title: DDAVP challenge tests in boys with mild/moderate haemophilia A.
abstract: Desmopressin (DDAVP) increases plasma factor VIII coagulant activity (FVIII:C) levels in patients with mild/moderate haemophilia A. In some subjects, FVIII can be increased to haemostatic levels, thereby avoiding use of factor VIII concentrates. We reviewed our hospital's experience with 62 boys with FVIII:C levels 0.01-0.3 IU/ml who had a DDAVP challenge test (i.v. 0.3 microg/kg) following diagnosis. A therapeutic response was defined as a 1 h post-FVIII:C increase at least twofold over baseline and > 0.3 IU/ml. Of the total group, 29 (47%) boys responded to DDAVP, all of them with mild haemophilia (baseline FVIII:C > or = 0.05 IU/ml), yielding a response rate of 57% in this subgroup. Boys who responded to DDAVP had higher baseline FVIII:C levels (mean +/- SEM, 0.17 +/- 0.01 vs 0.10 +/- 0.01 IU/ml, P < 0.01) and were older (5.2 +/- 0.8 vs 3 +/- 0.4 years, P = 0.02) than those who failed to do so. The association between DDAVP response and age, however, remains unclear: seven boys who failed the initial challenge test responded to re-challenge after a mean of 6.3 years (median 4.9, range 0.5-12.5), increasing the response rate in boys with mild haemophilia to 71%. Age and FVIII:C association with DDAVP response are both important in boys with mild/moderate haemophilia A. Absence of response to DDAVP should therefore be confirmed by later re-challenge.
authors.affiliation: Department of Paediatrics, The Hospital for Sick Children and the University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
authors.forename: Shoshana
authors.initials: S
authors.lastname: Revel-Vilk
authors.forename: Victor S
authors.initials: VS
authors.lastname: Blanchette
authors.forename: Cathy
authors.initials: C
authors.lastname: Sparling
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Stain
authors.forename: Manuel D
authors.initials: MD
authors.lastname: Carcao
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003894:Deamino Arginine Vasopressin / Q000627:therapeutic use*; D005169:Factor VIII / Q000032:analysis*; D006467:Hemophilia A / Q000097:blood / Q000188:drug therapy*; D006728:Hormones / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D008297:Male; D012189:Retrospective Studies
chemical_list: D006728:Hormones; D005169:Factor VIII; D003894:Deamino Arginine Vasopressin