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

Improved cognition and preserved hippocampal fractional anisotropy in subjects undergoing carotid endarterectomy "CEA preserves cognition & hippocampal structure"

OBJECTIVES

A growing body of data indicates that extracranial carotid artery disease (ECAD) can contribute to cognitive impairment. However, there have been mixed reports regarding the benefit of carotid endarterectomy (CEA) as it relates to preserving cognitive function. In this work, diffusion magnetic resonance imaging (dMRI) and neurocognitive testing are used to provide insight into structural and functional brain changes that occur in subjects with significant carotid artery stenosis, as well as changes that occur in response to CEA.

MATERIALS AND METHODS

The study design was a prospective, non-randomized, controlled study that enrolled patients with asymptomatic carotid stenosis. Thirteen subjects had severe ECAD (≥70% stenosis in at least one carotid artery) and were scheduled to undergo surgery. Thirteen had asymptomatic ECAD with <70% stenosis, therefore not requiring surgery. All subjects underwent neurocognitive testing using the Montreal Cognitive Assessment test (MoCA) and high angular resolution, multi-shell diffusion magnetic resonance imaging (dMRI) of the brain at baseline and at four-six months follow-up. Changes in MoCA scores as well as in Fractional anisotropy (FA) along the hippocampus were compared at baseline and follow-up.

RESULTS

At baseline, FA was significantly lower along the ipsilateral hippocampus in subjects with severe ECAD compared to subjects without severe ECAD. MoCA scores were lower in these individuals, but this did not reach statistical significance. At follow-up, MoCA scores increased significantly in subjects who underwent CEA and remained statistically equal in control subjects that did not have CEA. FA remained unchanged in the CEA group and decreased in the control group.

CONCLUSIONS

This study suggests that CEA improves cognition and preserves hippocampal white matter structure compared to control subjects not undergoing CEA.

The Effects of Carotid Revascularization on 1-Year Cognitive Performance in Patients With Carotid Artery Stenosis

PURPOSE

The impact of carotid revascularization on cognitive function for patients with severe carotid artery stenosis remains uncertain. This study is aimed to investigate the 1-year neurocognitive outcomes of patients who accept carotid revascularization and identify the risk factors associated with postoperative cognitive decline.

METHODS

From April 2019 to April 2021, patients with ≥70% carotid artery stenosis who were treated with carotid endarterectomy (CEA) or carotid artery stenting (CAS) were recruited for this study. The Montreal Cognitive Assessment (MoCA) instrument was used to evaluate cognitive function preoperatively and at 3, 6, and 12 months postoperatively. Logistic regression analysis was built to identify potential risk factors for postoperative long-term cognitive decline.

RESULTS

A total of 89 patients who met the criteria were enrolled and completed 1-year follow-up. At 3, 6, and 12 months after carotid revascularization, the total MoCA score, attention, language fluency, and delayed recall score were significantly improved compared with the baseline scores (p<0.05). At 12 months, there was also a significant improvement in cube copying compared with baseline (p=0.034). Logistic regression analysis showed that the advancing age, left side, and symptomatic carotid artery stenosis were independent risk factors for cognitive deterioration at 12 months after surgery.

CONCLUSIONS

Overall, carotid revascularization has a beneficial effect on cognition function in patients with severe carotid artery stenosis, while advancing age, left side, and symptomatic carotid artery stenosis were significantly related to a decreased cognitive score after carotid revascularization.

CLINICAL IMPACT

This study focused on the changes in cognitive function within 1 year after carotid revascularization in patients with severe carotid stenosis. Of course, carotid revascularization can improve the cognition function in these patients. On the other hand, we found the advancing age, left side and symptomatic carotid artery stenosis were significantly associated with decreased cognitive scores at 1 year after carotid revascularization, which suggests that clinicians may need to be aware of patients with these characteristics.

Long-term cognitive and neurovascular changes after carotid endarterectomy

BACKGROUND

Carotid endarterectomy (CEA) has been associated with both cognitive decline and improvement, but the underlying neurovascular mechanisms are unclear. The aim of this study was to investigate the relationship between neurovascular indices and cognitive changes after CEA.

METHODS

We studied 55 patients with severe (≥70%) symptomatic or asymptomatic carotid stenosis before and six months after CEA. A wide array of neuropsychological tests was arranged in eight cognitive domains and cognitive functions specific to hemisphere ipsilateral to operation. Differences in cognitive performance between patients and 38 matching healthy controls were studied with linear mixed models. Neurovascular functioning and microembolic signals were assessed with transcranial Doppler ultrasound of the middle cerebral artery. Associations between neurovascular indices and cognitive change were assessed with linear regression analyses.

RESULTS

On group level, the CEA patients improved more than controls in working memory, whereas no cognitive deterioration was detected. Also on individual level, improvement was most frequently observed in working memory. Worse preoperative cerebrovascular reactivity was related with improvement in cognitive functions of the ipsilateral hemisphere. Low preoperative pulsatility index was associated with improvement in executive functioning and ipsilateral cognitive functions. Poorer preoperative blood flow velocity associated with improvement in complex attention. Microembolic signals were rare.

CONCLUSION

The present findings suggest that CEA may have beneficial long-term effects on cognition. These effects may specifically involve patients with impaired preoperative circulatory adaptive mechanisms.

Long-Term Resveratrol Intake for Cognitive and Cerebral Blood Flow Impairment in Carotid Artery Stenosis/Occlusion

BACKGROUND AND PURPOSE

Carotid artery stenosis or occlusion (CASO) is a causative disease of vascular cognitive impairment (VCI) attributed to cerebral hypoperfusion, even without the development of symptomatic ischemic stroke. Preclinically, resveratrol has been demonstrated to play an important role in improving cognitive function in rodent CASO models. This study investigated the association between long-term resveratrol intake and improvements in cognitive and cerebral hemodynamic impairments in patients with CASO.

METHODS

A retrospective cohort study was conducted on patients with asymptomatic carotid artery stenosis of ≥50% or occlusion who underwent 15O-gas positron emission tomography (15O-gas PET) and neuropsychological tests such as Montreal Cognitive Assessment (MoCA) and Alzheimer's Disease Assessment Scale-Cognitive Subscale 13 (ADAS-Cog) twice between July 2020 and March 2022 allowing >125-day interval. Patients were administered 30 mg/day resveratrol after the first 15O-gas PET and neuropsychological tests were compared with those who were not.

RESULTS

A total of 79 patients were enrolled in this study; 36 received resveratrol and 43 did not. Over a mean follow-up of 221.2 and 244.8 days, long-term resveratrol treatment significantly improved visuospatial/executive function (P=0.020) in MoCA, and memory domain (P=0.007) and total score (P=0.019) in ADAS-Cog. Cerebral blood flow demonstrated improvement in the right frontal lobe (P=0.027), left lenticular nucleus (P=0.009), right thalamus (P=0.035), and left thalamus (P=0.010) on 15O-gas PET. No adverse events were reported.

CONCLUSION

Long-term daily intake of oral resveratrol may prevent or treat VCI by improving the cerebral blood flow in asymptomatic patients with CASO.

