Cerebral microembolization after protected carotid artery stenting in surgical high-risk patients: results of a 2-year prospective study

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.

Transradial carotid artery stenting using double layer micromesh stent and novel post-dilation balloon with integrated embolic protection

OBJECTIVES

The highest rate of embolization during carotid artery stenting occurs during post-dilation. We evaluated the ability of the Paladin system (Contego Medical, Raleigh, NC), a novel PTA balloon with an integrated 40-ɥm pore filter, to collect microemboli that may pass into the cerebral circulation when used during post-dilation.

METHODS

25 symptomatic patients underwent transradial CAS using the Paladin system in conjunction with the Roadsaver (Terumo Corporation, Tokyo, Japan) micromesh stent. No additional embolic protection was used. The Paladin filters were collected following the procedure and preserved in formalin for histological analysis. The contents were evaluated for particle count and size. Subjects were followed for 30 days and evaluated for major cardiac adverse events (death, stroke and MI). Secondary endpoints included procedure success, device success, access site complications according to EASY score classification, major vascular or ischemic complications at follow up and in-stent restenosis rate evaluated with duplex ultrasound.

RESULTS

Mean age of patients was 68,5 years. Type 2 aortic arch was present in 77 % of patients and type 1 and type 3 in 12 % and 11 % of patients respectively. Procedural and device success was obtained in all cases without complications. The 30-day MAE rate was 0 %. Twenty-three filters underwent histological analysis. Microscopic debris was present in 100 % of filters, and 75 % of particles were less than 100ɥm in size. The mean number of particles per filter was 3352 ± 1567 (IQR 4300-2343), and the mean number of particles between 40-100ɥm per filter was 2499 ± 1240 (IQR 3227-1575).

CONCLUSION

CAS through radial approach can be safely and effectively performed using the IEP technology Paladin device and double-layer micromesh Roadsaver stent. This strategy can simplify the procedure and decrease peri-procedural complications and procedural time.

Carotid Artery Stenting versus Carotid Endarterectomy in Terms of Neuroprotection DW-MRI Detected and Neuropsychological Assessment Impairment

BACKGROUND

Carotid artery stenting (CAS) versus carotid endarterectomy (CEA) is well issue known, but the purpose of this study is to compare CAS versus CEA in terms of asymptomatic Diffusion-weighted magnetic resonance imaging (DW-MRI) demonstrated microembolic scattering of infarction and neuropsychological assessment impairment.

METHODS

We performed a prospective, observational, cohort study on 211 consecutive carotid revascularizations at our institution. Patients were divided into 2 different cohorts: CEA was performed in n = 116 patients (Group A); CAS was performed in n = 95 (Group B). Adverse events were collected at 30 days and 6 months postoperative. Differences in terms of DW-MRI demonstrated microembolic scattering of infarction were analyzed and considered significative for P ≤ 0.05. Secondary objectives were: major and minor stroke, neuropsychological assessment impairment, death, myocardial infarction (MI).

RESULTS

CEA was associated with a significative decreased rate of asymptomatic DW-MRI demonstrated microembolic scattering of infarction (13.8% vs. 51%; P = 0.0001) and of 6 months neuropsychological assessments impairment (0.8 vs. 7.4) (P = 0.04) in asymptomatic patients. There was no significant difference between 2 groups in terms of comorbidities. Stroke rates were similar at 30 days (1.7% CEA vs. 4.1% CAS) and 6 months (2.6% CEA vs. 5.3% CAS P = 0.32). There were no differences in terms of central neurological events, death, transient ischemic attack, MI between the groups. The composite end point of stroke/death/MI at 6 months postoperatively was 2.6% vs. 6.3% (P = 0.19).

CONCLUSIONS

According to these results, CEA achieved better outcomes compared to patients treated by CAS with distal filter in terms of asymptomatic microembolic event and impairment National Institutes of Health Stroke Scale scale and neuropsychological assessments. Limitations of the study lead to limited conclusions only in the specific population and not generalized. Further, comparative randomized studies are warranted.

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.

Safety and Efficacy of Tirofiban Bridging Therapy During a Hybrid Carotid Artery Stenting and Off-Pump Coronary Artery Bypass Grafting Surgery: A Single-Center Study

PURPOSE

The optimal perioperative antithrombosis management for carotid artery stenting (CAS) and coronary artery bypass grafting (CABG) hybrid surgeries remains unclear; however, a more aggressive antithrombotic therapy might be required after a hybrid CAS + CABG duo stent-related intimal injury or the use of protamine-neutralizing heparin. This study evaluated the safety and efficacy of tirofiban as a bridging therapy after a hybrid CAS + CABG surgery.

METHODS

Between June 2018 and February 2022, a total of 45 patients undergoing a hybrid CAS + off-pump CABG surgery were divided into either the control group (standard dual antiplatelet therapy postsurgery, n = 27) or the tirofiban group (tirofiban bridging + dual antiplatelet therapy, n = 18). The 30-day outcome was compared between the 2 groups, and the primary end points included stroke, postoperative myocardial infarction, and death.

FINDINGS

Two patients (7.41%) from the control group experienced a stroke. There was a trend toward a lower rate of composite end points, including stroke, postoperative myocardial infarction, and death, within the tirofiban group that did not reach statistical significance (0% vs 11.1%; P = 0.264). The need for a transfusion was similar between the 2 groups (33.33% vs 29.63%; P = 0.793). There were no major bleeding events in the 2 groups.

IMPLICATIONS

Tirofiban bridging therapy was safe, with a trend toward reducing the risk of ischemic events after a hybrid CAS + off-pump CABG surgery. Tirofiban might be a feasible periprocedural bridging protocol in high-risk patients.

Comparing Outcomes of Transfemoral Versus Transbrachial or Transradial Approach in Carotid Artery Stenting (CAS)

BACKGROUND

While Transfemoral Carotid Artery Stenting (TFCAS) is a valid minimally invasive option for patients who also might be suitable for carotid endarterectomy (CEA) or transcarotid artery revascularization (TCAR), alternative access sites such as transbrachial (TB) or transradial (TR) are only utilized when anatomic factors preclude direct carotid or transfemoral access. In this study, we aimed to evaluate the outcomes of TR/TB access in comparison to TF for percutaneous carotid artery revascularization.

