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):70-3. doi: 10.1007/s10047-010-0543-7. Epub 2011 Jan 18.
Bridge to recovery has become a major goal after left-ventricular-assist-device (LVAD) implantation thanks to recent development in adjunctive therapies. Precise assessment of native heart function under minimum LVAD support is the key for successful LVAD explantation. However, weaning of centrifugal LVADs normally generates diastolic intracircuit backward flow. This retrograde flow may become excessive load for the native heart during off-pump test. The flow itself is an inevitable characteristic of centrifugal pumps. Therefore, evaluating this retrograde flow in vitro is of considerable significance, even if its amount is different from that in clinical settings. The purpose of this study was to assess diastolic backflow of continuous-flow centrifugal LVADs in a mock circulation model. A centrifugal LVAD (EVAHEART, Sun Medical Technology) was installed in a mock circulation model by the left ventricle uptake and the ascending aortic return. Pump flow was measured at the pump rotational speed of 1000, 1500, 2000, and 2500 rpm, and pulse rate of the virtual native heart was varied to 60, 90, and 120 beats/min. After data collection, pump flow was integrated, and forward and backward intracircuit flow were calculated. As a result, nonphysiological reverse flow of approximately 2.0 L/min exists at the rotational speed, providing 0 L/min mean pump flow. An ideal off-test trial condition should be realizing both ± 0 L/min pump flow and no intracircuit backward flow at the same time. We are developing a novel EVAHEART drive mode that can change its rotational speed in synchronization with cardiac cycle with the aim of controlling this retrograde flow with the new drive mode and creating an ideal off-test condition.
由于辅助治疗的最新进展，恢复桥梁已成为左心室辅助装置（LVAD）植入后的主要目标。在最小LVAD支持下精确评估天然心脏功能是LVAD成功取出的关键。然而，离心式LVAD的撤机通常会产生舒张期回路内逆流。这种逆流在非体外循环测试期间可能会成为天然心脏的过度负荷。这种流动本身是离心泵不可避免的特性。因此，即使其数量与临床情况不同，在体外评估这种逆流也具有相当重要的意义。本研究的目的是在模拟循环模型中评估连续流式离心LVAD的舒张期逆流。通过左心室摄取和升主动脉回流，将离心式LVAD（EVAHEART，太阳医疗技术公司）安装在模拟循环模型中。在泵转速为1000、1500、2000和2500转/分钟时测量泵流量，虚拟天然心脏的脉搏率变化为60、90和120次/分钟。数据收集后，对泵流量进行积分，并计算回路内的正向和反向流量。结果，在转速为0升/分钟平均泵流量时，存在约2.0升/分钟的非生理性逆流。理想的非测试试验条件应该是同时实现泵流量为±0升/分钟且回路内无逆流。我们正在开发一种新型的EVAHEART驱动模式，该模式可以与心动周期同步改变其转速，目的是用新的驱动模式控制这种逆流并创造理想的非测试条件。
