Cerebrovascular dysregulation and postoperative cognitive alterations after carotid endarterectomy

Abstract

There are controversial data about the effect of carotid endarterectomy regarding postoperative cognitive function. Our aim was to analyze the effect of cerebral tissue saturation monitored by near-infrared spectroscopy (NIRS) on cognitive function. Perioperative data of 103 asymptomatic patients undergoing elective carotid surgery under general anesthesia were analyzed. Preoperatively and 3 months after the operation, MMSE (Mini Mental State Examination) and MoCA (Montreal Cognitive Assessment) tests were conducted. For cerebral monitoring, NIRS was used, and the lowest rSO₂ value and the degree of desaturation were calculated. Cognitive changes were defined as one standard deviation change from the preoperative test scores, defined as postoperative neurocognitive decline (PNCD) and cognitive improvement (POCI). PNCD was found in 37 patients (35.92%), and POCI was found in 18 patients (17.47%). Female gender, patients with diabetes, and the degree of desaturation were independently associated with PNCD. The degree of desaturation during the cross-clamp period negatively correlated with the change in the MoCA scores (R = - 0.707, p = 0.001). The 15.5% desaturation ratio had 86.5% sensitivity and 78.8% specificity for discrimination. For POCI, a desaturation of less than 12.65% had 72.2% sensitivity and 67.1% specificity. POCI was associated with lower preoperative MOCA scores and a lower degree of desaturation. We found a significant relation between the change of postoperative cognitive function proven by the MoCA test and cerebral tissue saturation during the clamping period in patients undergoing carotid endarterectomy.

Keywords: Carotid endarterectomy; Cerebral tissue saturation; Cognitive function; Near-infrared spectroscopy; Postoperative neurocognitive disorder.

Fig. 1

Consort flow diagram of the enrollment and follow-up

Fig. 2

The correlation of the change in the MoCA scores and the degree of desaturation during the cross-clamp period

Fig. 3

ROC curve of rSO₂ desaturation for detecting postoperative cognitive decline proven by MoCA test. AUC, area under the curve; CI, confidence interval

Fig. 4

ROC curve of rSO₂ desaturation for detecting postoperative cognitive improvement proven by MoCA test. AUC, area under the curve; CI, confidence interval

Fig. 5

Comparison of the degree of desaturation between patients with different direction of cognitive change proven by the MoCA test. NCCF group: patients with no change in cognitive status proven by the MoCA, PNCD group: patients with postoperative cognitive decline confirmed by the MoCA, POCI group: patients with postoperative cognitive improvement confirmed by the MoCA

Fig. 6

Comparison of the lowest rSO₂ values between patients with different directions of cognitive change proven by the MoCA test. NCCF group: patients with no change in cognitive status proven by the MoCA, PNCD group: patients with postoperative cognitive decline confirmed by the MoCA, POCI group: patients with postoperative cognitive improvement confirmed by the MoCA