Moyamoya arteriopathy.

OPINION STATEMENT: The arteriopathy of moyamoya is progressive and results in severe disability from cerebral ischemia. Once the diagnosis is confirmed with magnetic resonance imaging (MRI) and catheter angiography, initial measures should consist of administration of low dose aspirin (usually 81 mg daily, barring pre-existing contraindications), maintenance of good hydration and avoidance of hyperventilation (to reduce the risk of reflex cerebral vasoconstriction). Definitive treatment is predicated on surgical revascularization of the affected cerebral hemispheres. Operative treatment should be undertaken at a high-volume center with experienced surgeons and anesthesia staff. The specific technique employed depends on the individual presentation and surgeon preference, although most centers will offer indirect approaches such as pial synangiosis to children and young adults, with direct bypass often reserved for older patients or those presenting with crescendo symptoms. Follow-up is important, with postoperative imaging (either MRI or catheter angiogram) and office visits to confirm surgical efficacy and resolution of symptoms.