Prospective neurocognitive evaluation of patients undergoing carotid interventions

Asymptomatic Carotid Artery Stenosis, Cognitive Function, and the Impact of Carotid Revascularization: A Narrative Review

BACKGROUND

The association between asymptomatic carotid artery stenosis and impaired cognition, and the cognitive changes after revascularization remain active areas of interest in the field of carotid disease. This narrative review focuses on the association between carotid artery atherosclerosis and impaired cognitive function, proposed mechanisms, and the effects of carotid revascularization on cognition.

METHODS

A critical review of the literature to identify studies evaluating carotid artery stenosis, cognition, and carotid revascularization was performed using PubMed to query the MEDLINE database through March 2023.

RESULTS

Many studies demonstrate a link between carotid disease and cognitive impairment but direct evidence is lacking. Revascularization may offer cognitive benefits but the effect is likely subtle and affected by the choice of revascularization procedure.

CONCLUSIONS

Integrating cognitive outcomes into ongoing randomized controlled trials such as the nested CREST-H arm of the CREST-2 trial hold promise for offering new insight into the role of carotid artery stenosis and carotid revascularization on cognition.

New Ischemic Cerebral Lesions in Postprocedural Magnetic Resonance Imaging in Carotid Artery Stenting Versus Carotid Endarterectomy: A Systematic Review and Meta-Analysis

BACKGROUND

Recent randomized controlled trials (RCTs) have demonstrated similar outcomes in terms of ischemic stroke incidence after carotid endarterectomy (CEA) or carotid artery stenting (CAS) in asymptomatic carotid disease, while CEA seems to be the first option for symptomatic carotid disease. The aim of this meta-analysis is to assess the incidence of silent cerebral microembolization detected by magnetic resonance imaging (MRI) following these procedures.

METHODS

A systematic search was conducted using PubMed, Scopus, and Cochrane databases, including comparative studies involving symptomatic or asymptomatic patients undergoing either CEA or CAS and reporting on new cerebral ischemic lesions in postoperative MRI. The primary outcome was the newly detected cerebral ischemic lesions. Pooled effect estimates for all outcomes were calculated using the random-effects model. Prespecified random effects metaregression and subgroup analysis were conducted to examine the impact of moderator variables on the presence of new cerebral ischemic lesions.

RESULTS

25 studies reporting on a total of 1827 CEA and 1500 CAS interventions fulfilled the eligibility criteria. The incidence of new cerebral ischemic lesions was significantly lower after CEA compared to CAS, regardless of the time of MRI assessment (first 24 hours; OR: 0.33, 95% CI: 0.17-0.64, P < 0.001), (the first 72 hours, OR: 0.25, 95% CI 0.18-0.36, P < 0.001), (generally within a week after the operation; OR: 0.24, 95% CI: 0.17-0.34, P < 0.001). Also, the rate of stroke (OR: 0.38, 95% CI: 0.23-0.63, P < 0.001) and the presence of contralateral new cerebral ischemic lesions (OR: 0.16, 95% CI 0.08-0.32, P < 0.001) were less frequent after CEA. Subgroup analysis based on the study design and the use of embolic protection device during CAS showed consistently lower rates of new lesions after CEA.

CONCLUSIONS

CEA demonstrates significant lower rates of new silent cerebral microembolization, as detected by MRI in postoperative period compared with CAS.

Does Carotid Intervention Improve Cognitive Function?

Carotid artery disease has been linked to baseline cognitive impairment, even in asymptomatic patients. Therefore, there has been a persistent interest in investigating the impact of carotid revascularization on cognitive functions, but the results have been heterogeneous. Our recent prospective evaluation showed improved cognitive scores across multiple cognitive measures following carotid intervention. Herein, we summarize the studies published to date, identify the potential contributors to the inconsistency of post-interventional cognitive outcomes, and explore further opportunities in cognitive evaluations.

A multiple imputation-based sensitivity analysis approach for regression analysis with a missing not at random covariate

Missing covariate problems are common in biomedical and electrical medical record data studies while evaluating the relationship between a biomarker and certain clinical outcome, when biomarker data are not collected for all subjects. However, missingness mechanism is unverifiable based on observed data. If there is a suspicion of missing not at random (MNAR), researchers often perform sensitivity analysis to evaluate the impact of various missingness mechanisms. Under the selection modeling framework, we propose a sensitivity analysis approach with a standardized sensitivity parameter using a nonparametric multiple imputation strategy. The proposed approach requires fitting two working models to derive two predictive scores: one for predicting missing covariate values and the other for predicting missingness probabilities. For each missing covariate observation, the two predictive scores along with the pre-specified sensitivity parameter are used to define an imputing set. The proposed approach is expected to be robust against mis-specifications of the selection model and the sensitivity parameter since the selection model and the sensitivity parameter are not directly used to impute missing covariate values. A simulation study is conducted to study the performance of the proposed approach when MNAR is induced by Heckman's selection model. Simulation results show the proposed approach can produce plausible regression coefficient estimates. The proposed sensitivity analysis approach is also applied to evaluate the impact of MNAR on the relationship between post-operative outcomes and incomplete pre-operative Hemoglobin A1c level for patients who underwent carotid intervetion for advanced atherosclerotic disease.

Procedural embolic protection strategies for carotid artery stenting: current status and future prospects

INTRODUCTION

Carotid artery angioplasty and stenting (CAS) is an established procedure to treat carotid artery stenosis for either primary or secondary prevention of stroke. Randomized clinical trials have shown an increased risk of periprocedural cerebrovascular events with CAS compared with carotid endarterectomy (CEA). Several strategies have been proposed to mitigate this risk, including alternative vascular access site, proximal/distal embolic protection devices, and dual-layer stents, among others.

AREAS COVERED

This review provides a general overview of current embolic protection strategies for CAS. The phases of the procedure which can affect the early risk of stroke and how to reduce it with novel techniques and devices have been discussed.

EXPERT OPINION

Innovations in device technologies have dramatically improved the safety and efficacy of CAS. To minimize the gap with surgery, a thorough, patient-oriented approach should be pursued. Endovascular technologies and techniques should be selected on an individual basis to address unique lesion characteristics and vascular anatomies. Meticulous pre-procedural planning, both clinical and anatomical, is needed to assess the embolic risk of each procedure. Only by having an in-depth understanding of the wide range of available endovascular devices and techniques, the operator will choose the most appropriate strategy to optimize CAS results.

From surgical clamping to endovascular flow arrest/reversal: the concept behind the system

Carotid artery lesions are frequently composed of friable, thrombotic, ulcerated and/or hemorrhagic materials which can embolize during surgical or endovascular interventions. The use of embolic protection devices (EPD) during carotid angioplasty and stenting (CAS) has been proven to be associated with a reduction of the embolic load. Many studies indicate that the clinical results of CAS are comparable with the best surgical series, when EPD are routinely applied. The proximal EPD work by interrupting or reversing the blood flow in the common carotid artery/internal carotid artery (CCA/ICA). Once established the endovascular flow arrest/reversal, these systems have the advantages of promoting a protected crossing of the lesion and blocking both macro-emboli and micro-emboli. Moreover, proximal neuroprotection implies no manipulation of the device in the distal ICA, neither during device deployment nor during device retrieval, and reduces the risk of arterial spasm, dissection, or intimal damage. The choice between transfemoral and transcervical proximal EPD should account for different factors: local availability, operator expertise, and patient characteristics including anatomical features precluding flow arrest/reversal (e.g., incomplete circle of Willis), femoral access (e.g., unfavorable aortic arch anatomy), or transcervical access (e.g., diseased CCA).

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.

