Key result
Cyclic high shear stress in a mechanical shuttle flow tester caused a logarithmic increase in hemolysis and rapid dissipation of large von Willebrand factor multimers within five cycles.
Why the study?
Mechanical revolving motions in artificial MCS systems induce cleavage in large VWF multimers, making nonsurgical bleeding likely to occur after mechanical hemodynamic support.
Does cyclic shear stress from a mechanical shuttle shear flow tester cause hemolysis and VWF degradation in goat blood?
Does cyclic shear stress from a mechanical shuttle shear flow tester cause hemolysis and VWF degradation in goat blood?
Cyclic shear stress in a mechanical shuttle flow tester causes a logarithmic increase in hemolysis and rapid degradation of large VWF multimers within seconds, simulating blood trauma from mechanical circulatory support devices.
May signal hemolysis and VWF degradation risk in MCS devices; leaves open translation from this animal model to humans.
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.
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Shiraishi et al. (2021) studied Hemolysis and von Willebrand factor degradation (MCS-related blood trauma). Cyclic shear stress via mechanical shuttle shear flow tester vs. Baseline/low cycle numbers was evaluated on Plasma-free hemoglobin levels and large VWF multimer index. Cyclic high shear stress in a mechanical shuttle flow tester caused a logarithmic increase in hemolysis and rapid dissipation of large von Willebrand factor multimers within five cycles.
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