Posterior Circulation Hyperperfusion Syndrome after Bilateral Vertebral Artery Intracranial Stenting

Hyperperfusion syndrome is a well-documented clinical complication after endarterectomy and carotid stenting. However, little is known about this complication immediately after vertebral artery stenting. A 51-year-old woman who had repeated episodes of dizziness, nausea, and vomiting was diagnosed with vertebrobasilar insufficiency. Diffusion-weighted magnetic resonance imaging showed a lesion in the posterior inferior cerebellar artery territory. The patient underwent bilateral vertebral stenting due to severe stenosis in both intracranial segments of the vertebral arteries. Three hours after the procedure, she had severe headache with vomiting and gradually went into a coma. An urgent brain computed tomographic scan showed hemorrhage in the right cerebellum and subarachnoid region. Also, transcranial Doppler revealed approximate doubling of blood flow velocity in vertebral artery area compared with her baseline value. Cerebral blood flow and blood pressure monitoring, together with intensive antihypertensive therapy, are necessary to reduce the risk of hyperperfusion syndrome after vertebral stenting. Moreover, the safety and efficacy of intracranial vertebral stenting should be further reevaluated by large-scale randomized trials.