Hemolysis and von Willebrand factor degradation in mechanical shuttle shear flow tester

Yasuyuki Shiraishi, Yuma Tachizaki, Yusuke Inoue, Masaki Hayakawa, Akihiro Yamada, Michinori Kayashima, Masanori Matsumoto, Hisanori Horiuchi, Tomoyuki Yambe

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Chronic blood trauma caused by the shear stresses generated by mechanical circulatory support (MCS) systems is one of the major concerns to be considered during the development of ventricular assist devices. Large multimers with high-molecular-weight von Willebrand factor (VWF) are extended by the fluid forces in a shear flow and are cleaved by ADAMTS13. Since the mechanical revolving motions in artificial MCSs induce cleavage in large VWF multimers, nonsurgical bleeding associated with the MCS is likely to occur after mechanical hemodynamic support. In this study, the shear stress (~ 600 Pa) and exposure time related to hemolysis and VWF degradation were investigated using a newly designed mechanical shuttle shear flow tester. The device consisted of a pair of cylinders facing the test section of a small-sized pipe; both the cylinders were connected to composite mechanical heads with a sliding-sleeve structure for axial separation during the withdrawing motion. The influence of exposure time, in terms of the number of stress cycles, on hemolysis and VWF degradation was confirmed using fresh goat blood, and the differences in the rates of dissipation of the multimers were established. The plasma-free hemoglobin levels showed a logarithmic increase corresponding to the number of cycles, and the dissipation of large VWF multimers occurred within a few seconds under high shear stress flow conditions.

Original languageEnglish
Pages (from-to)111-119
Number of pages9
JournalJournal of Artificial Organs
Issue number2
Publication statusPublished - 2021 Jun


  • Hemolysis
  • Large multimer
  • Shuttle shear flow tester
  • Von Willebrand factor


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