From the Guidelines
An increased platelet count, particularly above 1,000 x 10^9/L, is associated with an immediate risk of major hemorrhage but not with the risk of thrombosis in patients with essential thrombocythemia (ET), and may even be associated with a significantly lower rate of thrombosis in some cases. When evaluating an increased platelet count, it is essential to determine the underlying cause, whether it be reactive (secondary) or primary thrombocytosis, such as essential thrombocythemia 1.
Key Considerations
- Advanced age (above 60 years) and history of thrombosis are the most consistent risk factors associated with the risk of thrombosis 1.
- The potential benefit of initiation of cytoreductive therapy based on elevated blood counts (leukocytosis or thrombocytosis) at diagnosis has not been evaluated in prospective studies 1.
- Elevated platelet counts at diagnosis (>1,000 x 10^9/L) may be associated with a significantly lower rate of thrombosis, even in patients with JAK2-mutated ET 1.
Management
- For patients with significantly elevated platelet counts and risk factors for clotting, medications such as low-dose aspirin or hydroxyurea may be prescribed to reduce clotting risk and lower platelet production.
- In severe cases with very high counts or active clotting, plateletpheresis might be performed to rapidly reduce platelet numbers.
Outcome Prioritization
- The primary goal in managing an increased platelet count is to minimize the risk of morbidity, mortality, and improve quality of life by preventing thrombotic and hemorrhagic complications 1.
From the Research
Increased Platelet Count
- Increased platelet count is a characteristic of essential thrombocythaemia, a myeloproliferative neoplasm that can lead to life-threatening thrombosis 2.
- The management of essential thrombocythaemia involves the use of platelet-lowering agents, such as anagrelide and hydroxyurea, to reduce the risk of vascular complications 3, 4, 5.
Treatment Options
- Anagrelide is an oral imidazoquinazoline agent that is effective in reducing elevated platelet counts in patients with essential thrombocythaemia 3.
- Hydroxyurea is also a commonly used platelet-lowering agent, and studies have shown that it is superior to anagrelide in reducing the risk of vascular events in high-risk patients 5.
- The combination of hydroxyurea and anagrelide has been explored as an alternative strategy, and studies have shown that it can be effective in reducing platelet counts with lower toxicity 2.
Patient Subgroups
- Young patients with essential thrombocythaemia may benefit from anagrelide treatment, particularly those with the JAK2 mutation 6.
- However, anagrelide treatment has been associated with the development of progressive anemia and bone marrow fibrosis in some patients, highlighting the need for periodic monitoring 6.