Preliminary Clinical Results and Mechanical Behavior of a New Double-Layer Carotid Stent

Next-generation transcarotid artery revascularization: TransCarotid flOw Reversal Cerebral Protection And CGUARD MicroNET-Covered Embolic Prevention Stent System To Reduce Strokes - TOPGUARD Study

BACKGROUND

Stent-assisted carotid artery revascularization employing surgical cutdown for transcervical access and dynamic flow reversal (TCAR) is gaining popularity. TCAR, despite maximized intra-procedural cerebral protection, shows a marked excess of 30-day neurologic complications in symptomatic vs. asymptomatic stenoses. The TCAR conventional single-layer stent (free-cell area 5.89mm2) inability to seal embologenic lesions may be particularly relevant after the flow reversal neuroprotection is terminated.

METHODS

We evaluated peri-procedural and 30-day major adverse cerebral and cardiac events (MACCE) of TCAR (ENROUTE, SilkRoad Medical) paired with MicroNET-covered neuroprotective stent (CGuard, InspireMD) in consecutive patients at elevated risk of complications with transfemoral/transradial filter-protected stenting (increased lesion-related and/or access-related risk). CGuard (MicroNET free cell area ≈0.02-0.03 mm2) has level-1 evidence for reducing intra- and abolishing post-procedural lesion-related cerebral embolism.

RESULTS

One hundred and six increased-risk patients (age 72 [61-76] years, median [Q1-Q3]; 60.4% symptomatic, 49.1% diabetic, 36.8% women, 61.3% left-sided index lesion) were enrolled in three vascular surgery centers. Angiographic stenosis severity was 81 (75-91)%, lesion length 21 (15-26)mm, increased-risk lesional characteristics 87.7%. Study stent use was 100% (no other stent types). 74.5% lesions were predilated; post-dilatation rate was 90.6%. Flow reversal duration was 8 (5-11)min. One stroke (0.9%) occurred in an asymptomatic patient prior to establishing neuroprotection (index lesion disruption with the sheath insertion wire); there were no other peri-procedural MACCE. No further adverse events occurred by 30-days. 30-day stent patency was 100% with normal velocities and absence of any in-stent material by Duplex Doppler.

CONCLUSIONS

Despite a high proportion of increased-risk lesions and clinically symptomatic patients in this study, TCAR employing the MicroNET-covered anti-embolic stent showed 30-day MACCE rate <1%. This suggests a clinical role for combining maximized intra-procedural prevention of cerebral embolism by dynamic flow reversal with anti-embolic stent prevention of peri- and post-procedural cerebral embolism (TOPGUARD NCT04547387).

Flow Diversion Effect in a Saphenous Vein Graft Aneurysm Using a Double-Layer Micromesh Stent: A Case Report

BACKGROUND AND IMPORTANCE

A double-layer micromesh stent is designed for the treatment of carotid artery stenosis that has been reported to potentially provide a flow diversion effect. However, the actual flow diversion effect of stents remains unclear. Here, we present a case of a growing saphenous vein graft (SVG) aneurysm treated with the placement of the double-layer micromesh stent using its flow diversion effect.

CLINICAL PRESENTATION

A 66-year-old woman, who underwent high-flow bypass using a SVG for a blister-like internal carotid artery aneurysm 13 years earlier at our institute, was referred to our hospital with a pulsatile cervical mass. Magnetic resonance angiography showed a 9-mm aneurysm on the left SVG, although the aneurysm was a small pouch 4 years earlier. Digital subtracted angiography demonstrated a 9.4 × 8.3-mm aneurysm from the SVG at the auricular level. Because the diameter of the graft was larger than that of the available flow diverter stents in Japan, we decided to place the double-layer micromesh stent (CASPER RX, 7 × 25 mm MicroVention) using its flow diversion effect. Computational fluid dynamics analysis before and after stent deployment showed a significant reduction in the average flow velocity and wall shear stress in the aneurysm, indicating actual flow diversion. An angiogram 2 months postoperatively showed complete obliteration of the aneurysm.

CONCLUSION

Obliteration of the saphenous vein aneurysm was achieved because of the flow diversion effect of the double-layer micromesh stent. The stents might be a feasible alternative for treating cervical carotid aneurysms.

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.

