Von Willebrand Factor — A Rapid Sensor of Paravalvular Regurgitation during TAVR?

Abstract

Von Willebrand factor is unique among coagulation factors by virtue of its highly multimeric structure, which allows it to function as an endogenous sensor of hemodynamic forces.(1) Under conditions of low shear stress (below the usual physiologic range), von Willebrand factor self-associates into compacted, high-molecular-weight (HMW) multimers that are unable to promote platelet adhesion. During physiologic shear stress (shear rate of 100 to 5000 sec-1), von Willebrand factor undergoes partial unfolding and elongation, exposing binding sites for platelets and collagen and allowing the metalloprotease ADAMTS13 to regulate the size distribution of the HMW multimers by cleaving von Willebrand factor . . .