New practice guidelines for von Willebrand disease: Clinical perspectives

Abstract

von Willebrand disease (VWD) is a congenital bleeding disorder that is caused by quantitative and qualitative abnormalities in the von Willebrand factor (VWF); moreover, VWD is associated with an extremely diverse pathophysiology. VWD is classified into the following subtypes: quantitative defects (Type 1), qualitative defects (Type 2), and near-complete absence of plasma VWF (Type 3). Further, type 2 VWD is subcategorized into types 2A, 2B, 2M, and 2N. The most common symptom of VWD is mucocutaneous bleeding due to impaired primary hemostasis, typically menorrhagia in women with VWD. Hemarthrosis and intramuscular hematoma due to impaired secondary hemostasis occur in Type 3 and 2N, wherein the level of coagulation factor VIII is markedly decreased. Distinguishing between patients with VWD and healthy individuals based exclusively on their bleeding symptoms is challenging, since mucocutaneous bleeding and menorrhagia occur even in healthy individuals. Patients with VWF levels <30% are diagnosed with VWD; however, accurate diagnosis is difficult in some cases because numerous factors affect the plasma VWF levels. Consequently, VWF levels vary across a wide range (50–200%), even in healthy individuals. Desmopressin and VWF concentrate are used for the treatment of VWD. In addition to plasma-derived VWF/FVIII products, recombinant VWF is also available for clinical use. A clear understanding and knowledge regarding the characteristics of VWF and the diverse pathophysiology of VWD is important for the accurate diagnosis and treatment of VWD, based on the new clinical practice guideline established by the Japanese Society on Thrombosis and Hemostasis.