Neurocognitive Functioning after Carotid Revascularization: A Systematic Review

Abstract

Background: The objective of this study was to review the recent literature regarding the neurocognitive consequences of carotid endarterectomy (CEA) and carotid stenting (CAS). Methods and Results: A PubMed and Web of Science search was conducted using the key words ‘carotid' in combination with ‘cognitive', ‘cognition', ‘neurocognition', ‘neurocognitive', ‘neuropsychology', and ‘neuropsychological'. Bibliographies of relevant articles were cross-referenced. We included 37 studies published since 2007 of which 18 examined CEA, 12 CAS, and 7 compared CEA to CAS. There is a wide variability in the reported neurocognitive outcome following CEA and CAS. Nonetheless, none of the included studies unveiled significant differences between CEA and CAS on postoperative neurocognitive functioning. Postoperative changes observed for CEA and CAS separately seem limited to a small percentage (around 10-15%) of patients and can either present as an improvement or impairment. Key Messages: The available data seem to suggest that no obvious cognitive differences between CAS and CEA can be observed after intervention. Both improvement and deterioration in cognitive functioning can be observed following CAS or CEA. Methodological differences such as patient heterogeneity, implementation and type of control groups, type of psychometric tests used, statistical analyses, or timing of the assessments play an important role in explaining the sometimes divergent results of the included studies. Large-scale and methodologically solid studies comparing CEA and CAS on neurocognitive outcome remain warranted. Future studies should implement adequate control groups to correct for practice effects in the target groups.

Prospective comparison of cognitive effects of carotid endarterectomy versus carotid stenting with flow reversal or distal filters

“…None of the 18 variables showed a significant group difference, and only one showed a small interaction effect. The fact that CEA and CASdp have similar effects on cognition is in agreement with previous research (Paraskevas et al, 2014;Plessers et al, 2014). We now showed that also direct access using flow reversal does not lead to any significant cognitive changes compared with other techniques.…”

“…Exclusion criteria were history of previous carotid interventions, coronary artery bypass grafting, or stroke within 2 years, age >80 years, psychiatric or neurological disorders, alcohol abuse, and a Mini Mental State Examination (MMSE) score lower than 24. Following Plessers et al (Plessers et al, 2014), to avoid any influence of recent brain damage on the possible cognitive changes evoked by revascularization, symptomatic patients were also excluded if they had had a stroke. Consequently, only symptomatic patients that had experienced a TIA and/or amaurosis fugax were included.…”

“…Publications are often contradictory due to differences in demographics (educational level of the patient) and clinical presentation-for example, stroke versus transient ischemic attack (TIA), affected side, and severity of the stenosis (Plessers, Van Herzeele, Vermassen, & Vingerhoets, 2014). Studies evaluating the cognitive changes after carotid treatment often have no (matched) control group, and the timing of assessments and type of tests used vary widely, which also plays an important role in the sometimes conflicting findings (Plessers et al, 2014). Without an appropriate control group, the impact of practice effects cannot be estimated adequately.…”

“…On the other hand, perioperative microembolization and hypoperfusion with or without postoperative hyperperfusion could inflict cerebral damage and impair cognitive functions (De Rango et al, 2008;Lal et al, 2011). Furthermore, the jury is still out there as to whether CEA or CASdp have a similar impact on a cognitive level (De Rango et al, 2008;Paraskevas, Lazaridis, Andrews, Veith, & Giannoukas, 2014;Plessers et al, 2014). Both cognitive improvement and deterioration have been reported after either technique in 10 to 15% of patients (Plessers et al, 2014).…”

“…Furthermore, the jury is still out there as to whether CEA or CASdp have a similar impact on a cognitive level (De Rango et al, 2008;Paraskevas, Lazaridis, Andrews, Veith, & Giannoukas, 2014;Plessers et al, 2014). Both cognitive improvement and deterioration have been reported after either technique in 10 to 15% of patients (Plessers et al, 2014).…”