METHODS

All patients undergoing non-TCAR carotid artery stenting (CAS) from January 2012 to June 2021 in the Vascular Quality Initiative (VQI) Database were included. Patients were divided into 2 groups based on the access site for CAS: TF or TR/TB. Primary outcomes included stroke/death, technical failure and access site complications (hematoma, stenosis, infection, pseudoaneurysm and AV fistula). Secondary outcomes included stroke, TIA, MI, death, non-home discharge, extended length of postoperative stay (LOS) (>1 day), and composite endpoints of stroke/MI and stroke/death/MI. Univariable and multivariable logistic regression models were used to assess postoperative outcomes, and results were adjusted for relevant potential confounders including age, gender, race, degree of stenosis, symptomatic status, anesthesia, comorbidities, and preoperative medications.

RESULTS

Out of the 23,965 patients, TR/TB approach was employed in 819 (3.4%) while TF was used in 23,146 (96.6%). Baseline characteristics found men were more likely to undergo revascularization using TR/TB approach (69.4% vs. 64.9%, P = 0.009). Patients undergoing TR/TB approach were also more likely to be symptomatic (49.9% vs. 28.6%, P < 0.001). Guideline directed medications were more frequently used with TR/TB including P2Y12 inhibitor (80.3% vs. 74.7%, P < 0.01), statin (83.8% vs. 80.6%), and aspirin (88.3% vs. 84.5%, P = 0.003) preoperatively. On univariate analysis, patients with TB/TR approach experienced higher rates of adverse outcomes. After adjusting for potential confounders, TR/TB patients had no significant increase in the risk of stroke/death [aOR 1.10 (0.69-1.76), P = 0.675]; however, the use of TR/TB access was associated with a more than 2-fold increase in risk for in-hospital MI [aOR 2.39 (1.32-4.30), P = 0.004] and 2-fold increase in risk of technical failure [aOR 2.21 (1.31-3.73) P = 0.003]. The use of TR/TB access was also associated with a 50% reduction in the risk of access site complications [aOR 0.53 (0.32-0.85), P = 0.009].

CONCLUSIONS

This study confirms that although technically more challenging, TR or TB approach serves as a reasonable alternative with lower access site complications for CAS particularly in patients where anatomic factors preclude revascularization by TFCAS or TCAR. However, TR/TB is associated with an increased risk of technical failure and myocardial infarction, which requires further study.

Clinical Outcomes of Second- versus First-Generation Carotid Stents: A Systematic Review and Meta-Analysis

Background: Single-cohort studies suggest that second-generation stents (SGS; “mesh stents”) may improve carotid artery stenting (CAS) outcomes by limiting peri- and postprocedural cerebral embolism. SGS differ in the stent frame construction, mesh material, and design, as well as in mesh-to-frame position (inside/outside). Objectives: To compare clinical outcomes of SGS in relation to first-generation stents (FGSs; single-layer) in CAS. Methods: We performed a systematic review and meta-analysis of clinical studies with FGSs and SGS (PRISMA methodology, 3302 records). Endpoints were 30-day death, stroke, myocardial infarction (DSM), and 12-month ipsilateral stroke (IS) and restenosis (ISR). A random-effect model was applied. Results: Data of 68,422 patients from 112 eligible studies (68.2% men, 44.9% symptomatic) were meta-analyzed. Thirty-day DSM was 1.30% vs. 4.11% (p < 0.01, data for SGS vs. FGS). Among SGS, both Casper/Roadsaver and CGuard reduced 30-day DSM (by 2.78 and 3.03 absolute percent, p = 0.02 and p < 0.001), whereas the Gore stent was neutral. SGSs significantly improved outcomes compared with closed-cell FGS (30-day stroke 0.6% vs. 2.32%, p = 0.014; DSM 1.3% vs. 3.15%, p < 0.01). At 12 months, in relation to FGS, Casper/Roadsaver reduced IS (−3.25%, p < 0.05) but increased ISR (+3.19%, p = 0.04), CGuard showed a reduction in both IS and ISR (−3.13%, −3.63%; p = 0.01, p < 0.01), whereas the Gore stent was neutral. Conclusions: Pooled SGS use was associated with improved short- and long-term clinical results of CAS. Individual SGS types, however, differed significantly in their outcomes, indicating a lack of a “mesh stent” class effect. Findings from this meta-analysis may provide clinically relevant information in anticipation of large-scale randomized trials.

Randomized Controlled Trial of Conventional Versus MicroNet-Covered Stent in Carotid Artery Revascularization

OBJECTIVES

The aim of this study was to compare procedure-related ipsilateral cerebral embolism with a conventional (Acculink, Abbott Vascular) versus a MicroNet-covered (CGuard, InspireMD) stent in carotid artery stenting (CAS).

BACKGROUND

The MicroNet-covered stent may reduce periprocedural cerebral embolism in CAS, but level 1 evidence is lacking.

METHODS

A total of 100 consecutive patients were randomized 1:1 to filter-protected CAS using the Acculink or the CGuard device. The study was powered for its primary endpoint of at least 50% reduction in ipsilateral diffusion-weighted magnetic resonance imaging lesion average volume 48 hours postprocedure (blinded external core laboratory analysis).

RESULTS

The baseline characteristics of the study groups were similar. Eighty-two (total volume = 18,212 mm³) diffusion-weighted magnetic resonance imaging postprocedural cerebral lesions occurred in 26 Acculink-treated patients and 45 lesions (total volume = 3,930 mm³; 78.4% reduction) in 25 CGuard-treated patients. New cerebral lesion average volume was 171 mm³ vs 73 mm³ (P = 0.017) per affected patient and 222 mm³ vs 84 mm³ (P = 0.038) per lesion (Acculink vs CGuard). In lesion-affected patients, the average sum of lesion volumes was 701 mm³ vs 157 mm³ (P = 0.007). The Acculink significantly increased the risk for multiple (≥5) cerebral lesions (relative risk: 7.8; 95% CI: 1.3-14.9; P = 0.021). At 30 days, new permanent (fluid-attenuated inversion recovery) lesion prevalence was 3:1 (P < 0.001), with total permanent lesion volume 7,474 mm³ vs 574 mm³ (92.3% reduction with the CGuard). There were 6 vs 0 new ipsilateral lesions (P = 0.030) and 2 versus 0 strokes.

