Department of Cardiovascular Surgery, Tokyo Medical and Dental University Graduate School of Medical and Dental Sciences, Tokyo, Japan.
School of Engineering, Tokyo Institute of Technology, Tokyo, Japan.
Artif Organs. 2020 Sep;44(9):968-975. doi: 10.1111/aor.13743. Epub 2020 Jul 7.
Although the magnetically levitated centrifugal blood pump (mag-lev pump) is considered superior to other pumps in antithrombogenicity, thrombotic complications are still reported. Research into thrombus detection inside a mag-lev pump is very important for solving this problem. Our research group has already proposed a method to detect a thrombus inside a mag-lev pump in real time without an additional sensor, which is named the impeller vibration method. To efficiently advance our research with reproducibility, a preconditioning method to induce thrombus inside the pump was thought to be necessary. Therefore, this study aimed to develop a preconditioning method that induces thrombus formation. To verify this method, in vitro experiments for thrombus detection were performed. A mag-lev pump developed at Tokyo Institute of Technology was used. A fibrinogen solution was coated on the inner surfaces of the bottom housing to induce thrombus formation at the target point inside the pump. The thrombus is detected by utilizing the phenomenon that the phase difference between the impeller displacement and input current to the magnetic bearing increases when a thrombus is formed inside a pump. Five hundred mL of porcine blood anticoagulated with heparin sodium was circulated in the mock circuit, and protamine sulfate was administered. Flow rate (1 L/min), impeller vibrational frequency (70 Hz), and vibrational amplitude (30 µm) were set to constant. The experiment was terminated when the phase difference increased by over 2° from the minimum value. The experiments were performed in fibrinogen-coated (group F, n = 5) and non-coated pumps (group N, n = 5). In group F, thrombus formation was observed at the fibrinogen-coated point of the housing. In contrast, a relatively small thrombus was observed in varying locations such as the housing or the impeller in group N. Thrombus formation time (the time from when the phase difference takes the minimum value to when the experiment is terminated) was different between the two groups. The mean time was significantly shorter in group F (44 ± 29 minutes) than in group N (143 ± 38 minutes; p = 0.0019). Therefore, a preconditioning method that induced thrombus formation at the target point inside a blood pump was successfully developed.
尽管磁悬浮离心式血泵（磁悬浮泵）在抗血栓形成方面被认为优于其他泵，但仍有血栓形成的并发症报告。研究磁悬浮泵内血栓的检测对于解决这个问题非常重要。我们的研究小组已经提出了一种无需额外传感器即可实时检测磁悬浮泵内血栓的方法，称为叶轮振动法。为了高效推进我们的研究并具有可重复性，我们认为有必要开发一种在泵内诱导血栓形成的预处理方法。因此，本研究旨在开发一种诱导血栓形成的预处理方法。为了验证这种方法，进行了体外血栓检测实验。使用东京工业大学开发的磁悬浮泵。在泵内的目标点处，将纤维蛋白原溶液涂覆在底壳的内表面上，以诱导血栓形成。通过利用当泵内形成血栓时，叶轮位移和磁轴承输入电流之间的相位差增大的现象来检测血栓。将 500 毫升肝素钠抗凝的猪血在模拟回路中循环，并给予硫酸鱼精蛋白。流量（1 L/min）、叶轮振动频率（70 Hz）和振动幅度（30 µm）设置为恒定。当相位差从最小值增加超过 2°时，实验终止。在纤维蛋白原涂层组（组 F，n = 5）和非涂层组（组 N，n = 5）中进行了实验。在组 F 中，在外壳的纤维蛋白原涂层处观察到血栓形成。相比之下，在组 N 中，在外壳或叶轮等不同位置观察到相对较小的血栓。血栓形成时间（相位差取最小值到实验结束的时间）在两组之间有所不同。组 F 的平均时间（44 ± 29 分钟）明显短于组 N（143 ± 38 分钟；p = 0.0019）。因此，成功开发了一种在血液泵内目标点诱导血栓形成的预处理方法。
