The diagnostic accuracy of intraoperative near-infrared spectroscopy in carotid artery endarterectomy under general anesthesia: A systematic review with meta-analysis

Background: Carotid endarterectomy (CEA) carries a risk of perioperative stroke, particularly during carotid cross-clamping. While neurological monitoring is reliable for patients under regional anesthesia, alternative options are needed for those unsuitable for regional anesthesia. Near-infrared spectroscopy (NIRS) is commonly used during CEA, but its diagnostic accuracy varies, particularly under general anesthesia. Methods: A systematic review with meta-analysis was performed to assess the diagnostic accuracy of intraoperative NIRS in detecting clamp-associated hemodynamic cerebral ischemia in patients under general anesthesia. MEDLINE, Google Scholar, and Web of Science were searched for studies that compared NIRS with the occurrence of immediate or early postoperative neurological deficits in patients undergoing CEA under GA. Meta-regression was performed to explore causes of heterogeneity. Results: A total of 28 studies involving 5729 patients were included. The results show that NIRS has a summary sensitivity of 47.5% and a summary specificity of 90.3% in diagnosing clamp-associated cerebral ischemia under general anesthesia, with an area under the ROC curve (AUC-ROC) of 0.85. The presence of a contralateral carotid occlusion (CCO) increased summary sensitivity while smoking history the presence of CCO and smoking history decreased summary specificity. For postoperative stroke prediction, NIRS has a summary sensitivity of 49.5% and summary specificity of 88.5%, with an AUC-ROC of 0.85. Conclusions: NIRS is a specific but not highly sensitive tool for detecting cerebral ischemia during CEA, and its use in combination with more sensitive neuromonitoring methods is recommended, in order to guide intraoperative neuroprotective strategies.