Pathophysiology and probable etiology of cerebral small vessel disease in vascular dementia and Alzheimer's disease

Vascular cognitive impairment and dementia (VCID) is commonly caused by vascular injuries in cerebral large and small vessels and is a key driver of age-related cognitive decline. Severe VCID includes post-stroke dementia, subcortical ischemic vascular dementia, multi-infarct dementia, and mixed dementia. While VCID is acknowledged as the second most common form of dementia after Alzheimer's disease (AD) accounting for 20% of dementia cases, VCID and AD frequently coexist. In VCID, cerebral small vessel disease (cSVD) often affects arterioles, capillaries, and venules, where arteriolosclerosis and cerebral amyloid angiopathy (CAA) are major pathologies. White matter hyperintensities, recent small subcortical infarcts, lacunes of presumed vascular origin, enlarged perivascular space, microbleeds, and brain atrophy are neuroimaging hallmarks of cSVD. The current primary approach to cSVD treatment is to control vascular risk factors such as hypertension, dyslipidemia, diabetes, and smoking. However, causal therapeutic strategies have not been established partly due to the heterogeneous pathogenesis of cSVD. In this review, we summarize the pathophysiology of cSVD and discuss the probable etiological pathways by focusing on hypoperfusion/hypoxia, blood-brain barriers (BBB) dysregulation, brain fluid drainage disturbances, and vascular inflammation to define potential diagnostic and therapeutic targets for cSVD.

High-on-treatment platelet reactivity predicts adverse outcome after carotid artery stenting: A prospective study

BACKGROUND AND PURPOSE

High-on-treatment platelet reactivity (HTPR) has been established as a predictor of major adverse cardiovascular events (MACE) in patients undergoing percutaneous coronary interventions on dual antiplatelet therapy (DAPT), but no data are available on its predictive value in patients on DAPT after carotid artery stenting (CAS). We aimed to evaluate the possible association between HTPR in patients on aspirin plus clopidogrel therapy after CAS and subsequent MACE.

METHODS

All consecutive patients treated with CAS in a single institution were enrolled in a prospective clinical study. HTPR was evaluated with 5 different laboratory assays carried out just before CAS. MACE incidence (cerebral ischemia, myocardial infarction, stent thrombosis, acute limb ischemia and vascular death) was evaluated at 30 days and thereafter at yearly visits.

RESULTS

A total of 300 patients were enrolled in the study, and eight were then excluded because blood samples resulted unsuitable for the laboratory testing or CAS aborted for technical problems. Median follow-up was 5.8 years and during this period 47 MACE occurred. HTPR detected by multiplate electronic aggregometry (MEA) and the VASP phosphorylation assay (VASP) were associated with a significantly enhanced risk of MACE (p = 0.048 and p = 0.038, respectively). However, HTPR to three tests (HTPR3) was more strongly predictive of increased risk of a vascular event at follow up (p = 0.005) at bivariate analysis and also at Cox regression multivariate analysis (p = 0.002).

CONCLUSIONS

HTPR to three different assays (mainly to VASP + PFA P2Y+ VerifyNow) in patients on DAPT after CAS has predictive value for subsequent MACE. Prospective studies to assess whether platelet function testing-guided antiplatelet therapy is superior to standard DAPT in patient undergoing CAS should be considered.

Effects of carotid artery stenting on cognitive impairment in patients with severe symptomatic carotid artery stenosis

The effect of carotid artery stenting and medication on improvement of cognitive function in patients with severe symptomatic carotid artery stenosis is unknown. To investigate the effect of stenting compared with medication alone for severe carotid atherosclerotic stenosis on cognitive impairment. Patients with carotid stenosis and cognitive impairment were prospectively randomly divided into 2 groups of stenting or medication alone. Cognitive function was evaluated with the Montreal cognitive assessment (MoCA), Mini-Mental State Examination, and Barthel Index of Activities of Daily Living (BI). Continuous data in normal distribution were tested with the t-test but with the Mann-Whitney U test if not in normal distribution. Categorical data were presented as frequency and percentages and tested with the Fisher exact test. A P value < .05 was regarded as statistical significant. Carotid artery stenting was successfully performed in all patients (100%) in the stenting group. Compared with before treatment, the Mini-Mental State Examination, MoCA and BI scores at 6 months in the medication alone group and at 1, 3, and 6 months in the stenting group were significantly (P < .005) improved. The stenting group had significantly (P < .05) better scores than the medication alone group at the same time. At 6-month follow-up, the visuospatial/executive functions (3.69 ± 1.42 vs 2.42 ± 1.23), attention (5.24 ± 1.52 vs 3.63 ± 1.47), and language (2.64 ± 0.71 vs 1.96 ± 0.69) were significantly (P < .05) improved in the stenting group compared with the medication alone group. Carotid artery stenting may significantly improve cognitive impairment and neurological function compared with medication alone in patients with severe carotid atherosclerotic stenosis concurrent with cognitive impairment.

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.

Association between carotid revascularization for asymptomatic stenosis and cognitive functions

Summary: Asymptomatic carotid stenosis (ACS) can cause cognitive dysfunction, related to cerebral hypoperfusion and microemboli. These mechanisms could be treated by carotid revascularization, but the impact of carotid angioplasty stenting (CAS) or carotid endarterectomy (CEA) on cognitive functions remains unclear. The aim of this systematic review was to realize a report on the actual state of results about asymptomatic carotid stenosis revascularization and cognitive function. We performed a systematic literature review to analyze all studies assessing the impact of asymptomatic carotid stenosis revascularizations on cognitive functions. We reviewed all publications published in Medline database and Cochrane between January 2010 and January 2020 including subjects with a cognitive evaluation and receiving carotid revascularization for asymptomatic stenosis. We identified 567 records for review, and finally we included in the systematic review 20 studies about ACS revascularization and cognitive functions. Only observational studies analyzed the impact of CEA and CAS on cognitive functions. Thus, too heterogeneous data associated to the lack of randomized controlled trials with an evaluation of optimal medical treatment did not enable to affirm the interest of the revascularization management of ACS in cognitive domain. There was a lack of standardization and finally studies were too heterogeneous to conclude on the impact of carotid revascularization on cognitive functions. There is an urgent need to harmonize research in this domain in order to prevent and treat cognitive dysfunction related to ACS, especially in our society with an aging population.

Functional MRI evaluation of cognitive effects of carotid stenosis revascularization

INTRODUCTION

Severe internal carotid stenosis, if left untreated, can pose serious risks for ischemic stroke and cognitive impairments. The effects of revascularization on any aspects of cognition, however, are not well understood, as conflicting results are reported, which have mainly been centered on paper-based cognitive analyses. Here, we summarized and evaluated the publications to date of functional MRI (fMRI) studies that examined the mechanisms of functional brain activation and connectivity as a way to reflect cognitive effects of revascularization on patients with carotid stenosis.

METHODS

A PubMed and Google Scholar (covering the relevant literature until November 1, 2021) search yielded eight original studies of the research line, including seven resting-state and one task-based fMRI reports.

RESULTS

Findings demonstrated treatment-related alterations in fMRI signal intensity and symmetry level, regional fMRI activation pattern, and functional brain network connectivity. The functional brain changes were associated largely with improvement in cognitive function assessed using standard cognitive test scores.

CONCLUSIONS

These findings support the contribution of fMRI to the understanding of brain functional activation and connectivity changes revealing cognitive effects of revascularization in the management of severe carotid stenosis. The review also highlighted the importance of reproducibility through enhancing experimental designs and cognitive task applications with future research for potential clinical translation.

Asymptomatic Carotid Disease and Cognitive Impairment: What Is the Evidence?

