Near-infrared spectroscopy to predict cerebral hyperperfusion after carotid endarterectomy

Abstract

The aim: to conduct retrospective study of cerebral regional oxygen saturation (rSO2) at all stages of carotid endarterectomy (CEA) to define ischemia and cerebral hyperperfusion predictors. Material and Methods ― rSO 2 were registered in 169 patients under general anesthesia after induction, before carotid artery clamping, 2 minutes after and each 10 minutes after clamping, before, 2 and 5 minutes after reperfusion and at the end of the operation. We estimated baseline values and intraoperative changes of rSO 2 in terms of clinical and instrumental findings. Logistic regression analysis was aimed to define significant risk predictors of cerebral ischemia and hyperperfusion and ROC-curve analysis - to set a cut-off point of rSO 2 reduction and elevation. Results ― Arterial hypertension III grade (HR 9.5%; CI 95%: 1.1-82.7) appeared to be an independent predictor according to the results of multivariate analysis. It was revealed that the most significant predictor of hyperperfusion syndrome is absolute increase of rSO 2 after reperfusion by more than 11.3. Sensitivity, specificity, positive and negative predicative value of the defined parameter were 87.4%, 83%, 35% and 98.4% respectively. Conclusion ― The conducted multivariate analysis demonstrated that only long-term arterial hypertension is a significant risk factor for hyperperfusion syndrome development after CEA. In our study the most accurate parameter for Fore-Sight oximeter is maximum value of absolute increase in rSO 2 after reperfusion by more than 11.3. Cerebral oximetry is a non-invasive method which is easy to use and interpret and enables to estimate both ischemia and cerebral hyperperfusion during CEA and in the early postoperative period.