Abstract Number: PB1579
Meeting: ISTH 2020 Congress
Background: Von Willebrand disease type 2B (VWD-2B), caused by gain-of-function mutations in von Willebrand factor (VWF) gene, is characterized by increased VWF affinity for GPIbα platelet receptor associated with variable loss of high-molecular-weight VWF multimers (HMW-VWF), variable thrombocytopenia and, in severe defects, a thrombopathy. Desmopressin is classically contraindicated in VWD-2B patients due to the risk of thrombocytopenia after abnormal VWF release. However, this contraindication is based on small patients’ series, not always taking into account the mutations. Moreover its impact on thrombopathy associated with VWD-2B is not known.
Aims: To evaluate in VWD-2B patients without basal thrombocytopenia the impact of desmopressin administration on VWF and platelet function.
Methods: We assessed platelet count, plasma VWF activity (VWF:Act) and PFA-100 closure times (collagen/epinephrine-CEPI and collagen/adenosine diphosphate-CADP) before and 30 minutes, 1, 2 and 4 hours after desmopressin injection (0.3µg/kg) to VWD-2B patients.
Results: Fourteen patients (from 7 different families) were included; 8 with R1341Q mutation and 6 with R1306Q mutation, 2 of the most frequently observed mutations in VWD-2B. Before injection, all patients have a platelet count>150G/L, a partial or total HMW-VWF reduction, a VWF:Act< 50% and CEPI and CADP>300sec. Two hours after desmopressin administration, the platelet count decreased (p=0.002) without thrombocytopenia except for one patient (at 143G/L). Moreover, despite a VWF:Act correction (>50%) in all patients, CEPI remain >300sec while CADP shorten (p=0,01).
Conclusions: In conclusion, this study shows that the use of desmopressin in VWD-2B patients allows VWF:Act correction and does not often lead to thrombocytopenia. These results contradict a systematic contraindication of desmopressin in VWD-2B patients with R1341Q or R1306Q and without basal thrombocytopenia. In addition, the persistence of a major prolongation of CEPI in these patients, after VWF:Act correction and in absence of thrombocytopenia, suggests an associated thrombopathy whose impact on hemorrhagic phenotype and involved molecular mechanisms remain to be described.
To cite this abstract in AMA style:Dupont A, Rauch A, Paris C, Lassalle F, Hochart A, Wibaut B, Bauters A, Goudemand J, Zawadzki C, Jeanpierre E, Susen S. Desmopressin in Patients with Type 2B von Willebrand Disease: Differential Impact on VWF and Platelet Function [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/desmopressin-in-patients-with-type-2b-von-willebrand-disease-differential-impact-on-vwf-and-platelet-function/. Accessed January 23, 2022.
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