The development of cognitive dysfunction and dementia is a complex, multifactorial process. One of the contributors to various types of cognitive dysfunction is carotid atherosclerosis which can frequently be seen in asymptomatic individuals. There are a number of different manifestations of asymptomatic carotid atherosclerosis including arterial stiffness, carotid intima-media thickening, flow-limiting stenosis, and complex, atherosclerotic plaque. Each of these forms of atherosclerosis may contribute to cerebral parenchymal damage, contributing to cognitive dysfunction. In this review article, we will discuss each of these forms of carotid atherosclerosis, present the potential mechanistic underpinnings behind an association, and then review the scientific evidence supporting potential associations to cognitive dysfunction and dementia.

Carotid revascularization and cognitive impairment: the neglected role of cerebral small vessel disease

Carotid atherosclerosis is a pathological process that leads to narrowing of the vessel lumen and a consequent risk of stroke. Revascularization procedures such as carotid endarterectomy (CEA) and carotid stenting aim to reduce occurrence of stroke in selected patients. Due to the proven benefit and low intraoperative risk, CEA is currently the preferred choice in candidates for carotid revascularization. However, the risk of cognitive impairment subsequent to CEA has not been fully elucidated and is unclear whether certain conditions, such as frailty, may increase this risk. There is consistent evidence that shows that frail patients have higher risk of cognitive impairment after surgical procedure. Moreover, brain pre-existing conditions may play a role in cognitive impairment after CEA. Cerebral small vessel disease (SVD) is a pathology that involves microcirculation and is detectable with computed tomography or magnetic resonance. SVD shares common vascular risk factors with carotid atherosclerosis, is a major contributor to vascular cognitive impairment and vascular dementia, and has been proposed as a marker of brain frailty. In this review, we discuss the current evidence about the link between carotid revascularization and cognitive impairment and advance the hypothesis that SVD may play a relevant role in development of cognitive impairment after carotid revascularization.

Development of cerebral microbleeds in patients with cerebral hyperperfusion following carotid endarterectomy and its relation to postoperative cognitive decline

OBJECTIVE

A primary cause of cognitive decline after carotid endarterectomy (CEA) is cerebral injury due to cerebral hyperperfusion. However, the mechanisms of how cerebral hyperperfusion induces cerebral cortex and white matter injury are not known. The presence of cerebral microbleeds (CMBs) on susceptibility-weighted imaging (SWI) is independently associated with a decline in global cognitive function. The purpose of this prospective observational study was to determine whether cerebral hyperperfusion following CEA leads to the development of CMBs and if postoperative cognitive decline is related to these developed CMBs.

METHODS

During the 27-month study period, patients who underwent CEA for ipsilateral internal carotid artery stenosis (≥ 70%) also underwent SWI and neuropsychological testing before and 2 months after surgery, as well as quantitative brain perfusion SPECT prior to and immediately after surgery.

RESULTS

According to quantitative brain perfusion SPECT and SWI before and after surgery, 12 (16%) and 7 (9%) of 75 patients exhibited postoperative cerebral hyperperfusion and increased CMBs in the cerebral hemisphere ipsilateral to surgery, respectively. Cerebral hyperperfusion was associated with an increase in CMBs after surgery (logistic regression analysis, 95% CI 5.08-31.25, p < 0.0001). According to neuropsychological assessments before and after surgery, 10 patients (13%) showed postoperative cognitive decline. Increased CMBs were associated with cognitive decline after surgery (logistic regression analysis, 95% CI 6.80-66.67, p < 0.0001). Among the patients with cerebral hyperperfusion after surgery, the incidence of postoperative cognitive decline was higher in those with increased CMBs (100%) than in those without (20%; p = 0.0101).

CONCLUSIONS

Cerebral hyperperfusion following CEA leads to the development of CMBs, and postoperative cognitive decline is related to these developed CMBs.

Effect of Carotid Interventions on Cognitive Function in Patients With Asymptomatic Carotid Stenosis: A Systematic Review

OBJECTIVE

To determine the effect of carotid endarterectomy (CEA) and carotid artery stenting (CAS) on early (baseline vs. maximum three months) and late (baseline vs. at least five months) cognitive function in patients with exclusively asymptomatic carotid stenoses (ACS).

METHOD

Searches were conducted in PubMed/Medline, Embase, Scopus, and the Cochrane library. This systematic review includes 31 non-randomised studies.

RESULTS

Early post-operative period: In 24 CEA/CAS/CEA+CAS cohorts (n = 2 059), two cohorts (representing 91/2 059, 4.4% of the overall study population) reported significant improvement in cognitive function, while one (28/2 059, 1%) reported significant decline. Three cohorts (250/2 059, 12.5% reported "mixed findings" where some cognitive scores significantly improved, and a similar proportion declined. The majority (nine cohorts; 1 086/2 059, 53%) reported no change. Seven cohorts (250/2 059, 12.1%) were mostly unchanged but one to two individual test scores improved, while two cohorts (347/2 059, 16.8%) were mostly unchanged with one to two individual test scores worse. Late post-operative period: In 21 cohorts (n = 1 554), one (28/1 554, 1.8%) reported significantly worse cognitive function, one reported significant improvement (24/1 554, 1.5%), while a third (19/1 554, 1.2%) reported "mixed findings". The majority were unchanged (six cohorts; 1 073/1 554, 69%) or mostly unchanged, but with one to two cognitive tests showing significant improvement (11 cohorts; 386/1 554, 24.8%). Overall, there was a similar distribution of findings in small, medium, and large studies, in studies with controls vs. no controls, in studies comparing CEA vs. CAS, and in studies with shorter/longer late follow up.

CONCLUSION

Notwithstanding accepted limitations regarding heterogeneity within non-randomised studies, CEA/CAS rarely improved overall late cognitive function in ACS patients (< 2%) and the risk of significant cognitive decline was equally low (< 2%). In the long term, the majority were either unchanged (69%) or mostly unchanged with one to two test scores improved (24.8%). Until new research identifies vulnerable ACS subgroups (e.g., impaired cerebral vascular reserve) or provides evidence that silent embolisation from ACS causes cognitive impairment, evidence supporting intervention in ACS patients to prevent/reverse cognitive decline is lacking.

Decreasing Spatial Variability of Individual Watershed Areas by Revascularization Therapy in Patients With High-Grade Carotid Artery Stenosis

BACKGROUND

Carotid artery stenosis can impair cerebral hemodynamics especially within watershed areas (WSAs) between vascular territories. WSAs can shift because of collateral flow, which may be an indicator for increased hemodynamic implications and hence higher risk for ischemic stroke. However, whether revascularization treatment can reverse the spatial displacement of individual WSAs (iWSAs) and impaired hemodynamics remains unknown.

HYPOTHESIS

That iWSAs spatially normalize because of hemodynamic improvement resulting from revascularization treatment.

STUDY TYPE

Prospective.

POPULATION

Sixteen patients with unilateral, high-grade carotid artery stenosis confirmed by duplex ultrasonography and 17 healthy controls.

FIELD STRENGTH/SEQUENCES

A 3 T-magnetization-prepared rapid acquisition gradient echo (MPRAGE), gradient-echo echo planar dynamic susceptibility contrast (DSC), and fluid-attenuated inversion recovery (FLAIR) sequences. Additionally, contrast-enhanced 3D gradient echo magnetic resonance angiography (MRA) and diffusion-tensor imaging (DTI) spin-echo echo planar imaging were performed.

