Comparison of embolization protection device-specific technical difficulties during carotid artery stenting

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.

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

OBJECTIVE

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

MATERIALS & METHODS

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

RESULTS

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

CONCLUSIONS

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

Proximal balloon occlusion versus distal filter protection in carotid artery stenting: A meta-analysis and review of the literature

INTRODUCTION

Carotid artery stenting (CAS) is typically performed using embolic protection devices (EPDs) as a means to reduce the risk of procedure-related stroke. In this study, we compared procedural morbidity and mortality associated with distal (D-EPD) vs. proximal (P-EPD) protection.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were queried from January 1998 through May 2015. Only studies comparing (D-EPD) and (P-EPD) were included. Two independent reviewers selected and appraised studies and extracted data in duplicate. Random-effects meta-analysis was used to pool outcomes across studies. Heterogeneity of treatment effect among studies was assessed using the I² statistics. Publication bias was assessed using inspection of funnel plots. The primary endpoints included 30-day mortality and stroke. Secondary endpoints included new cerebral lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) and contralateral lesions on DW-MRI.

RESULTS

A total of 12,281 patients were included from 18 studies (13 prospective and 5 retrospective) comparing (D-EPD) and (P-EPD) in the setting of CAS. The mean patient age was 69 years and 64% of patients were male. No evidence of publication bias was detected. There was no significant difference between the two modalities in terms of the risk of stroke (risk difference [RD] 0.0, 95% confidence interval [CI] -0.01 to 0.01) or mortality (RD 0.0, 95% CI -0.01 to 0.01) nor was there any difference in the incidence of new cerebral lesions on DW-MRI or contralateral DW-MRI lesions.

CONCLUSIONS

In patients undergoing CAS, both D-EPD and P-EPD provide similar levels of protection from peri-procedural stroke and 30 days mortality. © 2016 Wiley Periodicals, Inc.

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.

Management of extracranial carotid artery disease

Stroke is the third leading cause of death in developed nations. Up to 88% of strokes are ischemic in nature. Extracranial carotid artery atherosclerotic disease is the third leading cause of ischemic stroke in the general population and the second most common nontraumatic cause among adults younger than 45 years. This article provides comprehensive, evidence-based recommendations for the management of extracranial atherosclerotic disease, including imaging for screening and diagnosis, medical management, and interventional management.

Carotid artery stenting: current and emerging options

Carotid artery stenting technologies are rapidly evolving. Options for endovascular surgeons and interventionists who treat occlusive carotid disease continue to expand. We here present an update and overview of carotid stenting devices. Evidence supporting carotid stenting includes randomized controlled trials that compare endovascular stenting to open surgical endarterectomy. Carotid technologies addressed include the carotid stents themselves as well as adjunct neuroprotective devices. Aspects of stent technology include bare-metal versus covered stents, stent tapering, and free-cell area. Drug-eluting and cutting balloon indications are described. Embolization protection options and new direct carotid access strategies are reviewed. Adjunct technologies, such as intravascular ultrasound imaging and risk stratification algorithms, are discussed. Bare-metal and covered stents provide unique advantages and disadvantages. Stent tapering may allow for a more fitted contour to the caliber decrement between the common carotid and internal carotid arteries but also introduces new technical challenges. Studies regarding free-cell area are conflicting with respect to benefits and associated risk; clinical relevance of associated adverse effects associated with either type is unclear. Embolization protection strategies include distal filter protection and flow reversal. Though flow reversal was initially met with some skepticism, it has gained wider acceptance and may provide the advantage of not crossing the carotid lesion before protection is established. New direct carotid access techniques address difficult anatomy and incorporate sophisticated flow-reversal embolization protection techniques. Carotid stenting is a new and exciting field with rapidly advancing technologies. Embolization protection, low-risk deployment, and lesion assessment and stratification are active areas of research. Ample room remains for further innovations and developments.

