AIM: To document the incidence of symptomatic cerebral hyperperfusion after carotid stenting and to determine possible predisposing factors.METHODS: A prospective study of 29 consecutive patients undergoing carotid stenting. All patients underwent 1) brain computed tomography scan and magnetic resonance imaging, 2) transcranial Doppler including assessment of cerebrovascular reactivity of the ipsilateral middle cerebral artery and 3) 99m hexamethyl-propyleneamine oxime brain single photon emission computed tomography, before and after the procedure.RESULTS: A total of 5 patients developed adverse neurological events, 4 of them transient. Cerebral hyperperfusion was documented in two of these (6.9%). Both had exhausted cerebrovascular reactivity in the preoperative transcranial Doppler examination. No consistent pattern of interhemispheric asymmetry in brain perfusion was found in these patients.CONCLUSIONS: Symptomatic cerebral hyperperfusion is not uncommon after carotid stenting. There seems to be a link between exhausted cerebrovascular reactivity of the ipsilateral middle cerebral artery and increased risk of cerebral hyperperfusion.