ASSESSMENT

iWSAs were delineated by a recently proposed procedure based on time-to-peak maps from DSC perfusion MRI, which were also used to evaluate perfusion delay. We spatially compared iWSAs and perfusion delay before and after treatment (endarterectomy or stenting). Additionally, the Circle of Willis collateralization status was evaluated, and basic cognitive testing was conducted.

STATISTICAL TESTS

Statistical tests included two-sample t-tests and Chi-squared tests. A P value < 0.05 was considered to be statistically significant.

RESULTS

After revascularization, patients showed a significant spatial shift of iWSAs and significantly reduced perfusion delay ipsilateral to the stenosis. Spatial shift of iWSA (P = 0.007) and cognitive improvement (P = 0.013) were more pronounced in patients with poor pre-existing collateralization. Controls demonstrated stable spatial extent of iWSAs (P = 0.437) and symmetric perfusion delays between hemispheres over time (P = 0.773).

DATA CONCLUSION

These results demonstrate the normalization of iWSA and impaired hemodynamics after revascularization in patients with high-grade carotid artery stenosis.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Carotid endarterectomy restores decreased vision due to chronic ocular ischemia

BACKGROUND

The therapeutic effect of carotid endarterectomy (CEA) on visual disturbance caused by chronic ocular ischemia due to carotid artery stenosis has not been validated. This prospective observational study aims to investigate whether CEA is associated with an increase in ocular blood flow (OBF) and postoperative visual improvement.

METHODS

In total, 41 patients with carotid artery stenosis treated by CEA between March 2015 and September 2018 were enrolled in this study. OBF was evaluated by laser speckle flowgraphy, which can measure the mean blur ratio (MBR) which is well correlated to the absolute retinal blood flow. Visual acuity was assessed before and after CEA by subjective improvement and objective visual assessment using CSV-1000, an instrument used to test contrast sensitivity.

RESULTS

OBF increased after CEA on the operated side (mean MBR 33.5 vs 38.2, p < 0.001) but not on the non-operated side (mean MBR 37.8 vs 37.5, p = 0.50). After CEA, 23 patients (56.1%) reported subjective visual improvement on the operated side. The mean CSV-1000 score among the patients with increased OBF after CEA (5.44 vs 5.88, p = 0.04) but not among those without increased OBF (5.48 vs 5.95, p = 0.09). The mean CSV-1000 scores increased significantly after CEA in 18 patients with decreased vision and decreased OBF (4.51 vs 5.37, p < 0.001), but not in the 23 patients without those (6.19 vs 6.31, p = 0.6).

CONCLUSION

CEA may successfully reverse visual dysfunction caused by chronic ocular ischemia due to carotid artery stenosis by increasing OBF.

Comparison of Subjective and Objective Assessments on Improvement in Gait Function after Carotid Endarterectomy

The purpose of the present study was to determine whether objective gait test scores obtained using a tri-axial accelerometer can detect subjective improvement in gait as determined by the patient after carotid endarterectomy (CEA). Each patient undergoing CEA for ipsilateral internal carotid artery stenosis determined whether their gait was subjectively improved at six months after CEA when compared with preoperatively. Gait testing using a tri-axial accelerometer was also performed preoperatively and six months postoperatively. Twelve (15%) of 79 patients reported subjectively improved gait. Areas under the receiver operating characteristic curve for differences between pre- and postoperative test values in stride time, cadence, and ground floor reaction for detecting subjectively improved gait were 0.995 (95% confidence interval (CI), 0.945-1.000), 0.958 (95%CI, 0.887-0.990), and 0.851 (95%CI, 0.753-0.921), respectively. Cut-off points for value differences in detecting subjectively improved gait were identical to mean -1.7 standard deviation (SD) for stride time, mean +1.6 SD for cadence, and mean +0.4 SD for ground floor reaction of control values from normal subjects. Objective gait test scores obtained using the tri-axial accelerometer can detect subjective gait improvements after CEA. When determining significant postoperative improvements in gait using a tri-axial accelerometer, optimal cut-off points for each test value can be defined.

Plaque imaging volume analysis: technique and application

The prevention and management of atherosclerosis poses a tough challenge to public health organizations worldwide. Together with myocardial infarction, stroke represents its main manifestation, with up to 25% of all ischemic strokes being caused by thromboembolism arising from the carotid arteries. Therefore, a vast number of publications have focused on the characterization of the culprit lesion, the atherosclerotic plaque. A paradigm shift appears to be taking place at the current state of research, as the attention is gradually moving from the classically defined degree of stenosis to the identification of features of plaque vulnerability, which appear to be more reliable predictors of recurrent cerebrovascular events. The present review will offer a perspective on the present state of research in the field of carotid atherosclerotic disease, focusing on the imaging modalities currently used in the study of the carotid plaque and the impact that such diagnostic means are having in the clinical setting.

Two-Year Clinical, Cerebral Hemodynamic, and Cognitive Outcomes of Adult Patients Undergoing Medication Alone for Symptomatically Ischemic Moyamoya Disease Without Cerebral Misery Perfusion: A Prospective Cohort Study

BACKGROUND

In nonsurgical adult moyamoya disease (MMD) patients with ischemic onset and stable hemodynamics, the cerebral hemodynamic and cognitive course remains unclear.

OBJECTIVE

To clarify, through a prospective cohort study, 2-yr clinical, cerebral hemodynamic, and cognitive outcomes of adult patients receiving medication alone for symptomatically ischemic MMD without cerebral misery perfusion.

METHODS

Seventy patients without cerebral misery perfusion on the first 15O gas positron emission tomography (PET) were clinically followed up for 2 yr. The second PET was performed at the end of the 2-yr follow-up. Neuropsychological tests were also performed at the study entry and the end of the 2-yr follow-up.

RESULTS

During the 2-yr follow-up period, 2 patients (3%) developed further cerebral ischemic symptoms and showed new cerebral misery perfusion on PET performed at recurrence. None of the 68 patients without further ischemic symptoms showed cerebral misery perfusion on second PET. All 66 patients who underwent the first and second neuropsychological tests displayed unchanged interval cognition at the 2-yr follow-up.

CONCLUSION

Among adult patients receiving medication alone for symptomatically ischemic MMD without cerebral misery perfusion, the incidence of recurrent ischemic events was 3% per 2 yr. In patients without recurrent ischemic events, cerebral hemodynamics and cognitive function had not deteriorated by 2 yr after the last event.

Changes in Cognition, Depression and Quality of Life after Carotid Stenosis Treatment

BACKGROUND

Although several studies have evaluated the change of cognitive performance after severe carotid artery stenosis, the results still remain elusive. The objective of this study was to assess changes in cognitive function, depressive symptoms and Health Related Quality of Life (HRQoL) after carotid stenosis revascularisation and Best Medical Treatment (BMT).

METHODS

Study involved 213 patients with ≥70% carotid stenosis who underwent assessment of cognitive function using Montreal Cognitive Assessment scale (MoCA), depressive symptoms - using Patient Health Questionnaire-9 (PHQ-9) and HRQoL - using Medical Outcome Survey Short Form version 2 (SF-36v2). The assessment was performed before and at 6 and 12 months followup periods in patients who had Carotid Endarterectomy (CEA), Carotid Artery Stenting (CAS) or received BMT only.

