Recent advances and controversial issues in the optimal management of asymptomatic carotid stenosis.

OBJECTIVE: The optimal management of patients with asymptomatic carotid stenosis (AsxCS) is enduringly controversial. We updated our 2021 Expert Review and Position Statement, focusing on recent advances in the diagnosis and management of patients with AsxCS. METHODS: A systematic review of the literature was performed up to August 1, 2023, using PubMed/PubMed Central, EMBASE and Scopus. The following keywords were used in various combinations: "asymptomatic carotid stenosis," "carotid endarterectomy" (CEA), "carotid artery stenting" (CAS), and "transcarotid artery revascularization" (TCAR). Areas covered included (i) improvements in best medical treatment (BMT) for patients with AsxCS and declining stroke risk, (ii) technological advances in surgical/endovascular skills/techniques and outcomes, (iii) risk factors, clinical/imaging characteristics and risk prediction models for the identification of high-risk AsxCS patient subgroups, and (iv) the association between cognitive dysfunction and AsxCS. RESULTS: BMT is essential for all patients with AsxCS, regardless of whether they will eventually be offered CEA, CAS, or TCAR. Specific patient subgroups at high risk for stroke despite BMT should be considered for a carotid revascularization procedure. These patients include those with severe (≥80%) AsxCS, transcranial Doppler-detected microemboli, plaque echolucency on Duplex ultrasound examination, silent infarcts on brain computed tomography or magnetic resonance angiography scans, decreased cerebrovascular reserve, increased size of juxtaluminal hypoechoic area, AsxCS progression, carotid plaque ulceration, and intraplaque hemorrhage. Treatment of patients with AsxCS should be individualized, taking into consideration individual patient preferences and needs, clinical and imaging characteristics, and cultural, ethnic, and social factors. Solid evidence supporting or refuting an association between AsxCS and cognitive dysfunction is lacking. CONCLUSIONS: The optimal management of patients with AsxCS should include BMT for all individuals and a prophylactic carotid revascularization procedure (CEA, CAS, or TCAR) for some asymptomatic patient subgroups, additionally taking into consideration individual patient needs and preference, clinical and imaging characteristics, social and cultural factors, and the available stroke risk prediction models. Future studies should investigate the association between AsxCS with cognitive function and the role of carotid revascularization procedures in the progression or reversal of cognitive dysfunction.

An international, multispecialty, expert-based Delphi Consensus document on controversial issues in the management of patients with asymptomatic and symptomatic carotid stenosis.

OBJECTIVE: Despite the publication of various national/international guidelines, several questions concerning the management of patients with asymptomatic (AsxCS) and symptomatic (SxCS) carotid stenosis remain unanswered. The aim of this international, multi-specialty, expert-based Delphi Consensus document was to address these issues to help clinicians make decisions when guidelines are unclear. METHODS: Fourteen controversial topics were identified. A three-round Delphi Consensus process was performed including 61 experts. The aim of Round 1 was to investigate the differing views and opinions regarding these unresolved topics. In Round 2, clarifications were asked from each participant. In Round 3, the questionnaire was resent to all participants for their final vote. Consensus was reached when ≥75% of experts agreed on a specific response. RESULTS: Most experts agreed that: (1) the current periprocedural/in-hospital stroke/death thresholds for performing a carotid intervention should be lowered from 6% to 4% in patients with SxCS and from 3% to 2% in patients with AsxCS; (2) the time threshold for a patient being considered "recently symptomatic" should be reduced from the current definition of "6 months" to 3 months or less; (3) 80% to 99% AsxCS carries a higher risk of stroke compared with 60% to 79% AsxCS; (4) factors beyond the grade of stenosis and symptoms should be added to the indications for revascularization in AsxCS patients (eg, plaque features of vulnerability and silent infarctions on brain computed tomography scans); and (5) shunting should be used selectively, rather than always or never. Consensus could not be reached on the remaining topics due to conflicting, inadequate, or controversial evidence. CONCLUSIONS: The present international, multi-specialty expert-based Delphi Consensus document attempted to provide responses to several unanswered/unresolved issues. However, consensus could not be achieved on some topics, highlighting areas requiring future research.

