Abstract
Cell exclusion in spiral groove bearing (SGB) excludes red blood cells from high shear regions in the bearing gaps and potentially reduce haemolysis in rotary blood pumps. However, this mechanobiological phenomenon has been observed in ultra-low blood haematocrit only, whether it can mitigate blood damage in a clinically-relevant blood haematocrit remains unknown. This study examined whether cell exclusion in a SGB alters haemolysis and/or high-molecular-weight von Willebrand factor (HMW vWF) multimer degradation. Citrated human blood was adjusted to 35% haematocrit and exposed to a SGB (n=6) and grooveless disc (n=3, as a non-cell exclusion control) incorporated into a custom-built Couette test rig operating at 2000RPM for an hour; shearing gaps were 20, 30, and 40 μm. Haemolysis was assessed via spectrophotometry and HMW vWF multimer degradation was detected with gel electrophoresis and immunoblotting. Haemolysis caused by the SGB at gaps of 20, 30 and 40μm were 10.6±3.3, 9.6±2.7 and 10.5±3.9 mg/dL.hr compared to 23.3±2.6, 12.8±3.2, 9.8±1.8 mg/dL.hr by grooveless disc. At the same shearing gap of 20 μm, there was a significant reduced in haemolysis (P=0.0001) and better preserved in HMW vWF multimers (p<0.05) when compared SGB to grooveless disc. The reduction
in blood trauma in the SGB compared to grooveless disc is indicative of cell exclusion occurred at the gap of 20μm. This is the first experimental study to demonstrate that cell exclusion in a SGB mitigates the shear-induced blood trauma in a clinically-relevant blood haematocrit of 35%, which can be potentially utilised in future blood pump design.
in blood trauma in the SGB compared to grooveless disc is indicative of cell exclusion occurred at the gap of 20μm. This is the first experimental study to demonstrate that cell exclusion in a SGB mitigates the shear-induced blood trauma in a clinically-relevant blood haematocrit of 35%, which can be potentially utilised in future blood pump design.
Original language | English |
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Article number | 111394 |
Number of pages | 8 |
Journal | Journal of Biomechanics |
Volume | 146 |
Early online date | 26 Nov 2022 |
DOIs | |
Publication status | Published - 30 Nov 2022 |
Bibliographical note
© 2022 Elsevier Ltd. All rights reserved.Funding: Chris H.H. Chan is supported by The Prince Charles Hospital Foundation Research Fellowship (RF2019-02), Australia. Tomotaka Murashige is supported by a Grant-in-Aid for Japan Society for the Promotion of Science Fellow (17J08128), Japan. The authors would like to recognise the financial assistance provided by The Prince Charles Hospital Foundation Team Grant (TM2017-04) and Innovation Grant (INN2021-06), Australia.
Keywords
- Left ventricular assist device
- spiral groove bearing
- cell exclusion
- haemolysis
- HMW vWF multimer degradation