Acquired von Willebrand syndrome: Data from an International Registry

The acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder wit h laboratory findings similar to those of congenital von Willebrand disease (vWD). Despite the numerous cases reported in the literature until 1999 (n = 266), large studies on AvWS are not available. Moreover, diagnosis of Av WS has been difficult and treatment empirical. These considerations prompte d us to organize an international registry. A questionnaire, devised to col lect specific information on AvWS, was sent to all the members of the Inter national Society on Thrombosis and Haemostasis (ISTH), who were invited to respond if they had diagnosed cases with the AvWS cases. 156 members answer ed the questionnaire and 54 of them sent information on 211 AvWS cases from 50 centers. Data were compared with those already published in the literat ure and 25 cases already described or not correctly diagnosed were excluded . The 186 AvWS cases that qualified for the registry were associated with l ymphoproliferative (48%) and myeloproliferative disorders (15%), neoplasia (5%), immunological (2%), cardiovascular (21%) and miscellaneous disorders (9%). Ristocetin cofactor activity (vWF:RCo) or collagen binding activity ( vWF:CBA) were usually low in AVWS (median values 20 U/dL, range 3-150), whi le factor Vm coagulant activity was sometimes normal (median 25 U/dL, range 3-191). FVIII/vWF inhibiting activities were present in only a minority of cases (16%). Bleeding episodes in AVWS were mostly of mucocutaneous type ( 68%) and were managed by DDAVP (32%), FVIII/vWF concentrates (37%), intrave nous immunoglobulins (33%), plasmapheresis (19%), corticosteroids (19%) and immunosuppressive or chemotherapic agents (35%). Based upon the data of th is international registry, it appears that AvWS is especially frequent in l ympho- or myeloproliferative and cardiovascular diseases. Therefore, AvWS s hould be suspected and searched with the appropriate laboratory tests espec ially when excessive bleeding occurs in patients with these disorders. On t he basis of the information provided by this registry guidelines for diagno sis and management of the AvWS are given.