Neuropsychological Outcome 6 Months after Unilateral Carotid Stenting

Changes in Cognitive Functions after Carotid Endarterectomy and Carotid Stenting: A Decade-Apart Comparison

BACKGROUND

This study investigates changes in cognitive function in patients with severe carotid stenosis who underwent carotid endarterectomy (CEA) and carotid stenting (CAS) over two decades.

METHODS

We compared cognitive function within 30 days after the procedure in 267 patients (first 100 each for CEA and CAS in two periods: 2008-2012 and 2018-2022) in a single institution. Assessments used Adenbrooke's Cognitive Examination-Revised (ACE-R), the Mini-Mental State Examination (MMSE), Speech Fluency Test (SFT), and Clock Drawing Test (CDT), conducted before and 30 ± 2 days after surgery.

RESULTS

Patients (mean age 67.2 years, 70%+ carotid stenosis) exhibited different cognitive changes over periods. In 2008-2012, significant declines in MMSE (CEA, p = 0.049) and CDT (CAS, p = 0.015) were observed among asymptomatic patients. On the contrary, in 2018-2022, improvements were observed in ACE-R and MMSE for symptomatic and asymptomatic patients undergoing CEA and CAS.

CONCLUSION

Over a decade, advances in interventional techniques and patient management have reduced risks of cognitive decline in patients with asymptomatic carotid stenosis and also have improved cognitive functions in both symptomatic and asymptomatic individuals.

Carotid Intervention Improves Cognitive Function in Patients With Severe Atherosclerotic Carotid Disease

INTRODUCTION

Carotid revascularization procedures are effective in stroke prevention in appropriately selected patients. We sought to understand the effects of the carotid intervention on cognitive function in a well-defined cohort of prospectively recruited patients.

METHODS

A total of 170 consecutive patients undergoing carotid intervention for severe carotid stenosis were recruited. Patients received neuropsychometric testing preintervention, and at 1, 6, and 12 months postoperative. Patients were screened with the Mini-Mental State Examination. Rey Auditory Verbal Learning test (RAVLT) test was the primary outcome measure and multiple cognitive tests were used to evaluate executive function. Paired t test and McNemar test were performed to compare age-adjusted and education-adjusted postoperative scores at the individual time point with the preoperative scores.

RESULTS

Our patients had a high prevalence of cardiovascular risks and 51.2% of whom were symptomatic. The usages of statin and antiplatelet were high (88.8% and 69.4%, respectively). A total of 140 patients had 1 or more postoperative neuropsychometric tests in addition to their preoperative tests were included. The average RAVLT preoperative score was lower ( z =-0.79, SD=1.3, confidence interval: -1 to -0.53) than the age-adjusted norm. We observed a significant improvement in RAVLT memory scores at 1 and 6 months postoperative compared with preoperative. We also observed significant improvement in multiple executive functions measures up to 12 months postoperative. The improvement on patients with preoperative stroke symptoms was less consistent.

CONCLUSIONS

This prospective study showed that carotid intervention improved memory and executive function in patients with the severe carotid occlusive disease. It highlights the cognitive benefit of the carotid intervention in appropriately selected patients.

Cognitive Functions after Carotid Artery Stenting-1-Year Follow-Up Study

Background: The revascularization of carotid arteries minimizes the risk of future cerebral stroke and usually improves cognitive functions. The aim of this study was to assess changes in cognitive function and verify the hypothesis assuming an improvement of selected cognitive functions—psychomotor speed, visuospatial episodic memory, executive function and verbal fluency—in patients after carotid artery stenting during a 12-month follow-up. Methods: 47 persons subject to CAS, including 13 symptomatic persons, were examined before and 12 months after a procedure with a psychological test battery (digit symbol test—DS, Rey–Osterrieth complex figure test—ROCF, Wisconsin Card Sorting Test—WCST, letter verbal fluency—LVF). Sociodemographic data and clinical parameters were acquired from an author questionnaire. Results: The one-year follow-up, after the performed CAS procedure, demonstrated a significant improvement of psychomotor speed, visuospatial episodic memory, and executive function. No changes in the area of verbal fluency or decline in any of cognitive functions under analysis were observed. Conclusions: Carotid artery stenting improves cognitive functioning, both in the area of basic and more complex cognitive functions in persons with carotid atherosclerosis.

