Acquired von Willebrand Syndrome in Cardiac Patients

摘要

VON WILLEBRAND DISEASE (VWD) was first described by Erik von Willebrand in 1926. It is caused by quantitative and/or qualitative defects of the von Willebrand factor (VWF). VWF is a multimeric plasma protein composed of -250 kilodal-ton subunits and a multimer fraction that shows a wide range in size from -500 krilodaltons to >10 million daltons. High-molecular-weight (HMW) VWF multimers mediate platelet adhesion alongside vascular injury by .binding to connective tissue and to platelets. VWF also binds and stabilizes coagulation factor FVID. Therefore, patients' bleeding symptoms may refer to platelet dysfunction and/or deficiency of FVm. VWD is classified as 3 main types: type 1 (VWF moderately reduced), type 3 (VWF absent), and type 2 (VWF antigen in normal range, but qualitative defect). Type 2 VWD is divided into subtypes, with type 2A showing decreased platelet adhesion resulting from the deficiency of multimer fractions, type 2B with increased affinity for platelet glycoprotein lb, type 2M with reduced platelet adhesion despite relatively normal multimer fraction, and type 2N with decreased -affinity for FVHI and low FVIH levels. Inherited VWD is the most frequent bleeding disorder, showing an autosomal dominant or recessive inheritance pattern in most cases, and the majority of patients exhibit mild-to-moderate mucocutaneous bleeding symptoms.