Anatomical Modifications After Stent Implantation: A Comparative Analysis Between CGuard, Wallstent, and Roadsaver Carotid Stents

PURPOSE

Carotid revascularization can be associated with modifications of the vascular geometry, which may lead to complications. The changes on the vessel angulation before and after a carotid WallStent (WS) implantation are compared against 2 new dual-layer devices, CGuard (CG) and RoadSaver (RS).

MATERIALS AND METHODS

The study prospectively recruited 217 consecutive patients (112 GC, 73 WS, and 32 RS, respectively). Angiography projections were explored and the one having a higher arterial angle was selected as a basal view. After stent implantation, a stent control angiography was performed selecting the projection having the maximal angle. The same procedure is followed in all the 3 stent types to guarantee comparable conditions. The angulation changes on the stented segments were quantified from both angiographies. The statistical analysis quantitatively compared the pre-and post-angles for the 3 stent types. The results are qualitatively illustrated using boxplots. Finally, the relation between pre- and post-angles measurements is analyzed using linear regression.

RESULTS

For CG, no statistical difference in the axial vessel geometry between the basal and postprocedural angles was found. For WS and RS, statistical difference was found between pre- and post-angles. The regression analysis shows that CG induces lower changes from the original curvature with respect to WS and RS.

CONCLUSION

Based on our results, CG determines minor changes over the basal morphology than WS and RS stents. Hence, CG respects better the native vessel anatomy than the other stents.Level of Evidence: Level 4, Case Series.

Carotid endarterectomy for acute carotid thrombosis after carotid artery stenting with CASPER Rx® stent: A case report

Background

Acute carotid stent thrombosis (ACST) is a rare but devastating complication for carotid artery stenting (CAS). That requires early diagnosis and immediate treatment. Although administration of drugs or endovascular treatment is the most widely used approach for patients with ACST, there is no consensus on the standard treatment of this disease.

Case Description

The present study reports on an 80-year-old female patient with the right internal carotid artery stenosis (ICS) that had been followed up by ultrasonography for 8 years. Although the optimal medical treatment was followed, the patient's right ICS worsened, and the patient was subsequently hospitalized for CAS. On the 12^th day after CAS, left paralysis and dysarthria were observed. Head magnetic resonance imaging (MRI) showed acute obstruction of the stent and scattered cerebral infarction in the right cerebral hemisphere caused possibly by the discontinuation of temporary antiplatelet drug therapy as a means to prepare for embolectomy of the femoral artery. Stent removal and carotid endarterectomy (CEA) were selected as the appropriate treatment approach. CEA was performed with the precaution of stent removal and distal embolism, and complete recanalization was obtained. Postoperative head MRI showed no new findings of cerebral infarction, and the patients remained symptom-free after 6 months of postoperative follow-up.

Conclusion

Stent removal with CEA could be an appropriate curative option in some cases with ACST except in patients at high risk of CEA and in the chronic phase after CAS.

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.

Efficacy of Post-Dilatation during Carotid Artery Stenting for Unstable Plaque Using a Double-Layer Stent Evaluated by OFDI

Objective

This study aimed to use optical frequency domain imaging (OFDI) to evaluate the efficacy of post-dilatation (PD) after stent placement for unstable plaques during carotid artery stenting (CAS) using a double-layer stent.

Methods

Twelve unstable carotid plaque lesions diagnosed by MRI were evaluated using OFDI during CAS. The pre-procedural minimum lumen diameter was 1.6 ± 0.7 mm. Each lesion was pre-dilated with balloon catheters (diameter, 5.3 ± 0.5 mm), and a double-layer stent was deployed. PD was performed with balloon catheters of the same size as those used for pre-dilatation. Cross-sectional OFDI images within the stented segment were evaluated at 1-mm intervals for a 20-mm segment, including the most stenotic lesion. Slice rates for the presence of in-stent plaque protrusion (PP) and plaque between the double-layer lumen were calculated.

Results

No procedural complications occurred with the use of an embolic protection device. Compared to after stent placement, slice rates for any PP (44 ± 19% to 62 ± 22%, P <0.05) and plaque between the double-layer lumen (79 ± 16% to 91 ± 34%, P <0.05) were significantly increased after PD; slice rates for >500 μm PP (7.5 ± 14% to 0%, P <0.05) were significantly decreased. Visible debris were captured in 50% of lesions.