Cognitive Functions in Patients after Carotid Artery Revascularization-A Narrative Review

Carotid revascularization may lead to improved cognitive function beyond stroke prevention. This article summarizes the conclusions from available studies on the effects of carotid reperfusion procedures on cognitive function. The papers cited used different neuropsychological tests for cognitive assessment, resulting in different methodologies and the results obtained were not always convergent. However, most studies reported an improvement in neurocognitive abilities after both vascular interventions, but a more precise assessment of the specific benefits is still awaited. Clinical determinants to predict the effects of these treatments on cognitive function are still being sought, but results are not yet satisfactory. In view of these studies, carotid stenosis seems to be an independent risk factor for cognitive deterioration, and the main mechanisms responsible are embolism and cerebral hypoperfusion. The aim of this study is to order the knowledge about the effects of carotid artery stenting (CAS) and endarterectomy (CEA) on neurocognitive functions and to verify the usefulness of using these treatments.

Carotid Artery Stenting and Its Impact on Cognitive Function: A Prospective Observational Study

PURPOSE

Carotid artery stenting (CAS) has evolved as a first-line therapeutic option for carotid revascularization in indicated patients for stroke prevention, but there is still a lack of data on its effect on cognitive function (CF), especially among Indian patients. To determine the effect of CAS on CF and to study the immediate and delayed complications of CAS in Indian patients.

MATERIALS AND METHODS

This was a prospective, observational, single-center study. CF was assessed using Addenbrooke's cognitive examination version III (ACE) before and 3 months after stenting. The demographic and clinical parameters were also assessed. A follow-up evaluation after 3 months was done to compare CF and to observe the occurrence of any complications.

RESULTS

Out of 31 patients, 3 were lost to follow up. There were no immediate or delayed procedure-related complications. There was a statistically significant improvement in overall ACE score and memory before and after stenting. On subgroup analysis of those with and without strokes, there was a significant improvement in visuospatial function and mean ACE score. Those with left CAS had significant improvement in memory, visuospatial, language, and ACE scores than right CAS.

CONCLUSION

CAS was associated with significant improvement in CF in patients.

Depression, quality of life, activities of daily living, and subjective memory after deep brain stimulation in Parkinson disease-A reliable change index analysis

OBJECTIVES

In the field of Parkinson disease (PD) research, many studies have shown that deep brain stimulation (DBS) can soften side effects, which arise during long-term medical therapy. This study focuses on the changes in depressive symptoms, quality of life (with the subdivisions physical and mental health), activities of daily living, and subjective memory functioning in PD patients testing the baseline and the outcome 1 year after DBS.

METHODS

For the first time, the reliable change index (RCI) methodology was applied to compare PD-DBS patients (n = 22) with best medically treated PD patients (PD-BMT; n = 28), subjects with mild cognitive impairment (MCI, n = 43) and healthy controls (n = 25) in the above-mentioned domains. The used questionnaires included the revised Beck Depression Inventory (BDI-II), the Short Form (36) Health Survey (SF-36), the Bayer Activities of Daily Living Scale (B-ADL), and the Forgetfulness Assessment Inventory (FAI).

RESULTS

The reliable change indices show high constant or improved results of the PD-DBS patients in the domains subjective memory (85.7%-100.0%), activities of daily living (60.0%-90.0%), physical health summary (77.8%), depressive symptoms (61.9%), and mental health summary (50.0%) in comparison with the PD-BMT, MCI, and control group.