Optimal Management of Asymptomatic Carotid Stenosis in 2021: The Jury is Still Out. An International, Multispecialty, Expert Review and Position Statement.

OBJECTIVES: The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement is to reconcile the conflicting views on the topic. MATERIALS AND METHODS: A literature review was performed with a focus on data from recent studies. RESULTS: Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients < 75 years and microembolic signals on transcranial Doppler. There is growing evidence that 80-99% ACS indicate a higher stroke risk than 50-79% stenoses. CONCLUSIONS: Although aggressive risk factor control and BMT should be implemented in all ACS patients, several high-risk features that may increase the risk of a future cerebrovascular event are now documented. Consequently, some guidelines recommend a prophylactic carotid intervention in high-risk patients to prevent future cerebrovascular events. Until the results of the much-anticipated randomized controlled trials emerge, the jury is still out regarding the optimal management of ACS patients.

In situ bypass and extra-anatomic bypass procedures result in similar survival in patients with secondary aortoenteric fistulas.

OBJECTIVE: The optimal revascularization modality in secondary aortoenteric fistula (SAEF) remains unclear in the literature. The purpose of this investigation was to determine the revascularization approach associated with the lowest morbidity and mortality using real-world data in patients with SAEF. METHODS: A retrospective, multi-institutional study of SAEF from 2002 to 2014 was performed using a standardized database. Baseline demographics, comorbidities, and operative and postoperative variables were recorded. The primary outcome was long-term mortality. Descriptive statistics, Kaplan-Meier survival analysis, and univariate and multivariate analyses were performed. RESULTS: During the study period, 182 patients at 34 institutions from 11 countries presented with SAEF (median age, 72 years; 79% male). The initial aortic procedures that resulted in SAEF were 138 surgical grafts (76%) and 42 endografts (23%), with 2 unknown; 102 of the SAEFs (56%) underwent complete excision of infected aortic graft material, followed by in situ (in-line) bypass (ISB), including antibiotic-soaked prosthetic graft (53), autogenous femoral vein (neoaortoiliac surgery; 17), cryopreserved allograft (28), and untreated prosthetic grafts (4). There were 80 patients (44%) who underwent extra-anatomic bypass (EAB) with infected graft excision. Overall median Kaplan-Meier estimated survival was 319 days (interquartile range, 20-2410 days). Stratified by EAB vs ISB, there was no significant difference in Kaplan-Meier estimated survival (P = .82). In comparing EAB vs ISB, EAB patients were older (74 vs 70 years; P = .01), had less operative hemorrhage (1200 mL vs 2000 mL; P = .04), were more likely to initiate dialysis within 30 days postoperatively (15% vs 5%; P = .02), and were less likely to experience aorta-related hemorrhage within 30 days postoperatively (3% aortic stump dehiscence vs 11% anastomotic rupture; P = .03). There were otherwise no significant differences in presentation, comorbidities, and intraoperative or postoperative variables. Multivariable Cox regression showed that the duration of antibiotic use (hazard ratio, 0.92; 95% confidence interval, 0.86-0.98; P = .01) and rifampin use at time of discharge (hazard ratio, 0.20; 95% confidence interval, 0.05-0.86; P = .03) independently decreased mortality. CONCLUSIONS: These data suggest that ISB does not offer a survival advantage compared with EAB and does not decrease the risk of postoperative aorta-related hemorrhage. After repair, <50% of SAEF patients survive 10 months. Each week of antibiotic use decreases mortality by 8%. Further study with risk modeling is imperative for this population.

Contemporary Outcomes After Partial Resection of Infected Aortic Grafts.

INTRODUCTION: Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection. METHODS: A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002 to 2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed. RESULTS: One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%. The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (P = 0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; P = 0.01) as well as aortoenteric fistula (HR 1.9, P = 0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, P = 0.04), as well as those with American Society of Anesthesiologists classification less than 3 (HR 0.35, P = 0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs. 60 years, P = 0.01) and less likely to have patent repairs during follow up (59% vs. 32%, P = 0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs. 29%, P < 0.01) CONCLUSION: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material.

