From the Guidelines
Elevated red blood cell (RBC) count and hematocrit (HCT) levels should be promptly evaluated and managed to prevent complications such as blood clots, stroke, and heart problems, with therapeutic phlebotomy considered for patients with hemoglobin greater than 20 g per dL and hematocrit greater than 65% associated with symptoms of hyperviscosity 1. The implications of elevated RBC and HCT levels can be significant, and it is essential to determine the underlying cause of these elevations.
- Polycythemia vera, a primary cause of elevated RBC and HCT levels, requires treatment to reduce the risk of thrombosis and evolution to more severe conditions such as myelofibrosis, myelodysplastic syndrome, or acute myeloid leukemia 1.
- Secondary polycythemia, caused by conditions like chronic hypoxia, smoking, dehydration, or living at high altitude, requires treatment of the underlying cause. Key considerations in managing elevated RBC and HCT levels include:
- Therapeutic phlebotomy to reduce blood volume and prevent hyperviscosity symptoms, with careful monitoring to avoid iron depletion and decreased oxygen-carrying capacity 1.
- Low-dose aspirin (81-100mg daily) to prevent clotting in patients with polycythemia vera 1.
- Cytoreductive therapy, such as hydroxyurea, for higher-risk cases of polycythemia vera 1. Regular monitoring of complete blood counts is necessary to track the condition and adjust treatment, and symptoms like headaches, dizziness, and visual disturbances warrant prompt medical attention. Without intervention, persistently high RBC and HCT levels can lead to serious complications, including blood hyperviscosity, impaired circulation, and increased risk of stroke and heart problems.
From the Research
Implications of Elevated Red Blood Cell (RBC) Count and Hematocrit (HCT) Levels
Elevated RBC count and HCT levels are associated with an increased risk of thrombosis, hemorrhage, myelofibrosis, and acute myeloid leukemia 2, 3. The main goal of therapy in patients with elevated RBC count and HCT levels is to prevent thrombohemorrhagic complications.
Risk Factors for Thrombosis
Risk factors for thrombosis in patients with elevated RBC count and HCT levels include:
- Advanced age
- Leukocytosis
- Thrombosis history
- Presence of extreme thrombocytosis (platelets >1000 × 10(9)/L)
- JAK2 gene variant 2, 3
Treatment Strategies
Treatment strategies for patients with elevated RBC count and HCT levels include:
- Phlebotomy to keep hematocrit below 45%
- Low-dose aspirin (81 mg) once daily
- Cytoreductive therapy with hydroxyurea or interferon for high-risk patients
- Ruxolitinib for patients with severe and protracted pruritus or marked splenomegaly that is not responding to other treatments 2, 3, 4
Prognosis
The prognosis for patients with elevated RBC count and HCT levels varies depending on the treatment strategy employed. Median survival is approximately 10-14 years, with causes of morbidity and mortality including thrombotic complications, leukemia, and cytopenias 2, 5.
Disease Progression
Disease progression can lead to myelofibrosis, acute myeloid leukemia, and postpolycythemic myeloid metaplasia, with 10-50% of patients moving into a spent phase 5. Phlebotomy requirement under hydroxyurea therapy can identify a subset of patients with increased proliferation of polycythemia vera and higher risk of thrombosis 6.