Aspirin Dosing for Hemorrhagic Moyamoya Disease
For patients with hemorrhagic Moyamoya disease, low-dose aspirin (75-100mg daily) is recommended following direct revascularization surgery, but aspirin should generally be avoided in patients with hemorrhagic presentation who have not undergone surgical revascularization. 1
Rationale for Aspirin Use in Moyamoya Disease
Aspirin therapy in Moyamoya disease requires careful consideration of the disease presentation (hemorrhagic vs. ischemic) and whether the patient has undergone surgical revascularization:
Hemorrhagic Presentation Without Surgery
- Antiplatelet therapy is generally not recommended for patients with hemorrhagic Moyamoya who have not undergone revascularization due to the increased risk of rebleeding
- The risk of rebleeding in hemorrhagic Moyamoya can occur as late as 20 years after the initial hemorrhage, with a mortality rate of approximately 28.6% 2
Post-Surgical Management
- After direct revascularization surgery for hemorrhagic Moyamoya, low-dose aspirin (75-100mg daily) is recommended to prevent thrombotic complications at the surgical site 1
- The Japan Adult Moyamoya (JAM) trial supports direct revascularization for hemorrhagic Moyamoya to reduce rebleeding risk 1
Dosing Considerations
When aspirin is indicated (primarily post-revascularization):
- Recommended dose: 75-100mg daily 1
- Higher doses of aspirin (>100mg) are associated with increased bleeding risk and should be avoided 3
- Duration of therapy: Typically continued for a certain period after surgery rather than indefinitely 4
Regional Practice Variations
There are significant differences in antiplatelet management between Asian and non-Asian experts:
- Asian experts (who see more Moyamoya cases) are less likely to recommend long-term antiplatelet therapy 5
- Non-Asian experts more frequently recommend antiplatelet drugs 5
- This difference may reflect variations in disease presentation between populations
Alternative Approaches
For patients who cannot undergo surgical revascularization:
- Antiplatelet therapy may be considered as an alternative treatment, but evidence for efficacy is limited 6
- In a study of ischemic Moyamoya patients, antiplatelet therapy showed better outcomes than conservative treatment but was less effective than surgical revascularization in preventing recurrent ischemic events 6
Monitoring and Follow-up
For patients on aspirin therapy:
- Regular clinical and radiographic follow-up is essential
- Monitor for signs of bleeding complications
- Approximately 27% of patients with unilateral disease eventually develop bilateral involvement, requiring ongoing assessment 1
Important Cautions
- Avoid anticoagulants such as warfarin in Moyamoya disease due to high hemorrhage risk 1
- Medications causing vasoconstriction should be avoided 1
- Maintain normotension and avoid hypotension which can increase ischemic risk 1
The management of hemorrhagic Moyamoya disease requires careful consideration of the balance between preventing thrombotic complications and minimizing bleeding risk, with surgical revascularization being the primary treatment strategy for reducing rebleeding risk.