Dexmedetomidine decreases cerebral hyperperfusion incidence following carotid stenting: A randomized, double-blind trial

Background Cerebral hyperperfusion syndrome (CHS) is not a common but severe complication after carotid artery stenting (CAS). We investigated whether prophylactic low-dose dexmedetomidine, a selective α 2 -adrenoceptor agonist, can decrease cerebral hyperperfusion induced brain injury after carotid artery stenting. Methods This randomised, double-blind, placebo-controlled trial was conducted in a tertiary-care hospital in Zhengzhou, China. Patients aged 18 to 80 years old who had undergone CAS and from whom written informed consent was obtained, were enrolled between Jul 20, 2019 and Oct 10, 2022. Patients were randomly assigned to receive either intravenous dexmedetomidine (0·1 μg/kg/h, from insertion of the laryngeal mask until 72hr on postoperative day 3) (n = 80) or placebo (intravenous normal saline) (n = 80). The primary endpoint was the incidence of cerebral hyperperfusion (CH) and cerebral hyperperfusion syndrome (CHS), which were assessed six times with Transcranial Doppler sonography (TCD) during the postoperative three days. This study was registered with the Chinese Clinical Trial Registry, www.chictr.org.cn , ChiCTR1900024416. Results CH occurred in 30 (37·5%) of 80 patients given a placebo and in 9 (11·2%) of 80 patients given dexmedetomidine (odds ratio [OR] 0·211, 95% CI 0·09-0·48; p<0·001). Further, CHS was significantly lower in the Dex group than in the placebo group (2.5% vs 13·75%; [OR] 0·16, 95% CI 0·03-0·71; p=0·017). Correspondingly, dexmedetomidine significantly upregulated serum brain-derived neurotrophic factor (BDNF) and downregulated neuronal injury biomarker neurofilament light chain (Nfl). The hierarchical clustering analysis revealed little difference in lipids metabolites between the two groups pre- and post-operatively, with Dex treatment uniquely increased lysphosphatidylethanolamine (LPE). Conclusions A low prophylactic dose of dexmedetomidine significantly decreased the occurrence of cerebral hyperperfusion and cerebral hyperperfusion syndrome during the first three days after carotid artery stenting surgery.