From the Guidelines
The target hematocrit for patients with polycythemia vera should be less than 45% to reduce the risk of thrombotic complications, as evidenced by the CYTO-PV trial 1. This recommendation is based on the most recent and highest quality study available, which demonstrated a significant reduction in cardiovascular death and major thrombotic events in patients with a hematocrit level of <45% compared to those with a hematocrit level of 45% to 50% 1. Key points to consider in the management of polycythemia vera include:
- Therapeutic phlebotomy as the first-line approach to achieve and maintain target hematocrit levels
- Cytoreductive therapy with hydroxyurea or interferon-alpha for high-risk patients or those who require frequent phlebotomies
- Low-dose aspirin (81-100 mg daily) for all patients without contraindications to further reduce thrombotic risk
- Regular monitoring of complete blood counts to adjust therapy accordingly The goal of maintaining a hematocrit level of <45% is to reduce blood viscosity, improve microcirculation, and decrease the risk of both arterial and venous thrombosis, ultimately improving morbidity, mortality, and quality of life for patients with polycythemia vera 1.
From the Research
Target Hematocrit in Polycythemia Vera
- The target hematocrit in polycythemia vera (PV) is generally considered to be below 45% 2, 3, 4.
- This target is recommended to decrease the risk of thrombosis, which is a major cause of morbidity and mortality in PV patients 2, 3.
- Phlebotomy is commonly used to reduce hematocrit levels, with the goal of maintaining a hematocrit below 45% 2, 4.
- Cytoreductive therapy, such as hydroxyurea or interferon, may also be used to control hematocrit levels and reduce the risk of thrombosis 2, 3, 4, 5.
Rationale for Target Hematocrit
- The target hematocrit of below 45% is based on evidence from clinical trials and studies that have demonstrated a reduced risk of thrombosis and improved outcomes in PV patients with controlled hematocrit levels 2, 3, 4.
- The use of phlebotomy and cytoreductive therapy to control hematocrit levels is a cornerstone of PV management, and is recommended by various clinical guidelines 2, 4.
- The choice of cytoreductive agent and the intensity of therapy may vary depending on individual patient factors, such as risk of thrombosis and presence of symptoms 2, 4, 5.