The restoring of interhemispheric brain connectivity following carotid endarterectomy: an exploratory observational study

This study aimed to evaluate the differences of brain connectivity between healthy subjects (HS) and patients with extracranial internal carotid artery (eICA) stenosis before and after carotid endarterectomy (CEA). An exploratory prospective study was designed. The study population consisted of a patient group (PG) of 20 patients with eICA stenosis eligible for CEA, and a control group (CG) of 20 HS, matched for age and sex. The subjects of the PG group underwent Magnetic Resonance Imaging (MRI) for resting-state functional connectivity MRI (rs-fc MRI) analysis within one week from the CEA (pre-CEA) and 12 months following CEA (post-CEA). The CG underwent a single MRI with the same protocol utilized for the PG. Three region-of-interest to region-of-interest (ROI-to-ROI) rs-fc MRI analyses were conducted: analysis 1 to compare pre-CEA PG and CG; analysis 2 to compare pre-CEA PG and post-CEA PG; analysis 3 to compare post-CEA PG and CG. The Functional Network Connectivity multivariate parametric technique was used for statistical analysis, adopting a p-uncorrected (p-unc) < 0.05 as connection threshold, and a cluster level False Discovery Rate corrected p (p-FDR) < 0.05 as cluster threshold. The clusters were defined by using a data-driven hierarchical clustering procedure. Analysis 1 revealed two clusters of reduced interhemispheric connectivity of pre-CEA PG when compared to CG. Analysis 2 and 3 showed no statistically significant differences. Our exploratory analysis suggests that patients with eICA stenosis have reduced interhemispheric connectivity when compared to a matched control group, and this difference was not evident anymore following endarterectomy.

Carotid revascularization improves cognitive function in patients with asymptomatic carotid artery stenosis

OBJECTIVE

To investigate cognitive changes after carotid revascularization in elderly patients with asymptomatic carotid artery stenosis. We also compared cognitive outcomes of carotid endarterectomy with stenting in asymptomatic patients.

METHODS

From April 2019 to December 2019, patients with ≥70% asymptomatic carotid stenosis who were treated with CEA or CAS were recruited for this study. The Montreal cognitive assessment (MoCA) instrument was used to evaluate cognitive function preoperatively and postoperatively at 3, 6, and 12 months. The incidence of ipsilateral ischemic cerebrovascular events and restenosis were analyzed within 12 months.

RESULTS

In 50 patients treated with CEA or CAS, baseline cognitive function was not different between CEA and CAS groups (P > 0.05). There was no difference in the incidence of ipsilateral ischemic cerebrovascular events and restenosis within the first 12 months between the two groups. There was a significant improvement in the total MoCA score, scores of attention, and delayed recall at 3, 6 and 12 months after revascularization compared with scores at baseline (all p<0.001). At 12 months, scores of cube copying and clock drawing were significantly improved (P=0.014, P=0.020). The clock drawing score was improved at 12 months after CAS compared with CEA (P=0.040).

CONCLUSIONS

Carotid revascularization has a beneficial effect on cognition in asymptomatic patients within 12 months of the procedure. Compared with CEA, CAS show improved test scores of executive functioning by 1 year.

Cognitive Sequelae of Silent Ischemic Lesions Following Carotid Artery Stenting: Possible Role of Age-Related Moderation

Background: The occurrence of ischemic lesions is common in patients receiving carotid artery stenting (CAS), and most of them are clinically silent. However, few studies have directly addressed the cognitive sequelae of these procedure-related silent ischemic lesions (SILs).

Objective: In this study, we attempted to investigate the effects of SILs on cognition using a comprehensive battery of neuropsychological tests.

Method: Eighty-five patients with unilateral carotid stenosis and 25 age-matched healthy volunteers participated in this study. Brain MRI was performed within 1 week before and 1 week after CAS to monitor the occurrence of post-CAS SILs. A comprehensive battery tapping reading ability, verbal and non-verbal memory, visuospatial function, manual dexterity, executive function, and processing speed was administered 1 week before and 6 months after CAS. To control for practice effects on repeated cognitive testing, the reliable change index (RCI) derived from the healthy volunteers was used to determine the cognitive changes in patients with carotid stenosis.

Results: Among the 85 patients with carotid stenosis, 21 patients received medical treatment (MED group), and procedure-related SILs were noted in 17 patients (SIL+ group) but not observed in 47 patients (SIL– group) after undergoing CAS. Two-way (group × phase) ANOVA revealed that the volunteer group showed improved scores in most cognitive tests while only limited improvement was noted in the SIL– group. The MED and control groups tended to show improvement in the follow-up cognitive testing than the SIL+ group. However, most of the cognitive changes for each patient group did not exceed the upper or lower limits (z = ±1.0) of the RCI.

Conclusions: Although the occurrence of procedure-related SILs is common in patients undergoing CAS, their impacts on cognitive changes after CAS may be limited. The practice effect should be taken into consideration when interpreting cognitive changes following CAS.

The effect of complex vascular anatomy on silent new ischemic cerebral lesions in carotid artery stenting procedures (from the COMPLEX-CAS Trial)

BACKGROUND

Carotid artery stenting is a minimally invasive, durable alternative treatment option, which is an alternative to the reference method, carotid endarterectomy, for patients with carotid artery stenosis; however, silent new ischemic cerebral lesions (SNICLs) after carotid artery stenting remain as a matter of concern. Hence, we aimed to assess the effect of complex vascular anatomy on silent new ischemic cerebral lesions in carotid artery stenting procedures.

METHODS

We prospectively evaluated 122 patients (mean age: 69.5 ± 7.1 years, male:83) who underwent carotid artery stenting for carotid artery revascularization. The patients having symptomatic transient ischemic attack or stroke after carotid artery stenting were excluded. The presence of a new hyperintense lesions on diffusion-weighted imaging without any neurological findings was considered as the SNICL. Patients were classified into two groups as DWI-positive and DWI-negative patients.

RESULTS

Among the study population, 32 patients (26.2%) had SNICLs. The DWI-positive group had a significantly higher common carotid artery (CCA)-internal carotid artery (ICA) angle, older age, more frequent history of stroke, a higher proportion of type III aortic arch, and longer fluoroscopy time than the DWI-negative group. High CCA-ICA angle was identified as one of the independent predictors of SNICL (OR (odds ratio) = 1.103 95%CI (confidence interval): (1.023-1.596); p = 0.034), and CCA-ICA angle higher than 34.5 degrees predicted SNICL with a sensitivity of 62.5% and a specificity of 62.2% (area under the curve: 0.680; 95% CI: 0.570 to 0.789; p = 0.003).

CONCLUSIONS

The higher CCA-ICA angle may predict pre-procedure SNICL risk in carotid artery stenting and may have clinical value in the management of patients with carotid artery stenosis.

The predictive value of CHADS2 score for subclinical cerebral ischemia after carotid artery stenting (from the PREVENT-CAS trial)

BACKGROUND

Carotid artery stenting (CAS) is being increasingly used as an alternative revascularization procedure to carotid endarterectomy; however, subclinical ischemic cerebral lesions after CAS remain as a matter of concern. Hence, we aimed to assess the clinical utility of the CHADS₂ score in predicting subclinical ischemic events after CAS.

METHODS

We prospectively evaluated 107 patients (mean age: 70.4 ± 6.6 years, male:77) who underwent CAS for carotid artery revascularization. The patients having symptomatic transient ischemic attack or stroke after CAS were excluded. The presence of new hyperintense lesion on diffusion-weighted imaging (DWI) without any neurological findings was considered as silent ischemia. Patients were classified into two groups as DWI-positive and DWI-negative patients.