CONCLUSIONS

The MicroNet-covered stent significantly reduced periprocedural and abolished postprocedural cerebral embolism in relation to a conventional carotid stent. This is consistent with the MicroNet-covered stent's sustained embolism prevention, translating into cerebral protection not only during but also after CAS. The present findings may influence decision making in carotid revascularization. (The SIBERIA Trial [Acculink™ Versus CGuard™]; NCT03488199).

Risk factors for new ischemic cerebral lesions after carotid artery stenting: A systematic review and meta-analysis

BACKGROUND

New ischemic cerebral lesions (NICL) are commonly occur after carotid artery stenting (CAS) with an incidence rate ranging from 18-58% and are detected by diffusion-weighted imaging-magnetic resonance imaging (DWI-MRI). Numerous studies have reported that NICL could increase the risk of future cerebrovascular events and cognitive impairment. This systematic review and meta-analysis aimed to identify risk factors for NICL after CAS.

METHODS

Relevant literature reporting risk factors for NICL after CAS were searched. Randomized controlled trials, case-control studies, or cohort studies were included in accordance with the pre-specified eligibility criteria. The risk of bias was assessed using the Cochrane Collaboration criteria and the quality of evidence was assessed with the corresponding scale. Data were analyzed using the RevMan V. 5.3 analysis software.

RESULTS

The final analyses included a total of 21 studies and 1907 participants, including 764 NICL-positives and 1143 NICL-negatives. Determinants for NICL-positivity were age (mean deviation (MD): 2.60; 95% confidence interval (CI): [1.53-3.68]), symptomatic carotid lesions (odds ratio (OR): 1.77; 95% CI: [1.39-2.25]) and smoking (OR: 0.74; 95% CI: [0.58-0.94]). For symptomatic patients, risk factors for NICL-positive included diabetes mellitus (OR: 1.76; 95% CI: [1.09-2.82]), but smoking (OR: 0.54; 95% CI: [0.31-0.93]) was a protective factor. Risk factors for centers with high NICL incidence were age (MD: 2.05; 95% CI: [0.93-3.17]) and symptomatic carotid lesions (OR: 1.77; 95% CI: [1.29-2.45]).

CONCLUSIONS

Older age and symptomatic carotid lesions are associated with an increased risk of post-CAS NICL whereas smoking is associated with a decreased risk. Risk factors for NICL in symptomatic patients is diabetes mellitus, while those for patients at centers with high incidence are age and symptomatic carotid lesions. Systematic review registration: CRD42019121129.

Radial Access for Neurointerventions

Transradial access (TRA) has become the standard approach for cardiac intervention, with a large body of evidence demonstrating a lower incidence of vascular complications, better patient experience and cost reduction. There has been increasing interest in using TRA both for diagnostic neuroangiography and for interventional neurovascular procedures. This aim of this article is to discuss the advantages and limitations of TRA for neurointerventions. General technical details, such as pre-procedure recommendations, prevention of spasm and occlusion, haemostasis protocols and distal TRA puncture, are also described, along with the specific technical details of TRA for aneurysm embolisation, stroke thrombectomy and other neurovascular interventions. TRA provides additional tools to the neurointerventionist and – with appropriate training – the whole spectrum of intervention procedures can be achieved using this approach.

Age and the risk of new ischemic lesions on diffusion weighted imaging after carotid artery stenting: A systematic review and meta-analysis

To perform a systematic review and meta-analysis to show the association between age and the risk of new ischemic lesions on diffusion-weighted magnetic resonance imaging (DWI) after carotid artery stenting in patients with carotid artery stenosis. We searched PubMed and EMBASE from their dates of inception to March 14, 2019 for eligible studies. Standardized mean difference (SMD) and pooled odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the association between age and new DWI lesions. Sensitivity analysis was performed to detect the possible source of heterogeneity. Twenty-three studies enrolling 2127 patients were included. The incidence of new DWI lesions was 62% in older patients and 41% in younger patient (OR 2.44, 95%CI 1.57-3.79; p < 0.0001). The patients with new DWI lesions were older than those without (SMD 0.24, 95% CI 0.08-0.39; p = 0.003). The risk of new DWI lesions increased by 1.07 per added year (95%CI 1.04-1.11, p < 0.0001). The results remained stable in sensitivity analyses and after adjusting for publication bias. It was concluded that older age was at higher risk of new DWI lesions after stenting in patients with carotid artery stenosis.

Advanced ultrasound methods in assessment of carotid plaque instability: a prospective multimodal study

Background

A significant proportion of ischemic strokes are caused by emboli from atherosclerotic, unstable carotid artery plaques. The selection of patients for endarterectomy in current clinical practice is primarily based on the degree of carotid artery stenosis and clinical symptoms. However, the content of the plaque is known to be more important for stroke risk. Intraplaque neovascularization (IPN) has recently emerged as a possible surrogate marker for plaque instability. Neo-microvessels from the adventitial vasa vasorum grow into the full thickness of the vessel wall in an adaptive response to hypoxia, causing subsequent intraplaque haemorrhage and plaque rupture. Conventional ultrasound cannot detect IPN. Contrast-enhanced ultrasound and Superb Microvascular Imaging (SMI), have, however, shown promise in IPN assessment. Recent research using Shear Wave Elastography (SWE) has also reported reduced tissue stiffness in the artery wall (reduced mean Young’s modulus) in unstable compared to stable plaques. The purpose of this study is to identify unstable carotid artery plaques at risk of rupture and future ischemic stroke risk using multimodal assessments.

Methods

Forty five symptomatic and 45 asymptomatic patients > 18 years, with > 50% carotid stenosis referred to Oslo University Hospital ultrasound lab will be included in this on-going project. Patients will undergo contrast enhanced ultrasound, SMI, carotid-MRI and PET-(¹⁸F-FDG). Contrast enhanced ultrasound will be analyzed semi-quantitatively (5-levels visual classification) and quantitatively by plotting time-intensity curve analyses to obtain plaque peak contrast enhancement intensity. Plaques removed at carotid endarterectomy will be assessed histologically and the number of microvessels, areas of inflammation, granulation, calcification, lipid and fibrosis will be measured.

Discussion

This multimodality study will primarily provide information on the clinical value of advanced ultrasound methods (SMI, SWE) for the detection of unstable carotid artery plaque in comparison with other methods including contrast-enhanced ultrasound, carotid-MRI and PET-(¹⁸F-FDG) using histology as the gold standard. Secondly, findings from the methods mentioned above will be related to cerebrovascular symptoms, blood tests (leukocytes, CRP, ESR, lipoproteins and inflammatory markers) and cardiovascular risk factors at inclusion and at 1-year follow-up. The overall aim is to optimize detection of plaque instability which can lead to better preventive decisions and reduced stroke rate.

