Recovery of cerebrovascular reserves after stenting for symptomatic carotid artery stenosis.

Although a decrease in cerebrovascular reserves (CVR) is known to enhance the risk of stroke, changes in this parameter after carotid artery stenting (CAS) have rarely been investigated. The present study is the first to compare CVR recoveries after applying CAS to patients with symptomatic carotid artery disease. CAS was performed for 31 consecutive patients with symptomatic carotid artery disease. They underwent acetazolamide-challenged single photon emission computed tomography (SPECT) before and after CAS to obtain data on resting stage cerebral blood flow (CBF(rest) values) in various regions of interest (ROIs) defined by a three-dimensional stereotactic ROI template. CVR values on ipsilateral and contralateral hemispheric sides were then calculated based on the CBF(rest) data. The 31 patients were dichotomized into unilateral (n=22) and bilateral (n=9) lesion groups, and no significant between-group differences were observed in CBF(rest) before and after CAS. In the unilateral group, there were no differences in CVR values before and after CAS. In the bilateral group, however, the CVR values significantly increased in nearly all the investigated ROIs on the contralateral side. Also, the hemispheric CVR values on both sides significantly increased after CAS in the bilateral group, while no such increase was observed in the unilateral group. CAS in patients with symptomatic bilateral carotid artery disease has the potential utility for their haemodynamic improvement even on the contralateral hemispheric side.