The corresponding dominating mechanism is the excessive proteolysis of HMWM-vWFs by ADAMTS-13 in the context of the high shear stress related to stenotic valves, which not only predisposes patients to bleed but also induces submucosal arteriovenous malformations in the digestive tract [4, 5]. Here, ADAMTS13 is linked to arteriovenous hemangioma/malformation.