心室摄取和升主动脉回流将旋转泵（EVAHEART，太阳医疗技术研究公司）连接到模拟循环。我们在以下四种条件下驱动它：（A）1500转/分钟的连续模式，（B）反搏模式（收缩期1500转/分钟，舒张期2500转/分钟），（C）2000转/分钟的连续模式，以及（D）反搏模式（收缩期2000转/分钟，舒张期2500转/分钟）。收集了每种条件下有关转速、泵流量左心室压力、主动脉压力和压头（即主动脉压力-左心室压力）的数据。数据收集后，我们分析了泵流量，并计算了其正向和反向流量。与连续模式相比，反搏模式减少了泵的反向流量[平均反向流量，在（A）、（B）、（C）和（D）条件下分别为-4、-1、-0.5、0升/分钟]。平均反向流量的实际数值可能与临床情况不同；然而，这种新型旋转泵驱动模式在泵撤离期间可相对减少泵的反向流量，有利于安全且合适的泵关闭试验。目前正在进行进一步的体内研究。
