Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland.
Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, Maryland.
Artif Organs. 2019 Sep;43(9):870-879. doi: 10.1111/aor.13471. Epub 2019 May 22.
In vitro hemolysis testing remains one of the most important performance measures to judge the hemocompatibility of a left ventricular assist device (LVAD). Clinically relevant operating conditions and appropriate testing blood are essential to infer in vitro data for potential clinical use. This in vitro study was carried out to evaluate and compare the hemolytic performance of a newly developed magnetically levitated (maglev) LVAD (CH-VAD) with two clinically used LVADs (HVAD and HeartMate II (HMII)) using fresh human blood. A small volume (~300 mL) in vitro circulating flow loop was constructed with a LVAD generated flow of 4.5 L/min at the nominal or reported clinical operating speed for each LVAD. The blood was circulated in the loop for 4 hours with samples drawn at baseline and hourly. Plasma-free hemoglobin (PFH) concentrations in the hourly blood samples were determined with spectrophotometry. Normalized index of hemolysis (NIH) was calculated to compare the hemolytic performance of the CH-VAD and the two reference LVADs. Platelet activation was measured with flow cytometry. The experimental test for each device was repeated at least 7 times. The data from this study showed that all the three LVADs generated very low hemolysis (NIH <0.01 g/100 L). The CH-VAD was found to have a significantly lower NIH value (0.00135 ± 0.00032 g/100 L) compared to the HVAD (0.00525 ± 0.00183 g/100 L) and the HMII (0.00583 ± 0.00182 g/100 L). No statistically significant difference in device-generated hemolysis was found between the HVAD and the HMII. The level of platelet activation induced by the CH-VAD is significantly lower than those by the HVAD and the HMII. The data suggest that the shear-induced hemolysis and platelet activation of the CH-VAD are acceptable relative to the two LVADs currently in clinical use.
体外溶血试验仍然是判断左心室辅助装置（LVAD）血液相容性的最重要的性能指标之一。临床相关的工作条件和适当的测试血液对于推断潜在的临床应用的体外数据至关重要。本体外研究旨在使用新鲜人体血液评估和比较新型磁悬浮（maglev）LVAD（CH-VAD）与两种临床应用的 LVAD（HVAD 和 HeartMate II（HMII））的溶血性能。构建了一个小体积（约 300 毫升）体外循环流量回路，以 LVAD 产生的 4.5 L/min 的流量在每个 LVAD 的标称或报告的临床工作速度下运行。血液在回路中循环 4 小时，在基线和每小时抽取样本。用分光光度法测定每小时血液样本中的游离血红蛋白（PFH）浓度。计算归一化溶血指数（NIH）以比较 CH-VAD 和两种参考 LVAD 的溶血性能。用流式细胞术测量血小板激活。每种装置的实验测试至少重复 7 次。该研究的数据表明，所有三种 LVAD 的溶血率都非常低（NIH <0.01 g/100 L）。与 HVAD（0.00525 ± 0.00183 g/100 L）和 HMII（0.00583 ± 0.00182 g/100 L）相比，CH-VAD 的 NIH 值（0.00135 ± 0.00032 g/100 L）明显较低。HVAD 和 HMII 之间的溶血生成无统计学差异。CH-VAD 引起的血小板激活水平明显低于 HVAD 和 HMII。数据表明，与目前临床应用的两种 LVAD 相比，CH-VAD 的剪切诱导溶血和血小板激活是可以接受的。