RESULTS

Improvement in the total MoCA scores was observed after 6 and 12 months (p<0.001, Kendall's W=0.28) in the CEA group. In the CAS group - after 12 months (p=0.01, Kendall's W=0.261) whereas in the BMT group - no significant changes (p=0.295, Kendall's W=0.081) were observed. Reduction of depressive symptoms was not found in any of the study groups. Comparing mean SF-36v2 scores in the CEA group, there was no significant difference in any of 10 subscales. Likewise in the CAS group - no significant difference in 9 of 10 subscales (p=0.028, η2=0.343) was observed. Three subscales worsened in the BMT group during the 1-year follow-up period.

CONCLUSION

Patients with severe carotid stenosis who underwent revascularisation enhanced their cognitive performance without exerting significant change of depressive symptoms. Preoperative HRQoL may be maintained for at least one year in the CEA group.

The stronger one-sided relative hypoperfusion, the more pronounced ipsilateral spatial attentional bias in patients with asymptomatic carotid stenosis

Patients with asymptomatic, high-grade internal carotid artery stenosis often suffer from subtle cognitive impairments with unclear underlying neuro-cognitive mechanisms. Thus, we hypothesized that stenosis-related unilateral cerebral hypoperfusion leads to an ipsilateral attentional bias; 22 patients with asymptomatic, one-sided high-grade carotid stenosis and 24 age-matched healthy controls underwent pseudo-continuous arterial spin labeling to assess brain perfusion in the territory of the carotid arteries. Furthermore, a parametric assessment of attention functions was carried out on the basis of the computational Theory of Visual Attention. Both patients' perfusion and spatial attention were significantly more lateralized than those of healthy controls. Critically, both asymmetry indices were significantly correlated in patients, i.e. the stronger one-sided relative hypoperfusion, the stronger ipsilateral bias of attention. This association was specifically pronounced in parietal cortices and independent of white matter hyperintensities as a surrogate for cerebrovascular brain damage. Results provide evidence for a link between lateralized hypoperfusion and lateralized attentional weighting in asymptomatic, high-grade carotid stenosis. Data suggest that lateralized hypoperfusion with simultaneous spatial attentional bias might serve as a potential therapeutic target in one-sided carotid stenosis.

Functional connectivity analysis and prediction of cognitive change after carotid artery stenting

OBJECTIVE

The neurocognitive course of patients who have undergone cerebral revascularization has been the subject of many studies, and the reported effects of carotid artery stenting (CAS) on cognitive function have varied from study to study. The authors hypothesized that cognitive amelioration after CAS is associated with alteration of the default mode network (DMN) connectivity, and they investigated the correlation between functional connectivity (FC) of the DMN and post-CAS changes in cognitive function in order to find a clinical marker that can be used to predict the effect of cerebral revascularization on patients' cognitive function in this preliminary exploratory study.

METHODS

The authors examined post-CAS changes in cognitive function in relation to FC in patients treated for unilateral carotid artery stenosis. Resting-state functional MRI (rs-fMRI) was performed with a 3-T scanner before and 6 months after CAS in 8 patients. Neuropsychological tests (Wechsler Adult Intelligence Scale III and Wechsler Memory Scale-Revised) were administered to each patient before and 6 months after CAS. The DMN was mapped for each patient through independent component analysis of the rs-fMR images, and the correlation between FC of the DMN and post-CAS change in cognitive function was analyzed on a voxel level. Multivariable regression analysis was performed to identify preoperative factors associated with a post-CAS change in cognitive function.

RESULTS

Post-CAS cognitive function varied between patients and between categories of neuropsychological tests. Although there was no significant overall improvement in Working Memory scores after CAS, post-CAS Working Memory scores changed in negative correlation with changes in FC between the DMN and the precentral/superior frontal gyrus and between the DMN and the middle frontal gyrus. In addition, the preoperative FC between those areas correlated positively with the post-CAS improvement in working memory.

CONCLUSIONS

FC between the DMN and working memory-related areas is closely associated with improvement in working memory after CAS. Preoperative analysis of FC of the DMN may be useful for predicting postoperative improvement in the working memory of patients being treated for unilateral stenosis of the extracranial internal carotid artery.Clinical trial registration no.: UMIN000020045 (www.umin.ac.jp/ctr/index.htm).

Flow-metabolism uncoupling in patients with asymptomatic unilateral carotid artery stenosis assessed by multi-modal magnetic resonance imaging

Oxygen extraction (OEF), oxidative metabolism (CMRO₂), and blood flow (CBF) in the brain, as well as the coupling between CMRO₂ and CBF due to cerebral autoregulation are fundamental to brain's health. We used a clinically feasible MRI protocol to assess impairments of these parameters in the perfusion territories of stenosed carotid arteries. Twenty-nine patients with unilateral high-grade carotid stenosis and thirty age-matched healthy controls underwent multi-modal MRI scans. Pseudo-continuous arterial spin labeling (pCASL) yielded absolute CBF, whereas multi-parametric quantitative blood oxygenation level dependent (mqBOLD) modeling allowed imaging of relative OEF and CMRO₂. Both CBF and CMRO₂ were significantly reduced in the stenosed territory compared to the contralateral side, while OEF was evenly distributed across both hemispheres similarly in patients and controls. The CMRO₂-CBF coupling was significantly different between both hemispheres in patients, i.e. significant interhemispheric flow-metabolism uncoupling was observed in patients compared to controls. Given that CBF and CMRO₂ are intimately linked to brain function in health and disease, the proposed easily applicable MRI protocol of pCASL and mqBOLD imaging might serve as a valuable tool for early diagnosis of potentially harmful cerebral hemodynamic and metabolic states with the final aim to select clinically asymptomatic patients who would benefit from carotid revascularization therapy.

Rationale and Design for the Remote Ischemic Preconditioning for Carotid Endarterectomy Trial

BACKGROUND

While the perioperative stroke rate after carotid endarterectomy (CEA) is low, "silent" microinfarctions identified by magnetic resonance imaging (MRI) are common and have been correlated with postoperative neurocognitive decline. Our study will investigate the role of remote ischemic preconditioning (RIPC) as a potential neuroprotective mechanism. RIPC is a well-tolerated stimulus that, through neuronal and humoral pathways, generates a systemic environment of greater resistance to subsequent ischemic insults. We hypothesized that patients undergoing RIPC before CEA will have improved postoperative neurocognitive scores compared with those of patients undergoing standard care.

METHODS

Patients undergoing CEA will be randomized 1:1 to RIPC or standard clinical care. Those randomized to RIPC will undergo a standard protocol of 4 cycles of RIPC. Each RIPC cycle will involve 5 min of forearm ischemia with 5 min of reperfusion. Forearm ischemia will be induced by a blood pressure cuff inflated to 200 mm Hg or at least 15 mm Hg higher than the systolic pressure if it is >185 mm Hg. This will occur after anesthesia induction and during incision/dissection but before manipulation or clamping of the carotid; thus, patients will be blinded to their assignment. Before carotid endarterectomy, all patients will undergo baseline neurocognitive testing in the form of a Montreal Cognitive Assessment (MoCA) and National Institutes of Health (NIH) Toolbox. MoCA testing only will be conducted on postoperative day 1 in the hospital. The full neurocognitive testing battery will again be conducted at 1-month follow-up in the office. Changes from baseline will be compared between arms at the follow-up time points. Assuming no drop-ins or dropouts and a 10% loss to follow-up, we would need a sample size of 43 patients for 80% power per treatment arm. The primary endpoint, change in MoCA scores, will be analyzed using a random effects model, and secondary outcomes will be analyzed using either linear or logistic regression where appropriate.