New predictors of complications in carotid body tumor resection.

OBJECTIVE: This study examined the relationship between two new variables, tumor distance to base of skull (DTBOS) and tumor volume, with complications of carotid body tumor (CBT) resection, including bleeding and cranial nerve injury. METHODS: Patients who underwent CBT resection between 2004 and 2014 were studied using a standardized, multi-institutional database. Demographic, perioperative, and outcomes data were collected. CBT measurements were determined from computed tomography, magnetic resonance imaging, and ultrasound examination. RESULTS: There were 356 CBTs resected in 332 patients (mean age, 51 years; 72% female); 32% were classified as Shamblin I, 43% as Shamblin II, and 23% as Shamblin III. The mean DTBOS was 3.3 cm (standard deviation [SD], 2.1; range, 0-10), and the mean tumor volume was 209.7 cm3 (SD, 266.7; range, 1.1-1642.0 cm3). The mean estimated blood loss (EBL) was 257 mL (SD, 426; range, 0-3500 mL). Twenty-four percent of patients had cranial nerve injuries. The most common cranial nerves injured were the hypoglossal (10%), vagus (11%), and superior laryngeal (5%) nerves. Both Shamblin grade and DTBOS were statistically significantly correlated with EBL of surgery and cranial nerve injuries, whereas tumor volume was statistically significantly correlated with EBL. The logistic model for predicting blood loss and cranial nerve injury with all three variables-Shamblin, DTBOS, and volume (R2 = 0.171, 0.221, respectively)-was superior to a model with Shamblin alone (R2 = 0.043, 0.091, respectively). After adjusting for Shamblin grade and volume, every 1-cm decrease in DTBOS was associated with 1.8 times increase in risk of >250 mL of blood loss (95% confidence interval, 1.25-2.55) and 1.5 times increased risk of cranial nerve injury (95% confidence interval, 1.19-1.92). CONCLUSIONS: This large study of CBTs demonstrates the value of preoperatively determining tumor dimensions and how far the tumor is located from the base of the skull. DTBOS and tumor volume, when used in combination with the Shamblin grade, better predict bleeding and cranial nerve injury risk. Furthermore, surgical resection before expansion toward the base of the skull reduces complications as every 1-cm decrease in the distance to the skull base results in 1.8 times increase in >250 mL of blood loss and 1.5 times increased risk of cranial nerve injury.

Changes in Arterial Stiffness and N-terminal pro-brain natriuretic peptide Levels after Endovascular Repair of Descending Thoracic Aorta.

BACKGROUND: Limited data exist concerning the biomechanical and central hemodynamic changes induced by endograft implantation in the descending thoracic aorta. The aim of this prospective ongoing study was to evaluate changes in arterial stiffness, assessed by pulse wave velocity (PWV; m/sec), and N-terminal pro-brain natriuretic peptide (NT-proBNP; pg/mL) levels in patients undergoing endovascular repair of descending thoracic aorta (thoracic endovascular aortic repair [TEVAR]). METHODS: Twenty-seven patients with thoracic aorta pathology who underwent elective TEVAR were included in the study. Blood samples were obtained preoperatively, 24 hr, 48 hr, and 6 months postoperatively, and serum levels of NT-proBNP were measured. PWV was determined before and 6 months after TEVAR. One-way analysis of variance by ranks was used to test the alterations in PWV (from baseline to 6 months) and NT-proBNP (along the 4 phases of evaluation). Post hoc analyses were appropriately performed. RESULTS: We recorded an increase in values of NT-proBNP from baseline (median = 96.1, interquartile range [IQR] = 82.7-117.9) to 24 hr postoperative (median = 201.6, IQR = 82.8-425.9), 48 hr postoperative (median = 317.0, IQR = 102.5-1,479.5), and 6 months postoperative (median = 144, IQR = 82.8-276.4). The Kruskal-Wallis H test showed a statistically significant increase (x2(3) = 11.17, P = 0.01) in NT-proBNP from baseline (rank mean = 22.19) toward the postoperative time points of evaluation (24 hr postoperative: 35.17 [change: +12.9, P = 0.02]; 48 hr postoperative: 42.64 [change: +20.5, P < 0.001]; 6 month postoperative: 34.91 [change: +12.7, P = 0.03]). An increase in PWV values was recorded from baseline (median = 11.9, IQR = 10.0-13.5) to 6 months postoperatively (median = 13.9, IQR = 11.9-16.4). That change achieved statistically significant level [x2(1) = 4.86, P = 0.03], with an increase in mean rank PWV (+7.5). CONCLUSIONS: Implementation of thoracic stent grafts may be associated with considerable increase of both arterial stiffness and NT-proBNP serum levels along time. Those results may indicate an adverse cardiac impact of TEVAR. However, the early and long-term effects of TEVAR on cardiovascular outcomes require further investigation.