RESULTS

Among study population, 28 patients (26.2%) had subclinical embolism. The DWI-positive group had a significantly higher CHADS2 scores, older age, more frequent history of stroke, higher proportion of type III aortic arch, and longer fluoroscopy time than the DWI-negative group. Increased CHADS₂ score was identified as one of the independent predictors of silent embolism (OR = 5.584; 95%CI: 1.516-20.566; p = .010), and CHADS₂ score higher than 2.5 predicted subclinical cerebral ischemia with a sensitivity of 72% and a specificity of 71% (AUC: 0.793; 95% CI: 0.696 - 0.890; p < .001).

CONCLUSIONS

CHADS₂ score was able to predict the risk of periprocedural subclinical ischemic events in CAS and might be of clinical value in the management of patients with carotid artery stenosis.

Correlation between Higher Brain Dysfunction and Cerebral Blood Flow after Carotid Artery Stenting

Objective

This study investigated the changes in higher brain function and cerebral blood flow (CBF) after carotid artery stenting (CAS), the relationship with CBF, and the impact of high intensities in diffusion-weighted imaging (DWI) after CAS.

Methods

We performed CAS between September 2017 and September 2019 in our department in 88 patients. Patients who did not undergo higher brain function tests according to our protocol or those who did not consent to participate in our study were excluded. This study targeted the 26 patients who were able to undergo the tests, including the Kana Pick-out Test (KPOT) II, three times: before, 1 week after, and 1-3 months after CAS. We investigated the chronological changes in higher brain function and their relationship with high intensity on DWI.

Results

The results of Symbol Digit Modalities Tests (SDMT) and KPOT I and II improved significantly. There was a significant correlation between the improvement of higher brain function and CBF in patients with stenosis exceeding 60%, a score of the Mini-Mental State Examination (MMSE) of 26 or less, and without other cause of higher brain dysfunction, including known dementia. High-intensity spots on DWI after CAS had no significant impact on higher brain function.

Conclusion

Higher brain function associated with attention and working memory improved significantly after CAS. There was a correlation between the improvement of higher brain function and CBF in patients with severe stenosis, mild cognitive impairment, and no known dementia. The prevention of subsequent ischemic attack and higher brain function should both be taken into account when performing CAS.

Carotid Revascularization Improves Cognition in Patients With Asymptomatic Carotid Artery Stenosis and Cognitive Decline. Greater Improvement in Younger Patients With More Disordered Neuropsychological Performance

OBJECTIVES

There has been a growing interest in whether carotid revascularization may reverse cognitive decline. In this study the aim was to assess cognitive changes after carotid artery endarterectomy and stenting, using neuropsychological assessment with MoCA and CANTAB test.

MATERIALS AND METHODS

Seventy patients with asymptomatic carotid artery stenosis, qualified for CEA (study group A) and CAS (study group B) have been prospectively assessed. 20 patients with lower extremity artery disease (control group C) and 15 patients qualified for inguinal hernia surgery (control group D) have served as a control group. Patients have been evaluated 1 day before surgery and 6 months after, using MoCA and CANTAB test. Logistic regression models were built to determine variables affecting cognitive performance.

RESULTS

After the procedure in the study group A the cognitive evaluation showed improvement in 5 cognitive domains tested in MoCA: visuospatial/executive (p=.0496), naming (p=.0831), language (p=.0009), abstraction (p=.0126) and delayed recall (p=.0016). In CANTAB there were improvement in PAL (p=.0290) and SWM (p=.0105). In study group B positive cognitive changes were seen in visuospatial/executive (p=.0827) and delayed recall (p=.0041) tested with MoCA and in PAL (PALFAMS28 p=.0315, PALNPR28 p=.0090, PALTEA28 p=.0058) and SWM (p=.0882) tested with CANTAB. Using a regression model, the only strong predictors of cognitive improvement on the follow-up visit were younger age and lower MoCA score on the first visit.

CONCLUSIONS

Carotid revascularization, both open and endovascular, lead to cognitive improvement in patients with severe carotid stenosis and cognitive decline. This effect seems to be stronger in younger patients with worst cognitive performance before surgery.

A multiple imputation-based sensitivity analysis approach for data subject to missing not at random

Missingness mechanism is in theory unverifiable based only on observed data. If there is a suspicion of missing not at random, researchers often perform a sensitivity analysis to evaluate the impact of various missingness mechanisms. In general, sensitivity analysis approaches require a full specification of the relationship between missing values and missingness probabilities. Such relationship can be specified based on a selection model, a pattern-mixture model or a shared parameter model. Under the selection modeling framework, we propose a sensitivity analysis approach using a nonparametric multiple imputation strategy. The proposed approach only requires specifying the correlation coefficient between missing values and selection (response) probabilities under a selection model. The correlation coefficient is a standardized measure and can be used as a natural sensitivity analysis parameter. The sensitivity analysis involves multiple imputations of missing values, yet the sensitivity parameter is only used to select imputing/donor sets. Hence, the proposed approach might be more robust against misspecifications of the sensitivity parameter. For illustration, the proposed approach is applied to incomplete measurements of level of preoperative Hemoglobin A1c, for patients who had high-grade carotid artery stenosisa and were scheduled for surgery. A simulation study is conducted to evaluate the performance of the proposed approach.

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.

WIRION™ embolic protection system for carotid artery stenting and lower extremity endovascular intervention

Aim: To summarize all available literature regarding the Wirion™ embolic protection system (EPS) and present examples from our center. Materials & methods: A review of literture was performed about the utilization of Wirion EPS. Results: One study was identified investigating the outcomes of Wirion during carotid artery stenting. The study demonstrated 98.3% procedural success with stroke occurring in only 2.5%. Two single arm studies were identified investigating the efficacy of the Wirion filter during lower extremity endovascular interventions. The reported device success ranged from 95.1 to 97.3%. Conclusion: While carotid artery stenting should always be performed with adjunctive EPS in order to decrease the risk of cerebrovascular accidents, the routine use of EPS in femorpopliteal interventions remains an active area of investigation.

Patient risk factors associated with embolic stroke volumes after revascularization

OBJECTIVE

Previous research has shown that subclinical, microembolic infarcts result in long-term cognitive changes. Whereas both carotid endarterectomy (CEA) and carotid artery stenting (CAS) have potential for microembolic events, CAS has been shown to have a larger volume of infarct. We have previously shown that large-volume infarction is associated with long-term memory deterioration. The purpose of this study was to identify independent risk factors that trend toward higher embolic volumes in both procedures.

METHODS

A total of 162 patients who underwent carotid revascularization procedures were prospectively recruited at two separate institutions. Preoperative and postoperative brain magnetic resonance images were compared to identify procedure-related microinfarcts. A novel semiautomated approach was used to define volumes of infarcts for each patient. Patient-related factors including comorbidities, symptomatic status, and medications were analyzed. Tweedie regression analysis was used to identify risk factors associated with procedure-related infarct volume. Variables with an unadjusted P value of ≤ .05 were included in the multivariate analysis.

RESULTS

There were 80 CAS and 82 CEA procedures performed and analyzed for the data set; 81% of CAS patients had procedure-related new infarcts with a mean volume of 388.15 ± 927.90 mm³ compared with 30% of CEA patients with a mean volume of 74.80 ± 225.52 mm³. In the CAS cohort, increasing age (adjusted coefficient ± standard error, 0.06 ± 0.02; P < .01) and obesity (1.14 ± 0.35; P < .01) were positively correlated with infarct volume, whereas antiplatelet use (-1.11 ± 0.33; P < .001) was negatively correlated with infarct volume. For the CEA group, diabetes (adjusted coefficient ± standard error, 1.69 ± 0.65; P < .01) was identified as the only risk factor positively correlated with infarct volume, whereas increasing age (-0.10 ± 0.05; P = .03) was negatively correlated with infarct volume.