CONCLUSIONS

RIPC, if shown to be effective in protecting patients from neurocognitive decline after CEA, represents a safe, inexpensive, and easily implementable method of neuroprotection.

Neurocognitive Changes After Carotid Revascularization According to Perfusion Parameters: A Meta-analysis of Current Literature

BACKGROUND

Although the clinical outcomes continue to be scrutinized, there are a few data summarizing the changes in perfusion parameters in postoperative patients. The objective was to undertake a systematic literature review and perform a meta-analysis to assess the effects of cerebral perfusion changes in cognitive and functional status.

METHODS

A systematic search was conducted in July 2018 identifying articles comparing perfusion parameter changes before and after carotid revascularization in patients with carotid artery stenosis. Combined overall effect sizes were calculated using random-effects models.

RESULTS

The literature search identified 1031 unique articles eligible for analysis. Sixteen studies including 755 patients were identified. The studies were different for many methodological factors, for example, sample size, type of patients, statistical measure, type of test, timing of assessment, and so on. There were no differences in cerebral blood volume (CBV), cerebral metabolic rate of oxygen (CMRO₂), and relative cerebral blood volume (rCBV) between preintervention and postintervention, but there was a significant increase of cerebral blood flow (CBF) (95% confidence interval [CI] standardized mean difference [Std. MD] : -0.83 [-1.27, -0.40]; P = 0.0002; I² = 68%) and relative cerebral blood flow (rCBF) (95% CI Std. MD: -0.72 [-1.61, -0.27]; P < 0.0001; I² = 48%) after operation. In addition, the perfusion of mean transit time (MTT) (95% CI Std. MD: 1.26 [0.62, 1.90]; P = 0.0001; I² = 84%), oxygen extraction fraction (OEF) (95% CI Std. MD: 0.78 [0.24, 1.33]; P = 0.005; I² = 0%), time to peak (TTP) (95% CI Std. MD: 0.46 [0.16, 0.77]; P = 0.003; I² = 47%), and relative mean transit time (rMTT) (95% CI Std. MD: 0.41 [0.33, 0.50]; P < 0.00001; I² = 67%) was higher before than after operation.

CONCLUSIONS

The increase in changes in CBF and rCBF and the decrease in MTT, OEF, TTP, and rMTT after operation may indicate the improvement of cognition in the short term. Intraoperative perfusion parameters could be an important adjuvant monitoring method in neurocognitive changes after carotid revascularization.

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

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.

Dynamics of brain perfusion and cognitive performance in revascularization of carotid artery stenosis

INTRODUCTION

There is evidence suggesting a detrimental effect of asymptomatic carotid artery stenosis on cognitive function even in the absence of ischemic cerebral lesions. Hypoperfusion has been suggested as pathophysiological mechanism causing cognitive impairment. We aimed to assess cognitive performance and cerebral perfusion changes in patients with carotid artery stenosis without ischemic lesions by arterial spin labeling (ASL) and contrast enhanced (CE) perfusion MRI before and after revascularization therapy.

METHODS

17 asymptomatic patients with unilateral high-grade (≥70%) carotid artery stenosis without evidence of structural brain lesions underwent ASL and CE perfusion MRI and cognitive testing (MMSE, DemTect, Clock-Drawing Test, Trail-Making Test, Stroop Test) before and 6-8 weeks after revascularization therapy by endarterectomy or stenting. Multiparametric perfusion maps (ASL: cerebral blood flow (ASL-CBF), bolus arrival time (ASL-BAT); CE: cerebral blood flow (CE-CBF), mean transit time (CE-MTT), cerebral blood volume (CE-CBV)) were calculated and analyzed by vascular territory. Relative perfusion values were calculated.

RESULTS

Multivariate analysis revealed a significant impact of revascularization therapy on all perfusion measures analyzed. At baseline post-hoc testing showed significant hypoperfusion in MCA borderzones as assessed by ASL-CBF, ASL-BAT, CE-MTT and CE-CBV. All perfusion alterations normalized after revascularization. We did not observe any significant correlation of cognitive test results with perfusion parameters. There was no significant change in cognitive performance after revascularization.

CONCLUSION

We found evidence of traceable perfusion alterations in patients with high grade carotid artery stenosis in the absence of structural brain lesions, which proved fully reversible after revascularization therapy. In this cohort of asymptomatic patients we did not observe an association of hypoperfusion with cognitive performance.

Cilostazol may improve cognition better than clopidogrel in non-surgical adult patients with ischemic moyamoya disease: subanalysis of a prospective cohort

OBJECTIVE

Adult patients with ischemic moyamoya disease (MMD) who receive treatment with antiplatelet drugs reportedly show improvements in neuropsychological test scores after around 2 years. The purpose of the present study subanalyzing the same patient cohort used in a previous study was to determine which antiplatelet drug, clopidogrel or cilostazol, results in better improvement of cognitive function among non-surgical adult patients showing ischemic MMD without severe hemodynamic compromise.

METHODS

Sixty-six patients without cerebral misery perfusion on ¹⁵O gas positron emission tomography were treated with pharmacotherapy alone. Patients ≥50 years old and <50 years old initially received clopidogrel and cilostazol, respectively. Any patient suffering side effects of the antiplatelet drug switched to the other antiplatelet drug. Neuropsychological tests were performed at study entry and at the end of the 2-year follow-up, and differences in each neuropsychological test score between the two time points (second test score - first test score) were calculated and defined as Δ scores.

RESULTS

Among the five neuropsychological tests, Δ scores for two tests were significantly greater in patients treated with cilostazol (n = 36) than in those treated with clopidogrel (n = 30), and Δ scores of the remaining three tests did not differ between patient groups. Based on Δ scores, 15 patients (23%) were defined as showing interval cognitive improvement. On multivariate analysis, cilostazol administration (95% confidence interval, 1.19-193.98; P = 0.0361) represented an independent predictor of interval cognitive improvement.

CONCLUSIONS

Cilostazol may improve cognition better than clopidogrel in non-surgical adult patients with ischemic MMD.

Reduced Hypoxic Tissue and Cognitive Improvement after Revascularization Surgery for Chronic Cerebral Ischemia

BACKGROUND

Hypoxic but viable neural tissue is seen on 1-(2-18F-fluoro-1-[hydroxymethyl]ethoxy) methyl-2-nitroimidazole (18F-FRP170) positron emission tomography (PET) in patients with chronic cerebral ischemia with a combination of misery perfusion and moderately reduced oxygen metabolism. Cognitive function sometimes improves after revascularization surgery in patients with chronic cerebral ischemia.

OBJECTIVES

We used brain perfusion single-photon emission computed tomography (SPECT) and 18F-FRP170 PET to determine whether hypoxic tissue was reduced following the restoration of cerebral perfusion after carotid endarterectomy (CEA) in patients with severe stenosis of the cervical internal carotid artery (ICA) and whether the reduction in hypoxic tissue was associated with cognitive improvement.

METHOD

Eighteen patients with abnormally reduced cerebral blood flow (CBF) in the affected cerebral hemispheres on preoperative brain perfusion SPECT -underwent CEA. They underwent 18F-FRP170 PET and neuropsychological tests preoperatively and 6 months postoperatively. Brain perfusion SPECT was also performed 6 months postoperatively. Regions of interest were placed in the bilateral middle cerebral artery territories on SPECT and PET images, and the ratio of values in the affected versus contralateral hemispheres was calculated.

