What are the treatment options to reduce the risk of arterial and venous thrombotic events in polycythemia vera (PV)?

Updated: Aug 20, 2019
  • Author: Srikanth Nagalla, MBBS, MS, FACP; Chief Editor: Koyamangalath Krishnan, MD, FRCP, FACP  more...
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Answer

The long-term risks of polycythemia vera (PV) include leukemic and fibrotic transformation, which occur in fewer than 5% and 10% of patients, respectively, at 10 years. Current treatment modalities do not change these outcomes. Instead, treatment for PV is intended to decrease the risk of arterial and venous thrombotic events, which could be approximately 20%.

Patients can be risk-stratified for their risk of thrombosis according to their age and history of thrombosis. Patients older than 60 years or with a previous history of thrombosis are considered to be high risk. Patients younger than 60 years and with no prior history of thrombosis are considered low risk.

All patients with PV should undergo phlebotomy to keep their hematocrit below 45%. Lower hematocrit targets have been proposed for women with PV, but no empiric evidence supports that recommendation. [1]

All patients with PV should take aspirin, 81 mg daily, unless contraindicated by major bleeding or gastric intolerance. [1] A systematic review concluded that in patients with PV, use of low-dose aspirin is associated with a reduction in the risk of fatal thrombotic events and all-cause mortality; however, the reduction was statisticallly nonsignificant (P = 0.07). The review found no increased risk of major bleeding with low-dose aspirin therapy in PV. [20]  The initial Polycythemia Vera Study Group (PVSG) study of antiplatelet drugs, which used aspirin at 300 mg 3 times a day plus dipyridamole at 75 mg 3 times a day, showed an increase in the incidence of hemorrhage.

If a patient is at high risk for thrombosis, cytoreductive therapy is added to the management plan. Hydroxyurea at a starting dose of 500 mg twice daily is the most commonly used cytoreductive agent. It can be titrated on the basis of blood counts. In patients who are refractory to or intolerant of hydroxyurea, interferon-alpha can be used as an alternative. Busulfan is also an option for patients older than 65 years. [21]


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