CONCLUSIONS

Risk factors for CAS- or CEA-related infarct volumes are identified in our study. Although the result warrants further validation, this study showed that advanced age, obesity, and diabetes independently predicted volume of microinfarcts related to CAS and CEA. These data provide valuable information for patient factor-based risk stratification and preoperative consultation for each procedure.

Intravascular ultrasound-guided internal carotid artery stenting

AIM

The study was aimed at demonstrating efficacy and feasibility of intravascular ultrasound during internal carotid artery stenting for assessment of atheromatous plaque protrusion through a stent.

PATIENTS AND METHODS

Over the period from October to December 2018, the specialists of our Centre performed a total of 90 internal carotid artery stenting procedures in 83 patients (of these, 7 patients underwent bilateral staged stenting of both internal carotid arteries) using intravascular ultrasound in order to assess intraoperative protrusion of an atherosclerotic plaque through the implanted stent. The patients' age varied from 42 to 87 (mean 68.6±6.9) years. Symptomatic lesions of internal carotid arteries were revealed in 14 (16.9%) operated patients and asymptomatic lesions in 69 (83.1%). The degree of stenosis varied from 60% to 90% according to the findings of preliminary duplex ultrasonography and was subsequently confirmed by the results of multislice computed tomography or selective angiography. The assessment of the patients' neurological status, as well as duplex ultrasonography of brachiocephalic arteries were performed at a scheduled follow-up visit on day 30 after discharge from hospital.

RESULTS

The technical success of stenting was achieved in 100% of patients. According to the findings of intravascular ultrasound, plaque protrusion was observed in eight (8.8%) stented patients. Among them, six (6.6%) were free from angiographic signs of protrusion and only two (2.2%) had apparent angiographic signs of protrusion. During the early postoperative period, transient ischaemic attack was identified in four (4.4%) cases. One (1.1%) patient was found to develop ST-segment elevation acute myocardial infarction 24 hours after internal carotid artery stenting, followed by large hemispheric stroke on the side of stenting revealed on postoperative day 3. Nine (10%) patients according to the findings of intravascular ultrasound were diagnosed as having incomplete stent apposition after postdilatation, with the absence of such signs on angiography.

CONCLUSION

Intravascular ultrasound during carotid stenting provides a more accurate assessment of such an event as atherosclerotic plaque protrusion through a stent's cells. At the same time, IVUS-guided assessment of the intraoperative outcome may prevent the risk for the development of stroke in the early postoperative period. Besides, intravascular ultrasound allows a more detailed assessment of stent apposition and the degree of stent expansion in order to optimize and improve the remote results of the operation.

Optimization of a Novel Preferential Covered Stent through Bench Experiments and in Vitro Platelet Activation Studies

Bare metal stenting (BMS) does not adequately address the atheroembolic characteristic of carotid artery stenosis. While simple covered stents (CS) may prevent dislodged fragments of the atherosclerotic plaque from entering the blood stream, they also block blood flow into the major branches of the artery alongside the lesion, which is not desirable. Preferential covered stents (PCS) behave as a covered stent in a tubular part of a vessel but maintain side-branch flow over the bifurcation region by means of slits in the membrane. Stent design, membrane material, and slits configuration are the three main components contributing to stent performance. Optimization of PCS designs was conducted and tested.

METHODS

A newly designed BMS was developed and compared to a commercially available peripheral stent. Two materials (expanded poly(tetrafluoroethylene)) and silicone polyurethane co-polymers (Elast-eon E2A) were used as stent coverings with slits applied using various cutting methods to form the PCS. These PCS samples were tested for physical resilience, flexibility, ability to preserve side-branch flow, slit edge roughness, and platelet activation.

RESULTS

Fabrication of E2A-coated stents required pretreatment of the stent with poly(ethylene glycol) to achieve firm attachment. The newly designed BMS with nine crowns design and larger cell size showed higher flexibility than commercially available stents. A combination of a larger stent cell size, E2A membrane coating, and three slits per stent cell unit configuration resulted in preserved side-branch flow similar to physiological conditions in the flow experiment. Slit edge roughness changed with different cutting methods and laser machine cutting parameters. In vitro studies showed platelet activation was minimal with lower slit edge roughness samples.

CONCLUSION

An optimized PCS prototype was developed consisting of a newly designed stent, E2A membrane, and a three-slit pattern created by specific femtosecond laser cutting.

Cognitive improvement after carotid artery stenting in patients with symptomatic internal carotid artery near-occlusion

BACKGROUND AND PURPOSE

To investigate the influence of carotid artery stenting (CAS) with embolic protection device (EPD) on the cognitive function of patients with near-occlusion of the cervical internal carotid artery (ICA).

METHODS

From February 2014 to December 2017, a total of 79 symptomatic patients were recruited in this study. Of these patients, 31 patients refused to receive CAS therapy. They were divided into the CAS group (48 patients) and the medical treatment group (31 patients). Montreal cognitive assessment (MoCA) instrument was used for the evaluation of cognitive function. The analyzed endpoints included cumulative 12 month incidence of ipsilateral ischemic cerebrovascular events and MoCA scores at 1 month and 12 months after treatment.

RESULTS

Cumulative 12 months incidence of ipsilateral ischemic cerebrovascular events was lower in patients who underwent CAS than in patients on medical treatment (P < 0.05). In CAS group, the total MoCA score, scores of attention and delayed recall at months 1 and 12 increased when compared with those at baseline (P < 0.05). In medical treatment group, the total MoCA score and attention score at month 12 decreased when compared with those at baseline (P < 0.05). In CAS group, the total MoCA score, scores of line connection test, drawing clock, attention and delayed recall were improved at 1 and 12 months when compared with medical treatment at the same time points (P < 0.05).

CONCLUSIONS

CAS with EPD not only decreases the risk of ipsilateral TIA and stroke but also may improve the cognitive function of symptomatic patients with ICA near-occlusion.

Risk factors associated with microembolization after carotid intervention

BACKGROUND

Microembolization after carotid artery stenting (CAS) and carotid endarterectomy (CEA) has been documented and may confer risk for neurocognitive impairment. Patients undergoing stenting are known to be at higher risk for microembolization. In this prospective cohort study, we compare the microembolization rates for patients undergoing CAS and CEA and perioperative characteristics that may be associated with microembolization.

METHODS

Patients undergoing CAS and CEA were prospectively recruited under local institutional review board approval from an academic medical center. All patients also received 3T brain magnetic resonance imaging with a diffusion-weighted imaging sequence preoperatively and within 24 hours postoperatively to identify procedure-related new embolic lesions. Preoperative, postoperative, procedural factors, and plaque characteristics were collected. Factors were tested for statistical significance with logistic regression.

RESULTS

A total of 202 patients were enrolled in the study. There were 107 patients who underwent CAS and 95 underwent CEA. Patients undergoing CAS were more likely to have microemboli than patients undergoing CEA (78% vs 27%; P < .0001). For patients undergoing CAS, patency of the external carotid artery (odds ratio [OR], 11.4; 95% confidence interval [CI], 1.11-117.6; P = .04), lesion calcification (OR, 5.68; 95% CI, 1.12-28.79; P = .04), and lesion length (OR, 0.29; 95% CI, 0.08-1.01; P = .05) were all found to be independent risk factors for perioperative embolization. These factors did not confer increased risk to patients undergoing CEA.

CONCLUSIONS

Patients undergoing CAS are at higher risk for perioperative embolization. The risk for perioperative embolization is related to the length of the lesion and calcification. Identifying the preoperative risk factors may help to guide patient selection and, thereby, reduce embolization-related neurocognitive impairment.

