1-DESAMINO-8-ARGININE-VASOPRESSIN CORRECTS THE HEMOSTATIC DEFECTS IN TYPE 2B VON WILLEBRANDS DISEASE

DDAVP is effective treatment in most types of von Willebrand's disease ; however, in type 2B von Willebrand's disease the use of DDAVP has be en contraindicated due to DDAVP-induced thrombocytopenia. Several repo rts have confirmed the thrombocytopenic effects of DDAVP and the prese nce of circulating platelet aggregates in type 2B von Willebrand's dis ease, We have infused three type 2B patients with DDAVP, The three pat ients had different mutations of their vWf, All three patients had a m issense mutation which resulted in a single amino acid substitution in the disulfide loop of the Al domain. Administration of 20 mu g of DDA VP resulted in significant elevations of factor VIII, vWf antigen, and ristocetin cofactor levels, In contrast to other studies, DDAVP did n ot induce or enhance thrombocytopenia in these three patients, When bl ood was obtained by fingerstick and diluted into sodium oxalate (Unope tte(R)) or EDTA (Microvette(R)), the platelet counts did not change ov er 4 hr. In contrast, blood collected directly into evacuated tubes co ntaining sodium citrate, lithium heparin, or EDTA consistently demonst rated varying degrees of thrombocytopenia and platelet clumping; We al so observed a shortening of the preinfusion bleeding time over the 4 h r period. All three patients have been studied twice and each has show n consistent results. DDAVP appears to be a useful form of treatment i n type 2B vWd. (C) 1996 Wiley-Liss, Inc.