Prevalence of acquired von Willebrand syndrome during essential thrombocythemia: a retrospective analysis of 170 consecutive patients

INTRODUCTION The identification of patients with essential thrombocythemia (ET) who are at increased
risk of acquired von Willebrand syndrome (AVWS) would likely facilitate individualization of treatment
and improve its outcomes.
OBJECTIVES The aim of the study was to determine the prevalence of AVWS in patients with ET and
to verify whether individuals with and without this bleeding disorder differ in terms of their baseline
clinical parameters.
PATIENTS AND METHODS The study included 170 consecutive patients with ET. AVWS was diagnosed on
the basis of reduced levels of von Willebrand factor and abnormal results of other routine tests. Patients
with and without concomitant AVWS were compared in terms of their demographic characteristics, past
and current medical histories, and laboratory parameters.
RESULTS Concomitant AVWS was found in 34 patients (20%). Individuals with AVWS were diagnosed
with ET at a significantly younger age than those without the syndrome. In addition, these patients
significantly less often were in remission at the time of testing, had significantly higher erythrocyte and
platelet counts, and showed abnormalities of the coagulation profile corresponding to defects of primary
hemostasis as well as abnormal values of most parameters used i n the routine diagnosis of AVWS.
CONCLUSIONS Even every fifth patient with ET may develop AVWS. Young age at diagnosis of ET and the
lack of response to its previous treatment are potential risk factors for AVWS that should be considered
during the management of the primary condition. All patients with ET and signs of a bleeding disorder,
irrespective of the platelet count, should be tested for the pr esence of AVWS.