RESULTS

The CBF ratio (p = 0.0006) and 18F-FRP170 ratio (p = 0.0084) were significantly increased and reduced, respectively, after surgery compared to the corresponding ratios before surgery. The difference in the 18F-FRP170 ratio (postoperative - preoperative value) was negatively correlated with the difference in the CBF ratio (ρ = -0.695; p = 0.0009). The difference in the 18F-FRP170 ratio was significantly lower in patients with postoperative improved cognition compared to that in those without (p = 0.0007). The area under the receiver operating characteristics curve for the difference in the 18F-FRP170 ratio for detecting postoperative improved cognition was significantly greater than that for the difference in the CBF ratio (difference between areas, 0.278; p = 0.0248).

CONCLUSIONS

Hypoxic tissue is reduced following the restoration of cerebral perfusion with revascularization surgery in patients with severe atherosclerotic stenosis of the cervical ICA. The reduction in hypoxic tissue is associated with cognitive improvement in such patients.

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.

Failure to account for practice effects leads to clinical misinterpretation of cognitive outcome following carotid endarterectomy

Carotid endarterectomy (CEA) is a surgical procedure to remove stenotic atherosclerotic plaque from the origin of the carotid artery to reduce the risk of major stroke. Its impact on postoperative cognitive function (POCF) remains controversial; complicated, in part, by a traditional failure to account for practice effects incurred during consecutive psychometric testing. To address this for the first time, we performed psychometric testing (learning and memory, working memory, attention and information processing, and visuomotor coordination) in 15 male patients aged 68 ± 8 years with symptomatic carotid stenosis the day before and 24 h following elective CEA (two consecutive tests, 48 h apart). Multiple baselining was also performed in a separate cohort of 13 educationally, anthropometrically and age‐matched controls (63 ± 9 years) not undergoing revascularization at identical time points with additional measures performed over a further 96 h (four consecutive tests, each 48 h apart). A single consecutive test in the control group resulted in progressive improvements in learning and memory, working memory, and attention and information (P < 0.05 vs. Test 1), with three tests required before cognitive performance stabilized. Following correction for practice effects in the patient group, CEA was associated with a deterioration rather than an improvement in learning and memory as originally observed (P < 0.05). These findings highlight the potential for the clinical misinterpretation of POCF unless practice effects are taken into account and provide practical recommendations for implementation within the clinical setting.

Perceived Cognition after Percutaneous Coronary Intervention: Association with Quality of Life, Mood and Fatigue in the THORESCI Study

Purpose

Percutaneous coronary intervention (PCI) is a common invasive procedure for the treatment of coronary artery diseases. Long-term cognitive functioning after PCI and its association with health-related quality of life (HRQL) and psychological factors is relatively unknown. The aim of this study is to examine whether perceived cognitive functioning during the year after PCI is associated with HRQL over this time period, and whether mood, fatigue, and age are associated with changes in perceived cognition and HRQL.

Methods

Patients undergoing PCI (n = 384, 79% male, mean age = 63, SD = 10) were recruited in the observational Tilburg Health Outcome Registry of Emotional Stress after Coronary Intervention (THORESCI) cohort study. Perceived concentration and attention problems, HRQL, mood, and fatigue were assessed at baseline, at 1-month and 12-month follow-up.

Results

General linear mixed modeling analysis showed that across time, between- and within-subject differences in perceived concentration problems were associated with a reduced HRQL in all domains independent of clinical and demographic covariates. Only a part of this association could be explained by negative mood, fatigue, and older age. Similar findings were found for between-subject differences in perceived attention problems.

Conclusions

Between-subject differences and within-subject changes in perceived cognition in PCI patients were strongly associated with HRQL across time, such that poorer perceived cognition was associated with poorer HRQL, independent of demographic and clinical variables. Most of the associations were also independent of mood and fatigue. The results should increase the awareness of clinicians for the role of cognition in the cardiac rehabilitation and recovery post-PCI.

Which patients with asymptomatic carotid stenosis benefit from revascularization?

PURPOSE OF REVIEW

To summarize why there are polarized opinions regarding the management of patients with asymptomatic carotid disease and whether it is possible to identify patients who might benefit from carotid interventions.

RECENT FINDINGS

Carotid Revascularization Endarterectomy Versus Stenting Trial and Asymptomatic Carotid Trial 1 (ACT-1) recently concluded that outcomes after carotid endarterectomy and carotid stenting were not significantly different in asymptomatic patients and that procedural risks were below the accepted 3% threshold. However, systematic reviews suggest that Carotid Revascularization Endarterectomy Versus Stenting Trial/ACT-1 results may not be generalizable into routine practice. In parallel, meta-analyses suggest that stroke rates on medical therapy may be declining, suggesting that Asymptomatic Carotid Atherosclerosis Study/Asymptomatic Carotid Surgery Trial data, which have underpinned every practice guideline since 1995, are too historical for use in 2017. A recent review has, however, identified a number of clinical/imaging features that may be associated with higher rates of stroke on medical therapy.

SUMMARY

The majority of surgeons/interventionists are unlikely to accept radical changes in practice until new randomized trials confirm that the risk of stroke on modern medical therapy is significantly lower than that previously accepted. In the interim, it would be preferable to target interventions into a smaller cohort who present with clinical/imaging features that might render them 'higher risk for stroke' on medical therapy.

Carotid Stenosis and Impaired Cognition: The Effect of Intervention

There is a clear association between carotid artery stenosis and cognitive impairment. However, there is no consensus as to how to interpret this association, and what, if any, impact this connection should have on the management of carotid stenosis. A review of the relevant literature suggests that although an intervention to relieve carotid stenosis in patients without clinically significant cognitive impairment does not improve cognition, there may be a cognitive benefit with intervention for carotid stenosis in those patients with clinically significant cognitive disorders.

The Impact of Carotid Artery Stenting on Cerebral Perfusion, Functional Connectivity, and Cognition in Severe Asymptomatic Carotid Stenosis Patients

Background and purpose

Asymptomatic carotid artery stenosis can lead to not only stroke but also cognition impairment. Although it has been proven that carotid artery stenting (CAS) can reduce the risk of future strokes, the effect of CAS on cognition is conflicting. In recent years, pulsed arterial spin labeling (pASL) MRI and resting-state functional MRI (R-fMRI) have been employed in cognitive impairment studies. For the present study, cognition is evaluated in severe asymptomatic carotid artery stenosis patients undergoing CAS, and the mechanisms underlying the cognitive change are explored by pASL MRI and R-fMRI.

Materials and methods

We prospectively enrolled 24 asymptomatic, severe (≥70%), unilateral internal carotid artery stenosis patients, who were expecting the intervention of CAS. Cognition assessment (including the Montreal Cognitive Assessment Beijing Version, the Minimum Mental State Examination, the Digit Symbol Test, the Rey Auditory Verbal Learning Test, and the Verbal Memory Test) and an integrated MRI program (pASL MRI, and R-fMRI) were administered 7 days before and 3 months after CAS.

Results

16 subjects completed the follow-up study. After stenting, significant improvement in the scores of the MMSE, the Verbal Memory test, and the delayed recall was found. No significant difference was found in the scores of the Montreal Cognitive Assessment Beijing Version, the Digit Symbol Test, and the immediate recall. After CAS treatment, asymptomatic carotid artery stenosis patients showed increased perfusion in the left frontal gyrus, increased amplitude of low-frequency fluctuation (ALFF) in the right precentral gyrus, and increased connectivity to the posterior cingulate cortex (PCC) in the right supra frontal gyrus. However, no significant correlations were found between these imaging changes and cognition assessments.