Conclusion

PD after double-layer carotid stent placement decreases in-stent large PP. Double-layer construction contributed to the prevention of large PP, as the PP may have been crushed into debris by PD.

Casper stent in the treatment of pulsatile tinnitus in fibromuscular dysplasia: Therapeutic review and case report

Fibromuscular dysplasia (FMD) is a known cause of pulsatile tinnitus that can, on rare occasion, evolve into an incapacitating condition. It is a noninflammatory and nonatherosclerotic arteriopathy of unknown cause that affects medium-sized vessels, such as the carotid and renal arteries, occurring mainly in women. We describe a 72-year-old woman suffering from pulsatile tinnitus refractory to medical treatment who was successfully treated with Casper stent in the carotid artery. The different treatment strategies published in the literature were reviewed.

Contemporary Results of Carotid Artery Stenting Using Low-Profile Dual-Metal Layer Nitinol Micromesh Stents in Relation to Single-Layer Carotid Stents

PURPOSE

To evaluate patients characteristics, procedural details, perioperative outcomes, and midterm results of carotid artery stenting (CAS) performed with the Roadsaver/Casper stent (Terumo Corp, Tokyo, Japan) as compared to concurrent patients treated with other commercially available carotid stents.

MATERIALS AND METHODS

This is a single-center, retrospective, nonrandomized study including 200 consecutive patients who underwent a total of 205 elective CAS procedures due to severe internal carotid artery stenosis between April 2015 and December 2018. Procedural data and outcomes for patients treated with the Roadsaver/Casper stent implantation (100 procedures, in 97 patients) vs first-generation carotid stents implantations (90 procedures, in 88 patients) were compared. Fifteen patients were treated with CGuard carotid stent (InspireMD, Tel Aviv, Israel), and outcomes were reported separately. Primary endpoints were the occurrence of major adverse cerebrovascular events (MACE), including death, ipsilateral stroke, and transitory ischemic attack (TIA). Secondary endpoints were the rate of intrastent stenosis, the need for reintervention, and the occurrence of adverse cardiovascular events, including myocardial infarction, arrhythmias, and need for inotropic support.

RESULTS

No difference in demographics and preoperative risk factors were observed between patients treated with and without the Roadsaver/Casper stent. The mean procedure time was shorter in the Roadsaver/Casper group (40.7±16.9 vs 49.4±27.3 minutes; p=0.008), while radial percutaneous access was more frequent (24% vs 5%; p<0.001). The rate of stroke/TIA/death at 30 days was 3% in the Roadsaver group vs 1% in the first-generation stent group (p=0.623). The primary patencyrate was 100% and 93.4% at 1- and 3-year of follow-up in the Roadsaver/Casper groupand 99% and 94.3% in the other stent group, respectively (p=0.95).

CONCLUSIONS

In this real-world cohort of patients undergoing CAS, the Roadsaver/Casper stent was used to treat more symptomatic and vulnerable carotid plaques as compared to other carotid stents. Nevertheless, patients treated with this low-profile dual-layer micromesh stent showed low events rates at both 30 days and follow-up, similar to that observed for other stents.

Influence of Drug Incorporation on the Physico-Chemical Properties of Poly(l-Lactide) Implant Coating Matrices-A Systematic Study

Local drug delivery has become indispensable in biomedical engineering with stents being ideal carrier platforms. While local drug release is superior to systemic administration in many fields, the incorporation of drugs into polymers may influence the physico-chemical properties of said matrix. This is of particular relevance as minimally invasive implantation is frequently accompanied by mechanical stresses on the implant and coating. Thus, drug incorporation into polymers may result in a susceptibility to potentially life-threatening implant failure. We investigated spray-coated poly-l-lactide (PLLA)/drug blends using thermal measurements (DSC) and tensile tests to determine the influence of selected drugs, namely sirolimus, paclitaxel, dexamethasone, and cyclosporine A, on the physico-chemical properties of the polymer. For all drugs and PLLA/drug ratios, an increase in tensile strength was observed. As for sirolimus and dexamethasone, PLLA/drug mixed phase systems were identified by shifted drug melting peaks at 200 °C and 240 °C, respectively, whereas paclitaxel and dexamethasone led to cold crystallization. Cyclosporine A did not affect matrix thermal properties. Altogether, our data provide a contribution towards an understanding of the complex interaction between PLLA and different drugs. Our results hold implications regarding the necessity of target-oriented thermal treatment to ensure the shelf life and performance of stent coatings.

