BACKGROUND AND OBJECTIVE: In animal models, the magnitude of early post-ischemic hyperemia tends to correlate with the duration and intensity of prior ischemic insult. The aim of this study was to determine whether early post-ischemic hyperemia in human brain during carotid endarterectomy (CEA) is associated with the severity of cerebral ischemic insult during clamping of the internal carotid artery (ICA). METHODS: Transcranial cerebral oxygen saturation using near-infrared spectroscopy was monitored intraoperatively in 171 patients undergoing CEA for ipsilateral ICA stenosis (>70%) to assess the intensity of cerebral hemispheric ischemia during ICA clamping and the magnitude of early post-ischemic hyperemia after ICA declamping. RESULTS: Early post-ischemic hyperemia peaked within 3 minutes after ICA declamping and resolved at 20 minutes after ICA declamping. A significant correlation was observed between the magnitude of early post-ischemic hyperemia and the intensity of cerebral ischemia (r=0.697; p<0.0001). Eight patients recovered from anesthesia with a new minor neurological deficit on the side contralateral to the CEA (4.7%). Analysis by receiver operating characteristics (ROC) curve was used to estimate the ability to discriminate between patients with and without post-operative development of new neurological deficits. Area under the ROC curve was significantly greater when analysing the magnitude of early post-ischemic hyperemia (1.00; 95% CI: 0.99-1.00) when compared with the intensity of cerebral ischemia (0.93; 95% CI: 0.89-0.98) (p<0.01). CONCLUSION: Early post-ischemic hyperemia in CEA is correlated with the severity of cerebral ischemic insult during clamping of the ICA.
BACKGROUND AND OBJECTIVE: In animal models, the magnitude of early post-ischemic hyperemia tends to correlate with the duration and intensity of prior ischemic insult. The aim of this study was to determine whether early post-ischemic hyperemia in human brain during carotid endarterectomy (CEA) is associated with the severity of cerebral ischemic insult during clamping of the internal carotid artery (ICA). METHODS: Transcranial cerebral oxygen saturation using near-infrared spectroscopy was monitored intraoperatively in 171 patients undergoing CEA for ipsilateral ICA stenosis (>70%) to assess the intensity of cerebral hemispheric ischemia during ICA clamping and the magnitude of early post-ischemic hyperemia after ICA declamping. RESULTS: Early post-ischemic hyperemia peaked within 3 minutes after ICA declamping and resolved at 20 minutes after ICA declamping. A significant correlation was observed between the magnitude of early post-ischemic hyperemia and the intensity of cerebral ischemia (r=0.697; p<0.0001). Eight patients recovered from anesthesia with a new minor neurological deficit on the side contralateral to the CEA (4.7%). Analysis by receiver operating characteristics (ROC) curve was used to estimate the ability to discriminate between patients with and without post-operative development of new neurological deficits. Area under the ROC curve was significantly greater when analysing the magnitude of early post-ischemic hyperemia (1.00; 95% CI: 0.99-1.00) when compared with the intensity of cerebral ischemia (0.93; 95% CI: 0.89-0.98) (p<0.01). CONCLUSION: Early post-ischemic hyperemia in CEA is correlated with the severity of cerebral ischemic insult during clamping of the ICA.