Comparison of Cerebral Oximetry and Neurological Status Testing in the Awake Patient in the Detection of Cerebral Ischemia During Carotid Endarterectomy - a Randomized Controlled Trial

Cerebral ischemia during carotid endarterectomy (CEA) remains one of the most important causes of perioperative neurological morbidity and mortality. During carotid artery clamping, cerebral perfusion depends on the adequacy of collateral circulation, most importantly through the Circle of Willis. Inadequate collateral flow may lead to hypoperfusion, resulting in transient or permanent ischemic brain injury. For this reason, intraoperative cerebral monitoring is widely used to identify patients who require placement of an intraluminal shunt during carotid cross-clamping in order to maintain adequate cerebral blood flow.

In patients undergoing CEA under regional anesthesia, awake neurological testing is considered a reliable method for detecting cerebral hypoperfusion. By continuously assessing verbal communication and contralateral hand motor function, the surgical team can identify early neurological deterioration indicating cerebral ischemia. However, this approach is operator-dependent, subjective, and cannot provide continuous quantitative data on cerebral perfusion. In addition, subtle or subclinical ischemic events may go undetected by neurological testing alone.

Near-infrared spectroscopy (NIRS) is a non-invasive monitoring technique that measures regional cerebral oxygen saturation and reflects changes in cerebral perfusion. NIRS provides continuous, real-time, and objective assessment of cerebral oxygenation during surgery. A decrease in NIRS values during carotid artery clamping has been associated with cerebral hypoperfusion and may indicate a need for shunt placement. Despite increasing use of NIRS in vascular surgery, its diagnostic accuracy and equivalence to awake neurological testing for detection of cerebral ischemia during CEA have not been definitively established.

This prospective randomized controlled trial is designed to compare awake neurological testing and NIRS monitoring for the detection of intraoperative cerebral ischemia during carotid endarterectomy. The study will be conducted at the Clinic for Vascular and Endovascular Surgery, University Clinical Center of Serbia, between January 1, 2026 and January 1, 2028. Adult patients with symptomatic or asymptomatic carotid artery stenosis who meet criteria for surgical treatment will be eligible for inclusion. The indication for carotid endarterectomy will be established based on duplex ultrasonography and multislice computed tomography (CT) angiography of the carotid and cerebral vessels.

After providing written informed consent, patients will be randomized electronically in a 1:1 ratio into two groups. In both groups, carotid endarterectomy will be performed under cervical block anesthesia, allowing continuous neurological assessment. Near-infrared spectroscopy will be recorded in all patients; however, the decision to insert an intraluminal shunt will be guided by the randomized monitoring method.