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.

Anesthesia type determines risk of cerebral infarction after carotid endarterectomy

OBJECTIVE

Silent and symptomatic cerebral infarctions occur in up to 34% of patients after carotid endarterectomy (CEA). This prospective study compared the risk of new brain infarctions detected by magnetic resonance imaging (MRI) in patients with internal carotid artery stenosis undergoing CEA with local anesthesia (LA) vs general anesthesia (GA).

METHODS

Consecutive patients with internal carotid artery stenosis indicated for CEA were screened at two centers. Patients without contraindication to LA or GA were randomly allocated to the LA or GA group by ZIP code randomization. Brain MRI was performed before and 24 hours after CEA. Neurologic examination was performed before and 24 hours and 30 days after surgery. The occurrence of new infarctions on the control magnetic resonance images, stroke, transient ischemic attack, and other complications was statistically evaluated.

RESULTS

Of 210 randomized patients, 105 underwent CEA with LA (67 men; mean age, 68.3 ± 8.1 years) and 105 with GA (70 men; mean age, 63.4 ± 7.5 years). New infarctions were more frequently detected on control magnetic resonance images in patients after CEA under GA compared with LA (17.1% vs 6.7%; P = .031). Stroke or transient ischemic attack occurred within 30 days of CEA in three patients under GA and in two under LA (P = 1.000). There were no significant differences between the two types of anesthesia in terms of the occurrence of other complications (14.3% for GA and 21.0% for LA; P = .277).

CONCLUSIONS

The risk of silent brain infarction after CEA as detected by MRI is higher under GA than under LA.

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.

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.

Laboratory-Based Markers as Predictors of Brain Infarction During Carotid Stenting: a Prospective Study

AIM

New ischemic lesions in the brain can be detected in approximately 50% of patients undergoing carotid artery stenting (CAS). We wished to discover the laboratory-based predictors of new infarctions in the brain after CAS.

METHODS

All consecutive patients with internal carotid artery stenosis of ≥70% with indication for CAS were enrolled in a prospective study for 16 months. All patients used dual antiplatelet therapy for ≥7 days before CAS. Neurologic examination and magnetic resonance imaging (MRI) of the brain were undertaken before and at 24 h after CAS. Samples of venous blood were collected at ＜24 h before CAS for the evaluation of hematology, reticulocytes, coagulation markers (PT, APTT, Fbg, Clauss), vWF antigen, PAI-1 activity, PAI-1 polymorphism 4G/5G, and the multiplate (aspirin and clopidogrel) resistance test. Blood samples for the assessment of anti-Xa activity were collected during CAS. Differences in the values of laboratory markers between patients with and without new ischemic lesions of the brain on control MRI were evaluated.

RESULTS

The cohort comprised 81 patients (53 males; mean age, 67.3±7.2 years). New ischemic infarctions in the brain on control MRI were found in 46 (56.8%) patients. Three of seven patients with resistance to aspirin or clopidogrel had a new ischemic infarction in the brain. No significant differences for particular markers were found between patients with and without an ischemic lesion in the brain.

CONCLUSION

A high risk of a new ischemic infarction in the brain was detected in patients undergoing CAS, but a laboratory-based predictor of such an infarction could not be identified.

Brain Injury Secondary to Carotid Intervention

Causes of brain injury during endovascular carotid intervention are protean. Mechanisms of injury include embolic and hemodynamic events, acute carotid occlusions occurring through a variety of means, and the relatively rare contrast-induced encephalopathy.

Embolic injury may result from micro- and macroembolization and most commonly causes ischemic stroke when sufficiently severe. Hemodynamic injury may proceed from hemodynamic depression and hypoperfusion (which may result in watershed infarction) or the hyperperfusion syndrome, which may, if severe, result in hemorrhagic stroke.

Embolic and dynamic causes of stroke may either occur intraprocedurally or at a variable time after stent placement and may be co-related. Impaired clearance of emboli due to relative hypoperfusion may exacerbate their clinical relevance. Other causes of stroke include acute carotid occlusions, which most commonly occur procedurally due to flow-limiting spasm, acute dissection, and, if a filter-type cerebral protection device has been used, filter occlusion due to a large trapped embolic load. These scenarios may result in stroke if not recognized and dealt with appropriately. Acute stent thrombosis may occur within 24 hours of the procedure as a result of adverse hemodynamic factors or suboptimal patient response to procedural heparin and antiplatelet agents, or it may occur after the procedure, again perhaps as a result of suboptimal response to antiaggregate drugs.

Comparison of Flow Impairment during Carotid Artery Stenting Using Two Types of Eccentric Filter Embolic Protection Devices

We investigated the angiographic findings and the clinical outcomes after carotid artery stenting (CAS) using two different, eccentric filter embolic protection devices (EPDs). Between July 2010 and August 2015, 175 CAS procedures were performed using a self-expandable closed-cell stent and a simple eccentric filter EPD (FilterWire EZ in 86 and Spider FX in 89 procedures). The angiographic findings (i.e., flow impairment and vasospasm) at the level of EPDs, neurologic events, and post-operative imaging results were compared between the FilterWire EZ and the Spider FX groups. The CAS was angiographically successful in all 175 procedures. However, the angiographs were obtained immediately after CAS-detected flow impairment in the distal internal carotid artery (ICA) in 11 (6.3%) and ICA spasms at the level of the EPD in 40 cases (22.9%). The incidence of these complications was higher with FilterWire EZ than Spider FX (ICA flow impairment of 10.5% vs. 2.2%, P = 0.03; vasospasm 30.2% vs. 15.7%, P = 0.03). There were nine neurologic events (5.1%); five patients were presented with transient ischemic attacks, three had minor strokes, and one had a major stroke. New MRI lesions were seen in 25 (29.1%) FilterWire-group and in 36 (40.4%) Spider-group patients. The neurologic events and new MRI lesions were not associated with the type of EPD used. Although the ICA flow impairment may result in neurologic events, there was no significant association between the FilterWire EZ and the Spider FX CAS with respect to the incidence of neurologic events by the prompt treatment such as catheter aspiration.