Pathophysiology of flow impairment during carotid artery stenting with an embolus protection filter

OBJECTIVE

Carotid artery stenting (CAS) is a well-accepted treatment for atherosclerotic stenosis of carotid arteries. Since the occurrence of distal embolization with CAS is still a major concern embolus protection devices (EPD) are usually employed during the procedure. We examined two types of embolus protection filters (Angioguard XP (AG); Filterwire EZ (FW)) and evaluated the function. Thus, the filter was examined postoperatively and the cause of intraoperative flow impairment was evaluated.

MATERIALS AND METHODS

CAS was performed for 54 patients with carotid artery stenosis (55 lesions: 25 AG; 27 FW; 3 others). After completing CAS the filter membrane was stained with hematoxylin-eosin (HE) solution and removed from the filter strut. Once mounted on a glass slide the filter was evaluated under a microscope. The area occupied with debris was measured and the relationship to intraoperative flow impairment was evaluated. Furthermore, the relationship between perioperative ischemic complications and intraoperative flow impairment was statistically analyzed.

RESULTS

Microscopic observation of the slide revealed the pore density of the FW was 1.5 times higher than that of the AG and the filter area of the FW was 2.5 times wider than than the AG. HE staining facilitated characterization of the debris composition. The area occupied with debris was significantly more in the AG (0.241 ± 0.13 cm(2)) than in the FW (0.129 ± 0.093 cm(2)). Thus, fibrin was significantly more precipitated in the AG. Flow impairment occurred in 6 AG cases (24.0 %) and 4 FW cases (14.8 %). It was induced by filter obstruction in the AG and by vasospasms in the FW. Three cases treated with AG (12.0 %) were complicated with cerebral infarction and all of them were related to flow impairment. One FW case (3.7 %) was complicated with cerebral infarction in presence of preserved flow throughout the intervention.

CONCLUSION

Filter function is different according to each design. The cause of flow impairment was attributable to filter obstruction in the AG group and to vasospasms in the FW group. Filter obstruction tends to result in cerebral infarction.

Carotid artery stenting without post-stenting balloon dilatation

PURPOSE

To evaluate the clinical outcome and MRI findings after carotid artery stenting (CAS) without post-dilatation.

METHODS

Between May 2005 and April 2012, a total of 169 consecutive patients (61.4% symptomatic) underwent 176 CAS procedures performed with an embolic protection device (GuardWire, n=116; FilterWire EZ, n=60). All stents were deployed without post-dilatation. Periprocedural complications and mid-term outcomes were analyzed.

RESULTS

The stroke rate was 2.3% within 30 days post-CAS (asymptomatic patients 1.5%; symptomatic patients 2.8%). Cerebral infarction occurred in one asymptomatic patient (1.5%) and one symptomatic patient (0.9%). Intracranial hemorrhage occurred in two symptomatic patients (1.9%). Post-CAS diffusion-weighted imaging (DWI) revealed a high-intensity area in 26 of 176 procedures (14.8%). Ipsilateral stroke after 31 days occurred in two patients (1.1%) and restenosis occurred in six (3.4%). A post-CAS comparison of the embolic protection devices revealed no difference in stroke incidence within 30 days and in DWI high-intensity area.

CONCLUSIONS

Our CAS procedure without post-dilatation is feasible, safe and associated with a low incidence of stroke and restenosis.

Management of carotid stenosis. History and today

Internal carotid stenosis constitutes a significant clinical challenge, since it is the cause of 20–25% of ischemic brain strokes. The management of the internal carotid stenosis for many years has been raising controversies amongst neurologists, vascular surgeons and interventional radiologists mainly due to the introduction of endovascular stenting as an alternative to surgical treatment. Its application, however, requires knowledge of specific selection criteria for this kind of treatment as well as of the methods of monitoring patients after stent implantation into the internal carotid artery. Duplex Doppler ultrasound examination is currently a basis for the diagnosis of the arterial stenosis of precranial segments of the carotid arteries. It allows a reliable assessment of not only the course and morphology of the walls, but also of the hemodynamics of blood flow. Interventional treatment is applicable in patients with internal carotid stenosis of ≥70%, which is accompanied by an increase of the systolic flow velocity above 200 cm/s and the end-diastolic velocity above 50–60 cm/s in the stenotic lumen. In most cases, such a diagnosis in duplex Doppler ultrasound examination does not require any confirmation by additional diagnostic methods and if neurological symptoms are also present, it constitutes a single indication for interventional treatment. When deciding about choice of surgical or endovascular method of treatment, the following factors are of crucial importance: morphology of atherosclerotic plaque, its size, echogenicity, homogeneity of its structure, its surface and outlines. By means of ultrasound examinations, patients can be monitored after endovascular stent implantation. They enable evaluation of the degree of stent patency and allow for an early detection of symptoms indicating stenosis recurrence or presence of in-stent thrombosis. When interpreting the findings of the US checkup, it is essential to refer to the initial examination performed in the first days after the procedure and the next ones conducted during the monitoring period.

