First-in-Man Implantation of a New Hybrid Carotid Stent to Prevent Periprocedural Neurological Events During Carotid Artery Stenting

Carotid artery revascularization using second generation stents versus surgery: a meta-analysis of clinical outcomes

INTRODUCTION

Meta-analyses and emerging randomized data indicate that second-generation ('mesh') carotid stents (SGS) may improve outcomes versus conventional (single-layer) stents but clinically-relevant differences in individual SGS-type performance have been identified. No comparisons exist for SGS versus carotid endarterectomy (CEA).

EVIDENCE ACQUISITION

Thirty-day death (D), stroke (S), myocardial infarction (M), and 12-month ipsilateral stroke and restenosis in SGS studies were meta-analyzed (random effect model) against CEA outcomes. Eligible studies were identified through PubMed/EMBASE/COCHRANE. Forest plots were formed for absolute adverse evet risk in individual studies and for relative outcomes with each SGS deign versus contemporary CEA outcomes as reference. Meta-regression was performed to identify potential modifiers of treatment modality effect.

EVIDENCE SYNTHESIS

Data were extracted from 103,642 patients in 25 studies (14 SGS-treated, 41% symptomatic; nine randomized controlled trial (RCT)-CEA-treated, 37% symptomatic; and two Vascular Quality Initiative (VQI)-CEA-treated, 23% symptomatic). Casper/Roadsaver and CGuard significantly reduced DSM versus RCT-CEA (-2.70% and -2.95%, P<0.001 for both) and versus VQI-CEA (-1.11% and -1.36%, P<0.001 for both). Gore stent 30-day DSM was similar to RCT-CEA (P=0.581) but increased against VQI-CEA (+2.38%, P=0.033). At 12 months, Casper/Roadsaver ipsilateral stroke rate was lower than RCT-CEA (-0.75%, P=0.026) and similar to VQI-CEA (P=0.584). Restenosis with Casper/Roadsaver was +4.18% vs. RCT-CEA and +4.83% vs. VQI-CEA (P=0.005, P<0.001). CGuard 12-month ipsilateral stroke rate was similar to VQI-CEA (P=0.850) and reduced versus RCT-CEA (-0.63%, P=0.030); restenosis was reduced respectively by -0.26% and -0.63% (P=0.033, P<0.001). Twelve-month Gore stent outcomes were overall inferior to surgery.

CONCLUSIONS

Meta-analytic integration of available clinical data indicates: 1) reduction in stroke but increased restenosis rate with Casper/Roadsaver, and 2) reduction in both stroke and restenosis with CGuard MicroNET-covered stent against contemporary CEA outcomes at 30 days and 12 months used as a reference. This may inform clinical practice in anticipation of large-scale randomized trials powered for low clinical event rates (PROSPERO-CRD42022339789).

12-Month Outcomes of Carotid Artery Stenting With CGuard MicroNET-Covered Stent: A Single-Center Study in 113 Patients

Dual layer mesh stents constitute a novel treatment option for patients who undergo carotid artery stenting (CAS). The aim of this prospective study is to report 12 month outcomes of patients who underwent CAS with CGuard (Inspire MD, Tel Aviv, Israel) microNET self-expanding stent with embolic protection system in a tertiary center from October 2018 to March 2022. Primary endpoints included in-stent restenosis >70% verified by ultrasound (DUS), ipsilateral transient ischemic attack (TIA), and stroke at 12 months. Secondary endpoints included cardiovascular-related mortality (stroke, myocardial infarction, heart failure) and all-cause mortality during follow-up. One hundred thirteen patients were included in the study (male 72.5%), symptomatic 47.8%. Median follow-up was 25 months (2-48). By 12 months, there was one in-stent occlusion that manifested as stroke (1/113, 0.8%) but no other forms of in-stent restenosis. Two patients experienced contralateral TIA (1.7%). CVRM was 3.5% (4 MI) and all-cause mortality was 6% at follow-up. This prospective study shows that CAS with CGuard MicroNET-covered stent is safe with minimal neurological adverse events at 12 months follow-up. Larger, and longer-term studies are necessary to define CGuard long-term safety and protection against carotid-related stroke.