Transcervical Carotid Stenting With Dynamic Flow Reversal Demonstrates Embolization Rates Comparable to Carotid Endarterectomy

PURPOSE

To evaluate a series of patients treated electively with carotid endarterectomy (CEA), transfemoral carotid artery stenting with distal filter protection (CASdp), and transcervical carotid stenting with dynamic flow reversal (CASfr) monitored continuously with transcranial Doppler (TCD) during the procedure to detect intraoperative embolization rates.

METHODS

Thirty-four patients (mean age 67.6 years; 24 men) with significant carotid stenosis underwent successful TCD monitoring during the revascularization procedure (10 CEA, 8 CASdp, and 16 CASfr). Ipsilateral microembolic signals were segregated into 3 phases: preprotection (until internal carotid artery cross-shunted or clamped if no shunt was used, filter deployed, or flow reversal established), protection (until clamp/shunt was removed, filter retrieved, or antegrade flow reestablished), and postprotection (after clamp/shunt or filter removal or restoration of normal flow).

RESULTS

CASdp showed higher embolization rates than CEA or CASfr in the preprotection phase (p<0.001). In the protection phase, CASdp was again associated with more embolization compared with CEA and CASfr (p<0.001). In the postprotection phase, no differences between the revascularization therapies were observed. CASfr and CEA did not show significant differences in intraoperative embolization during any of the phases.

CONCLUSION

TCD recordings demonstrated a significant reduction in embolization to the brain during transcervical carotid artery stent placement with the use of dynamic flow reversal compared to transfemoral CAS using distal filters. No significant differences in microembolization could be detected between CEA and CASfr. The observed lower embolization rates and lack of adverse events suggest that transcervical CAS with dynamic flow reversal is a promising technique and may be the preferred method when performing CAS.

Randomized clinical trial comparing neurological outcomes after carotid endarterectomy or stenting

Background

Silent infarction in the brain can be detected in around 34 per cent of patients after carotid endarterectomy (CEA) and 54 per cent after carotid angioplasty and stenting (CAS). This study compared the risk of new infarctions in the brain in patients undergoing CEA or CAS.

Methods

Consecutive patients with internal carotid artery (ICA) stenosis exceeding 70 per cent were screened for inclusion in this prospective study. Patients with indications for intervention, and eligible for both methods, were allocated randomly to CEA or CAS. Neurological examination, cognitive function tests and MRI of the brain were undertaken before and 24 h after intervention.

Results

Of 150 randomized patients, 73 (47 men; mean age 64·9(7·1) years) underwent CEA and 77 (58 men; 66·4(7·5) years) had CAS. New infarctions on MRI were found more frequently after CAS (49 versus 25 per cent; P = 0·002). Lesion volume was also significantly greater after CAS (P = 0·010). Multiple logistic regression analyses identified intervention in the right ICA as the only independent predictor of brain infarction (odds ratio 2·10, 95 per cent c.i. 1·03 to 4·25; P = 0·040). Stroke or transient ischaemic attack occurred in one patient after CEA and in two after CAS. No significant differences were found in cognitive test results between the groups.

Conclusion

These data confirm a higher risk of silent infarction in the brain on MRI after CAS in comparison with CEA, but without measurable change in cognitive function. Registration number: NCT01591005 (http://www.clinicaltrials.gov).

Carotid Artery Angioplasty and Stenting for Patients Less than 70 Years-of-Age

Background:

Recent studies have suggested that carotid artery angioplasty and stenting (CAS) is a safe alternative to carotid endarterectomy (CEA) in average risk patients <70 years of age. We examined a consecutive series of patients who underwent CAS in order to determine the influence of patient age on outcome.

Methods:

A retrospective, longitudinal cohort study of consecutive patients who underwent CAS at St. Michael's Hospital, Canada between January 2001 and November 2010 was performed. The outcome measures were 30-day stroke and 30-day composite death, stroke and acute myocardial infarction (MI). Patients were stratified based on age <70 and ≥70 years.

Results:

One hundred and fifty-nine patients underwent 165 CAS procedures. The 30-day risk of stroke was 3.8% while the composite outcome of death/stroke/MI was 8.2%. When stratified by age <70 and ≥70 years, the 30-day stroke rate was 0% versus 7.4% (p=0.03), and the composite outcome of death/stroke/MI was 2.6% versus 13.6% (p=0.02), respectively.

Conclusions:

Patients <70 years of age undergoing CAS have a low rate of major complications, comparing favourably with historical CEA adverse event rates, and supporting the recent carotid stenosis literature that in the younger population CAS has a similar complication rate compared to CEA.

Impact of coexisting coronary artery disease on the occurrence of cerebral ischemic lesions after carotid stenting

Background

Coronary artery disease (CAD) may coexist with extracranial carotid artery stenosis (ECAS), but the influence of CAD on procedure-related complications after carotid artery stenting (CAS) has not been well investigated. The study aimed to determine the impact of CAD on the occurrence of peri-CAS cerebral ischemic lesions on diffusion-weighted imaging (DWI) scanning.

Methods

Coronary angiography was performed within six months before CAS. DWI scanning was repetitively done within 1 week before and after CAS. Clinical outcome measures were stroke, angina, myocardial infarction and death within 30 days.

Results

Among 126 patients (69.5±9.0 years) recruited for unilateral protected CAS, 33 (26%) patients had peri-CAS DWI-positive lesions. CAD was noted in 79% (26 in 33) and 48% (45 in 93) of patients with and without peri-CAS DWI-positive lesions (OR, 4.0; 95% CI, 1.6–10.0; P = .0018), and the number of concomitant CAD on coronary angiography was positively correlated with the risk for peri-CAS DWI-positive lesions (P = .0032). In patients with no CAD (n = 55), asymptomatic CAD (n = 41) and symptomatic CAD (n = 30), the occurrence rates of peri-CAS DWI-positive lesions were 13%, 41% and 30% (P = .0048), and the peri-CAS stroke rates were 2%, 7% and 0% (P = .2120).

Conclusions

The severity of morphological CAD and the presence of either symptomatic or asymptomatic CAD are associated with the occurrence of peri-CAS cerebral ischemic lesions.