Conclusion

Successful CAS can partly improve cognition in asymptomatic carotid artery stenosis patients. The cognition improvement may be partly attributed to the increased perfusion in the left frontal gyrus, increased ALFF in the right precentral gyrus, and increased connectivity to the PCC in the right supra frontal gyrus.

The urgent need for contemporary clinical trials in patients with asymptomatic carotid stenosis

Asymptomatic extracranial internal carotid artery atherosclerotic stenosis increases with age and is more common in men. Studies performed more than 2 decades ago showed that carotid endarterectomy reduced the rate of stroke in carefully selected patients with asymptomatic carotid stenosis compared with medical therapy in the long term. Those trials were completed more than 20 years ago and with advances in the treatment of atherosclerotic disease, the question has been raised to as to whether endarterectomy is still of value for patients with asymptomatic narrowing. Perioperative risk of carotid revascularization procedures has also declined. Due to improvements in both medical and surgical treatments for carotid artery stenosis, it is timely to reevaluate the efficacy of carotid intervention relative to medical treatment for patients with asymptomatic stenosis.

Atherosclerotic carotid stenosis and cognitive function

Atherosclerosis carotid stenosis is associated with stroke and cognitive impairment. Progressive cognitive decline may be an even greater problem than stroke, but it has not been widely recognized and therefore must be adequately addressed. Although both Carotid Endarterectomy (CEA) and Carotid Artery Stenting (CAS) have been proven can prevent future stroke in patients with atherosclerotic carotid stenosis, the influence of CEA and CAS on cognitive function is not clear. In the first part of this review, we evaluated the literature concerning carotid stenosis and the risk of cognitive impairment. Studies have suggested that both symptomatic and asymptomatic carotid stenosis are associated with cognitive impairment. In the second part, we reviewed the impact of CEA and CAS on cognitive function, some studies have shown benefits, but others have not.

Beneficial effects of intravenous dexmedetomidine on cognitive function and cerebral injury following a carotid endarterectomy

The present study aimed to investigate the effects of dexmedetomidine (DEX) on cognition following a carotid endarterectomy (CEA). In addition, the neuroprotective effects of DEX against ischemia-reperfusion injury during CEA were analyzed. Patients due to undergo elective CEA under general anesthesia were randomly assigned to either the DEX-treated group (group D; n=25) or the control group (group C; n=25). Patients in group D were treated with 0.3 µg/kg DEX pre-CEA, followed by 0.3 µg/kg/h DEX intraoperatively up to 30 min prior to the completion of surgery, and the patients in group C received an equal volume of normal saline. Cognitive function was assessed prior to CEA (T0), and at 24, 48, and 72 h, 7 days and 1 month post-surgery (T1-5, respectively), using the Mini-Mental State Examination (MMSE). Blood samples were drawn from the ipsilateral jugular bulb of all patients at 20 min prior to anesthesia (t0), and at 10 min following tracheal intubation, 15 min following clamping and unclamping of the carotid artery, and at 6 and 24 h postoperatively (t1-5, respectively). The protein expression levels of markers of cerebral ischemia and injury, namely S100 calcium-binding protein B (S100B) and neuron-specific enolase (NSE), and the concentration of the oxidative stress marker malondialdehyde (MDA), were analyzed. Patients in group D exhibited elevated MMSE scores at T2 and T3 post-CEA, as compared with group C. Furthermore, the protein expression level of S100B and the concentration of MDA in the jugular bulb of group D patients were markedly decreased compared with those in group C at t3-5 and t3, respectively. The results of the present study suggested that DEX was able to enhance the recovery of cognition following CEA, and this was associated with decreased cerebral damage and antioxidative effects.

Post-carotid endarterectomy changes in cerebral glucose metabolism on 18F-fluorodeoxyglucose positron emission tomography associated with postoperative improvement or impairment in cognitive function

OBJECT

Cognitive function is often improved or impaired after carotid endarterectomy (CEA) for patients with cerebral hemodynamic impairment. Cerebral glucose metabolism measured using positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) correlates with cognitive function in patients with neurodegenerative diseases. The present study aimed to determine whether postoperative changes in cerebral glucose metabolism are associated with cognitive changes after CEA.

METHODS

In patients who were scheduled to undergo CEA for ipsilateral internal carotid artery (ICA) stenosis (≥ 70% narrowing), cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were assessed preoperatively using brain perfusion single-photon emission computed tomography (SPECT). CBF measurement using SPECT was also performed immediately after CEA. For patients with reduced preoperative CVR to acetazolamide in the cerebral hemisphere ipsilateral to surgery, cerebral glucose metabolism was assessed using FDG-PET before surgery and 3 months after surgery and was analyzed using 3D stereotactic surface projection. Neuropsychological testing was also performed preoperatively and 3 months postoperatively.

RESULTS

Twenty-two patients with reduced preoperative CVR to acetazolamide successfully underwent FDG-PET studies and neuropsychological testing before and after CEA. Seven, 9, and 6 patients were defined as showing improved, unchanged, and impaired postoperative cognition, respectively, based on the neuropsychological assessments. The cortical area with increased postoperative glucose metabolism was greater in patients with improved postoperative cognition than in those with unchanged (p < 0.001) or impaired (p < 0.001) postoperative cognition. The cortical area with decreased postoperative glucose metabolism was greater in patients with impaired postoperative cognition than in those with improved (p < 0.001) or unchanged (p < 0.001) postoperative cognition. All 7 patients with improved cognition exhibited postoperative hemispheric increases in glucose metabolism, while 5 of the 6 patients with impaired cognition exhibited postoperative hemispheric decreases in glucose metabolism. Brain perfusion SPECT revealed that the latter 6 patients experienced postoperative cerebral hyperperfusion, and 2 of the 6 patients exhibited cerebral hyperperfusion syndrome. The cortical area with decreased postoperative glucose metabolism in these 2 patients was greater than that in other patients.

CONCLUSIONS

Postoperative changes in cerebral glucose metabolism, as measured using FDG-PET, are associated with cognitive improvement and impairment after CEA.

Comparison of Neurocognitive Outcomes after Carotid Endarterectomy and Carotid Artery Stenting

Cognitive and emotional outcomes after carotid endarterectomy (CEA) and carotid artery stenting with embolic protection device (CAS + EPD) are not clear. Patients were entered prospectively into a United States Food and Drug Administration-approved single-center physician-sponsored investigational device exemption between 2004 and 2010 and received either CEA or CAS + EPD. Patients underwent cognitive testing preprocedure and at 6, 12, and 60 months postprocedure. Cognitive domains assessed included attention, memory, executive, motor function, visual spatial functioning, language, and processing speed. Beck Depression and anxiety scales were also compared. There were a total of 38 patients that met conventional indications for carotid surgery (symptomatic with ≥50% stenosis or asymptomatic with ≥70% stenosis)—12 patients underwent CEA, whereas 26 patients underwent CAS + EPD. Both CEA and CAS + EPD patients showed postprocedure improvement in memory and executive function. No differences were seen at follow-up in regards to emotional dysfunction (depression and anxiety), attention, visual spatial functioning, language, motor function, and processing speed. Only two patients underwent neuropsychiatric testing at 60 months—these CAS + EPD patients showed sustained improvement in memory, visual spatial, and executive functions. In conclusion, cognitive and emotional outcomes were similar between CEA and CAS + EPD patients.