PDF(Pubmed)
Abstract：
Obstruction of the LVAD flow path can occur when blood clots or tissue overgrowth form within the inflow cannula, pump body, or outflow graft, and it can lead to thrombus, embolism, and stroke. The goal of this study was to measure the impact of progressive pump inflow obstruction on the pressure and flow dynamics of the LVAD-supported heart using a mock circulatory loop. Pump obstruction (PO) was produced by progressively blocking a fraction of the LVAD inlet area. Pressures, flows, and the midplane velocity field of the LV were measured for three LVAD speeds and six PO levels. Pressure and flow decreased with PO, shifting more of the flow through the aortic valve such that the total flow decreased by 6-11% and decreased the efficiency of the work of the native heart up to 60%. PO restricts diastolic flow through the LVAD, which reduces mitral inflow and decreases the strength and energy of the intraventricular vortices. The changes in flow architecture produced by PO include flow stasis and increased shear, which predispose the system to thromboembolic risk. Analysis of the contributions to external work may enable early detection, which allows time for therapeutic intervention, reducing the likelihood of pump replacement and the risk of complications.
摘要：
当流入套管内形成血凝块或组织过度生长时，会发生LVAD流路阻塞。泵体,或外流移植，会导致血栓,栓塞,和中风。这项研究的目的是使用模拟循环回路测量渐进式泵流入阻塞对LVAD支持的心脏的压力和流量动力学的影响。泵阻塞（PO）是通过逐渐阻塞LVAD入口面积的一部分而产生的。压力,流量，并在三个LVAD速度和六个PO水平下测量了LV的中平面速度场。压力和流量随PO降低，通过主动脉瓣转移更多的流量，使总流量减少了6-11％，并使天然心脏的工作效率降低了60％。PO限制通过LVAD的舒张血流,这减少了二尖瓣流入并降低了脑室内涡流的强度和能量。PO产生的流动结构变化包括流动停滞和剪切增加，使系统容易发生血栓栓塞风险。分析对外部工作的贡献可以及早发现，这给了治疗干预的时间，减少泵更换的可能性和并发症的风险。
