Neural Damage Caused by Cerebral Hyperperfusion after Arterial Bypass Surgery in a Patient with Moyamoya Disease: Case Report

OBJECTIVE AND IMPORTANCE: The prognosis of cerebral hyperperfusion syndrome after vascular reconstructive surgery, including extracranial-intracranial arterial bypass, is not poor unless intracerebral hemorrhage develops secondary to hyperperfusion. CLINICAL PRESENTATION: A 48-year-old man with symptomatic moyamoya disease with misery perfusion in the right cerebral hemisphere underwent double right superficial temporal artery-to-middle cerebral artery bypasses. The postoperative course was uneventful until the patient developed headache and agitated delirium on the 4th postoperative day. INTERVENTION: Perfusion computed tomographic imaging demonstrated hyperperfusion in the right temporal lobe. The symptoms resolved by institution of intensive blood pressure control. Positron emission tomography performed 2 months after surgery demonstrated a postoperative reduction of the cerebral metabolic rate of oxygen in the right temporal lobe, where brain atrophy was observed on magnetic resonance images 3 months postoperatively. Neuropsychological testing performed 3 months postoperatively showed worsening digit span, which adversely affected the patient's quality of life. CONCLUSION: The current case suggests that cerebral hyperperfusion after vascular reconstructive surgery can cause irreversible neural damage, which results in cognitive impairment.