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.

Current status and outlook of biodegradable metals in neuroscience and their potential applications as cerebral vascular stent materials

Over the past two decades, biodegradable metals (BMs) have emerged as promising materials to fabricate temporary biomedical devices, with the purpose of avoiding potential side effects of permanent implants. In this review, we first surveyed the current status of BMs in neuroscience, and briefly summarized the representative stents for treating vascular stenosis. Then, inspired by the convincing clinical evidence on the in vivo safety of Mg alloys as cardiovascular stents, we analyzed the possibility of producing biodegradable cerebrovascular Mg alloy stents for treating ischemic stroke. For these novel applications, some key factors should also be considered in designing BM brain stents, including the anatomic features of the cerebral vasculature, hemodynamic influences, neuro-cytocompatibility and selection of alloying elements. This work may provide insights into the future design and fabrication of BM neurological devices, especially for brain stents.

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The current status of the application of biodegradable metals (BM) in neuroscience was presented.

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We analyzed the possibility of producing biodegradable cerebrovascular Mg alloy stents for ischemic stroke treatment.

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Key factors in designing BM brain stents were discussed.

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This work may provide insights into the future design and fabrication of BM neurological devices, especially for brain stents.

Is it possible to prevent cerebral embolization by improving the design and technology of carotid stent implantation?

INTRODUCTION

The prevention of atherosclerotic plaque fragmentation during carotid artery stenting is a fundamental problem in decreasing the risk of disability of patients. The goal of this review is to clarify whether the stent design can have a decisive impact on the rate of intraoperative and postoperative complications.

AREAS COVERED

Different designs of the carotid stents are briefed and the advantages and disadvantages of different stent designs are discussed as well as the results of their clinical use. Various solutions are presented to reduce cerebral embolism during carotid artery stenting.

EXPERT OPINION

There is no conclusive evidence for the benefits of closed cell and hybrid stents. The stent design cannot completely resolve the problem of cerebral embolism. Most of the events of cerebral microembolism occur at the stages of stent delivery rather than protrusion of an atherosclerotic plaque in the long-term follow-up. Most likely, minimization of the risks for periprocedural and postprocedural strokes requires not only the new solutions in stent design as well as the corresponding delivery systems and brain embolic protection systems, but also the new strategies of preprocedural drug stabilization of the atherosclerotic plaque in the carotid artery. Abbreviations: CAS, carotid artery stenting; CE, carotid endarterectomy; DW-MRI, diffusion-weighted magnetic resonance imaging; ECA, external carotid artery; ICA, internal carotid artery; IVUS, intravascular ultrasound examination; OCT, optical coherence tomography.

Thirty-day results from prospective multi-specialty evaluation of carotid artery stenting using the CGuard MicroNet-covered Embolic Prevention System in real-world multicentre clinical practice: the IRON-Guard study

AIMS

The aim of the present study was to evaluate periprocedural and 30-day outcomes in a prospective series of patients treated with the CGuard Embolic Prevention System (EPS).

METHODS AND RESULTS

From April 2015 to June 2016, a physician-initiated prospective multicentre study was performed in 200 consecutive patients admitted for protected carotid artery stenting (CAS) and treated using the CGuard EPS in twelve vascular centres. Outcome measures were: technical success, periprocedural (0-24 hours) and post-procedural (24 hours-30 days) major and minor strokes, death, acute myocardial infarction (AMI), transient ischaemic attack (TIA), and external carotid occlusion. In three centres, consecutive diffusion-weighted magnetic resonance cerebral imaging (DW-MRI) was performed ≤72 hours prior to and within 72 hours after the intervention. A distal embolic protection device was employed in 182 patients (91%). Technical success was 100%. No death, AMI or major stroke occurred periprocedurally. There were two TIAs and five periprocedural minor strokes (2.5%), including one thrombosis solved by surgery. In the remaining patients (199/200; 99.5%) one-month follow-up duplex ultrasound revealed optimal technical results. Post-procedural clinical follow-up was uneventful. No external carotid artery occlusion occurred. New post-procedural DW-MRI lesions were detected in 12 patients out of 61 (19.6%), including bilateral in five (8.2%) and isolated ipsilateral in six (9.8%), whereas one patient (1.6%) had contralateral only lesions.

