Brain Oxygen Supply Parameters in the Risk Assessment of Cerebral Complications During Carotid Endarterectomy

Abstract

Objective: To determine whether preoperative regional cerebral oxygen saturation (rSO₂) and the decrease in rSO₂ during carotid clamping were predictive of the risk for neurologic complications in carotid endarterectomy and to determine the cutoff values of the studied parameters.

Design: Cohort, prospective, nonrandomized trial.

Setting: Research Institute of Circulation Pathology, Novosibirsk, Russia.

Participants: The study comprised 466 adults who underwent carotid endarterectomy since 2012.

Interventions: None.

Measurements and main results: Patient characteristics, postoperative complications, and brain oxygen supply during carotid endarterectomy were analyzed. The primary endpoints were the perioperative and early postoperative neurologic complications. Ischemic stroke was diagnosed in 1.5% of patients, and cognitive disorders were reported in 2.6% of patients. Preoperative rSO₂ of 50% was the cutoff value for the prediction of stroke outcome after carotid endarterectomy, with a sensitivity of 90.7% and specificity of 66.7%. A 20% decrease in rSO₂ during temporary carotid clamping was the cutoff value for the prediction of stroke, with a sensitivity of 86.0% and specificity of 57.1%, and for the prediction of cognitive disorders, with a sensitivity of 88.1% and specificity of 58.3%. Preoperative rSO₂ less than 50% and a decrease in rSO₂ of at least 20% during temporary carotid artery clamping caused a significant increase in the hospitalization period.

Conclusions: A 20% or more decrease in rSO₂ during temporary internal carotid artery clamping during carotid endarterectomy caused a 10-fold increased risk of ischemic stroke and an 8-fold increased risk of cognitive disorders, whereas preoperative rSO₂ less than 50% resulted in a 6-fold increased risk of ischemic stroke in the perioperative and early postoperative periods of carotid endarterectomy.

Keywords: carotid endarterectomy; cerebral oxygen saturation; cognitive disorders; stroke.