Management of Low-Dose Aspirin in Myeloproliferative Disorders
Stopping low-dose aspirin in patients with myeloproliferative disorders is not safe and should be avoided unless there is active bleeding or severe thrombocytopenia (platelet count <10,000/μL). 1
Risk Assessment for Aspirin Therapy in MPNs
Myeloproliferative neoplasms (MPNs) such as polycythemia vera (PV) and essential thrombocythemia (ET) are characterized by a high risk of thrombotic complications:
- The pooled prevalence of thrombosis is 28.6% in PV and 20.7% in ET 2
- Thrombotic events can occur even before diagnosis 2
- Aspirin has been proven to significantly reduce thrombotic complications in these disorders 2
Evidence Supporting Continued Aspirin Use
For Polycythemia Vera:
- The ECLAP trial demonstrated that low-dose aspirin safely reduced the risk of cardiovascular events and major thrombosis (RR 0.40; 95% CI, 0.18–0.91) 2
- Aspirin (81-100 mg/day) plus phlebotomy (to maintain hematocrit <45%) is recommended for all patients with low-risk PV 2
- For high-risk PV, aspirin should be continued alongside cytoreductive therapy 2
For Essential Thrombocythemia:
- Aspirin (81-100 mg/day) is recommended for patients with low-risk JAK2-mutated ET and those with cardiovascular risk factors 2
- For high-risk ET, aspirin should be maintained alongside cytoreductive therapy 2
Special Considerations for Aspirin Management
Platelet Count Thresholds:
- Continue aspirin unless platelet count falls below 10,000/μL or there is active bleeding 1
- For patients with moderate thrombocytopenia (>30,000/μL) and high thrombotic risk (e.g., recent coronary stents), continuing aspirin is justified 1
Aspirin Resistance Concerns:
- Up to one-third of PV patients on once-daily aspirin show less-than-maximal platelet inhibition 3
- Patients with platelet counts ≥317 × 10^9/L are more likely to have high on-treatment residual platelet reactivity 4
- For patients with inadequate response to once-daily aspirin, consider:
Perioperative Management:
- Aspirin should be discontinued one week prior to elective surgery 2
- Restart 24 hours after surgery or when bleeding risk is acceptable 2
Monitoring Recommendations
- Regular platelet count monitoring (every 1-2 weeks initially)
- Watch for signs of bleeding (bruising, petechiae, mucosal bleeding)
- Monitor for symptoms of disease progression every 3-6 months 2
- Assess for thrombotic complications and acquired von Willebrand disease 2
Alternative Antiplatelet Agents
If aspirin is not tolerated due to gastrointestinal issues:
- Consider ticlopidine (500 mg/day) which has shown fewer gastrointestinal bleeding complications while maintaining similar efficacy in relieving erythromelalgia and painful paresthesia 6
Conclusion
The risk of thrombotic complications in myeloproliferative disorders significantly outweighs the bleeding risk associated with low-dose aspirin therapy in most patients. Discontinuation of aspirin should be avoided except in cases of severe thrombocytopenia (<10,000/μL) or active bleeding.