[Acquired von Willebrand syndrome]

Von Willebrand disease (VWD) is among the most common inherited bleeding disorders. Interestingly, acquired von Willebrand syndrome (AVWS) is diagnosed much less frequently, but can be identified in association with a substantial number of medical conditions and diseases, including lymphoproliferative (48%), cardiovascular (21%), myeloproliferative (15%), other neoplastic (5%), and autoimmune disorders (2%). Most recently, AVWS has been diagnosed in patients with aortic valve stenosis (AS, 79%) and continuous-flow left ventricular assist devices (LVAD, up to 100%).1) Immune mechanisms mediated reduction of VWF activityAutoantibodies to VWF have been identified in association with monoclonal gammopathies, lymphoid, neoplasms, and autoimmune diseases. Some autoantibodies have higher affinity to high molecular weight-VWF multimers (HMW-VWFMs); clearance of HMW-VWFMs leads to bleeding.2) Non-immune mechanisms induced reduction of VWF activityOne of the mechanisms is VWF adsorption onto malignant cells and paraproteins (i.e., as in multiple myeloma) and thereby removed from the blood circulation. VWF-linked proteolysis can be induced by shear stress. According to high levels of shear stress in AS and LVAD, HM-VWFMs are more susceptible to cleavage by ADAMTS13. We will find a large number of AVWS cases related to cardiovascular diseases.