Transcranial regional cerebral oxygen saturation monitoring during carotid endarterectomy as a predictor of postoperative hyperperfusion.

OBJECTIVE

Hyperperfusion syndrome is a rare but potentially devastating complication that can occur after carotid endarterectomy (CEA). The purpose of this study was to determine whether intraoperative transcranial regional cerebral oxygen saturation (rSO(2)) monitoring via near-infrared spectroscopy could be reliably used to identify patients at risk for post-CEA hyperperfusion.

METHODS

rSO(2) was intraoperatively monitored for 50 patients undergoing CEA for treatment of ipsilateral internal carotid artery stenosis (>/=70%). Cerebral blood flow (CBF) was also assessed, with single-photon emission computed tomography, before and immediately after CEA.

RESULTS

Post-CEA hyperperfusion (CBF increase of >/=100%, compared with preoperative values) was observed for six patients. A significant linear correlation was observed between the rSO(2) increases immediately after declamping of the internal carotid artery and the CBF increases immediately after CEA (r(2) = 0.247, P = 0.0002). The sensitivity and specificity of the rSO(2) increases for detection of post-CEA hyperperfusion were 100 and 86.4%, respectively, with a cutoff point of 5%. A strong linear correlation was observed between the rSO(2) increases at the end of the procedure and the CBF increases immediately after CEA (r(2) = 0.822, P < 0.0001). Both the sensitivity and the specificity of the rSO(2) increases for detection of post-CEA hyperperfusion were 100% with a cutoff point of 10%. Hyperperfusion syndrome developed for one patient with post-CEA hyperperfusion, but intracerebral hemorrhage did not occur.

CONCLUSION

Intraoperative rSO(2) monitoring can reliably identify patients at risk for hyperperfusion after CEA.