CONCLUSIONS

Multicentre multi-specialty use of the CGuard EPS in routine clinical practice was associated with no major periprocedural neurologic complications and a total elimination of post-procedural neurologic complications by 30 days.

Device selection for carotid stenting: reviewing the evidence

INTRODUCTION

Carotid artery stenting (CAS) has recently changed the status in the treatment of the extracranial carotid atheromasic disease. In recent years, evolution in both stents and protection devices as well as in carotid stenting techniques, has resulted in an important reduction in the rate of stroke in patients undergoing CAS procedures. Areas covered: The purpose of this article is reviewing the literature and summarizing the current evidence of the new available materials to underline the importance of the correct choice of the devices during the procedure. Expert commentary: Certainly a key issue in order to limit the periprocedural events to the lowest possible, is to select the appropriate device for the appropriate patient anatomy and clinical syndrome, the so called 'tailored approach'.

One swallow does not a summer make but many swallows do: accumulating clinical evidence for nearly-eliminated peri-procedural and 30-day complications with mesh-covered stents transforms the carotid revascularisation field

Atherosclerotic carotid artery stenosis (CS) continues to be a common cause of acute ischaemic stroke. Optimised medical therapy (OMT), the first-line treatment modality in CS, may reduce or delay - but it does not abolish - CS-related strokes. As per current AHA/ASA and ESC/ESVS/ESO guidelines, carotid artery stenting (CAS) is a less-invasive alternative to carotid endarterectomy (CEA) for CS revascularisation in primary and secondary stroke prevention. Ten-year follow-up from the CREST trial in patients with symptomatic and asymptomatic CS confirmed equipoise of CAS and CEA in the primary endpoint. Nevertheless CAS - using a widely open-cell, first-generation stent and first-generation (distal/filter) neuroprotection - has been criticised for its relative excess of (mostly minor) strokes by 30 days, a significant proportion of which were post-procedural. Atherosclerotic plaque protrusion through conventional carotid stent struts, confirmed on intravascular imaging, has been implicated as a leading mechanism of the relative excess of strokes with CAS vs. CEA, including delayed strokes with CAS. Different designs of mesh-covered carotid stents have been developed to prevent plaque prolapse. Several multi-centre/multi-specialty clinical studies with CGurad MicroNet-Covered Embolic Prevention Stent System (EPS) and RoadSaver/Casper were recently published and included routine DW-MRI cerebral imaging peri-procedurally and at 30 days (CGuard EPS). Data from more than 550 patients in mesh-covered carotid stent clinical studies to-date show an overall 30-day complication rate of ~1% with near-elimination of post-procedural events. While more (and long-term) evidence is still anticipated, these results - taken together with optimised intra-procedural neuroprotection in CAS (increased use of proximal systems including trans-carotid dynamic flow reversal) and the positive 12-month mesh-covered stent data reports in 2017 - are transforming the carotid revascularisation field today. Establishing effective algorithms to identify the asymptomatic subjects at stroke risk despite OMT, and large-scale studies with mesh-covered stents including long-term clinical and duplex ultrasound outcomes, are the next major goals.

The Casper carotid artery stent: a unique all metal micromesh stent designed to prevent embolic release

Background

Stroke due to the release of embolic debris during the placement of a stent to correct carotid artery stenosis is a constant procedural and peri-procedural threat. The new all metal Casper stent has been created with two layers of nitinol, the inner layer of which has pores diminutive enough to prevent embolic release.

Objective

To evaluate the safety, effectiveness, and utility of the double layer nitinol Casper carotid artery stent in the treatment of patients with severe carotid artery stenosis.

Methods

19 patients with severe internal carotid artery stenosis, 14 symptomatic and 5 asymptomatic, were treated with the Casper stent. After stent placement, angiographic and cone beam CT images were recorded in all patients.

