Cerebral hyperperfusion syndrome after revascularization surgery in patients with moyamoya disease

Moyamoya disease (MMD) is a progressive occlusive disease of the distal internal carotid artery that is primarily treated by superficial temporal artery-middle cerebral artery (STA-MCA) bypass. Despite its effectiveness, several postoperative complications have been reported with STA-MCA bypass. Cerebral hyperperfusion syndrome (CHS) after STA-MCA has attracted considerable attention as a hemodynamics-related complication because more cases of CHS after STA-MCA bypass are reported in MMD than in non-MMD patients. The mechanisms underlying CHS after revascularization in MMD patients are poorly understood. This report presents a comprehensive review of the literature on CHS after revascularization in MMD patients, focusing on the pathogenesis, clinical features, imaging techniques, treatment, and prognosis of CHS. Impaired cerebrovascular autoregulation has been implicated in the pathogenesis of CHS, which is characterized by unilateral headache, face and eye pain, seizures, and focal neurological deficits secondary to cerebral edema, and intracranial hemorrhage. Imaging techniques, such as single photon emission computed tomography (SPECT), 3-T magnetic resonance imaging/angiography, and selective arterial spin-labeling magnetic resonance imaging, are valuable for identifying patients at risk for CHS. Treatment strategies include strict blood pressure control, intracranial hemorrhage prevention, and free oxygen radical scavenger administration. Most patients can achieve a satisfying prognosis after effective treatment.