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 ― rSO2 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 rSO2 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 rSO2 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 rSO2 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 rSO2 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.

Keywords

• carotid endarterectomy
• cerebral oximetry
• near-infrared spectroscopy
• cerebral hyperperfusion syndrome.