CONCLUSIONS

DBS is an established alternative to best medical treatment of PD. The comparisons between the PD-DBS and PD-BMT groups do suggest that the domains mental health, depressive symptoms, and physical health benefit most, while the domains activities of daily living and subjective memory functioning are rather constant. Nevertheless, further research is needed to identify mechanisms and predictors that lead to improvement in individual cases.

Is Hemispheric Hypoperfusion a Treatable Cause of Cognitive Impairment?

PURPOSE OF REVIEW

To review the current literature that supports the notion that cerebral hemodynamic compromise from internal carotid artery stenosis may be a cause of vascular cognitive impairment that is amenable to treatment by revascularization.

RECENT FINDINGS

Converging evidence suggests that successful carotid endarterectomy and carotid artery stenting are associated with reversal of cognitive decline in many patients with severe but asymptomatic carotid artery stenosis. Most of these findings have been derived from cohort studies and comparisons with either normal or surgical controls. Failure to find treatment benefit in a number of studies appears to have been the result of patient heterogeneity or confounding from concomitant conditions independently associated with cognitive decline, such as heart failure and other cardiovascular risk factors, or failure to establish pre-procedure hemodynamic failure. Patients with severe carotid artery stenosis causing cerebral hemodynamic impairment may have a reversible cause of cognitive decline. None of the prior studies, however, were done in the context of a randomized clinical trial with large numbers of participants. The ongoing CREST-2 trial comparing revascularization with medical therapy versus medical therapy alone, and its associated CREST-H study determining whether cognitive decline is reversible among those with hemodynamic compromise may address this question.

A Prospective Evaluation of Systemic Biomarkers and Cognitive Function Associated with Carotid Revascularization

OBJECTIVE

To determine factors affecting cognition and identify predictors of long-term cognitive impairment following carotid revascularization procedures.

BACKGROUND

Cognitive impairment is common in older patients with carotid occlusive diseases.

METHODS

Patients undergoing carotid intervention for severe occlusive diseases were prospectively recruited. Patients received neurocognitive testing before, 1, and 6 months after carotid interventions. Plasma samples were also collected within 24 hours after carotid intervention and inflammatory cytokines were analyzed. Univariate and multivariate logistic regressions were performed to identify risk factors associated with significant cognitive deterioration (>10% decline).

RESULTS

A total of 98 patients (48% symptomatic) were recruited, including 55 patients receiving carotid stenting and 43 receiving endarterectomy. Mean age was 69 (range 54-91 years). Patients had overall improvement in cognitive measures 1 month after revascularization. When compared with carotid stenting, endarterectomy patients demonstrated postoperative improvement in cognition at 1 and 6 months compared with baseline. Carotid stenting (odds ratio 6.49, P = 0.020) and age greater than 80 years (odds ratio 12.6, P = 0.023) were associated with a significant long-term cognitive impairment. Multiple inflammatory cytokines also showed significant changes after revascularization. On multivariate analysis, after controlling for procedure and age, IL-12p40 (P = 0.041) was associated with a higher risk of significant cognitive impairment at 1 month; SDF1-α (P = 0.004) and tumor necrosis factor alpha (P = 0.006) were independent predictors of cognitive impairment, whereas interleukin-6 (P = 0.019) demonstrated cognitive protective effects at 6 months after revascularization.

CONCLUSIONS

Carotid interventions affect cognitive function. Systemic biomarkers can be used to identify patients at risk of significant cognitive decline postprocedures that benefit from targeted cognitive training.

Severe carotid artery stenosis evaluated by ultrasound is associated with post stroke vascular cognitive impairment

BACKGROUND

Acute ischemic stroke has been recognized as one key cause of vascular cognitive impairment (VCI). The purpose of this study was to evaluate the correlation between carotid artery stenosis and post VCI in acute ischemic stroke patients.