Silent brain infarcts on diffusion-weighted imaging after carotid revascularisation: A surrogate outcome measure for procedural stroke? A systematic review and meta-analysis

Aim

To investigate whether lesions on diffusion-weighted imaging (DWI+) after carotid artery stenting (CAS) or endarterectomy (CEA) might provide a surrogate outcome measure for procedural stroke.

Materials and Methods

Systematic MedLine® database search with selection of all studies published up to the end of 2016 in which DWI scans were obtained before and within seven days after CAS or CEA. The correlation between the underlying log odds of stroke and of DWI+ across all treatment groups (i.e. CAS or CEA groups) from included studies was estimated using a bivariate random effects logistic regression model. Relative risks of DWI+ and stroke in studies comparing CAS vs. CEA were estimated using fixed-effect Mantel-Haenszel models.

Results

We included data of 4871 CAS and 2099 CEA procedures (85 studies). Across all treatment groups (CAS and CEA), the log odds for DWI+ was significantly associated with the log odds for clinically manifest stroke (correlation coefficient 0.61 (95% CI 0.27 to 0.87), p = 0.0012). Across all carotid artery stenting groups, the correlation coefficient was 0.19 (p = 0.074). There were too few CEA groups to reliably estimate a correlation coefficient in this subset alone. In 19 studies comparing CAS vs. CEA, the relative risks (95% confidence intervals) of DWI+ and stroke were 3.83 (3.17-4.63, p < 0.00001) and 2.38 (1.44-3.94, p = 0.0007), respectively.

Discussion

This systematic meta-analysis demonstrates a correlation between the occurrence of silent brain infarcts on diffusion-weighted imaging and the risk of clinically manifest stroke in carotid revascularisation procedures.

Conclusion

Our findings strengthen the evidence base for the use of DWI as a surrogate outcome measure for procedural stroke in carotid revascularisation procedures. Further randomised studies comparing treatment effects on DWI lesions and clinical stroke are needed to fully establish surrogacy.

Easily Screenable Characteristics Associated with Cognitive Improvement and Dysfunction After Carotid Endarterectomy

BACKGROUND

Carotid endarterectomy (CEA) is an effective treatment for the prevention of stroke in patients with carotid artery stenosis. We aimed to clarify the incidence and risk factors for early cognitive dysfunction (eCD) and early cognitive improvement (eCI), defined as change in cognitive performance ≤24 hours after surgery, using a battery of neuropsychometric tests.

METHODS

In total, 585 patients undergoing CEA were tested with neuropsychometric tests before and after surgery; 155 patients undergoing "simple" spine surgery were the reference group. Patient performance for each test was evaluated by z scores. Cognitive change was defined as eCD (or eCI) if: 1) patients had a z score ≤-2 (or ≥2) in ≥2 cognitive domains or 2) patients had mean z scores across all domains ≤-1.5 (or ≥1.5). Associations between the categorical cognitive outcomes and variables of interest were modeled using the proportional odds model.

RESULTS

Of the 585 subjects, 24% had eCD, 6% had eCI, and 70% had "no change." Patients who had eCD were more likely to be statin naïve (odds ratio [OR] 1.23 [1.03-1.48], P = 0.02) or women (OR 1.27 [1.06-1.53], P = 0.02). Those with eCI were less likely to have less formal education (OR 0.95 [0.90-1.00], P = 0.04) and less likely to have diabetes mellitus (OR 0.8 [0.65-0.99], P = 0.04).

CONCLUSIONS

Patients having CEA may develop eCD or eCI postoperatively. Medications likely to be associated with less eCD are statins and aspirin, which correlate most strongly in asymptomatic patients. In addition to confirming previous findings, we found that women were more likely than men to develop eCD. More sex-specific studies and analysis are needed to better explore these findings.

Convergence Analysis of Micro-Lesions (CAML): An approach to mapping of diffuse lesions from carotid revascularization

Carotid revascularization (endarterectomy, stenting) prevents stroke; however, procedure-related embolization is common and results in small brain lesions easily identified by diffusion weighted magnetic resonance imaging (DWI). A crucial barrier to understanding the clinical significance of these lesions has been the lack of a statistical approach to identify vulnerable brain areas. The problem is that the lesions are small, numerous, and non-overlapping. Here we address this problem with a new method, the Convergence Analysis of Micro-Lesions (CAML) technique, an extension of the Anatomic Likelihood Analysis (ALE). The method combines manual lesion tracing, constraints based on known lesion patterns, and convergence analysis to represent regions vulnerable to lesions as probabilistic brain atlases. Two studies were conducted over the course of 12 years in an active, vascular surgery clinic. An analysis in an initial group of 126 patients at 1.5 T MRI was cross-validated in a second group of 80 patients at 3T MRI. In CAML, lesions were manually defined and center points identified. Brains were aligned according to side of surgery since this factor powerfully determines lesion distribution. A convergence based analysis, was performed on each of these groups. Results indicated the most consistent region of vulnerability was in motor and premotor cortex regions. Smaller regions common to both groups included the dorsolateral prefrontal cortex and medial parietal regions. Vulnerability of motor cortex is consistent with previous work showing changes in hand dexterity associated with these procedures. The consistency of CAML also demonstrates the feasibility of this new approach to characterize small, diffuse, non-overlapping lesions in patients with multifocal pathologies.

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Convergence Analysis of Micro-Lesions technique finds patterns in diffuse lesions.

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Lesions from carotid revascularization affect consistent brain targets.

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Motor cortex is the most vulnerable brain region to these lesions.

Low carotid stump pressure as a predictor for ischemic symptoms and as a marker for compromised cerebral reserve in octogenarians undergoing carotid endarterectomy

BACKGROUND

Carotid artery occlusive disease can cause stroke by embolization, thrombosis, and hypoperfusion. The majority of strokes secondary to cervical carotid atherosclerosis are believed to be of embolic etiology. However, cerebral hypoperfusion could be an important factor in perioperative stroke. We retrospectively reviewed the stump pressure (SP) of carotid endarterectomy (CEA) of patients at Pennsylvania Hospital to identify whether physiologic perfusion differences account for differences in perioperative stroke rates, particularly in octogenarians.

METHODS

We conducted a retrospective review of our prospectively maintained database for CEA performed between 1992 and 2015. SP was measured and recorded for 1190 patients. A low SP was defined as systolic pressure <50 mm Hg. Shunts were used only for patients under general anesthesia with SP <50 mm Hg, for awake patients with neurologic changes with carotid clamping, and in some patients with recent stroke.

RESULTS

Symptomatic patients were more likely to have SP <50 mm Hg compared with asymptomatic patients (35.6% vs 26.2%; P = .0015). Patients having SP <50 mm Hg had a higher postoperative stroke rate compared with patients with SP >50 mm Hg (2.9% vs 0.9%; P = .0174). Octogenarians were more likely to have a lower SP compared with patients younger than 80 years (35.7% vs 27.7%; P = .0328). Symptomatic patients with low SP were at highest risk for perioperative stroke (6.4% vs 1.2%; P = .001) compared with patients without these factors.

CONCLUSIONS

SP is a marker for decreased cerebrovascular reserve and along with symptomatic status identifies those at highest risk for periprocedural stroke with CEA. Whereas patients older than 80 years may benefit from carotid intervention, they are likely to be at somewhat elevated stroke risk because of higher prevalence of low SP, and shunting does not eliminate this risk.

