What medications are recommended after direct revascularization for moyamoya disease?

Medication Recommendations After Direct Revascularization for Moyamoya Disease

Aspirin is recommended for patients following direct revascularization surgery for moyamoya disease to prevent recurrent ischemic events. 1

Antiplatelet Therapy

Primary Recommendation

• Aspirin (75-100mg daily) is the most supported antiplatelet therapy following revascularization surgery 1
• The American Heart Association/American Stroke Association recommends aspirin for individuals with moyamoya after revascularization surgery (Class IIb, Level of Evidence C) 1

Evidence for Antiplatelet Use

• While data demonstrating long-term efficacy is limited, antiplatelet agents are routinely used in many operative series 1
• Antiplatelet therapy targets micro-thrombus formation at sites of arterial stenosis 1
• In a 2017 study of 184 adult patients with ischemic moyamoya disease who underwent direct or combined revascularization, aspirin (100mg/day) was associated with improved outcomes without increasing hemorrhage risk 2

Perioperative Management

Blood Pressure Management

• Maintain systolic blood pressure at or slightly above patient's baseline (avoid >180 mmHg) 3
• Avoid hypotension which can increase risk of perioperative stroke 1

Fluid Management

• Maintain euvolemia to mild hypervolemia 3
• Consider intravenous fluids at 1.5 times normal maintenance rate based on weight for 48-72 hours postoperatively 1

Other Perioperative Considerations

• Avoid hyperthermia and hypocarbia which can increase risk of perioperative stroke 1
• Implement adequate pain management to prevent hyperventilation-induced vasoconstriction 1, 3

Medications to Avoid or Use with Caution

Anticoagulants

• Anticoagulants such as warfarin are generally not recommended for most individuals with moyamoya due to hemorrhage risk (Class III, Level of Evidence C) 1
• Low-dose LMWH may be considered in specific situations but evidence is limited 1

Vasoconstrictive Medications

• Medications that cause vasoconstriction, inhibit vasodilation, or significantly lower blood pressure should be avoided 1
• For patients with moyamoya-related headaches, avoid triptans, ergots, and certain migraine therapies that affect cerebral vasculature 1

Long-term Management

Monitoring and Follow-up

• Regular clinical and radiographic follow-up is recommended as 27% of patients with unilateral disease eventually develop bilateral involvement 3
• Techniques such as TCD, perfusion CT, PET, and SPECT can help monitor cerebral blood flow and assess treatment efficacy 1, 3

Effectiveness of Revascularization

• Direct revascularization has shown superior outcomes compared to indirect revascularization in preventing recurrent ischemic events 4, 5
• In a study of direct revascularization, annual stroke rates decreased from 8.9% to 4.5% per hemisphere-year after treatment, with no events occurring over 41.1 hemisphere-years of follow-up when excluding perioperative events 5

Pitfalls and Caveats

• The evidence supporting antiplatelet therapy in moyamoya disease is limited (Level of Evidence C) 1
• Cerebral hyperperfusion syndrome occurs in approximately 16.5% of cases after revascularization and requires careful blood pressure management 3
• Repeat revascularization may be necessary in some patients with persistent symptoms, with direct bypass showing lower rates of requiring repeat procedures (1% vs 4% for indirect bypass) 6
• Antiplatelet therapy may not significantly increase bypass graft patency rates but does not appear to increase hemorrhage risk 2

In conclusion, while the evidence base is not robust, aspirin is the most supported medication following direct revascularization for moyamoya disease, with careful attention to perioperative management to optimize outcomes and reduce complications.