METHODS

In this study, B-mode ultrasound was applied to measure the degree of carotid artery stenosis. After 1 year, the stroke patients' cognitive function was assessed by the mini-mental state examination (MMSE) score. The relationship between the VCI and degree of carotid artery stenosis was evaluated by multivariate regression analysis.

RESULTS

VCI was observed in 136 (37.2%) of the 365 participants. High degree of carotid artery stenosis was significantly correlated with VCI (p < .01), and this correlation remained unchanged even adjustment for age, gender, education level, stroke features, and vascular risk factors.

CONCLUSIONS

These findings indicate that high-grade stenosis of carotid artery is positively correlated with post stroke VCI in patients with acute ischemic stroke. The evaluation of 1 year post stroke cognitive function may be a potential tool for screening stroke patients at risk of VCI.

Ignoring floor and ceiling effects may underestimate the effect of carotid artery stenting on cognitive performance

Introduction

Data on neuropsychological outcome after carotid artery stenting (CAS) remain inconsistent, furthermore cognitive outcome seems to be unpredictable in the individual case. Previous studies reporting improvement or decline might be due to ceiling and floor effects of the applied cognitive tests. We applied cognitive testing before and after CAS, avoiding the pitfall of ceiling and floor effects.

Methods

In our prospective database, we identified 72 patients free of clinical stroke with ≥70% carotid artery stenosis, who were treated with CAS. They were administered a neurocognitive test battery before and 3 months after CAS to compare cognitive performance before and after CAS. To avoid ceiling and floor effects of test performances, we additionally analysed subgroups of patients without baseline floor and ceiling cognitive performance.

Results

Pre-interventional to post-interventional cognitive performance improved significantly in the subtests measuring verbal episodic memory; deterioration was observed in spatial memory. The subgroups of patients without baseline floor and ceiling cognitive performance improved in measures of global cognition, verbal episodic memory (patients with left-sided CAS) and divided attention (patients with right-sided CAS); we observed no significant effects in the other domains.

Conclusions

Ignoring floor and ceiling effects may underestimate the impact of CAS on cognitive performance.

The impact of carotid artery stenting on cognitive function in patients with extracranial carotid artery stenosis

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.

The robust reliability of neuropsychological measures: meta-analyses of test-retest correlations

Test-retest reliability is an important psychometric property relevant to assessment instruments typically used in neuropsychological assessment. This review presents a quantitative summary of test-retest reliability coefficients for a variety of widely used neuropsychological measures. In general, the meta-analytic test-retest reliabilities of the test scores ranged from adequate to high (i.e., r=.7 and higher). Furthermore, the reliability values were largely robust across factors such as age, clinical diagnosis, and the use of alternate forms. The values for some of the memory and executive functioning scores were lower (i.e., less than r=.7). Some of the possible reasons for these lower values include ceiling effects, practice effects, and across time variability in cognitive abilities measured by those tests. In general, neuropsychologists who use these measures in their assessments can be encouraged by the magnitude of the majority of the meta-analytic test-retest correlations obtained.

Prospective neurocognitive evaluation of patients undergoing carotid interventions

OBJECTIVE

Distal cerebral embolization is a known complication of carotid interventions. We prospectively investigated whether subclinical microembolization seen on postoperative magnetic resonance imaging (MRI) leads to cognitive deficits in patients undergoing carotid revascularization procedures.

METHODS

Patients undergoing carotid interventions and eligible for MRI scanning were recruited. Among 247 patients who received preoperative and postoperative MRI evaluations, 51 also completed neuropsychologic testing before and at 1 month after their procedure. Cognitive evaluation included the Rey Auditory Verbal Learning Test (RAVLT) for memory evaluation and the Mini-Mental State Examination (MMSE) for general cognitive impairment screening.