Skin to Skin: Transradial Carotid Angiography and Stenting

Carotid artery stenting (CAS) is a proven alternative to carotid endarterectomy in patients with significant carotid disease. The femoral artery is the conventional access site for CAS procedures. However, this approach may be problematic because of peripheral vascular disease and anatomic variations. Access site complications are the most common adverse event after CAS from the transfemoral approach (TFA) and most technical failures are related to a complex aortic arch. The transradial approach has been evaluated to address the shortcomings of TFA. In cases involving a complex arch, transradial access may be a viable alternative strategy.

Antiplatelet therapy for carotid artery stenting

Carotid artery stenting (CAS) is less invasive and has a lower incidence of systemic complications such as myocardial infarction compared with carotid endarterectomy. However, CAS is known to have a high incidence of ischemic complications due to distal thromboembolism. Progress has been made in the development of various distal protection devices and protection methods aimed at preventing thromboembolism. Similar to these methods, perioperative antiplatelet therapy is also able to play a very important role in the prevention of ischemic events. Dual antiplatelet therapy has become standard for perioperative management of CAS.

Carotid artery stenting: patient, lesion, and procedural characteristics that increase procedural complications

From the earliest experiences with carotid artery stenting (CAS) presumptive high risk features have included thrombus-containing lesions, heavily calcified lesions, very tortuous vessels, and near occlusions. In addition patients have been routinely excluded from CAS trials if they have contra-indications to dual antiplatelet therapy (aspirin and thienopyridines), a history of bleeding complications and severe peripheral arterial disease (PAD) making femoral artery vascular access difficult. Variables that increase the risk of CAS complications can be attributed to patient characteristics, anatomic or lesion features, and procedural factors. Clinical features such as older age (≥80 years), decreased cerebral reserve (dementia, multiple prior strokes, or intracranial microangiopathy) and angiographic characteristics such as excessive tortuosity (more than two 90° bends within 5 cm of the target lesion) and heavy calcification (concentric calcification ≥ 3 mm in width) have been associated with increased CAS complications. Other high risk CAS features include those that prolong catheter or guide wire manipulation in the aortic arch, make crossing a carotid stenosis more difficult, decrease the likelihood of successful deployment or retrieval of an embolic protection device (EPD), or make stent delivery or placement more difficult. Procedure volume for the operator and the catheterization laboratory team are critical elements in reducing the risk of the procedure. In this article, we help CAS operators better understand procedure risk to allow more intelligent case selection, further improving the outcomes of this emerging procedure.

The influence of anti-platelet resistance on the development of cerebral ischemic lesion after carotid artery stenting

PURPOSE

Cerebral ischemic lesions are frequently observed after carotid artery stenting (CAS), and anti-platelet agents are used to prevent stent thrombosis and peri-procedural complications. However, despite the premedication, cerebral ischemic lesions are observed, suggesting that they may rather be related to anti-platelet resistance. We, therefore, investigated the effects of anti-platelet resistance on the development of cerebral ischemic lesions after CAS.

MATERIALS AND METHODS

We retrospectively reviewed patients who received CAS and selected patients for whom brain MRI was performed within 24 hours after CAS and for whom anti-platelet resistance was checked. Anti-platelet resistance was examined by the VerifyNow system. We analyzed the correlation between anti-platelet resistance and cerebral ischemic lesions detected on follow-up MRI.

RESULTS

Among 76 patients, 45 (59.2%) developed new ischemic lesions after CAS. Twelve (15.8%) patients showed aspirin resistance and 50 (65.8%) patients showed clopidogrel resistance. Patients with a new ischemic lesion demonstrated a significantly greater frequency of clopidogrel resistance than those who had no new ischemic lesion (82.2% versus 41.9%, p=0.001). The frequency of aspirin resistance was not significantly different between the groups of patients with and without new ischemic lesions (20.0% versus 9.7%, p=0.340). In multivariate analysis, clopidogrel resistance was a significant risk factor for post-procedural cerebral ischemia.

CONCLUSION

Anti-platelet resistance can be used to predict new ischemic lesions after CAS. Anti-platelet resistance should be evaluated in all patients prior to CAS to prevent ischemic complications related to CAS.

A diffusion-weighted magnetic resonance imaging-based study of transcervical carotid stenting with flow reversal versus transfemoral filter protection

BACKGROUND

Transfemoral carotid artery stenting (CAS) has been associated with a high incidence of embolic phenomena and silent brain infarction. The goal of this study was to compare the incidence of new ischemic cerebral lesions on diffusion-perfusion magnetic resonance imaging (MRI) sequences after transcervical CAS performed with carotid flow reversal vs stenting via transfemoral approach with distal filter protection.

METHODS

During a 26-month period, 64 consecutive patients diagnosed with significant carotid stenosis by ultrasound imaging were assigned to transcervical CAS with carotid flow reversal or a transfemoral approach with a distal filter. The Rankin stroke scale was administered by an independent neurologist, and diffusion-weighted MRI (DW-MRI) studies were performed ≤24 hours before and ≤24 to 48 hours after the procedure. DW-MRI studies were compared by two neuroradiologists not involved in the study and blinded for time, clinical status, and treatment option. Hyperintense DW-MRI signals found after the procedure were interpreted as postoperative ischemic infarcts. All patients were assessed at 1, 6, and 12 months after the intervention.

RESULTS

The distribution of demographic and pathologic variables was similar in both groups. All procedures were technically successful, with a mean carotid flow reversal time of 22 minutes. Twenty-one (70%) and 23 patients (69.69%) were symptomatic in the transcervical and transfemoral groups, respectively (P=.869). After intervention, new postprocedural DW-MRI ischemic infarcts were found in four transcervical (12.9%) and in 11 transfemoral (33.3%) patients (P=.03), without new neurologic symptoms. No major adverse events occurred at 30 days after the intervention. All patients remained neurologically intact, without an increase in stroke scale scoring. All stents remained patent, and all patients remained stroke-free during follow-up. In multivariate analysis, age (relative risk [RR], 1.022; P<.001), symptomatic status (RR, 4.109; P<.001), and open-cell vs closed-cell stent design (RR, 2.01; P<.001) were associated with a higher risk of embolization in the transfemoral group but not in the transcervical group.

CONCLUSIONS

These data suggest that transcervical carotid stenting with carotid flow reversal carries a significantly lower incidence of new ischemic brain infarcts than that resulting from transfemoral CAS with a distal filter. The transcervical approach with carotid flow reversal may improve the safety of CAS and has the potential to improve results in especially vulnerable patients such as the elderly and symptomatic.

