Aspirin Dosing for Hemorrhagic Moyamoya Disease
For patients with hemorrhagic Moyamoya disease, low-dose aspirin at 75-100mg daily is recommended when antiplatelet therapy is indicated, though it should be used with caution due to the inherent bleeding risk in this population. 1
Antiplatelet Therapy in Hemorrhagic Moyamoya: Risk vs. Benefit
The management of hemorrhagic Moyamoya disease presents a clinical challenge due to competing risks:
- Hemorrhagic Risk: Patients have already demonstrated a propensity for intracranial hemorrhage
- Ischemic Risk: Moyamoya disease also carries risk of ischemic events due to progressive stenosis
When to Consider Antiplatelet Therapy
Antiplatelet therapy in hemorrhagic Moyamoya should be considered in specific scenarios:
- After direct revascularization surgery to prevent ischemic complications 1
- In patients who cannot undergo surgical revascularization but have high ischemic risk 2
- Prior to planned revascularization surgery 2
When to Avoid Antiplatelet Therapy
Antiplatelet therapy should generally be avoided in:
- Acute hemorrhagic phase
- Patients with multiple prior hemorrhages
- Patients with evidence of microbleeds on MRI
- Asymptomatic Moyamoya disease 3
Dosing Recommendations
When antiplatelet therapy is indicated:
- First-line agent: Aspirin 75-100mg daily 1
- Duration:
- Post-surgical: For a defined period after revascularization (typically 3-6 months)
- Non-surgical: Ongoing if ischemic risk outweighs hemorrhagic risk
Evidence Analysis
The evidence for antiplatelet therapy in hemorrhagic Moyamoya is limited:
- The American Heart Association/American Stroke Association provides a Class IIb, Level of Evidence C recommendation for aspirin use following direct revascularization 1
- A worldwide survey of Moyamoya experts revealed significant regional differences in practice patterns, with non-Asian experts more likely to recommend antiplatelet therapy than Asian experts (p=0.0128) 4
- A 2020 study demonstrated that antiplatelet therapy was more effective than conservative management in preventing ischemic events in Moyamoya patients, though surgical revascularization showed the best outcomes 2
Important Considerations
- Bleeding Risk: Lower aspirin doses (75-100mg) are associated with lower bleeding risk compared to moderate (100-200mg) or high doses (>200mg) 5
- Surgical Priority: Direct or combined revascularization procedures should be prioritized over antiplatelet therapy when possible, as they provide better protection against both ischemic and hemorrhagic events 1, 6
- Monitoring: Regular clinical and radiographic follow-up is essential as rebleeding can occur years after initial hemorrhage (mean 7.3 years in one study) 6
Alternative Approaches
For patients with contraindications to aspirin:
- Consider cilostazol (less hemorrhagic risk but limited evidence in Moyamoya)
- Avoid anticoagulants such as warfarin due to high hemorrhage risk 1
The management of hemorrhagic Moyamoya disease requires careful consideration of competing risks, with surgical revascularization remaining the definitive treatment when feasible, and antiplatelet therapy serving as an adjunctive or alternative approach in select cases.