Die perioperative Therapie des Von-Willebrand-Syndroms

Von Willebrand disease (vWD) is the most widespread inherited bleeding disorder caused by quantitative or qualitative abnormalities ofvon Willebrand factor (vWF),an adhesive glycoprotein found in blood plasma and platelets and participating in primary and secondarylendothelium haemostasis as well. Although bleeding symptoms are often mild or moderate, patients with vWD represent a very heterogenous group with different phenotypes and a wide variability of the clinical pattern. In accordance with different defects of vWF, vWD is classified into various types and subtypes. This is illustrated by two case reports of patients with different types of vWD.Two main therapeutic options are available for the prevention and treatment of bleeding: desmopressin (DDAVP) and replacement therapy with plasma concentrates containing both factor VIII and vWF. DDAVP is the treatment of choice for most patients with type 1, representing about 80% of all patients with vWD. In patients with most types of type 2 and in all patients of type 3, DDAVP alone is ineffective or even contraindicated,and it is usually necessary to switch to plasma concentrates. Although treatment of vWD seems to be relatively simple in most cases, the exact diagnosis and phenotype characterization requires specialized or expert laboratory facilities. Furthermore, no reliable screening method for the diagnosis of vWD exists.Acquired vWD has similar clinical features and laboratory findings to the congenital forms and is mostly associated with lymphoproliferative or autoimmune disorders or neoplasia.