What is the treatment for Moya Moya disease?

Treatment of Moyamoya Disease

Surgical revascularization with direct or combined extracranial-intracranial bypass is the definitive treatment for moyamoya disease, particularly in patients with a history of ischemic stroke or TIA, as it markedly reduces stroke risk from 67% preoperatively to 4.3% at 5-year follow-up. 1

Surgical Management: The Primary Treatment

Indications for Surgery

• All patients with ongoing ischemic symptoms and/or evidence of compromised cerebral perfusion should undergo revascularization surgery (Class I, Level B recommendation). 2
• Even clinically asymptomatic patients demonstrating radiographic or functional evidence of impaired cerebral perfusion should be considered surgical candidates. 2, 3
• Surgery is highly effective when performed at high-volume centers on carefully selected patients, yielding excellent results compared to the natural history of untreated disease. 1

Surgical Technique Selection

Direct or combined bypass procedures are superior to indirect approaches alone:

• Direct bypass (superficial temporal artery to middle cerebral artery anastomosis) is the most appropriate intervention, particularly for hemorrhagic moyamoya, reducing rebleeding from 7.6% per year to 2.7% per year (P=0.04). 2, 3
• For adult patients, the Japanese guideline considers indirect procedures alone insufficient, recommending direct or combined procedures as necessary. 1
• The European guideline suggests direct/combined revascularization instead of an indirect approach alone. 1

Indirect procedures (pial synangiosis, encephaloduroarteriosynangiosis) are preferred in children due to small vessel size making direct bypass technically difficult. 2, 3

Perioperative Management: Critical for Success

The perioperative period carries a 4%-18% risk of ischemic stroke, requiring meticulous management: 2, 4

Hemodynamic goals:

• Maintain systolic blood pressure at or above preoperative baseline at which the patient was asymptomatic. 2, 5
• Administer intravenous fluids at 1.5 times normal maintenance rate for 48-72 hours postoperatively. 1
• Ensure euvolemia to mild hypervolemia before and after surgery. 2, 5

Ventilation parameters:

• Maintain strict normocapnia with end-tidal CO₂ between 35-45 mmHg—even mild hypocapnia causes vasoconstriction and ischemia in already compromised vessels. 2, 5
• Avoid hyperventilation, crying, and coughing, which lower PaCO₂ and induce ischemia. 1, 5

Additional perioperative measures:

• Use perioperative sedation and painless wound dressing techniques to reduce crying and hyperventilation in children. 1
• Avoid hypotension, hypovolemia, hyperthermia, and hypocarbia both intraoperatively and perioperatively. 1, 2
• Maintain normothermia (36-37°C) throughout the perioperative period. 5

Medical Management: Adjunctive Role

Antiplatelet Therapy

Aspirin monotherapy may be reasonable for prevention of ischemic events (Class 2b, Level C-LD recommendation), though evidence is limited and practice varies globally. 1

• Aspirin is most commonly used at 81 mg daily in children (weight-based dosing). 1, 2
• Antiplatelet agents are used to prevent microthrombi at sites of arterial stenosis. 1, 2
• Practice patterns vary significantly: antiplatelet use is more common in Western countries than Asia, where hemorrhagic presentation is more prevalent. 2

Anticoagulation: NOT Recommended

Anticoagulants like warfarin are NOT recommended (Class III recommendation) due to hemorrhage risk and difficulty maintaining therapeutic levels, particularly in children. 2, 3

Supportive Medical Measures

Maintain optimal cerebral perfusion through:

• Careful monitoring of fluid balance and avoidance of dehydration from illness, exercise, or hot weather. 1, 2
• Maintenance of intravascular volume—primary focus is on avoiding dehydration rather than supplementation. 1
• Mitigation of non-ischemic symptoms such as headache and seizures. 1, 2

Emerging Medical Therapies

• Cilostazol (a vasodilator) may improve survival, cerebral blood flow, and cognition compared to other antiplatelet drugs, though requires further validation. 2
• Atorvastatin may improve collateral circulation post-revascularization. 2
• Aggressive management of diabetes is essential, as it is an independent predictor of recurrent ischemic stroke. 2
• Control hypertension and dyslipidemia, which are risk factors for cerebrovascular events in asymptomatic moyamoya. 2

Long-Term Surveillance

Serial follow-up is necessary given the 5% annual risk of cerebrovascular events in asymptomatic patients and 20% disease progression rate: 2, 3

• Periodic follow-up by clinicians familiar with moyamoya is supported, with initial visits ideally annually for 3-5 years (Class IIb recommendation). 1
• Patients with unilateral moyamoya should obtain annual imaging with MRA or CTA to assess for disease progression for at least 3-5 years. 1
• Techniques to measure cerebral perfusion and blood flow reserve may assist in evaluation and follow-up. 3

Common Pitfalls to Avoid

Critical errors that worsen outcomes:

• Allowing hyperventilation or hypocapnia during crying, coughing, or straining—this causes vasoconstriction in already compromised vessels. 1, 2
• Permitting dehydration or hypovolemia, which decreases cerebral perfusion. 1, 2
• Using anticoagulation in children or hemorrhagic presentations due to bleeding risk. 2, 3
• Delaying surgical referral in symptomatic patients—medical management alone has failed to halt disease progression. 6
• Performing surgery at low-volume centers without moyamoya expertise, as outcomes are highly dependent on institutional experience. 1