Summary
The acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with 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 AvWS has been difficult and treatment empirical.
These considerations prompted us to organize an international registry. A questionnaire,
devised to collect specific information on AvWS, was sent to all the members of the
International Society on Thrombosis and Haemostasis (ISTH), who were invited to respond
if they had diagnosed cases with the AvWS cases. 156 members answered the questionnaire
and 54 of them sent information on 211 AvWS cases from 50 centers. Data were compared
with those already published in the literature and 25 cases already described or not
correctly diagnosed were excluded. The 186 AvWS cases that qualified for the registry
were associated with lymphoproliferative (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), while factor VIII 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%), intravenous immunoglobulins (33%), plasmapheresis (19%), corticosteroids
(19%) and immunosuppressive or chemotherapic agents (35%). Based upon the data of
this international registry, it appears that AvWS is especially frequent in lympho-or
myeloproliferative and cardiovascular diseases. Therefore, AvWS should be suspected
and searched with the appropriate laboratory tests especially when excessive bleeding
occurs in patients with these disorders. On the basis of the information provided
by this registry guidelines for diagnosis and management of the AvWS are given.
Keywords
Acquired von Willebrand syndrome - diagnosis - therapy