The Profile of Circulating Matrix Metalloproteinases in Patients Undergoing Lower Limb Endovascular Interventions for Peripheral Arterial Disease.

BACKGROUND: Matrix metalloproteinases (MMPs) play a significant role in the development and progression of atherosclerotic vascular disease. We aimed to document the profile of circulating MMPs in peripheral arterial disease (PAD) patients undergoing lower limb endovascular revascularization. METHODS: A total of 46 patients (37 male; mean age 66 ± 11 years) undergoing elective lower limb percutaneous revascularization (angioplasty/stent) for symptomatic PAD were recruited from 2 vascular centers. Exclusion criteria were: acute limb ischemia, active infection and/or wet gangrene, liver disease, end-stage renal disease, and cancer. Patients having open revascularization or hybrid (open combined with endovascular) procedures were also excluded. Peripheral venous blood samples were taken on admission and 24 hrs after the procedure. Levels of MMP-2, MMP-3, MMP-7, and MMP-9 were measured along with tissue inhibitors of MMPs (TIMPs) 1 and 2. RESULTS: Compared to baseline values, there was a significant elevation in serum MMP-3 (P = 0.014) and MMP-7 (P = 0.008) levels, whereas serum MMP-9 showed a nonsignificant trend to increase (P = 0.169). On the other hand, no significant alterations were found 24 hrs after angioplasty/stenting with regard to the MMP-2 level and TIMP-1 and 2 levels. CONCLUSIONS: This study documented the periprocedural profile of circulating MMPs in patients undergoing angioplasty/stenting for PAD. The implications of increased MMP-3 and MMP-7 activity after peripheral endovascular interventions and their potential clinical relevance require further investigation.

Endovascular treatment of mycotic aortic aneurysms: a European multicenter study.

BACKGROUND: Mycotic aortic aneurysm (MAA) is a rare and life-threatening disease. The aim of this European multicenter collaboration was to study the durability of endovascular aortic repair (EVAR) of MAA, by assessing late infection-related complications and long-term survival. METHODS AND RESULTS: All EVAR treated MAAs, between 1999 and 2013 at 16 European centers, were retrospectively reviewed. One hundred twenty-three patients with 130 MAAs were identified. Mean age was 69 years (range 39-86), 87 (71%) were men, 58 (47%) had immunodeficiency, and 47 (38%) presented with rupture. Anatomic locations were ascending/arch (n=4), descending (n=34), paravisceral (n=15), infrarenal aorta (n=63), and multiple (n=7). Treatments were thoracic EVAR (n=43), fenestrated/branched EVAR (n=9), and infrarenal EVAR (n=71). Antibiotic was administered for mean 30 weeks. Mean follow-up was 35 months (range 1 week to 149 months). Six patients (5%) were converted to open repair during follow-up. Survival was 91% (95% confidence interval, 86% to 96%), 75% (67% to 83%), 55% (44% to 66%), and 41% (28% to 54%) after 1, 12, 60, and 120 months, respectively. Infection-related death occurred in 23 patients (19%), 9 after discontinuation of antibiotic treatment. A Cox regression analysis demonstrated non-Salmonella-positive culture as predictors for late infection-related death. CONCLUSIONS: Endovascular treatment of MAA is feasible and for most patients a durable treatment option. Late infections do occur, are often lethal, and warrant long-term antibiotic treatment and follow-up. Patients with non-Salmonella-positive blood cultures were more likely to die from late infection.

