Pb2239: acquired von willebrand disease (avwd) diagnostic profile in myeloproliferative neoplasia (mn) patients in western-estonia

Topic: 16. Myeloproliferative neoplasms - Clinical Background: Myeloproliferative diseases (MD) patients have the complication in both side of hemostasis - related to bleeding and thrombosis. Reducing thrombosis risk, major impact on morbidity and mortality is a major goal of therapy. However, in lifelong evaluating quality of life during the disease course, the bleeding has also important role. Acquired von Willebrand disease (AvWD) may result from increased proteolysis together with platelet activation, which leads to reduced von Willebrand factor activity (vWFact). Aims: We analysed our MD patient cohort to lab analysis related to hemostatsis to better understand the patients profile. Methods: Chart review of the two Medical Centers case records with diagnosis of D47.3, D45 and D47.1 between years 2016-2021. Results: During 2016-2022 in total 145 patients with MD where in regular follow-up in both Centers. Patients with essential thrombocythemia (ET) consisted of 35.17%, with polycythemia vera (PV) of 33,79% and with primary myelofibrosis (PMF) of 31,03%. In 58 patients the analysis of von Willebrand factor antigen (vWFAg), vWFact, Factor 8 were measured in case of bleeding tendency or before operation and invasive procedures. Semiautomated von Willebrand factor multimer assay was performed in 53 patients. AvWD was diagnosed in 13 from 23 with ET, in 5 from 14 with PMF and in 3 from 12 patients with PV diagnosis. In all patients except two the vWFact/vWFAg ratio was below 0.7 and the multimeric assay shows decreased high molecular weight of multimers and in two ratio was normal but decreased high molecular weight of multimers at the same time. 7 patients died during the observation period, 3 of them from thrombosis, 1 from bleeding and 1 from thrombosis together with bleeding related courses. Summary/Conclusion: AvWD can be a complication of patients with ET, PV and PMF. We recommend VWF Ag and vWF act testing during course of disease and before planned surgical intervention or invasive procedures to diagnose potential AvWD. Keywords: Myeloproliferative disorder, Acquired von Willebrand syndrome