Pharmacokinetics of von Willebrand factor and factor VIII in canine von Willebrand disease and haemophilia A.

The pharmacokinetics of von Willebrand factor antigen (vWf:Ag) and factor VIII coagulant (FVIII:C) activity in dogs with von Willebrand Disease (vWD) and haemophilia A, respectively, were assessed after the administration of fresh frozen plasma (FFP) and cryoprecipitate. Loading doses necessary to attain target plasma concentrations of each factor were estimated to be 63 U kg-1 BW for FFP and 13 U kg-1 BW for cryoprecipitate to reach 35 U dl-1 vWf:Ag in vWD and 23 U kg-1 BW for FFP and 4 U kg-1 BW for cryoprecipitate to reach 30 U dl-1 FVIII:C in haemophilia A. The estimated volumes of FFP required to attain these target concentrations (49 ml kg-1 BW for vWD and 20 ml kg-1 BW for haemophilia A) are approximately 10-fold higher than the volumes of cryoprecipitate required (4 ml kg-1 BW for vWD and 2 ml kg-1 BW for haemophilia A). This indicates that cryoprecipitate is a more efficient and practical means of treating or preventing haemorrhage in these two haemostatic disorders.