In vitro hemolysis testing for blood pumps currently faces several challenges, including randomness in control group selection, and numerous sources of uncertainty in the testing methods. These issues lead to high uncertainty, insufficient result credibility, and limited comparability, which hinders the effective evaluation of blood damage induced by blood pumps. This study aims to address these limitations by developing a magnetically-levitated blood pump benchmark model and optimizing the hemolysis testing protocol to reduce result uncertainty. A magnetic bearing was utilized to minimize blood damage, and the injection molding was employed to enhance the machining precision of the pump. The experimental procedures, including blood collection, test loop setup, and the testing process, were optimized to effectively control experimental uncertainty. The results showed that the performance curve of the benchmark pump model was flat, and the coefficient of variation for the hydraulic experimental results was less than 5%. The secondary flow path exhibited good blood washout with no thrombus formation. Under low-flow condition, the average normalized index of hemolysis (NIH) was 0.014 g/100L, with a coefficient of variation of 19.50%. Under high-flow condition, the average NIH was 0.045 g/100L, with a coefficient of variation of 16.45%. The hemolysis values under both conditions were lower than the Abbott CentriMag. In conclusion, we designed a benchmark blood pump model with excellent hemocompatibility and optimized hemolysis testing protocol, which led to low uncertainty in experimental results. The benchmark and optimized hemolysis protocol help to improve the credibility and comparability of in vitro hemolysis testing data, providing a reliable solution for both the industry and regulatory agencies to assess hemocompatibility.
Objective To investigate the hemocompatibility of the acellular valved bovine jugular vein conduit (BJVC) treated with polyepoxy compound (PC), and discuss its application in cardiovascular surgery and tissue engineering in the future. Methods BJVC treated with PC was regarded as the experiment group and BJVC treated with glutaraldehyde (GA) was considered to be the control group. Rat blood was used for in vitro hemolytic test to calculate hemolytic rates of BJVC, and curve of absorbanceclotting time was drawn. Human blood was used to determine the level of D-dimeride and complement activation C3a des Arg, and test its hemocompatibility in vitro. We divided 20 canines into the experiment group (PC group, n=10) and the control group (GA group, n=10) by random digital table. The BJVC treated with PC or GA were implanted between the pulmonary artery and right ventricle. Ten months after the implantation, thrombus and histological observation were performed to evaluate the blood compatibility in vivo. Results The hemolytic rate in the PC group (0.23%) was lower than that in the GA group (0.35%), which was in accordance with the national standard of hemolytic test (lt;5%). The curve of absorbanceclotting time in the experiment group declined more slowly than that of the control group. The D-dimeride level in the experiment group was significantly lower than that of the control group (0.10±0.01 μg/ml vs. 0.12±0.02 μg/ml , t=3.277, P=0.004), but both of them were within the normal level. The level of complement C3a des Arg in the experiment group was significantly lower than that of the control group (0.74±0.09 μg/ml vs. 1.02±0.19 μg/ml, t=4.183, P=0.001). Eight canines survived 10 months after the implantation in both the two groups, and two other canines in each group died due to ventricular fibrillation. Three canines were discovered to have thrombus in the control group while no thrombus was observed in the experiment group. Conclusion Compared with GA, acellular BJVC treated with PC has superiority in hemocompatibility in vitro and vivo, and has potential application in clinical research and practice.