Results

The unique low profile delivery system allowed for easy stent placement, re-sheathing, and repositioning of the stent. The large cell external layer produced excellent apposition to the artery wall. The inner layer prevented prolapse of atherosclerotic debris through the device. Plaque coverage was achieved; residual stenosis ranged from 0% to 20%. Long term angiographic follow-up in 5 patients showed wall apposition of the device covering the lesion and no restenosis. There were no procedure related complications. Two patients experienced a delayed ischemic stroke, likely related to inconsistent medical management.

Conclusions

The Casper has been an excellent stent for the treatment of internal carotid artery stenosis and its internal micromesh layer has been effective in preventing plaque prolapse. It provides the flexibility of large cell stents and the inner layer provides maximum protection against plaque prolapse.

Clinical Results and Mechanical Properties of the Carotid CGUARD Double-Layered Embolic Prevention Stent

Purpose: To report early clinical outcomes with a novel double-layer stent for the internal carotid artery (ICA) and the in vitro investigation of the stent’s mechanical properties. Methods: A prospective single-center study enrolled 30 consecutive patients (mean age 73.1±6.3 years; 21 men) with symptomatic (n=25) or high-grade (n=5) ICA stenosis treated with the new double-layer carotid CGUARD Embolic Prevention System (EPS) stent, which has an inner open-cell nitinol design with an outer closed-cell polyethylene terephthalate layer. The average stenosis of the treated arteries was 84.1%±7.9% with a mean lesion length of 16.6±2.1 mm. In the laboratory, 8×40-mm stents where tested in vitro with respect to their radial force during expansion, the bending stiffness of the stent system and the expanded stent, as well as the collapse pressure in a thin and flexible sheath. The wall adaptation was assessed using fluoroscopy after stent release in step and curved vessel models. Results: The stent was successfully implanted in all patients. No peri- or postprocedural complications occurred; no minor or major stroke was observed in the 6-month follow-up. The bending stiffness of the expanded stent was 63.1 N·mm2 and (not unexpectedly) was clearly lower than that of the stent system (601.5 N·mm2). The normalized radial force during expansion of the stent to 7.0 mm, consistent with in vivo sizing, was relatively high (0.056 N/mm), which correlates well with the collapse pressure of 0.17 bars. Vessel wall adaptation was harmonic and caused no straightening of the vessel after clinical application. Conclusion: Because of its structure, the novel CGUARD EPS stent is characterized by a high flexibility combined with a high radial force and very good plaque coverage. These first clinical results demonstrate a very safe implantation behavior without any stroke up to 6 months after the procedure.

Initial Clinical Experience With the Micromesh Roadsaver Carotid Artery Stent for the Treatment of Patients With Symptomatic Carotid Artery Disease

Purpose: To assess the effectiveness, technical aspects, handling, and safety of the micromesh Roadsaver Carotid Artery Stent in the treatment of atherosclerotic carotid artery stenosis and tandem lesions in ischemic stroke patients. Methods: Seven patients (5 men; mean age 75±11.4 years, range 53–86) suffering from symptomatic internal carotid artery (ICA) stenosis (mean 76% diameter reduction) were treated with the dual layer closed-cell stent without embolic protection. Postdilation was performed in 6 of 7 patients. Two patients were treated in the context of ischemic stroke and concurrent middle cerebral artery occlusion. Mean National Institutes of Health Stroke Scale score at admission was 12.8±5. Results: All devices were deployed satisfactorily. One wall-adherent thromboembolus in a proximal ICA was covered with the Roadsaver stent in a tandem lesion setting. The modified Rankin Scale (mRS) declined from 3.7±0.7 to 2.4±0.8 in hospital, showing an improvement in clinical symptoms. No complications were detected during or after the procedure. The 30-day mRS was 1.7±1.1. At 6 months, ultrasound examination demonstrated patency of stents and the external carotid arteries. Conclusion: The Roadsaver double layer micromesh stent seems to be safe and effective in the treatment of extracranial ICA stenosis and in the context of tandem lesions in ischemic stroke. Further studies with larger populations are warranted.