Dexmedetomidine improves cognition after carotid endarterectomy by inhibiting cerebral inflammation and enhancing brain-derived neurotrophic factor expression

Abstract

Objectives: Carotid endarterectomy (CEA) is efficient in preventing stroke for patients with significant carotid stenosis, but results in mild cognitive dysfunction. Dexmedetomidine is neuroprotective in stroke models. We hypothesized that dexmedetomidine may improve cognition after CEA.

Methods: Forty-nine patients scheduled for elective CEA were randomly assigned to intravenous dexmedetomidine treatment group (n = 25) and control group C (normal saline, n = 24). Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MOCA), as well as lactate, TNF-α, IL-6, and BDNF levels in blood, were assessed before, during, and after surgery.

Results: MMSE and MOCA scores showed subtle decline in both groups at 24 hours postoperatively; this decline remained at 48 hours postoperatively in group C. Both scores were higher in group D than in group C at 48 and 72 hours postoperatively. TNF-α and IL-6 were lower from 5 minutes post-clamping through 24 hours postoperatively in group D; lactate was lower at 5 minutes post-clamping in group D. BDNF was higher from 5 minutes post-clamping through 1 hour postoperatively in both groups, and remained high in group D at 24 hours postoperatively.

Conclusions: Dexmedetomidine improved recovery of cognition after CEA, potentially due to reduced inflammation and enhanced BDNF expression.

Keywords: Carotid endarterectomy; Mini-Mental State Examination; Montreal Cognitive Assessment; brain-derived neurotrophic factor; cognitive dysfunction; dexmedetomidine; interleukin 6; lactate; stroke; tumor necrosis factor.

Figure 1.

Mini-Mental State Examination (a) and Montreal Cognitive Assessment (b) scores in the two groups. One day before the surgical procedure (t₀), 6 hours postoperatively (t₁), 24 hours postoperatively (t₂), 72 hours postoperatively (t₃), 7 days postoperatively (t₄), and 1 month postoperatively (t₅). *p < 0.05, significant intergroup differences; ^#p < 0.05, significant intragroup differences from baseline in both groups. MMSE, Mini-Mental State Examination; MOCA, Montreal Cognitive Assessment.

Figure 2.

Lactic acid (a), IL-6 (b), TNF-α (c), and BDNF (d) levels in blood from the jugular bulb in the two groups. Twenty minutes before anesthesia (T₀), 10 minutes after tracheal intubation (T₁), 15 minutes after clamping of the carotid artery (T₂), 15 minutes after unclamping of the carotid artery (T₃), 1 hour postoperatively (T₄), and 24 hours postoperatively (T₅). *p < 0.05, significant intergroup differences; ^#p < 0.05, significant intragroup differences from baseline in both groups.