VWF and myeloproliferative neoplasm: In conclusion, we found that elevated levels of vWF: Ag were associated with an increased risk of both arterial and venous thrombosis in MPN patients, AVWS was associated with an increased risk of total (including minor) bleeding, and JAK2V617F VAF ≥ 50% was associated with an increased risk of major and clinically relevant non-major bleeding.