RESULTS

The 51 patients (all men), comprising 16 with carotid artery stenting (CAS) and 35 with carotid endarterectomy (CEA), were a mean age of 71 years (range, 54-89 years). Among them, 27 patients (53%) were symptomatic preoperatively, including 11 who had prior stroke and 16 who had prior preoperative transient ischemic attack symptoms. Most patients had significant medical comorbidities, including hypertension (96%), diabetes (31.3%), coronary artery disease (47%), and chronic obstructive pulmonary disease (15.7%). Two patients (4%) had prior ipsilateral CEA and eight had contralateral carotid occlusion (15.7%). Memory decline evident on RAVLT was identified in eight CAS patients and 13 CEA patients. Eleven patients had evidence of procedure-related microemboli. Although there was no significant difference in baseline cognitive function or memory change between the CEA and CAS cohorts, the CAS cohort had a significantly higher incidence of microembolic lesions. Multivariate regression analysis showed that procedure-related microembolization was associated with memory decline (P = .016) as evident by change in RAVLT. A history of neurologic symptoms was significantly associated with poor baseline cognitive function (MMSE; P = .03) and overall cognitive deterioration (change in MMSE; P = .026), as determined by Wilcoxon rank sum test and linear regression analysis, respectively.

CONCLUSIONS

Although CEA and CAS are effective in stroke prevention, with minimal neurologic complication, neurocognitive effects remain uncertain. Procedure-associated microembolization and pre-existing neurologic symptoms are associated with poor baseline cognitive function and memory decline after the procedures. Further comprehensive cognitive evaluation to determine the benefit of carotid interventions is warranted.

Improvement in executive function after unilateral carotid artery stenting for severe asymptomatic stenosis

Object

Executive functions are crucial for organizing and integrating cognitive processes. While some studies have assessed the effect of carotid artery stenting (CAS) on cognitive functioning, results have been conflicting. The object of this study was to assess the effect of CAS on cognitive status, with special interest on executive functions, among patients with severe asymptomatic internal carotid artery (ICA) stenosis.

Methods

The authors prospectively assessed the neuropsychological status of 20 patients with unilateral asymptomatic extracranial ICA stenosis of 60% or more by using a comprehensive assessment battery focused on executive functions before and after CAS. Individual raw scores on neuropsychological tests were converted into z scores by normalizing for age, sex, and years of education. The authors compared baseline and 3-month postoperative neuropsychological scores by using Wilcoxon signed-rank tests.

Results

The mean preoperative cognitive performance was within normal ranges on all variables. All patients underwent a successful CAS procedure. Executive function scores improved after CAS, relative to baseline performance as follows: set shifting (Trail-Making Test Part B: −0.75 ± 1.43 vs −1.2 ± 1.48, p = 0.003) and processing speed (digit symbol coding: −0.66 ± 0.85 vs −0.97 ± 0.82, p = 0.035; and symbol search: −0.24 ± 1.32 vs −0.56 ± 0.77, p = 0.049). The benefit of CAS for working memory was marginally significant (digit span backward: −0.41 ± 0.61 vs −0.58 ± 0.76, p = 0.052). Both verbal (immediate Rey Auditory Verbal Learning Test: 0.35 ± 1.04 vs −0.22 ± 0.82, p = 0.011) and visual (delayed Rey-Osterrieth Complex Figure: 0.27 ± 1.26 vs −0.22 ± 1.01, p = 0.024) memory improved after CAS.

Conclusions

The authors found a beneficial effect on executive function and memory 3 months after CAS among their prospective cohort of consecutive patients with unilateral and asymptomatic ICA stenosis of 60% or more.

Impact of silent ischemic lesions on cognition following carotid artery stenting

OBJECTIVE

The occurrence of silent ischemic lesions (SILs) is a common finding after carotid artery stenting (CAS). This study aimed to evaluate the impact of SILs on cognitive functioning following CAS.

METHODS

The retrospective study separated 131 patients with unilateral carotid stenosis into three groups: medication only, MRI-evaluated CAS and CT-evaluated CAS, and compared the sociodemographic factors, post-CAS images and Mini-Mental State Examination scores performed before and 6-12 months after enrollment.

