Hematocrit 45 to 50% versus below 45% — rate of cardiovascular death and major thrombosis 10.9% vs 4.4%
Establishes hematocrit below 45% as mandatory therapeutic target
Class I recommendation based on CYTO-PV data and ELN guidelines
Phlebotomy versus cytoreductive strategy
Low-risk patients: phlebotomy plus aspirin — preferred initial strategy
Avoids chemotherapy exposure in younger patients
Maintain hematocrit below 45% with phlebotomy
High-risk patients: cytoreduction plus phlebotomy plus aspirin mandatory
Hydroxyurea first-line for high-risk — PROUD-PV and CONTINUATION-PV trial support
Hydroxyurea resistance or intolerance — ruxolitinib or interferon alpha
Anticoagulation strategy in splanchnic vein thrombosis
Indefinite anticoagulation recommended for all PV-related splanchnic thrombosis
High recurrence risk without ongoing anticoagulation
DOACs increasingly used; warfarin historically standard
Early anticoagulation plus cytoreduction improves recanalization rates
Secondary prevention principles
Cardiovascular risk factor modification
Blood pressure target below 130/80 mmHg
Statin therapy for hyperlipidemia
Smoking cessation — reduces both secondary erythrocytosis confounding and thrombosis risk
Iron supplementation avoidance
Iron deficiency from phlebotomy is a therapeutic consequence
Iron repletion reverses phlebotomy benefit and causes rapid hematocrit rebound
Patient Discharge Instructions
copy discharge instructions
Polycythemia vera home care
Take all medications exactly as prescribed
Aspirin daily as directed
Hydroxyurea or other cytoreductive medication without missing doses
Blood thinners as prescribed — take at same time each day
Stay well hydrated
At least 8 glasses of water per day
Dehydration makes your blood thicker and increases clot risk
Attend all scheduled phlebotomy (blood removal) appointments
Do not miss or delay phlebotomy without contacting your hematologist
Dietary guidance
Avoid iron-rich supplements and iron-fortified foods unless specifically advised
Limit purine-rich foods if you have had gout: red meat, organ meats, shellfish, alcohol
Return to emergency department immediately for
Sudden weakness, numbness, or paralysis on one side of the body
Sudden speech difficulty or confusion
Sudden loss of vision in one or both eyes
Severe sudden headache unlike any previous headache
Chest pain, shortness of breath, or sudden worsening of breathing
Severe abdominal pain
Leg swelling, redness, or pain suggesting a blood clot
Unusual or significant bleeding: heavy nosebleeds, vomiting blood, black stools
High fever or chills suggesting infection
Follow-up instructions
Hematologist appointment within 1 to 2 weeks — confirm before leaving hospital
CBC blood test at follow-up to check blood counts
Primary care physician within 2 to 4 weeks for cardiovascular risk factor review
Do not stop aspirin or blood thinners without speaking to your doctor first
General precautions
Avoid prolonged sitting or immobility — walk every 1 to 2 hours during long travel
Wear compression stockings during air travel or long car trips
Inform all healthcare providers including dentists and surgeons of your PV diagnosis and medications before procedures
References
Guidelines and key sources
Primary society guidelines
European LeukemiaNet (ELN) 2018 recommendations for polycythemia vera management
Defines high-risk and low-risk categories; endorses hematocrit target below 45%
Hydroxyurea first-line cytoreduction for high-risk patients
NCCN Clinical Practice Guidelines in Oncology: Myeloproliferative Neoplasms
Annual updates; provides algorithmic risk stratification and treatment pathways
British Committee for Standards in Haematology (BCSH) PV guidelines
Phlebotomy protocols and aspirin recommendations
Landmark trials
CYTO-PV trial
Marchioli R et al, NEJM 2013
Hematocrit below 45% reduces cardiovascular death and major thrombosis rate from 10.9% to 4.4%
PROUD-PV and CONTINUATION-PV trials
Ropeginterferon alfa-2b versus hydroxyurea in PV
Non-inferior response rates; favorable molecular response with interferon
RESPONSE trial
Ruxolitinib versus best available therapy for hydroxyurea-resistant or intolerant PV
Superior hematocrit control and spleen volume reduction
Key evidence sources
Barbui T et al — thrombosis risk and leukocytosis as emerging factor in PV
Tefferi A et al — survival and outcome studies in myeloproliferative neoplasms
WHO Classification of Haematolymphoid Tumours 2022 — diagnostic criteria update
Coding standards
ICD-10 D45 — polycythemia vera
ICD-10 D75.1 — secondary polycythemia
SNOMED CT 109992005 — polycythemia vera disorder concept
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.