Risk factors predictive of carotid artery stenting-associated subclinical microemboli

Subclinical microemboli documented on diffusion-weighted magnetic resonance imaging (DWI) are common following carotid artery stenting (CAS) procedures despite absence of neurological symptoms. This study was to evaluate risk factors predictive of microemboli in patients undergoing protected CAS with a distal embolic protection device. All CAS patients who received pre- and postprocedural magnetic resonance imaging (MRI) evaluations for carotid interventions at a single academic institution from July 2004 to December 2008 were examined. Microemboli were defined by new hyperintensities on postoperative DWI with corresponding decreased diffusion. Risk factors including patient demographics, medical comorbidities, clinical symptoms, lesion morphologies, and perioperative information were examined, and logistic regression analyses were utilized to determine predictors of CAS-related microemboli. A total of 204 patients underwent carotid interventions (76 CAS and 128 carotid endarterectomies) during the study period; 167 of them, including 67 CAS patients, received both preoperative and postoperative MRIs. Among those who underwent protected CAS, the incidence of microemboli was 46.3% despite a relative low incidence of associated neurological symptoms (2.9%). Univariate and multivariate regression analyses showed that date of procedure (odds ratio [OR] 30.6 and p = 0.019) and preoperative transient ischemic attack symptoms (OR 9.24 and p = 0.009) were independent predictors of developing postoperative changes on DWI in the ipsilateral hemisphere, and age >76 years was predictive of having new lesions on DWI in the contralateral hemisphere (OR 6.11 and p = 0.026). Our study underscores that certain risk factors are significantly associated with CAS-related microemboli and that physician experience and patient selection are essential in improving outcome of CAS procedures.

Prospective neurocognitive evaluation of patients undergoing carotid interventions

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Society for Vascular Surgery (SVS) Vascular Registry evaluation of comparative effectiveness of carotid revascularization procedures stratified by Medicare age

OBJECTIVE

Recent randomized controlled trials have shown that age significantly affects the outcome of carotid revascularization procedures. This study used data from the Society for Vascular Surgery Vascular Registry (VR) to report the influence of age on the comparative effectiveness of carotid endarterectomy (CEA) and carotid artery stenting (CAS).

METHODS

VR collects provider-reported data on patients using a Web-based database. Patients were stratified by age and symptoms. The primary end point was the composite outcome of death, stroke, or myocardial infarction (MI) at 30 days.

RESULTS

As of December 7, 2010, there were 1347 CEA and 861 CAS patients aged < 65 years and 4169 CEA and 2536 CAS patients aged ≥ 65 years. CAS patients in both age groups were more likely to have a disease etiology of radiation or restenosis, be symptomatic, and have more cardiac comorbidities. In patients aged <65 years, the primary end point (5.23% CAS vs 3.56% CEA; P = .065) did not reach statistical significance. Subgroup analyses showed that CAS had a higher combined death/stroke/MI rate (4.44% vs 2.10%; P < .031) in asymptomatic patients but there was no difference in the symptomatic (6.00% vs 5.47%; P = .79) group. In patients aged ≥ 65 years, CEA had lower rates of death (0.91% vs 1.97%; P < .01), stroke (2.52% vs 4.89%; P < .01), and composite death/stroke/MI (4.27% vs 7.14%; P < .01). CEA in patients aged ≥ 65 years was associated with lower rates of the primary end point in symptomatic (5.27% vs 9.52%; P < .01) and asymptomatic (3.31% vs 5.27%; P < .01) subgroups. After risk adjustment, CAS patients aged ≥ 65 years were more likely to reach the primary end point.

CONCLUSIONS

Compared with CEA, CAS resulted in inferior 30-day outcomes in symptomatic and asymptomatic patients aged ≥ 65 years. These findings do not support the widespread use of CAS in patients aged ≥ 65 years.

New ischemic brain lesions on diffusion-weighted MRI after carotid artery stenting with filter protection: frequency and relationship with plaque morphology

BACKGROUND AND PURPOSE

CAS carries an inherent risk of distal cerebral embolization, precipitating new brain ischemic lesions and neurologic symptoms. Our purpose was to evaluate the frequency of new ischemic lesions found on DWI after protected CAS placement and to determine its association with plaque morphology.

MATERIALS AND METHODS

Fifty patients (mean age 65.13 ± 7.08 years) with moderate and severe internal carotid artery stenosis underwent CAS with distal filter protection. Fibrolipid and fibrocalcified plaque morphology was determined by sonography according to the relative contribution of echogenic and echolucent material, and by multisection CT using plaque attenuation. There were 46.81% of patients with fibrolipid and 53.19% with fibrocalcified plaques. DWI was performed before and 24 hours after CAS.

RESULTS

Seven (14.89%) patients showed new lesions. Four (8.51%) had 6 new lesions inside the treated vascular territory. Three had a single lesion and 1 patient had 3 lesions (mean: 1.5 ± 1). Most lesions (66.66%) were subcortical, with a mean diameter of 9 mm (range 5-15 mm). All lesions occurred in the area supplied by the middle cerebral artery and were clinically silent. A significant relationship was found between plaque morphology and the appearance of new lesions. Patients with fibrolipid plaques had a significantly higher number of new lesions compared with patients with fibrocalcified plaques (P = .041). The absolute risk of new lesions in the fibrolipid group was 18.18%.

CONCLUSIONS

New ischemic lesions were observed in the treated vascular territory in 8.51% of patients. The appearance of new ischemic lesions was significantly related to the plaque morphology. Fibrolipid plaques were associated with higher numbers of new lesions.

Insight into the periprocedural embolic events of internal carotid artery angioplasty. A report of four cases and literature review

Thromboembolism is a major risk of carotid angioplasty and stenting (CAS). Although the incidence of distal embolism has been documented by MRI and TCD studies, the mechanisms and management of this complication are rarely reported. Here we describe four patients with periprocedural embolic events to demonstrate the mechanisms of thromboembolism in CAS. Different remedies were applied to these patients according to the underlying mechanisms of thromboembolism and good clinical outcomes were achieved.

Impact of silent ischemic lesions on cognition following carotid artery stenting

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The early and mid-term results of carotid artery stenting in high-risk patients

PURPOSE

This study aimed to investigate early and mid-term outcomes of carotid artery stenting (CAS).