Proximal embolic protection versus distal filter protection versus combined protection in carotid artery stenting: A systematic review and meta-analysis

OBJECTIVE

Proximal embolic protection devices (P-EPD) and distal filters (DF) are used to prevent distal cerebral embolizations during carotid artery stenting (CAS). We compared their comparative effectiveness in regards to prevention of intraprocedural and periprocedural adverse events, including ischemic lesions (ipsilateral and contralateral), stroke, transient ischemic attacks (TIA) and death. We also compared the combination of the two neuroprotection strategies vs. a single strategy in regards to ischemic lesions and stroke.

MATERIALS & METHODS

This study was performed according to the PRISMA and MOOSE guidelines and eligible studies were identified through search of PubMed, Scopus and Cochrane Central. A meta-analysis was conducted with the use of a random effects model. The I-square statistic was used to assess for heterogeneity.

RESULTS

Twenty-nine studies involving 16,307 patients were included. There was a significant reduction in ischemic lesions with the use of P-EPD among observational studies (RR: 0.66 [0.45-0.97]). There were no statistically significant differences for the other outcomes between the two treatment groups.

CONCLUSIONS

There is a number of studies reporting outcomes on the comparison between P-EPD and DF for CAS. P-EDP can reduce distal embolization phenomena resulting into ischemic lesions when compared to DF based on the results from real-world studies. P-EPD was not superior however, in regards to periprocedural stroke, TIA and death. Further studies are anticipated to provide a clear answer to this debate.

Magnetic resonance imaging and clinical outcome in patients with symptomatic carotid artery stenosis after carotid artery revascularization

Introduction

About 30% of patients with carotid artery stenosis (CAS) develop dementia after a cerebral ischemic event (CIE), and 20–50% suffer from CIE recurrence during 6 months. Carotid artery revascularization (CAR) may prevent CIE recurrence, at the cost of new microembolic lesions (MES). The impact of CAR on cognitive function is debatable.

Aim

To assess functional and cognitive outcome, cerebral flow on transcranial Doppler (TCD) and brain magnetic resonance imaging (MRI) in patients with symptomatic CAS referred for CAR.

Material and methods

Twenty-two patients (aged 69.0 ±7.2 y.o., 15 male) with recent CIE (21.9 ±20.9 days to CAR) related to CAS of mean 89.8 ±3.9% lumen reduction were prospectively evaluated with TCD, diffusion and perfusion MRI, Montreal Cognitive Assessment (MoCA), Mini Mental State Examination (MMSE), modified Rankin Scale (mRS) and the National Institutes of Health Stroke Scale (NIHSS) 24 h before, at 24–48 h and 1 month following CAR.

Results

New MES were found in 11 (50%) subjects following CAR. CAR resulted in a significant increase of cerebral flow velocity in the middle and anterior cerebral arteries (p < 0.002 and p = 0.003; respectively) and cerebral perfusion measured by time to peak (TTP) and mean transit time (MTT) (p = 0.0009 and p = 0.0002; respectively). Neurologic tests showed improvement in NIHSS (2.4 ±1.6 to 1.5 ±1.2, p = 0.003), mRS (from 1.3 ±0.9 to 0.7 ±0.9, p = 0.005), and MMSE (26.7 ±2.2 to 27.6 ±2.3, p = 0.019) at 1 month, while similar MoCA scores were observed before and 1 month after CAR (23.4 ±3.3 vs. 24.1 ±3.7, p = 0.136).

Conclusions

Improvement of cerebral flow and perfusion and functional outcome, as well as at least no cognitive decline, is observed after CAR for symptomatic CAS.

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.

Asymptomatic Carotid Artery Stenosis: Revascularization

In patients with carotid stenosis, the most common cause of stroke is atheroembolization, and the risk is strongly related to stenosis severity and symptomatic status (stroke or transient ischemic attack within 6months). Carotid revascularization by carotid endarterectomy (CEA) or carotid artery stenting (CAS) results in plaque "passivation" by lumen enlargement, plaque removal, or plaque coverage with subsequent endothelialization. While there is considerable circumstantial evidence linking a decrease in the risk of stroke to the use of "optimal medical therapy (OMT)", the components of OMT have not been defined, and such therapy has not been rigorously evaluated in any randomized clinical trial (RCT) compared with revascularization. Studies of other vascular patients suggest that statins decrease the risk of stroke by anti-inflammatory effects, rather than cholesterol reduction. The Carotid Revascularization Endarterectomy versus Stent Trial (CREST-2) is currently randomizing standard-risk patients with asymptomatic severe carotid stenosis to OMT alone versus OMT plus CEA or CAS, but results are not expected until 2020. In the meantime, data from several "landmark" trials of CEA versus aspirin demonstrated 45-65% reduction in the 5-year risk of stroke after CEA. Several RCTs demonstrate superiority of CAS over CEA in high-risk patients (those at high-risk for CEA), and equivalence of CAS and CEA in standard-risk patients (those at acceptable risk for CEA). Compared with CEA, CAS is associated with significantly less periprocedural myocardial infarction, cranial nerve injury, and neurological injury (cranial nerve injury plus stroke); higher risk of minor stroke; and similar risk of long-term stroke. Features that increase the risk of CAS include complex aortic arch and carotid anatomy, and features that increase the risk of CEA include severe underlying cardiopulmonary disease and hostile neck anatomy; age>80years, especially those with baseline cognitive impairment, are at higher risk for stroke after CEA and CAS.

Volume of subclinical embolic infarct correlates to long-term cognitive changes after carotid revascularization

OBJECTIVE

Carotid intervention is safe and effective in stroke prevention in appropriately selected patients. Despite minimal neurologic complications, procedure-related subclinical microemboli are common and their cognitive effects are largely unknown. In this prospective longitudinal study, we sought to determine long-term cognitive effects of embolic infarcts.

METHODS

The study recruited 119 patients including 46% symptomatic patients who underwent carotid revascularization. Neuropsychological testing was administered preoperatively and at 1 month, 6 months, and 12 months postoperatively. Rey Auditory Verbal Learning Test (RAVLT) was the primary cognitive measure with parallel forms to avoid practice effect. All patients also received 3T brain magnetic resonance imaging with a diffusion-weighted imaging (DWI) sequence preoperatively and within 48 hours postoperatively to identify procedure-related new embolic lesions. Each DWI lesion was manually traced and input into a neuroimaging program to define volume. Embolic infarct volumes were correlated with cognitive measures. Regression models were used to identify relationships between infarct volumes and cognitive measures.

RESULTS

A total of 587 DWI lesions were identified on 3T magnetic resonance imaging in 81.7% of carotid artery stenting (CAS) and 36.4% of carotid endarterectomy patients with a total volume of 29,327 mm³. Among them, 54 DWI lesions were found in carotid endarterectomy patients and 533 in the CAS patients. Four patients had transient postoperative neurologic symptoms and one had a stroke. CAS was an independent predictor of embolic infarction (odds ratio, 6.6 [2.1-20.4]; P < .01) and infarct volume (P = .004). Diabetes and contralateral carotid severe stenosis or occlusion had a trend of positive association with infarct volume, whereas systolic blood pressure ≥140 mm Hg had a negative association (P = .1, .09, and .1, respectively). There was a trend of improved RAVLT scores overall after carotid revascularization. Significantly higher infarct volumes were observed among those with RAVLT decline. Within the CAS cohort, infarct volume was negatively correlated with short- and long-term RAVLT changes (P < .05).

CONCLUSIONS

Cognitive assessment of procedure-related subclinical microemboli is challenging. Volumes of embolic infarct correlate with long-term cognitive changes, suggesting that microembolization should be considered a surrogate measure for carotid disease management.