Tratamento endovascular da reestenose carotídea: resultados em curto prazo

CONTEXTO: O tratamento cirúrgico da reestenose carotídea apresenta alta taxa de lesão neurológica. Contrariamente, o tratamento endovascular da doença obstrutiva carotídea extracraniana tem se tornado mais factível e gradualmente menores taxas de risco cirúrgico vêm sendo reportadas, tornando-se uma opção em situações especiais, e provavelmente poderá ser considerado o tratamento padrão para reestenose carotídea. OBJETIVOS: Avaliar a aplicabilidade, a segurança e a eficácia da angioplastia com o uso do stent (ACS) no tratamento da reestenose carotídea (REC) no intraoperatório e no pós-operatório recente (<30 dias). MÉTODOS: Análise retrospectiva dos pacientes portadores de reestenose carotídea submetidos à angioplastia com stent no período de março 2000 a junho de 2004. RESULTADOS: Foram analisados 19 pacientes com reestenose carotídea. Quatorze pacientes (74%) eram do sexo masculino, com média de idade de 74 anos. Quinze (79%) eram assintomáticos com estenose >80%, enquanto quatro (21%) eram sintomáticos com estenose >70%. Apenas em um paciente não foi utilizado sistema de proteção cerebral. O sucesso técnico foi obtido em todos os casos. Não houve morte ou acidente vascular encefálico no intra ou no pós-operatório recente (30 dias). CONCLUSÃO: O tratamento endovascular da reestenose carotídea mostrou-se uma abordagem factível e segura em curto prazo

Use of a guide wire system to insert guiding catheters

In patients with severe arteriosclerosis or anatomical variations such as a bovine arch, the insertion of a guiding catheter for carotid artery stenting is difficult. The authors use a guide wire system as an anchor and advance the guiding catheter to an area proximal to the stenotic structure. This method is useful and safer than others for carotid artery stenting.

Observation of the embolus protection filter for Carotid Artery Stenting

BACKGROUND

Carotid artery stenting in patients with high surgical risk is considered as an effective alternative to carotid endarterectomy. Because the occurrence of distal embolization with CAS is still a major concern, an embolus protection device is usually used during the procedure. We developed a technique for observation of embolus protection filter and evaluated the debris or thrombus microscopically, and the pathologic findings were compared with preoperative imaging studies.

METHODS

After completing CAS, the filter membrane was stained with HE solution and removed from filter strut. Mounting onto a glass slide, the filter was evaluated under a microscope. Plaque debris and appearance of filter membrane were evaluated, and the covered area was measured. The pathologic findings were compared with preoperative imaging studies.

RESULTS

Microscopic observation of the slide revealed atheromatous debris as well as thrombotic material to the filter membrane. Hematoxylin-eosin stain facilitates the characterization of the debris composition, namely, thrombotic debris, calcified debris, organized debris, fibrous debris, and lipid-rich debris. The subtypes of debris were consistent with preoperative imaging studies. Thus, in cases of intraprocedural flow impairment, more than 50% of the filter area was covered with debris or thrombotic material.

CONCLUSION

Carotid plaque debris captured during carotid stenting with protection filter can be visualized with HE stain on the glass side. This simple method allows us to better understand the plaque debris and appearance of embolus protection filter.

