Wu Eric L, Nestler Frank, Kleinheyer Matthias, Stevens Michael C, Pauls Jo P, Fraser John F, Gregory Shaun D
Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Brisbane, Australia.
School of Medicine, The University of Queensland, Brisbane, Australia.
Artif Organs. 2018 Jan;42(1):31-40. doi: 10.1111/aor.12967. Epub 2017 Jul 25.
Right ventricular failure is a common complication associated with rotary left ventricular assist device (LVAD) support. Currently, there is no clinically approved long-term rotary right ventricular assist device (RVAD). Instead, clinicians have implanted a second rotary LVAD as RVAD in biventricular support. To prevent pulmonary hypertension, the RVAD must be operated by either reducing pump speed or banding the outflow graft. These modes differ in hydraulic performance, which may affect the pulmonary valve opening (PVO) and subsequently cause fusion, valvular insufficiency, and thrombus formation. This study aimed to compare PVO with the RVAD operated at reduced speed or with a banded outflow graft. Baseline conditions of systemic normal, hypo, and hypertension with severe biventricular failure were simulated in a mock circulation loop. Biventricular support was provided with two rotary VentrAssist LVADs with cardiac output restored to 5 L/min in banded outflow and reduced speed conditions, and systemic and pulmonary vascular resistances (PVR) were manipulated to determine the range of conditions that allowed PVO without causing left ventricular suction. Finally, RVAD sine wave speed modulation (±550 rpm) strategies (co- and counter-pulsation) were implemented to observe the effect on PVO. For each condition, outflow banding had higher PVR (97 ± 20 dyne/s/cm higher) for when the pulmonary valve closed compared to reduced speed. In addition, counter-pulsation demonstrated greater PVO than co-pulsation and constant speed. For the purpose of reducing the risks of pulmonary valve insufficiency, fusion, and thrombotic event, this study recommends a RVAD with a steeper H-Q gradient by banding and further exploration of RVAD speed modulation.
右心室衰竭是与旋转式左心室辅助装置（LVAD）支持相关的常见并发症。目前，尚无临床批准的长期旋转式右心室辅助装置（RVAD）。相反，临床医生已将第二个旋转式LVAD作为RVAD植入以进行双心室支持。为预防肺动脉高压，RVAD必须通过降低泵速或绑扎流出道移植物来操作。这些模式在水力性能上有所不同，这可能会影响肺动脉瓣开放（PVO），进而导致融合、瓣膜功能不全和血栓形成。本研究旨在比较以降低速度运行或绑扎流出道移植物的RVAD的PVO情况。在模拟循环回路中模拟了全身正常、低血压和高血压伴严重双心室衰竭的基线情况。在绑扎流出道和降低速度的情况下，使用两个旋转式VentrAssist LVAD提供双心室支持，使心输出量恢复到5 L/min，并调节全身和肺血管阻力（PVR），以确定允许PVO而不引起左心室抽吸的条件范围。最后，实施RVAD正弦波速度调制（±550 rpm）策略（协同搏动和反向搏动）以观察对PVO的影响。对于每种情况，与降低速度相比，当肺动脉瓣关闭时，流出道绑扎的PVR更高（高97±20达因/秒/厘米）。此外，反向搏动显示出比协同搏动和恒速更大的PVO。为降低肺动脉瓣功能不全、融合和血栓形成事件的风险，本研究建议通过绑扎使用具有更陡H-Q梯度的RVAD，并进一步探索RVAD速度调制。
