VWF and hyperinsulinemic hypoglycemia, familial, 4: It has been shown that high stress in aortic stenosis causes shear-dependent cleavage of high molecular weight multimers of von Willebrand’s factor (vWF), leading to acquired vWF deficiency [17]: vWF is essential for the adhesion and aggregation of platelets to the sub-endothelium of damaged blood vessels.