Probable blood-brain barrier disruption after carotid artery stenting

A 74-year-old man presented with prolonged reversible neurological deficits caused by internal carotid artery stenosis. He underwent carotid artery stenting (CAS) and developed persistent neurological deficits shortly following the intervention. Delayed gadolinium enhancement of the cerebrospinal fluid space on fluid-attenuated inversion recovery images indicated probable blood-brain barrier (BBB) disruption. Post-procedural perfusion-weighted magnetic resonance images could not demonstrate distinct areas of hyperperfusion or hypoperfusion. The neurological deficits probably resulted from BBB disruption secondary to sudden hemodynamic change occurring during CAS.

The type of embolic protection does not influence the outcome in carotid artery stenting

OBJECTIVES

The goal of this study was to review our experience with embolic protection devices (EPDs) during carotid artery stenting (CAS). Specifically, we aimed to verify their clinical effectiveness and to compare clinical outcomes between specific devices and types of EPDs.

METHODS

The CAS databases at four participating centers were reviewed. Adverse events were defined as death, stroke (>24 hours), or transient ischemic attack (TIA) (<24 hours). We compared the risk of procedural and 30-day events between patients treated with and without an EPD. We also compared these risks between different EPDs and between the different types of EPDs.

RESULTS

A total of 3160 CAS procedures using nine EPDs were analyzed. The risk of a procedural adverse event was 0.9% in protected and 2.3% in unprotected procedures (P = .12). Compared with the most frequently used device (FilterWire, Boston Scientific, Natick, Mass), there was no significant difference in the risk of procedural adverse events for any of the other EPDs. There was, however, an increased risk of 30-day adverse events with the Accunet (Abbott Vascular, Redwood, Calif) filter compared with the FilterWire (relative risk [RR] 2.67, confidence interval [CI] 1.41 to 5.04, P = .005). Pairwise comparison of proximal occlusion balloons to filters, distal occlusion balloons to filters, and proximal to distal occlusion balloons revealed no significant difference in the risk of procedural or 30-day adverse events. There was no significant difference in risk of procedural events between eccentric and concentric filters, however, the relative risk of eccentric compared with concentric filters at 30 days was 0.59 (unadjusted, CI 0.38 to 0.92, P = .04). This difference was still apparent after adjustment for risk factors (RR 0.61, CI 0.39 to 0.95, P = .06), but not after adjustment for risk factors and stent-type [(open-cell vs closed-cell) RR 0.76, CI 0.47 to 1.22, P = .51].

CONCLUSION

The use of EPDs is associated with a low risk of procedural adverse events. We were unable to detect significant differences in risks of procedural adverse events between different devices or types of devices. We speculate that the observed differences seen at 30 days are largely attributable to differences in stent-type used.

Methods for Three-Dimensional Geometric Characterization of the Arterial Vasculature

Complex vascular anatomy often affects endovascular procedural outcome. Accurate quantitative assessment of three-dimensional (3D) in-vivo arterial morphology is therefore vital for endovascular device design, and preoperative planning of percutaneous interventions. The aim of this work was to establish geometric parameters describing arterial branch origin, trajectory, and vessel curvature in 3D space that eliminate the errors implicit in planar measurements. 3D branching parameters at visceral and aortic bifurcation sites, as well as arterial tortuosity were determined from vessel centerlines derived from magnetic resonance angiography data for three subjects. Errors in coronal measurements of 3D branching angles for the right and left renal arteries were 3.1 +/- 3.4 degrees and 7.5 +/- 3.7 degrees , respectively. Distortion of the anterior visceral branching angles from sagittal measurements was less pronounced. Asymmetry in branching and planarity of the common iliac arteries was observed at aortic bifurcations. The renal arteries possessed considerably greater 3D curvature than the abdominal aorta and common iliac vessels with mean average values of 0.114 +/- 0.015 and 0.070 +/- 0.019 mm(-1) for the left and right, respectively. In conclusion, planar projections misrepresented branch trajectory, vessel length, and tortuosity proving the importance of 3D geometric characterization for possible applications in planning of endovascular interventional procedures and providing parameters for endovascular device design.