Potential supplementary utility of combined PFA-100 and functional von Willebrand factor testing for the laboratory assessment of desmopressin and factor concentrate therapy in von Willebrand disease.
We performed a retrospective audit of cross-laboratory testing of desmopressin and factor concentrate therapy to assess the potential utility of supplementary testing using the PFA-100 with functional von Willebrand factor (VWF) activity testing. Data were evaluated for a large number of patients with von Willebrand disease of type 1, type 2A or type 2M, as well as a comparative subset of individuals with haemophilia or carriers of haemophilia. Laboratory testing comprised pre and postdesmopressin, or pre and postconcentrate, evaluation of factor VIII, VWF antigen (VWF:Ag) and VWF ristocetin cofactor activity as traditionally performed, supplemented with collagen-binding (VWF:CB) testing and PFA-100 closure times. In brief, both therapies tended to normalize VWF test parameters and closure times in individuals with type 1 von Willebrand disease, with the level of correction in closure times related to the level of normalization of VWF, particularly the VWF:CB. However, although occasional correction of closure times was observed in patients with type 2A or type 2M von Willebrand disease, these did not in general normalize PFA-100 closure times either with desmopressin or factor concentrate therapy. In these patients, improvement in closure times was more likely in those in whom VWF:CB values normalized or when VWF:CB/VWF:Ag ratios normalized. This study confirms that there is a strong relationship between the presenting levels of plasma VWF and PFA-100 closure times, and that the supplementary combination of PFA-100 and VWF:CB testing might provide added clinical utility to current broadly applied testing strategies limited primarily to VWF:Ag, VWF ristocetin cofactor and factor VIII:coagulant. Future prospective investigations are warranted to validate these relationships and to investigate their therapeutic implications.
Favaloro
Emmanuel J
EJ
Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, New South Wales, Australia. emmanuel.favaloro@swahs.health.nsw.gov.au
Thom
Jim
J
Patterson
David
D
Just
Sarah
S
Baccala
Maria
M
Dixon
Tracy
T
Meiring
Muriel
M
Koutts
Jerry
J
Rowell
John
J
Baker
Ross
R
D001779:Blood Coagulation Factors / Q000627:therapeutic use*; D003894:Deamino Arginine Vasopressin / Q000627:therapeutic use*; D016903:Drug Monitoring / Q000295:instrumentation / Q000379:methods*; D005169:Factor VIII / Q000032:analysis; D006467:Hemophilia A / Q000097:blood / Q000188:drug therapy; D006579:Heterozygote; D006801:Humans; D010979:Platelet Function Tests / Q000295:instrumentation*; D012189:Retrospective Studies; D013997:Time Factors; D056725:von Willebrand Disease, Type 1 / Q000097:blood / Q000188:drug therapy; D056728:von Willebrand Disease, Type 2 / Q000097:blood / Q000188:drug therapy; D014842:von Willebrand Diseases / Q000097:blood* / Q000188:drug therapy; D014841:von Willebrand Factor / Q000032:analysis*
D001779:Blood Coagulation Factors; D014841:von Willebrand Factor; C025667:prothrombin complex concentrates; D005169:Factor VIII; D003894:Deamino Arginine Vasopressin