Evaluation of desmopressin effect on primary haemostasis in pediatric patients with aspirin-like defect as hereditary thrombocytopathy

OBJECTIVES: Despite about 3 decades of clinical experience with the therapy of inherited thrombocytopathies (HTP) with desmopressin (DDAVP) the mechanisms of haemostatic effects of DDAVP in these diseases remain unclear. Therefore platelet function diagnostics was carried out in whole blood (WB) from children with aspirin-like defect as one of the clinically mild forms of HTP after DDAVP administration.

DESIGN AND METHODS: 11 children (age range: 3-16 years) were treated with DDAVP i.v. (0.3 μg/kg as short infusion). Before, after 120, and 240 min of DDAVP administration the following parameters were measured: platelet aggregation (PA) and ATP release induced by ADP, collagen, ristocetin and thrombin; PFA-100 closure times (CT), factor VIII activity (FVIII:C), Von Willebrand factor antigen (VWF:Ag), collagen binding activity (VWF:CB) and blood count.

RESULTS: PA, ATP release and blood count were not influenced by DDAVP administration. PFA-100 CTs were markedly reduced at 120 and 240 min after DDAVP, respectively. FVIII:C, VWF:Ag and VWF:CB were increased after 120 min.

CONCLUSION: The DDAVP-induced improvement of primary haemostasis in patients with aspirin-like defect is mainly due to the marked increase of the VWF. For the evaluation of the clinical effect of DDAVP administration in patients with aspirin-like defect the investigation of a larger group of patients is needed.