Pharmacokinetics-based clinical management of acquired von Willebrand syndrome: a case report.

von Willebrand disease (VWD) is a common bleeding disorder caused by defective or low levels of von Willebrand factor (VWF). Although most cases of VWD are caused by genetic mutations, some are acquired due to various disease states. In managing VWD, the aim is to normalize plasma levels of both VWF and factor VIII (FVIII), as this aids in hemostasis. Desmopressin usually corrects VWF level in type 1 VWD by inducing the release of endogenous VWF. In cases where desmopressin is ineffective or cannot be used, transfusion of virally inactivated, plasma-derived VWF/FVIII concentrate or infusion of recombinant VWF (Vonvendi) is indicated. Treatment of acquired von Willebrand syndrome (AVWS) aims to control the underlying disease while regulating life-threatening hemorrhages with infusions of VWF/FVIII concentrate. Wide intrasubject variability in VWF and FVIII levels, particularly in AVWS, necessitates verification of response to treatment by frequent monitoring of the plasmatic VWF level. Clinical pharmacokinetics of VWF may facilitate calculation of the necessary loading and maintenance doses of VWF/FVIII concentrate in the management of AVWS patients undergoing surgery, thereby avoiding unnecessary infusion of coagulation factor concentrate.