What is the management and treatment plan for a patient with a likely diagnosis of Moyamoya disease?

Management and Treatment of Moyamoya Disease

Surgical revascularization is the definitive treatment for all patients with symptomatic Moyamoya disease or those with evidence of compromised cerebral perfusion, as this intervention dramatically reduces stroke risk from 67% preoperatively to 4.3% at 5-year follow-up. 1, 2

Diagnostic Confirmation

Before initiating treatment, confirm the diagnosis with appropriate imaging:

• Cerebral digital subtraction angiography (DSA) remains the gold standard, particularly for unilateral lesions or cases complicated by atherosclerosis 1, 3
• Three angiographic findings are required: (1) stenosis of the distal internal carotid artery bifurcation and proximal anterior/middle cerebral arteries, (2) dilated basal collateral vessels creating the characteristic "puff of smoke" appearance, and (3) bilateral abnormalities 1, 3
• Perfusion imaging (SPECT, PET, or xenon-enhanced CT) and cerebrovascular reactivity assessment are critical for surgical planning and identifying patients with compromised cerebral blood flow reserve 1, 3

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). 1, 2, 3

• Even clinically asymptomatic patients demonstrating radiographic or functional evidence of impaired cerebral perfusion should be considered surgical candidates 2, 3
• The key factor determining successful outcomes is surgeon and institutional experience with Moyamoya care 1

Surgical Technique Selection

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) 1, 2, 3

• Indirect revascularization techniques (pial synangiosis, encephaloduroarteriosynangiosis, multiple burr holes) are preferred in children due to small vessel size making direct bypass technically difficult 2
• Combined direct and indirect approaches have shown superior results, with 96% probability of remaining stroke-free over 5 years 2

Perioperative Medical Management

Meticulous perioperative management is essential to minimize the 4%-18% risk of perioperative stroke. 1, 3

Hemodynamic Management

• Maintain systolic blood pressure at or above preoperative baseline; slight elevation may be beneficial 1, 2, 3
• Provide intravenous fluids at 1.5 times normal maintenance rate for 48-72 hours postoperatively to ensure euvolemia to mild hypervolemia 2
• Avoid systemic hypotension, hypovolemia, and hyperthermia 2

Respiratory Management

• Maintain strict normocapnia with end-tidal CO₂ between 35-45 mmHg as hypocapnia causes vasoconstriction and ischemia in already compromised vessels 1, 2, 3
• Minimize triggers of hyperventilation using perioperative sedation and painless wound dressing techniques 2

Complications to Monitor

• Cerebral hyperperfusion syndrome occurs in 16.5% overall (3.8% in pediatric patients, 19.9% in adults) 2
• Perioperative seizures may occur 2

Medical Management

Antiplatelet Therapy

Aspirin may be reasonable for prevention of ischemic events in both surgical and nonsurgical patients (Class IIb recommendation), though evidence is mixed and practice varies globally 1, 2, 3

• Typical dosing: 81 mg daily in children with weight-based adjustments 2
• Aspirin use is more common in Western countries than Asia, where hemorrhagic presentation is more prevalent 2

Anticoagulation

Anticoagulants like warfarin are NOT recommended (Class III recommendation) due to hemorrhage risk and difficulty maintaining therapeutic levels, particularly in children 1, 2

Adjunctive 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

Risk Factor Management

• Diabetes is an independent predictor of recurrent ischemic stroke and requires aggressive management 1, 2
• Hypertension and dyslipidemia are risk factors for cerebrovascular events in asymptomatic Moyamoya and should be controlled 2

Long-Term Surveillance and Follow-Up

Serial follow-up is necessary given the 5% annual risk of cerebrovascular events in asymptomatic patients and 20% disease progression rate over mean 6-year follow-up. 1, 2, 3

Imaging Surveillance

• Patients with unilateral Moyamoya should obtain annual imaging with MRA or CTA to assess for disease progression for at least 3-5 years (Class IIb recommendation) 1
• Transcranial Doppler (TCD) may be useful in evaluation and follow-up (Class IIb recommendation) 2
• Techniques to measure cerebral perfusion and blood flow reserve may assist in ongoing evaluation (Class IIb recommendation) 2, 3

Clinical Monitoring

• Screen for and manage headaches, which occur commonly and typically have migraine-like features (>50% with aura) or tension-type characteristics 2
• Monitor for seizures as part of the clinical spectrum 2
• Evaluate neuropsychological effects of Moyamoya as part of chronic care 4

Critical Pitfalls to Avoid

• Never use anticoagulation in Moyamoya patients due to hemorrhage risk 1, 2
• Avoid hypocapnia, hypotension, and hypovolemia as these trigger ischemia in compromised vessels 1, 2, 3
• Do not delay surgical referral in symptomatic patients, as medical therapy alone has failed to halt disease progression 5
• Recognize that posterior circulation involvement is associated with worse clinical presentation and higher recurrent hemorrhages 2