Inflammatory response and renal function following endovascular repair of the descending thoracic aorta.

PURPOSE: To evaluate inflammatory response and renal function after thoracic endovascular aortic repair (TEVAR) of lesions in the descending thoracic aorta. METHODS: Thirty-two consecutive patients treated with TEVAR from January 2010 to August 2013 were enrolled in this prospective study. Two were excluded owing to dissecting thoracic aortic aneurysm (TAA) extending into the renal arteries with renal failure in one and a saccular TAA in which a multilayer flow-modulating stent was implanted in the other. This left 30 patients (28 men; mean age 68.8±5.9 years) with 28 TAAs, an aortic dissection, and an aortic ulcer for the analysis. Temperature and serum levels of white blood cells (WBCs), C-reactive protein (CRP), interleukin-10 (IL-10), IL-6, IL-8, tumor necrosis factor-alpha (TNF-α), creatinine, urea, and cystatin C were measured preoperatively and at 24 and 48 hours postoperatively. RESULTS: Statistically significant increases in temperature and serum levels of WBCs, CRP, IL-10, and IL-6 were observed 24 and 48 hours postoperatively compared to baseline (all p<0.05). The number of endografts and the coverage of the celiac or subclavian artery did not affect the magnitude of the inflammatory response. No significant differences were observed concerning serum levels of IL-8, TNF-α, creatinine, or cystatin C from baseline to 24 or 48 hours postoperatively. CONCLUSION: Endograft implantation in the thoracic aorta may propagate an inflammatory response during the early postoperative period. No clinical adverse events related to the increased inflammatory response were observed. Renal function does not seem to be deteriorated after TEVAR in the descending thoracic aorta.

Management of Patients with Internal Carotid Artery Near-total Occlusion: An Updated Meta-analysis.

BACKGROUND: The decision for revascularization in patients with near-total internal carotid artery (ICA) occlusion still remains controversial. We undertook an extensive review of the literature and conducted a meta-analysis aiming to investigate the appropriate therapeutic approach for patients with near-total ICA occlusion. METHODS: A multiple electronic health database search was performed on all articles published up to December 2014. All available data were analyzed giving emphasis on the applied therapeutic approach (best medical therapy [BMT], carotid endarterectomy [CEA], and carotid artery stenting [CAS]), whereas the main endpoints of the meta-analysis were transient ischemic attack (TIA), stroke, stroke-related death, myocardial infarction (MI), major adverse event (MAE), overall mortality, and restenosis. RESULTS: Five articles on BMT and CEA, 8 articles on CEA, and 11 articles on CAS were deemed eligible. A statistically significant difference was recorded in pooled stroke incidence rates (IRs) per 100 patient-years (p-ys) of BMT (IR = 6.19) compared with CEA (IR = 2.24, P = 0.002) and CAS (IR = 1.64, P < 0.001) studies. No statistically significant differences were recorded in pooled IRs per 100 p-ys between CEA and CAS, concerning TIA (P = 0.96), stroke (P = 0.44), stroke-related death (P = 0.30), and MAE (P = 0.99), whereas a borderline significance was recorded concerning overall mortality (P = 0.08) and restenosis (P = 0.08). No nominally significant effects were demonstrated with respect to almost all the studied potential modifiers in meta-regression analysis among the eligible studies. CONCLUSIONS: An intervention is probably indicated for patients with near-total ICA occlusion. The results of our study underline the need for including patients with near-total ICA occlusion in future randomized controlled trials. Meanwhile, the treatment of these patients should be individualized.

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.