Effectiveness and safety of dual-layer stents in carotid artery disease: a systematic review

INTRODUCTION

Carotid artery stenting (CAS) has emerged as a minimally invasive alternative to carotid endarterectomy (CEA) in atherosclerotic carotid artery disease, even though the risk for procedural stroke after CAS remains significantly higher. Recently, in order to reduce embolic cerebral events after CAS, a new generation of dual-layer stents (DLS) has been developed. This review aimed to perform a detailed analysis of the available evidence on safety and efficacy of DLS in both symptomatic and asymptomatic atherosclerotic carotid artery stenosis.

EVIDENCE ACQUISITION

A systematic review was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The primary endpoint was the 30-day rate of myocardial infarction (MI), stroke and death. Secondary outcomes included rate and timing of stent occlusion/restenosis.

EVIDENCE SYNTHESIS

A total of 20 articles with 1193 patients were included. Thirty-day MI ranged from 0-5%, 30-day stroke ranged from 0-10.5% and 30-day mortality ranged from 0-10%. Stent occlusion rate ranged from 0-52.4%, the majority of which occurred intraprocedurally (N.=50; 61.7%), in emergency treated patients. The incidence of new ipsilateral cerebral ischemic lesions after CAS with DLS was reported in five studies, ranging from 5.5-37%.

CONCLUSIONS

Despite the theoretic advantage of reducing the risk for procedural embolic events when compared to conventional stents, high quality evidence is scarce. Also, safety issues regarding DLS in the emergency setting have been raised, particularly for thrombotic complications. Additional data from well-designed Randomized Controlled Trials are needed to assert the true value of DLS.

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.

Carotid Calcium Volume and Stenosis after Stent Implantation

INTRODUCTION

Internal carotid artery (ICA) stenosis could be treated with stent placement. It was hypothesized that calcium amount could be predictive of vessel stenosis after stent placement. We utilised computed tomography (CT) angiography to quantify volume of calcium material in bulbar ICA.

MATERIALS AND METHODS

28 patients with 31 treated ICA stenosis were collected and analysed using CT angiography-based calcium volume measurement. The Casper stent system (CSS) was used exclusively. Prospective data on emergent carotid stenosis were collected using serial ultrasound controls over a 12-month period.

RESULTS

Median age was 76 years (interquartile range (IQR) 67.5-77.8) and the majority were men (71.4%). Plaque median calcium volume was 0.142 cm3 (IQR 0.030 - 0.227) and median average Hounsfield Units (HU) were 561.0 (414.5-675.0). We detected positive linear relationship between average HU and ICA calcium volume. Furthermore, weak positive correlation was observed between calcium volume and residual stenosis as seen on post-interventional angiography, (correlation coefficient R = 0.38, p=0.035). Stronger positive correlation emerged between plaques' average HU and residual stenosis (R = 0.42, p=0.018). Angiographic stenosis showed univariate association with late stenosis as detected 12 months after CAS.

CONCLUSION

Calcium burden could be associated with residual stenosis after CSS placement. Larger studies are needed to confirm our preliminary data.

Endovascular flow-diversion of visceral and renal artery aneurysms using dual-layer braided nitinol carotid stents

BACKGROUND

Visceral and renal artery aneurysms (VRAAs) are uncommon but are associated with a high mortality rate in the event of rupture. Endovascular treatment is now first line in many centres, but preservation of arterial flow may be difficult in unfavourable anatomy including wide necked aneurysms, parent artery tortuosity and proximity to arterial bifurcations. Endovascular stenting, and in particular flow-diversion, is used in neurovascular intervention to treat intracranial aneurysms but is less often utilised in the treatment of VRAAs. The CASPER stent is a low profile dual-layer braided nitinol stent designed for carotid stenting with embolic protection and flow-diversion properties. We report the novel use of the CASPER stent for the treatment of VRAAs. We present a case series describing the treatment of six patients with VRAAs using the CASPER stent.

