Enhanced VWF Cleavage in Turbulence: Mechanistic Insights through Taylor-Green Vortex Flows

Mechanical circulatory assist devices, such as left ventricular assist devices (LVADs), often create non-laminar and turbulent flow conditions, leading to significant clinical challenges including increased risks of hemolysis, thrombosis, and bleeding. Recent studies suggest that device-generated turbulence can enhance the cleavage of the clotting-control biopolymer called von Willebrand Factor (VWF). However, the biophysical mechanisms underlying this turbulence-enhanced VWF cleavage remain unexplored. To address this gap, we develop a Taylor-Green vortex model coupled with the Langevin equation for VWF polymer suspension dynamics to investigate how turbulent flow eddies interact with VWF polymers in an idealized yet characteristically representative turbulent shear layer flow. Our study reveals that counter-rotating eddies, down to the Kolmogorov length scale, locally generate microscale elongational flow regions that significantly enhance the unfolding, tensile stretching, and subsequent cleavage of VWF in a molecular weight-dependent manner. Our work provides mechanistic insights into how turbulence enhances VWF cleavage and offers valuable hemodynamic considerations for optimizing the design of blood-contacting devices for improved hemocompatibility.