Near Infrared Spectroscopy Versus Stump Pressure in Detecting Cerebral Ischemia During Carotid Endarterectomy : A Prospective Multicenter Observational Study

Abstract

Background: Determining the need for shunt use during carotid endarterectomy (CEA) under general anesthesia (GA) can be based on different methods, and one of the most common is stump pressure (SP). Previous studies have found favorable results of near infrared spectroscopy (NIRS). Methods: Patients undergoing CEA in 2 swedish hospitals were prospectively included. SP, rSO2 at different timepoints as well as neurological symptoms during surgery were reported for all patients. Receiver operating curve (ROC) analysis was used to determine the optimal cutoff points for SP and rSO2. Results: A total of 293 patients underwent CEA under local anesthesia (LA) and 66 under GA in 2 hospitals. Thirty two patients operated under LA had neurological symptoms. A relative change in ipsilateral rSO2 <-9% had a negative predictive value (NPV) of 99% in detecting neurological symptoms during clamping. Patients who developed neurological symptoms during clamping had lower Delta rSO2 (-14% +/- 6% vs.-4 +/- 5%, P < 0.001) and lower SP (36 +/- 21 mm Hg vs. 56 +/- 19 mm Hg, P <0.001) compared to those who did not. A Delta rSO2 of <-9% had a sensitivity of 91% (95% confidence interval (CI): 75-98%) and a specificity of 82% (95% CI: 77-87%) in predicting cerebral ischemia, whereas a SP < 50 mm Hg had a sensitivity of 78% (95% CI: 58- 91%) and a specificity of 60% (95% CI: 54-67%). Conclusion: This study found that NIRS could reduce unnecessary shunting while still having a higher sensitivity compared to SP. Additionally, it can also monitor shunt patency