RESULTS

Seven minor strokes occurred in the 99 patients receiving CAS. SILs were detected in 12 of 55 patients with diffusion-weighted MR imaging (DWI) and in 3 of 37 patients with CT 1 week after CAS. In patients with DWI follow-up, the frequency of SILs was 8, 24, 43 and 60% in patients with 0-, 1-, 2- and 3-vessel coronary artery disease (p = 0.006). The frequency of SILs on DWI was 0, 32 and 33% in patients with improved, unchanged, or deteriorated cognitive functioning (p = 0.02). Such an association was not observed if based on SILs on CT or manifesting stroke.

CONCLUSION

The presence of coronary artery disease increases the risk for having post-CAS SILs, and the occurrence of SILs may be associated with cognitive changes after CAS.

Postoperative neurocognitive function and microembolus detection in patients undergoing neck dissection: a pilot study

BACKGROUND AND OBJECTIVE

Patients undergoing oncologic neck dissection may have many of the risk factors for carotid artery stenosis, thus predisposing them to perioperative cerebral ischaemic events. The present study was designed to investigate development of postoperative neurocognitive dysfunction in these patients.

METHODS

Twenty-six patients were assessed the day before surgery and 48 h and 12 months after surgery using a comprehensive neuropsychological test battery. Cognitive performance was compared with a matched control group to account for the practise effect associated with repeated testing. Doppler ultrasonography was used to detect intraoperative cerebral microembolism. S100beta protein values were evaluated before and immediately after anaesthesia.

RESULTS

On the second postoperative day, 26.9% of patients undergoing neck dissection had postoperative neurocognitive deficit (POCD), defined as a total deficit score of 2SD worse than the mean performance in the control group. Microemboli were found only in the neck dissection group. S100beta levels were significantly higher after neck dissection (Wilcoxon signed ranked test: P<0.001). After 12 months, the incidence of POCD was similar in both groups.

CONCLUSION

POCD was detectable only after neck dissection in the early postoperative period accompanied by increased incidence of microembolism and protein S100beta levels, but not 12 months after surgery.

Changes in cognitive function during the 1-year period following endarterectomy and stenting of patients with high-grade carotid artery stenosis

BACKGROUND

In patients with severe carotid artery stenosis, cognitive decline and changes in cognitive function before to after treatment have been noted, though the true effects of treatment in such patients remain unclear. A convenient and repeatable neuropsychological test battery is needed for such patients.

METHODS

In 26 patients with severe carotid artery stenosis treated by carotid endarterectomy (CEA) and stenting (CAS), cognitive function was examined before and 1 week, 3 months, 6 months, and 1 year after treatment. RBANS and MMSE were selected as a test battery, and changes in test scores and long-term results of revascularization were evaluated.

RESULTS

RBANS was useful and suitable for neuropsychological testing in such patients, and yielded the following results: (1) Patients before treatment had, on average, RBANS scores rated low average, with mild but relatively diffuse cognitive impairment; (2) RBANS scores were increased significantly at 3 months after CEA and CAS, and cognitive improvement was maintained over 1 year; and (3) scores were decreased temporarily at 1 week after CEA, but not after CAS.

CONCLUSIONS

Patients with severe carotid artery stenosis exhibited mild decline in cognitive function, which was improved after CEA and CAS. RBANS is a suitable test battery for this type of patient.

Incidence of moderate to severe cognitive dysfunction in patients treated with carotid artery stenting

OBJECTIVE

Approximately 25% of patients with carotid artery stenosis treated with carotid endarterectomy develop cognitive dysfunction (CD) between 1 day and 1 month after surgery compared with a control group. We hypothesized that patients with carotid artery stenosis treated with carotid artery stenting (CAS) performed under cerebral embolic protection also develop CD at similar time points compared with a control group.