Microembolization is associated with transient cognitive decline in patients undergoing carotid interventions

OBJECTIVE

Carotid interventions are important in helping to reduce the risk of stroke for patients with high-grade carotid artery stenosis; however, subclinical cerebral microemboli can occur during these procedures. Associations have been found between the incidence of microemboli and postoperative decline in memory. We therefore sought to determine whether this decline persisted long-term and to assess changes in other cognitive domains.

METHODS

Patients were prospectively recruited under an Institutional Review Board-approved protocol at a single academic center. Neuropsychological testing was administered preoperatively and at 1-month and 6-month intervals postoperatively. Cognitive domains that were evaluated included verbal memory, visual memory, psychomotor speed, dexterity, and executive function. Diffusion-weighted magnetic resonance imaging sequencing was performed preoperatively and ≤48 hours postoperatively to identify procedure-related microemboli. Univariate and multivariate regression models were used to identify relationships among microembolization, demographics, and cognition.

RESULTS

Included were 80 male patients with an average age of 69 years. Forty patients underwent carotid artery stenting and 40 underwent carotid endarterectomy. Comorbidities included diabetes in 45%, coronary artery disease in 50%, and prior neurologic symptoms in 41%. New postoperative microemboli were found in 45 patients (56%). Microembolization was significantly more common in the carotid artery stenting cohort (P < .005). Univariate analysis demonstrated that patients with procedurally related embolization showed decline 1 month postoperatively in verbal memory and Trail Making A measures. Multivariate analysis demonstrated that procedurally related embolization (odds ratio [OR], 2.8; P = .04) and preoperative symptomatic stenosis (OR, 3.2; P = .026) were independent predictors of decline for the Rey Auditory Verbal Learning Test Short Delay measure at 1 month. At 6 months, no significant relationship was found between emboli and decline on Rey Auditory Verbal Learning Test Short Delay, but age (OR, 1.1, P = .005) and chronic obstructive pulmonary disease (OR, 7.1, P = .018) were significantly associated with decline at 6 months after the intervention.

CONCLUSIONS

Microembolization that is associated with carotid artery intervention predicts short-term cognitive decline. However, some of these cognitive deficits persist at 6 months after the intervention, and further investigation is warranted to determine individual patient risk factors that may affect recovery.

Intervention versus Aggressive Medical Therapy for Cognition in Severe Asymptomatic Carotid Stenosis

BACKGROUND AND PURPOSE

Asymptomatic carotid stenosis of ≥70% increases the incidence of microembolism and/or chronic hypoperfusion, which may consequently impair neurocognition and brain connections. We sought controlled evidence for any cognitive benefit of aggressive medical therapy and combined carotid revascularization.

MATERIALS AND METHODS

Patients with asymptomatic, unilateral, ≧70% stenosis of the extracranial ICA chose either aggressive medical therapy alone or in combination with carotid artery stent placement in this nonrandomized controlled study. They were examined with a battery of neuropsychological tests, structural MR imaging, DTI, and resting-state fMRI before and 3 months after treatment.

RESULTS

Forty patients were included with 15 in the medical group and 25 in the stent-placement group. Among them, 13 and 21 in the respective groups completed neuroimaging follow-up. The baseline characteristics and the changes in cognitive performance during 3 months showed no differences between treatment groups. Nevertheless, compared with the medical group, the stent-placement group showed subjective dizziness alleviation (P = .045) and a small increase in fractional anisotropy at the splenium of the corpus callosum and the posterior periventricular white matter ipsilateral to carotid artery stent placement. Moreover, only the stent-placement group showed interval improvement in immediate memory and visuospatial performance, which was accompanied by an increase of functional connectivity at the insular cortex of the dorsal attention network and the medial prefrontal cortex of the default mode network.

CONCLUSIONS

Both aggressive medical therapy alone and combined carotid revascularization in ≧70% asymptomatic carotid stenosis similarly preserved cognition during 3-month follow-up, though the latter had the potential for dizziness alleviation and cognitive and connectivity enhancement.

Proximal occlusion versus distal filter for cerebral protection during carotid stenting: updated meta-analysis of randomised and observational MRI studies

AIMS

Proximal occlusion (PO) and distal filter (DF) serve for cerebral embolic protection during carotid artery stenting (CAS). New cerebral lesions at diffusion-weighted magnetic resonance imaging (DW-MRI) represent a surrogate endpoint for embolisation, though their clinical impact is controversial. We performed a meta-analysis of randomised and observational DW-MRI studies comparing PO and DF during CAS.

METHODS AND RESULTS

We searched electronic scientific databases. The primary endpoint was the incidence of new cerebral lesions at DW-MRI; secondary endpoints were the incidence of new ipsilateral and new contralateral cerebral lesions at DW-MRI and death/cerebrovascular events (CVE). A total of 392 patients (seven studies) received CAS. At DW-MRI after 48 hours 178 patients (48.3%) presented new cerebral lesions. The use of PO versus DF reduced neither the risk of new cerebral lesions (OR [95% confidence interval] 0.65 [0.28-1.52], p=0.32) nor the risk of death/CVE (0.59 [0.22-1.60], p=0.30). Diabetes, baseline stenosis and symptoms significantly modified the risk estimates for new cerebral lesions.

CONCLUSIONS

In this meta-analysis, one half of patients receiving protected CAS developed new embolic cerebral lesions at DW-MRI, although the overwhelming majority were asymptomatic. Cerebral protection with PO versus DF neither reduced cerebral embolisation nor impacted on clinical outcomes.

Genetic Polymorphisms Influence Cognition in Patients Undergoing Carotid Interventions

While carotid interventions help decrease the risk of stroke, nearly 40% of patients experience cognitive deterioration. Genetic polymorphism in apolipoprotein E (ApoE) and brain-derived neurotrophic factor (BDNF) have been implicated in cognitive impairment; however, it is unclear whether they may influence cognitive changes in patients undergoing carotid intervention. In this study, we seek to assess the role of genetic polymorphisms in carotid intervention-related cognitive change. Polymorphisms related to cognitive function were chosen for this preliminary analysis. Over 2 years, patients undergoing carotid interventions were prospectively recruited. Patients underwent neuropsychological testing 2 weeks prior to and at 1 month following their procedure. Saliva samples were collected for genetic analysis. Logistic regressions were used to identify associations between polymorphisms and cognitive measures. A total of 91 patients were included; all were male with an average age of 70 years. The majority of patients exhibited hypertension (95%) and a history of smoking (81%). Presence of ApoE 4 allele was associated with depression (p= 0.047). After correcting for age and genetic polymorphisms in BDNF and serotonin transporter (5-HTT), ApoE 4 allele was associated with depression (p= 0.044) and showed a trend with baseline cognitive impairment (p= 0.10). Age ≥ 70 years was associated with baseline cognitive impairment after adjusting for the three genetic polymorphisms (p= 0.03). Patients with ApoE 4 and BDNF A polymorphisms performed less well on the visual and verbal memory measures, respectively. Polymorphisms in ApoE and BDNF may provide insight on cognition in patients undergoing carotid interventions; however, the mechanism of this relationship remains unclear.

Brain structural connectivity distinguishes patients at risk for cognitive decline after carotid interventions

While brain connectivity analyses have been demonstrated to identify ill patients for a number of diseases, their ability to predict cognitive impairment after brain injury is not well established. Traditional post brain injury models, such as stroke, are limited for this evaluation because pre-injury brain connectivity patterns are infrequently available. Patients with severe carotid stenosis, in contrast, often undergo non-emergent revascularization surgery, allowing the collection of pre and post-operative imaging, may experience brain insult due to perioperative thrombotic/embolic infarcts or hypoperfusion, and can suffer post-operative cognitive decline. We hypothesized that a distributed function such as memory would be more resilient in patients with brains demonstrating higher degrees of modularity. To test this hypothesis, we analyzed preoperative structural connectivity graphs (using T1 and DWI MRI) for 34 patients that underwent carotid intervention, and evaluated differences in graph metrics using the Brain Connectivity Toolbox. We found that patients with lower binary component number, binary community number and weighted community number prior to surgery were at greater risk for developing cognitive decline. These findings highlight the promise of brain connectivity analyses to predict cognitive decline following brain injury and serve as a clinical decision support tool. Hum Brain Mapp 37:2185-2194, 2016. © 2016 Wiley Periodicals, Inc.

