What is the clinical presentation, complications, and treatment of Moya Moya disease with infarcts?

Moyamoya Disease with Infarcts: Clinical Presentation, Complications, and Treatment

For moyamoya disease presenting with ischemic infarcts, surgical revascularization should be offered to all patients with ongoing ischemic symptoms and/or evidence of compromised cerebral perfusion, as this reduces stroke risk from 67% preoperatively to 4.3% at 5-year follow-up. 1

Clinical Presentation

Ischemic Manifestations

• Children predominantly present with ischemic strokes or TIAs, often multiple and recurrent, involving the carotid circulation with infarctions in superficial, deep, or watershed territories 2
• Ischemic symptoms are frequently triggered by hyperventilation, crying, coughing, straining, or fever due to vasoconstriction in already compromised vessels 2
• Adults in Western countries more commonly present with recurrent ischemia compared to hemorrhagic events 2
• Characteristic electroencephalographic finding: slowing of background rhythm after cessation of hyperventilation ("rebuild-up" phenomenon) 2

Associated Symptoms

• Headaches occur commonly and typically have migraine-like features (>50% with aura) or tension-type characteristics 2
• Seizures may occur as part of the clinical spectrum 2
• Progressive neurological decline can occur in fulminant cases 2

Complications

Acute Complications

• Recurrent ischemic strokes with annual risk of cerebrovascular events around 5% in asymptomatic patients 2
• Perioperative ischemic events occur in 4%-18% of surgical cases, with contralateral hemisphere strokes occurring in 5.1% of cases 1, 3
• Cerebral hyperperfusion syndrome (CHS) occurs in 16.5% overall (3.8% in pediatric patients, 19.9% in adults) 2
• Seizures in the perioperative period 2
• Diffuse cerebral edema can occur as a devastating complication, particularly when aggressive blood pressure management is coupled with hypocapnia 4

Long-term Complications

• Disease progression occurs in 20% over mean follow-up of 6 years 2
• Posterior circulation involvement is associated with worse clinical presentation and higher recurrent hemorrhages 2
• Neuropsychological sequelae requiring long-term management 5
• Epilepsy development 5

Acute Treatment

Medical Management of Acute Infarcts

• Antiplatelet therapy (aspirin) may be reasonable for prevention of ischemic events, though evidence is mixed and practice varies globally 2
• Anticoagulants like warfarin are NOT recommended due to hemorrhage risk and difficulty maintaining therapeutic levels, particularly in children (Class III recommendation) 2, 1
• Maintain euvolemia to mild hypervolemia to avoid hypotension and decreased cerebral perfusion 2
• Maintain normocapnia with end-tidal CO2 between 35-45 mmHg as hypocapnia causes vasoconstriction and ischemia 2, 1
• Avoid systemic hypotension, hypovolemia, hyperthermia, and hypocarbia 2

Critical Pitfalls to Avoid

• Never allow hypocapnia - this causes vasoconstriction in poorly compliant arteries leading to worsened cerebral blood flow 4
• Avoid aggressive blood pressure lowering - maintain systolic BP at or above preoperative baseline when asymptomatic 2, 1
• Avoid medications that cause vasoconstriction (triptans, ergots), inhibit vasodilation (CGRP-targeted therapies), or lower blood pressure (β-blockers, calcium channel blockers) 2
• Avoid mannitol as it can worsen hypotension 2

Long-term Treatment

Surgical Revascularization - Primary Treatment

Indications:

• All patients with ongoing ischemic symptoms and/or evidence of compromised cerebral perfusion should undergo revascularization (Class I, Level B recommendation) 2, 1
• Even clinically asymptomatic patients with radiographic or functional evidence of impaired cerebral perfusion should be considered surgical candidates 2, 1

Surgical Techniques:

For Adults:

• Direct bypass (superficial temporal artery to middle cerebral artery) is the most appropriate intervention, particularly for hemorrhagic moyamoya, reducing rebleeding from 7.6%/year to 2.7%/year (P=0.04) 2, 1
• Direct bypass provides immediate revascularization but is more technically demanding with higher risk of cerebral hyperperfusion syndrome 2
• Indirect bypass (pial synangiosis, encephaloduroarteriosynangiosis) relies on angiogenic proliferation over days to weeks 2

For Children:

• Indirect revascularization techniques are preferred due to small vessel size making direct bypass technically difficult 1

Perioperative Management Protocol

Preoperative:

• Preadmission for IV fluids overnight to maintain hydration while NPO 2, 1
• Place arterial line before induction of anesthesia 2

Intraoperative:

• Maintain systolic BP at or above preoperative baseline (avoid >180 mmHg) 2, 1
• Strict normocapnia with end-tidal CO2 35-45 mmHg 2, 1
• Maintain euvolemia to mild hypervolemia 2, 1
• Avoid mannitol 2

Postoperative:

• Careful blood pressure control is crucial - intentional hypotension can cause contralateral hemisphere stroke 3
• Advanced moyamoya stage (Suzuki 4/5/6) and PCA involvement increase risk of contralateral ischemic complications 3

Medical Management - Adjunctive

Antiplatelet Therapy:

• Aspirin 81 mg daily in children (weight-based dosing) or standard adult dosing is most commonly used to prevent microthrombi at stenosis sites 1
• Cilostazol (a vasodilator) may improve survival, cerebral blood flow, and cognition compared to other antiplatelet drugs, though requires further validation 2
• More commonly prescribed in Western countries than Asia where hemorrhagic presentation predominates 2

Risk Factor Management:

• Diabetes is an independent predictor of recurrent ischemic stroke and requires aggressive management 2
• Hypertension and dyslipidemia are risk factors for cerebrovascular events in asymptomatic moyamoya 2
• Atorvastatin may improve collateral circulation post-revascularization 2

Supportive Measures:

• Maintain adequate hydration and intravascular volume 1
• Techniques to minimize anxiety and pain reduce hyperventilation-induced vasoconstriction 2
• Avoid anemia and hypoglycemia to promote cerebral oxygen delivery 5

Long-term Surveillance

• Serial follow-up is necessary given 5% annual risk of cerebrovascular events in asymptomatic patients and 20% disease progression rate 2
• Neuroimaging surveillance to assess disease progression 5
• Evaluation and management of neuropsychological effects, headache, and epilepsy 5