METHODS

Twenty-four patients scheduled for elective CAS were enrolled in a prospective institutional review board-approved study to evaluate cognitive function with a battery of 6 neuropsychometric tests before, and 1 day and 1 month after, CAS. Test performance was compared with 23 patients undergoing coronary artery procedures (control group). The mean and standard deviation of the difference scores in the control group were used to generate Z scores. We used a previously described point system to transform negative Z scores into injury points for each neuropsychometric test. Global performance is presented as average deficit score (sum of injury points divided by the number of completed tests). All patients underwent the procedures with mild sedation. Results were analyzed in 2 ways: group-rate and event-rate analysis. Outcome was dichotomized by defining moderate to severe CD as average deficit score at least 1.5 standard deviations worse than the control group. Fisher tests and multivariate logistic regression models were used to analyze group performance.

RESULTS

Control patients tended to be younger and had a lower incidence of stroke or previous transient ischemic attack. One day after surgery, 41% of patients (10 of 24) treated with CAS developed moderate to severe CD (P = 0.0422). Average deficit score was also significantly higher in the CAS group at 1 day (P = 0.0265). These differences were independent of age and history of stroke/transient ischemic attack. Interestingly, we found that the absence of oral statin medication may increase the probability of CD. By 1 month, 9% of patients (1 of 11) treated with CAS presented with CD. Other patients were lost to follow-up.

CONCLUSION

CAS is associated with a decline in cognitive performance that is at least moderate 1 day after surgery.

Neuropsychological sequelae of carotid angioplasty with stent placement: correlation with ischemic lesions in diffusion weighted imaging

Background and Purpose

Few studies investigated the neuropsychological outcome after carotid angioplasty with stent placement (CAS), yielding partially inconsistent results. The present investigation evaluated the effect of CAS in patients with high-grade stenosis and assessed the predictive value of ischemic lesion number for postinterventional cognitive deterioration.

Methods

22 patients were tested neuropsychologically before and six weeks after CAS. Cerebral ischemic changes were assessed with diffusion weighted imaging (DWI) prior to and after angioplasty.

Results

Pre- to postinterventional cognitive performance improved significantly in terms of verbal memory (t = −2.30; p<0.05), whereas significant deterioration was noted regarding verbal memory span (t = 2.31; p<0.05). 8 (36%) persons conformed to the criteria of cognitive improvement. 6 patients (27%) were postinterventionally classified as having deficits. Analysis yielded no statistically significant correlations between lesion quantity and cognitive change.

Conclusion

Both improvement and deterioration of cognitive functioning was observed in our collective of patients, leaving the neuropsychological outcome after percutaneous transluminal angioplasty unpredictable in individual cases. The presence of acute ischemic lesions on DWI was found to be not tightly associated with cognitive dysfunction after CAS.

The Role of Carotid Artery Stenting and Carotid Endarterectomy in Cognitive Performance

Background and Purpose— Change in cognition is being increasingly recognized as an important outcome measure; however, the role of carotid revascularization on this issue remains to be determined. It is still under debate whether carotid artery stenting and carotid endarterectomy have the same influence on neuropsychological functions.

Summary of Review— This article systematically reviews recent literature in an attempt to clarify this issue. A total of 32 papers reporting on neurocognition after carotid endarterectomy (n=25), carotid artery stenting (n=4), or carotid artery stenting versus carotid endarterectomy (n=3) were identified. The studies were different for many methodological factors, eg, sample size, type of patients and control group, statistical measure, type of test, timing of assessment, and so on. There was a lack of consensus in defining the improvement or impairment after either carotid artery stenting or carotid endarterectomy. Furthermore, there were nonuneqivocal results regarding the same domain of assessment (memory, visuomotor, attention). Based on available evidence, it is probable that carotid endarterectomy as well as carotid artery stenting do not change neuropsychological function “per se.”