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.

Utilization of Intravascular Ultrasound during Carotid Artery Stenting

For patients at high risk for surgery, carotid artery stenting (CAS) is a viable alternative to help reduce risk of stroke for patients with high-grade carotid artery stenosis; however, a higher incidence of perioperative stroke has been observed in patients undergoing stenting compared to those undergoing open surgery. Intravascular ultrasound (IVUS) is commonly used during coronary artery procedures to help evaluate lesions and to guide stent placement. Multiple groups have sought to determine whether IVUS could also be used during CAS. While IVUS has been shown to be both feasible and safe during CAS, there is limited evidence that demonstrates direct improvement in procedural outcomes. Further studies focusing on clinical outcomes should be conducted in order to justify routine use of this technology during CAS.

Effect of Carotid Artery Stenting on Cognitive Function in Patients with Internal Carotid Artery Stenosis and Cerebral Lacunar Infarction: A 3-Year Follow-Up Study in China

BACKGROUND AND OBJECTIVES

Carotid artery stenting (CAS) is an important therapeutic strategy for patients with carotid artery stenosis. However, the potential influence of CAS on cognitive function in patients with carotid artery stenosis and cerebral lacunar infarction has not been determined. This study investigated changes in cognitive function associated with CAS and the factors related to these changes.

METHODS

This prospective cohort study comprised 579 Chinese patients with cerebral lacunar infarction and carotid artery stenosis for whom CAS was indicated, and a matched control group of 552 healthy individuals. Cognitive function before CAS and at scheduled intervals from 6 months to 3 years was assessed with instruments that included the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scale. Potential factors that might affect cognitive function were analyzed via logistic regression.

RESULTS

The MMSE and MoCA scores of the patients before CAS were significantly lower than that of the control subjects. These scores were significantly higher 6 months after CAS and sustained or increased throughout the 3-year follow-up. Also significantly improved after CAS from baseline were scores for an alternating trail test, cube copying, clock-drawing, attention, and delayed recall in an auditory-verbal learning test. Logistic regression analyses showed that age greater than 65 y, little education, diabetes, and hypertension were independent risk factors for deteriorated MoCA scores 3 years after CAS.

CONCLUSION

CAS was associated with significantly improved cognitive function in cerebral lacunar infarction patients with severe stenosis.

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.

Influence of carotid artery stenting on cognition of elderly patients with severe stenosis of the internal carotid artery

Background

The aim of this study was to investigate the influence of carotid artery stenting (CAS) on the cognition and quality of life of elderly patients with severe stenosis of the internal carotid artery.

Material/Methods

65 elderly patients with symptomatic severe stenosis of internal carotid artery were recruited into 2 groups: the pharmacotherapy group (n=29) and the CAS group (n=36). Before surgery and 1, 3, 6, and 12 months after surgery, Montreal cognitive assessment (MoCA) was used for the evaluation of cognition and WHOQOL-BREF was used for the assessment of quality of life.

Results

At 12 months after surgery, total MoCA score and WHOQOL-BREF score in the pharmacotherapy group was significantly reduced when compared with those before surgery (P<0.05). In the CAS group, the total MoCA score, scores of attention and delayed recall, and WHOQOL-BREF score increased significantly at different time points after surgery when compared with those before surgery (P<0.05). Moreover, in CAS group, the MoCA score and WHOQOL-BREF markedly increased gradually over time (P<0.05). Compared with the pharmacotherapy group, cognition and quality of life in the CAS group were improved dramatically during the follow-up period (P<0.05).

Conclusions

Severe stenosis of the internal carotid artery is a cause of cognition impairment, and CAS may improve cognition and quality of life.

Intravascular ultrasound as a clinical adjunct for carotid plaque characterization

OBJECTIVE

Virtual histology intravascular ultrasound (VH IVUS) is valuable for estimating minimal lumen diameter and plaque characterization. The clinical use of IVUS in carotid intervention is not well characterized. We aim to evaluate the role of IVUS in carotid plaque characterization and determine whether it could be predictive of procedure-related microemboli.

METHODS

From July 2010, patients with severe carotid stenosis who underwent elective carotid stenting procedures were prospectively enrolled. IVUS evaluation was performed before stent placement. Patient demographics, comorbidities, and preoperative images were recorded. Comparison of pre- and postoperative diffusion-weighted magnetic resonance images was used to identify the number of procedure-related microemboli. IVUS-derived minimal lumen diameter and vessel wall plaque characteristics were collected. Univariate and multivariate logistic regressions were used to search for associations between IVUS-derived VH data and incidence of microemboli.

RESULTS

A total of 38 high-risk patients receiving carotid stenting were enrolled. Among them, 25 patients had type I aortic arches and 17 of the patients were symptomatic (preoperative stroke or transient ischemic attack). VH IVUS data did not show strong associations with microemboli, however, a trend was found between the area of fibrous tissue and median or more incidence of microemboli (P = .099). IVUS-defined vessel diameter maximum was associated with median or more incidence of microemboli (P = .042). In addition, median or more incidence of microemboli showed trends with proximal common carotid artery calcification (P = .056) and with being over the age of 80 (P = .06). Contralateral carotid occlusion or high-grade stenosis was associated with postoperative contralateral microemboli (P = .036).

CONCLUSIONS

We demonstrate that periprocedural carotid IVUS is clinically feasible. VH IVUS may be helpful in better understanding plaque morphology and determining optimal stent placement. However, its use in predicting microembolization remains limited.

The impact of carotid revascularization on cognitive function

The concept that carotid disease may compromise cognitive function was initially proposed by Fisher in 1951, based on an autopsy case. However, some topics involving cognitive function remain controversial, such as its correlation with carotid obstructive disease. So, the authors of this review evaluate the impact of carotid revascularization on cognitive function and the repercussions of the revascularization technique (carotid stenting vs. endarterectomy) chosen. It was clear from the literature reviewed that carotid stenosis is related to a decline in cognitive function over time. However, controversy still remains over the impact of carotid revascularization on cognitive function. With elation to the technique employed (carotid stenting vs. endarterectomy), the majority of studies found no difference between the two techniques in terms of overall cognitive outcome.

Influence of cognitive impairment on the management of ischaemic stroke

BACKGROUND

Because of ageing of the population, it is more and more frequent to treat ischaemic stroke patients with pre-stroke cognitive impairment (PSCI). Currently, there is no specific recommendation on ischaemic stroke management in these patients, both at the acute stage and in secondary prevention. However, these patients are less likely to receive treatments proven effective in randomised controlled trials, even in the absence of contra-indication.

OBJECTIVE

To review the literature to assess efficacy and safety of validated therapies for acute ischaemic stroke and secondary prevention in PSCI patients.

RESULTS

Most randomised trials did not take into account the pre-stroke cognitive status. The few observational studies conducted at the acute stage or in secondary prevention, did not provide any information that the benefit could be either lost or replaced by harm in the presence of PSCI.

CONCLUSIONS

There is no reason not to treat ischaemic stroke patients with PSCI according to the currently available recommendations for acute management and secondary prevention. Further observational studies are needed and pre-stroke cognition should be taken into account in future stroke trials.