Bleeding Complications in JAK2-Variant Essential Thrombocythemia: A Revisit in 2025

Area of Science:

• Hematology
• Oncology
• Internal Medicine

Background:

• Essential thrombocythemia (ET) is a myeloproliferative neoplasm defined by high platelet counts.
• Bleeding complications are a significant, yet often overlooked, clinical issue in ET patients.
• Patients with the JAK2-V617F mutation may have a higher risk of hemorrhage compared to those with CALR mutations.

Purpose of the Study:

• To investigate the mechanisms underlying bleeding complications in essential thrombocythemia.
• To explore the role of acquired von Willebrand syndrome (AvWS) and platelet dysfunction in ET-related hemorrhage.
• To discuss diagnostic approaches and perioperative management strategies for AvWS in ET.

Main Methods:

• Review of clinical observations and literature regarding ET, JAK2-V617F mutation, and bleeding.
• Analysis of the pathophysiology of acquired von Willebrand syndrome (AvWS) in the context of thrombocytosis.
• Discussion of diagnostic tests for VWF abnormalities and clinical management strategies.

Main Results:

• Acquired von Willebrand syndrome (AvWS) in ET is linked to extreme platelet counts causing VWF multimer proteolysis, mimicking type 2A von Willebrand disease.
• The platelet count threshold for developing AvWS is variable, with significant VWF anomalies occurring even below 1000 × 10^9/L.
• JAK2-V617F mutated ET patients may be more susceptible to bleeding due to AvWS and platelet dysfunction.

Conclusions:

• Bleeding risk in ET, particularly in JAK2-V617F positive patients, is often associated with acquired von Willebrand syndrome (AvWS).
• Diagnosis of AvWS relies on VWF testing, and management requires balancing antithrombotic and hemostatic needs.
• Tailored patient management is crucial to mitigate both bleeding and thrombotic events in essential thrombocythemia.