title: Desmopressin therapy to assist the functional identification and characterisation of von Willebrand disease: differential utility from combining two (VWF:CB and VWF:RCo) von Willebrand factor activity assays?
abstract: We performed a retrospective audit of desmopressin (DDAVP) usage to assist in the functional characterisation of von Willebrand disease (VWD). Data was evaluated for 208 patients, comprising those with VWD (Type 1 [n=160], Type 2A [n=19], Type 2M [n=10]), plus 19 individuals with haemophilia or carriers of haemophilia. Laboratory testing comprised pre- and post-DDAVP evaluation of factor VIII (FVIII:C), von Willebrand factor (VWF) antigen (VWF:Ag), VWF ristocetin cofactor (VWF:RCo) activity, VWF collagen binding (VWF:CB) activity, and in one laboratory an alternate VWF activity assay. In brief, combined usage of VWF:RCo and VWF:CB appears to provide improved functional characterisation and/or 'classification' of VWD types, in particular better differentiation of Type 2A and 2M VWD, and clearer validation of a Type 1 VWD diagnosis. Thus, (i) Type 1 VWD displayed generally good absolute and relative rises in all test parameters, although relative rises were greatest for FVIII:C and VWF:CB, and CB/Ag ratio increases overshadowed those for RCo/Ag; (ii) Type 2A VWD patients showed good absolute and relative rises in both FVIII:C and VWF:Ag, but poor absolute rises in both VWF:CB and VWF:RCo; although small rises in both CB/Ag and RCo/Ag were also observed, both ratios tended to remain below 0.7; (iii) finally, Type 2 M VWD patients generally showed good absolute and relative rises in FVIII:C, VWF:Ag and VWF:CB, but a poor absolute and relative rise in VWF:RCo; thus, there were good rises in CB/Ag ratios but little change in RCo/Ag, which tended to remain below 0.7. Future multi-centre prospective investigations are warranted to validate these findings and to investigate their therapeutic implications.
authors.affiliation: Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, NSW, Australia. emmanuel.favaloro@swahs.health.nsw.gov.au
authors.forename: Emmanuel J
authors.initials: EJ
authors.lastname: Favaloro
authors.forename: Jim
authors.initials: J
authors.lastname: Thom
authors.forename: David
authors.initials: D
authors.lastname: Patterson
authors.forename: Sarah
authors.initials: S
authors.lastname: Just
authors.forename: Tracy
authors.initials: T
authors.lastname: Dixon
authors.forename: Jerry
authors.initials: J
authors.lastname: Koutts
authors.forename: Maria
authors.initials: M
authors.lastname: Baccala
authors.forename: John
authors.initials: J
authors.lastname: Rowell
authors.forename: Ross
authors.initials: R
authors.lastname: Baker
mesh_terms: D003094:Collagen / Q000378:metabolism; D003894:Deamino Arginine Vasopressin / Q000627:therapeutic use*; D006490:Hemostatics / Q000627:therapeutic use; D006801:Humans; D066298:In Vitro Techniques; D012189:Retrospective Studies; D014842:von Willebrand Diseases / Q000097:blood* / Q000145:classification / Q000188:drug therapy*; D014841:von Willebrand Factor / Q000032:analysis / Q000378:metabolism*
chemical_list: D006490:Hemostatics; D014841:von Willebrand Factor; D003094:Collagen; D003894:Deamino Arginine Vasopressin