From the Guidelines
Phlebotomy is a crucial treatment for patients with polycythemia vera (PV), including those with normal ferritin levels, as it reduces blood volume and hematocrit, thereby improving symptoms and reducing complications. The procedure involves removing 300-500 mL of blood at regular intervals until the target hematocrit of less than 45% in men and less than 42% in women is achieved, as recommended by the European LeukemiaNet 1. Initially, phlebotomy may be performed 2-3 times weekly, then tapered to maintenance sessions every 2-3 months based on hematocrit levels.
During treatment, ferritin levels should be monitored as repeated phlebotomies will eventually deplete iron stores, which actually helps control erythropoiesis in PV patients, as noted in the management recommendations from European LeukemiaNet 1. This iron-deficient state is beneficial in managing the disease by limiting the bone marrow's ability to produce excess red blood cells. However, if the patient develops symptoms of severe iron deficiency such as fatigue, restless leg syndrome, or pica, the phlebotomy schedule may need adjustment, and iron supplementation may be indicated in cases of documented severe tissue iron deficiency associated with detrimental symptoms 1.
The therapeutic benefit of phlebotomy in PV works by reducing blood viscosity, which decreases the risk of thrombotic events like stroke, heart attack, and deep vein thrombosis that are common complications in untreated PV. According to the NCCN guidelines insights, phlebotomy is recommended to keep hematocrit <45% after 3 months of at least 2 g/d of hydroxyurea, or in cases of uncontrolled myeloproliferation, failure to reduce massive splenomegaly, or presence of leg ulcers or other unacceptable hydroxyurea-related nonhematologic toxicities 1.
Key points to consider in the management of PV patients undergoing phlebotomy include:
- Monitoring ferritin levels and adjusting the phlebotomy schedule as needed to avoid severe iron deficiency
- Maintaining a target hematocrit of less than 45% in men and less than 42% in women
- Managing cardiovascular risk factors aggressively
- Considering cytoreductive therapy in high-risk cases or in patients with poor tolerance to phlebotomy, as recommended by the European LeukemiaNet 1.
From the Research
Effects of Phlebotomy on Polycythemia Vera Patients
- Phlebotomy is a recommended treatment for patients with polycythemia vera (PV) to reduce the risk of thrombosis by maintaining a hematocrit level of less than 45% 2, 3, 4.
- The goal of phlebotomy in PV patients is to decrease blood viscosity and reduce the risk of thrombotic events, which can be life-threatening 2, 5.
- Patients with PV who undergo phlebotomy may experience a reduction in symptoms such as pruritus, erythromelalgia, and splenomegaly 2, 3.
Ferritin Levels and Phlebotomy
- A ferritin level of 68 is considered normal, and phlebotomy can help maintain normal ferritin levels by reducing iron stores 2, 4.
- However, the provided studies do not specifically address the effects of phlebotomy on PV patients with a ferritin level of 68 2, 3, 6, 5, 4.
Risk of Thrombosis and Phlebotomy
- Patients with PV who require frequent phlebotomies (3 or more per year) may have a higher risk of thrombosis due to increased proliferation of the disease 6.
- Phlebotomy dependency is an independent risk factor for thrombosis in PV patients, highlighting the importance of careful management and monitoring 6.
Management of Polycythemia Vera
- Aspirin and phlebotomy are first-line treatments for PV, with cytoreductive therapy (e.g., hydroxyurea) added as needed for high-risk patients or those with poor hematocrit control 2, 3, 4.
- Management of PV should also include addressing modifiable risk factors such as smoking cessation and cardiometabolic disease to reduce the risk of thrombosis 4.