Conclusions— Assessment of cognition after carotid revascularization is probably influenced by many confounding factors such as learning effect, type of test, type of patients, and control group, which are often minimized in their importance. The role of carotid revascularization is to prevent stroke in patients with severe carotid stenosis as highlighted by previous large randomized trials. Although an effect of carotid revascularization on cognition could be missed as a consequence of underpowered studies included in this review, at this time, no prediction can be done regarding its repercussions on higher intellectual functions. Larger studies appropriately designed and powered to assess cognition after carotid revascularization might change this view.

COGNITIVE OUTCOMES AFTER CAROTID REVASCULARIZATION

OBJECTIVE

Carotid artery stenting (CAS) and carotid endarterectomy (CEA) are currently being compared in ongoing randomized, controlled trials using postprocedural 30-day stroke rate, myocardial infarction, and mortality as primary endpoints. Recent data suggest that cognitive function may decline after CEA. Understanding the mechanisms that affect cognitive outcomes after carotid revascularization will be important in the design of future comparative studies of CAS and CEA incorporating cognitive outcome as an endpoint.

SUMMARY OF REVIEW

The effects of carotid revascularization procedures on cognitive outcome are unclear. Several factors contribute to the difficulty in interpreting cognitive data, including patient heterogeneity, variability of surgical techniques, and the differences in neuropsychological testing methodology. Mechanisms underlying cognitive effects during CEA have emerged, including the potential detrimental effect of procedural emboli and the beneficial effect of improved cerebral hemodynamics. The emergence of CAS as an alternative to CEA for treating carotid stenosis again raises questions about cognitive outcomes. Despite the use of distal protection devices, CAS is associated with a higher burden of microemboli. CAS does not, however, require the extent of temporary vessel occlusion associated with CEA. Quantifying microemboli and changes in cerebral hemodynamics along with standardization of neuropsychological testing may lead to meaningful comparisons of cognitive data for patients undergoing carotid revascularization procedures.

CONCLUSION

As use of CAS increases, it is important for randomized, controlled trials comparing CAS with CEA to include cognitive outcomes assessments. Furthermore, understanding the key mechanisms resulting in cognitive impairment during carotid revascularization procedures might limit injury.

Chronic ischemia and neurocognition

Cognitive impairment from a major stroke as a consequence of carotid disease is an acknowledged clinical outcome; however, cognitive impairment without major stroke is open to discussion. The three recognized mechanisms for cognitive dysfunction from internal carotid artery are microembolization, white-matter disease, and hypoperfusion. The last has been most difficult to characterize physiologically. In this article, the authors review evidence supporting the existence of chronic ischemia in the brain and its direct impact on cognitive functions. By incorporating the pathophysiology of chronic ischemia into the algorithm of the management of carotid artery disease, we may be able to extend the goals of carotid artery revascularization beyond merely preventing stroke to include preventing or reversing cognitive decline.

Neurocognitive changes after carotid revascularization: a review of the current literature

OBJECTIVE

The objective of this study was to review the current literature evaluating the effect of carotid revascularization on neurocognitive function.

METHODS

A PubMed search was performed using the following keywords: carotid surgery, carotid stenosis, cognition, and cognition disorders. Bibliographies were cross referenced and related-articles searches were performed once an article of interest had been identified.

RESULTS

Twenty-two studies have been identified from the literature since 1998. Seventeen articles evaluated carotid endarterectomy (CEA), four evaluated carotid stenting, and one compared CEA to stenting. Eight studies found improvements in mood and/or cognition after revascularization, 11 studies showed mixed results, and 3 studies found declines.

CONCLUSIONS

There is no consensus within the current literature as to the effect of carotid revascularization on neurocognitive function. Further research--with attention to laterality of neurocognitive effects, patients' symptomatology at the time of presentation, the role of perioperative embolization, and trial design including adequate control groups and comparison between open surgery and stenting factors--is necessary in order to clarify the effects of carotid revascularization on cognition.