METHODS

We retrospectively reviewed 111 patients who were treated for carotid stenosis between October 2004 and December 2009 (42 CASs and 69 carotid endarterectomies [CEAs]).

RESULTS

CAS group was older than CEA group (70 years vs. 67 years, P = 0.001). Coronary artery disease and high lesion above the 2nd cervical vertebral body were more common in CAS group (29% vs. 13%, P = 0.002; 4% vs. 24%, P = 0.004). The 30-days stroke rate was higher in CAS group (10% vs. 1% in CEA group, P = 0.067, Fisher's exact test). New brain lesions on diffusion-weighted magnetic resonance imaging were more common in CAS group (48% vs. 20% in CEA group, P = 0.002, chi-square test). The 1-, 3-year freedom from stroke were 91%, 84% in CAS group and 99%, 99% in CEA group (P = 0.007, log-rank test). Univariate analysis showed that female gender and age > 70 years were related with postprocedural neurological complications (P = 0.046 and P = 0.007, log-rank test). However, none were independent risk factors on multivariate analysis.

CONCLUSION

In our series, the rates of peri-procedural neurological complications in CAS group were significantly high. These results suggest that more experience and restricted patient selection will be needed for CAS.

Initial Experience With Transradial Access for Carotid Artery Stenting

We report our experience using transradial access (TRA) for carotid artery stenting (CAS). Eighty-eight patients underwent CAS using a nonfemoral approach, 79 of them by TRA. Carotid artery stenting was performed using standard techniques with a long hydrophilic sheath. Mean age was 69.5 years. A total of 46 patients were symptomatic and 34 were asymptomatic. Transradial access and procedural success were achieved in 98.8% and 96.6% of the cases, respectively. There were no deaths, myocardial infarction, or radial access site complications. In all, 2 patients sustained a stroke, 1 hemorrhage, and 1 ischemia. Carotid artery stenting using TRA was safe and technically feasible.

Safety and feasibility of a novel transcervical access neuroprotection system for carotid artery stenting in the PROOF Study

BACKGROUND

Randomized controlled trials have shown that periprocedural rates of stroke and death are higher with carotid artery stenting (CAS) than with carotid endarterectomy (CEA) in the treatment of carotid artery stenosis. Diffusion-weighted magnetic resonance imaging (DW-MRI) has shown higher rates of clinically silent new ischemic brain lesions when CAS is performed as compared with CEA. The Silk Road Medical Embolic PROtectiOn System: First-In-Man (PROOF) Study is a single-arm first-in-man study using the MICHI Neuroprotection System (Silk Road Medical Inc, Sunnyvale, Calif), a novel transcervical access and cerebral embolic protection system. This system enables stent implantation under controlled blood flow reversal of the carotid artery, also known as Flow Altered Short Transcervical Carotid Artery Stenting (FAST-CAS).

METHODS

Between March 2009 and February 2010, a total of 44 subjects were enrolled into the study. The primary composite endpoint was major stroke, myocardial infarction, or death within 30 days. Forty-three patients (97.7%) completed the study through the 30-day endpoint. One patient was lost to follow-up. In a subgroup of consecutive subjects, DW-MRI examinations were performed preprocedure and within 24 to 48 hours after the stent implantation. Blinded independent neuroradiologists reviewed all DW-MRI studies and confirmed the absence or presence of new ischemic brain lesions.

RESULTS

All enrolled patients were successfully treated, and no major adverse events were seen through the follow-up period. Thirty-one subjects had DW-MRI examinations. Of these, five patients (16%) had evidence of new ischemic brain lesions but no clinical sequelae. Transient intolerance to reverse flow was reported in 9% of cases, but in all cases, a stent was successfully placed, and the intolerance was managed by minimizing the duration of reverse flow during the procedure.

CONCLUSION

In this first-in-man experience, FAST-CAS using the MICHI Neuroprotection System was shown to be a safe and feasible method for carotid revascularization. DW-MRI findings suggest controlled reverse flow provides cerebral embolic protection similar to that seen with CEA.

Assembly of a multichannel video system to simultaneously record cerebral emboli with cerebral imaging

Stroke remains a significant risk of carotid revascularization for atherosclerotic disease. Emboli generated at the time of treatment either using endarterectomy or stent-angioplasty may progress with blood flow and lodge in brain arteries. Recently, the use of protection devices to trap emboli created at the time of revascularization has helped to establish a role for stent-supported angioplasty compared with endarterectomy. Several devices have been developed to reduce or detect emboli that may be dislodged during carotid artery stenting to treat carotid artery stenosis. A significant challenge in assessing the efficacy of these devices is precisely determining when emboli are dislodged in real time. To address this challenge, we devised a method of simultaneously recording fluoroscopic images, transcranial Doppler data, vital signs, and digital video of the patient/physician. This method permits accurate causative analysis and allows procedural events to be precisely correlated to embolic events in real time.

Embolic complications after carotid artery stenting or carotid endarterectomy are associated with tissue characteristics of carotid plaques evaluated by magnetic resonance imaging

BACKGROUND

Unstable carotid plaques are associated with an increased incidence of embolic complications after carotid artery stenting (CAS) or carotid endarterectomy (CEA). The aim of this study was to elucidate the relationship between the tissue components of carotid plaques and the incidence of new ipsilateral silent ischemic lesions (NISIL) after CAS or CEA.

METHODS

We performed CAS in 56 patients and CEA in 25 patients. We also performed quantitative analyses of carotid plaque characteristics before treatment using T1 weighted black-blood magnetic resonance imaging (BB-MRI). The signal intensity ratio (SIR) was defined as the ratio of signal intensity evaluated by BB-MRI in carotid plaques to that of sternocleidomastoid muscle. According to criteria that we and other investigators previously reported, an SIR ≥ 1.25 was defined as "high". NISIL were evaluated by diffusion-weighted imaging of MRI before and after CAS or CEA.

RESULTS

In the high SIR group, the incidence of NISIL was significantly greater after CAS than after CEA (61% vs 13%, respectively, p=0.006), whereas there were no significant difference in NISIL after the two procedures when the SIR was <1.25 (21% vs 0%). In multivariate regression analysis, the independent predictors of NISIL were CAS (p=0.002), symptomatic stenosis (p=0.036) and the SIR (p=0.049).

CONCLUSIONS

Noninvasive quantitative tissue characterization of carotid plaques using BB-MRI is useful to determine the indication for CAS.