title: The impact of carotid artery stenting on cognitive function in patients with extracranial carotid artery stenosis.
abstract: BACKGROUND
  The effect of carotid artery stenting (CAS) on cognitive function in patients with extracranial carotid artery stenosis is equivocal. The aim of this study was to examine the impact of CAS on various domains of cognitive function.
  
  
  METHODS
  We performed a meta-analysis of the studies evaluating various domains of cognitive function before and after CAS, namely, (1) global cognition using Mini-Mental State Examination (MMSE) and Rey Auditory Verbal Learning Test (RAVLT), (2) executive function using Trail Making Test (TMT) A or Color Trails Test (CTT) A and TMT B or CTT B, (3) language ability using Boston Naming Test (BNT), (4) memory, (5) attention/psychomotor speed, and (6) functional ability, using various cognitive tests. Pooled weighted mean differences (WMDs) and standardized mean differences (SMDs) with 95% confidence intervals (95% CIs) were appropriately calculated using fixed or random effects models after assessing between-study heterogeneity. Meta-regression analysis was performed with number of patients per study; mean age (years); follow-up (months); proportion of men; proportion of patients with hypertension, diabetes mellitus, hyperlipidemia, smoking, and coronary artery disease; proportion of symptomatic patients; and degree of ipsilateral and degree of contralateral carotid stenosis as covariates.
  
  
  RESULTS
  Sixteen studies were eligible, including a total of 626 CAS patients. A statistically significant improvement of global cognition was detected with MMSE (WMD = 0.67, 95% CI = 0.29-1.05, P < 0.001; follow-up = 5.6 months), but not with RAVLT (SMD = 0.45, 95% CI = -0.03 to 0.93, P = 0.07; follow-up = 2.4 months). Significant improvement of memory (SMD = 0.33, 95% CI = 0.11-0.55, P < 0.01; follow-up = 4.1 months) and attention/psychomotor speed (SMD = 0.21, 95% CI = 0.04-0.39, P = 0.02; follow-up = 4 months) was also detected. No statistically significant effect on executive function (TMT A/CTT A and TMT B/CTT B; SMD = 0.08, 95% CI = -0.10 to 0.26, P = 0.39; follow-up = 3.9 months and SMD = -0.02, 95% CI = -0.20 to 0.16, P = 0.82, respectively; follow-up = 3.9 months), language ability (BNT; SMD = 0.24, 95% CI = -0.05 to 0.54, P = 0.10; follow-up = 4 months), and functional ability (SMD = -0.05, 95% CI = -0.25 to 0.15, P = 0.63; follow-up = 3.8 months) was observed. No significant effects of the examined covariates were demonstrated in the meta-regression analyses.
  
  
  CONCLUSIONS
  CAS may be associated with improvement in global cognition, memory, and attention/psychomotor speed. There was no positive effect on executive function, language, and functional ability, but CAS was not associated with a decline in any area of cognitive function. Future studies in larger groups of patients are probably needed to fully investigate the long-term effect of CAS on cognition in patients with carotid artery stenosis.
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece. Electronic address: kostas.antonopoulos@gmail.com.
authors.forename: Constantine N
authors.initials: CN
authors.lastname: Antonopoulos
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: John D
authors.initials: JD
authors.lastname: Kakisis
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: George S
authors.initials: GS
authors.lastname: Sfyroeras
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: Konstantinos G
authors.initials: KG
authors.lastname: Moulakakis
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: Aristides
authors.initials: A
authors.lastname: Kallinis
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: Triantafillos
authors.initials: T
authors.lastname: Giannakopoulos
authors.affiliation: Department of Vascular Surgery, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: Christos D
authors.initials: CD
authors.lastname: Liapis
mesh_terms: D000368:Aged; D017130:Angioplasty / Q000295:instrumentation*; D001288:Attention; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D020127:Recovery of Function; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome; D014705:Verbal Behavior