From the The Intervention Centre, Oslo University Hospital, 0424 Oslo, Norway.
Faculty of Medicine, University of Oslo, 0372 Oslo, Norway.
ASAIO J. 2018 Sep/Oct;64(5):601-609. doi: 10.1097/MAT.0000000000000699.
Pump thrombosis and stroke are serious complications of left ventricular assist device (LVAD) support. The aim of this study was to test the ability of an accelerometer to detect pump thrombosis and thromboembolic events (TEs) using real-time analysis of pump vibrations. An accelerometer sensor was attached to a HeartWare HVAD and tested in three in vitro experiments using different pumps for each experiment. Each experiment included thrombi injections sized 0.2-1.0 mL and control interventions: pump speed change, afterload increase, preload decrease, and saline bolus injections. A spectrogram was calculated from the accelerometer signal, and the third harmonic amplitude was used to test the sensitivity and specificity of the method. The third harmonic amplitude was compared with the pump energy consumption. The acceleration signals were of high quality. A significant change was identified in the accelerometer third harmonic during the thromboembolic interventions. The third harmonic detected thromboembolic events with higher sensitivity/specificity than LVAD energy consumption: 92%/94% vs. 72%/58%, respectively. A total of 60% of thromboembolic events led to a prolonged third harmonic amplitude change, which is indicative of thrombus mass residue on the impeller. We concluded that there is strong evidence to support the feasibility of real-time continuous LVAD monitoring for thromboembolic events and pump thrombosis using an accelerometer. Further in vivo studies are needed to confirm these promising findings.
左心室辅助装置（LVAD）支持中，泵血栓和中风是严重的并发症。本研究旨在通过实时分析泵振动来测试加速度计检测泵血栓和血栓栓塞事件（TE）的能力。将加速度计传感器连接到 HeartWare HVAD，并在三个体外实验中使用不同的泵进行测试，每个实验都包括大小为 0.2-1.0ml 的血栓注射和对照干预：泵速改变、后负荷增加、前负荷降低和盐水弹丸注射。从加速度计信号中计算出声谱图，并使用该方法的第三谐波幅度来测试其灵敏度和特异性。将第三谐波幅度与泵能量消耗进行比较。加速度信号质量很高。在血栓栓塞干预过程中，加速度计的第三谐波发生了明显变化。与 LVAD 能量消耗相比，第三谐波检测血栓栓塞事件的灵敏度/特异性更高：92%/94%比 72%/58%。总共 60%的血栓栓塞事件导致第三谐波幅度延长变化，这表明叶轮上有血栓质量残留。我们得出结论，有强有力的证据支持使用加速度计对血栓栓塞事件和泵血栓进行实时连续 LVAD 监测的可行性。需要进一步的体内研究来证实这些有前途的发现。
