Near-infrared spectroscopy cerebral oximetry as a predictor of neurological intolerance during carotid artery stenting with proximal protection.

Carotid artery stenting (CAS) with proximal protection can expose occlusion intolerance (OI) due to ipsilateral cerebral hemisphere hypoperfusion. Near-infrared spectroscopy (NIRS) cerebral oximetry can monitor regional cerebral oxygenation (rSO2) in the frontal lobes, and is used during CAS to predict cerebral blood flow insufficiency. The aim of this study was to evaluate rSO2 as a predictor of OI during CAS. We retrospectively examined 146 patients who underwent CAS with proximal protection. An INVOS® NIRS oximeter was used for rSO2 measurement, which was compared with stump pressure (SP) measured by a guiding catheter during occlusion of the common carotid artery (CCA) and external carotid artery. For the lesion with OI, distal filter protection was combined with proximal protection if possible, and CCA was intermittently occluded during the procedure. Twenty-seven patients (18%) developed OI. The relative decrease in NIRS oximeter saturation (ΔrSO2) on the ipsilateral side was significantly lower in the OI group than in the tolerance group (14 ± 5.1% vs. 3.4 ± 3.5, p < 0.001). Using ΔrSO2 of 8% as the cutoff value for predicting OI, sensitivity was 92% and specificity was 89%. SP was significantly lower in the OI group than in the tolerance group (22 ± 13 mmHg vs. 40 ± 22 mmHg, p < 0.001). Using SP ≤25 mmHg as the cutoff value for predicting OI, sensitivity was 78% and specificity was 77%. ΔrSO2 was more reliable than SP for predicting OI. Distal filter protection should be combined with proximal protection to prevent prolonged neurological symptoms due to OI.