Aspirin Therapy in Polycythemia Vera

Introduction to Aspirin Therapy

The European Collaboration on Low-dose Aspirin in Polycythemia Vera recommends low-dose aspirin (100 mg daily) for all patients with polycythemia vera who have no contraindications, as it significantly reduces the risk of both arterial and venous thrombotic complications without substantially increasing bleeding risk 1, 2

The landmark ECLAP trial demonstrated a significant reduction in the combined endpoint of nonfatal myocardial infarction, nonfatal stroke, pulmonary embolism, major venous thrombosis, or death from cardiovascular causes (RR 0.40; 95% CI 0.18-0.91; P=0.03) 1, 2, 3
The ECLAP trial also showed a trend toward reduction in cardiovascular death, nonfatal MI, and nonfatal stroke (RR 0.41; 95% CI 0.15-1.15; P=0.09) 3
No significant increase in major bleeding compared to placebo was observed in the ECLAP trial 1, 2, 4

The standard dose is 100 mg once daily, which is the lowest effective dose demonstrated in the ECLAP trial for PV 1, 2, 5
Regular (non-enteric-coated) aspirin provides more reliable platelet inhibition, with peak plasma levels at 30-40 minutes and platelet inhibition evident within 1 hour 5

Aspirin is a cornerstone of PV therapy alongside phlebotomy to maintain hematocrit <45% 1, 2, 4
All PV patients (low and high risk) should receive phlebotomy to maintain hematocrit <45% + low-dose aspirin 100 mg daily 1, 2, 4
High-risk patients (age >60 years or prior thrombosis) should add cytoreductive therapy (hydroxyurea or interferon-alpha) 1, 2, 4

Aspirin should be withheld in patients with history of aspirin allergy or hypersensitivity 4
Aspirin should be withheld in patients with active bleeding or high bleeding risk 4
Aspirin should be withheld in patients with acquired von Willebrand syndrome (particularly with extreme thrombocytosis >1,500 × 10⁹/L) 4

Cardiovascular risk factor modification is essential: aggressive management of hypertension, diabetes, hyperlipidemia, and smoking cessation 1, 2, 4
Aspirin should be continued indefinitely unless contraindications develop 4

In patients with polycythemia vera who experience a recurrent ischemic stroke while on low‑dose aspirin (100 mg daily), adding warfarin to aspirin may be considered to further reduce the risk of additional cerebral ischemic events, although this combination substantially increases the risk of bleeding. 8