RESULTS

Six patients with unruptured VRAAs were treated electively. There were three splenic artery aneurysms and three renalartery aneurysms. Aneurysms were treated with the CASPER stent, with or without loose aneurysm coil packing or liquid embolic depending on size and morphology. All stents were successfully deployed with no immediate or periprocedural complications. Four aneurysms completely occluded after serial imaging follow up with one case requiring repeat CASPER stenting for complete occlusion. In one patient a single aneurysm remained patent at last follow up, A single case was complicated by delated splenic infarction and surgical splenectomy.

CONCLUSION

Preliminary experience with the CASPER stent suggests it is technically feasible and effective for use in the treatment of VRAAs.

Comparison of different carotid stent designs in endovascular therapy of severe carotid artery stenosis

Background:

One of the major periprocedural risks of carotid artery stenting is embolism caused either by plaque debris or by local thrombus forming. Double-layer micromesh stent design has shown to lower the chance of debris embolism but might have a slightly higher risk of local thrombus forming. Thus, we compared two different stent designs regarding safety and outcome profile in elective patients with high-grade carotid artery stenosis using a self-expanding, double-layer micromesh carotid stent system (DLCS) or a self-expanding hybrid carotid stent system (HCS).

Methods:

A single-center, open-label, retrospective cohort study of 67 consecutive, elective patients with high-grade symptomatic and asymptomatic carotid stenosis was executed at a comprehensive stroke center. Outcome measures were reocclusion rate, periprocedural symptomatic ischemic events, as well as other periprocedural complications, and recurrent stroke and mortality at 30 days’ follow-up.

Results:

Thirty-two patients (24% women, median age 75 years (interquartile range (IQR) 71–80) were treated with DLCS, and 35 patients (29% women, median age 71 years (IQR 63–76) years) with HCS. In both groups, pretreatment carotid stenosis degree was similar (median NASCET of 80%). Successful deployment was achieved in all cases without technical failure, and both groups did not differ in reocclusion rates, recurrent stroke, and mortality within 30 days.

Conclusions:

DCLS and HCS revealed to have similar safety and outcome profile in elective patients with high-grade symptomatic as well as asymptomatic carotid artery stenosis.

(In)comparability of Carotid Artery Stent Characteristics: A Systematic Review on Assessment and Comparison with Manufacturer Data

Purpose

Carotid stent (CS) characteristics, such as radial force, scaffolding and flexibility, are continuously modified by stent manufacturers aiming to improve stent performance. Since manufacturers’ definitions and assessment methods are not disclosed, it is unknown how characteristics of different CSs relate to each other or to published literature. We examined in vitro methodological techniques used to measure CS characteristics and assessed comparability between published papers and outcomes as provided by the manufacturers.

Methods

A systematic review was conducted in MEDLINE, Embase, Cochrane, and Scopus databases. Studies reporting on in vitro investigations of predefined characteristics of CS used in current everyday clinical practice were included. The predefined characteristics were radial force, scaffolding, flexibility, foreshortening, side-branch preservation and visibility. Eight manufacturers of 10 currently used CS were contacted and data on the predefined device characteristics was requested.

Results

12 published articles were included and six stent manufacturers provided data on six stents (two refused to share data). Used methodologies to measure stent characteristics in published literature and manufacturer data varied greatly for all included characteristics except foreshortening. The number of different units of measurement to express outcomes ranged from two for foreshortening to six for radial force.

Conclusion

A variety of methodologies and outcome measures is used to quantify CS characteristics, which hampers comparisons between published studies and manufacturer data. Future studies are encouraged to synchronize methodologies and outcome measures. Manufacturers are encouraged up to increase transparency of applied testing methodologies and outcomes.

Electronic supplementary material

The online version of this article (10.1007/s00270-020-02499-1) contains supplementary material, which is available to authorized users.

Follow-up after carotid stenting with the CASPER stent system: A duplex ultrasound evaluation

OBJECTIVE

To report results of duplex ultrasound evaluation of consecutive patients after carotid stenting with the double layer Carotid Artery Stent designed to Prevent Embolic Release (CASPER) stent system.

METHODS

Between January 2014 and June 2017, a single-center, retrospective study of 101 consecutive patients (21.8% female; median age, 72.1 years) was performed. Patients with internal carotid artery stenosis treated with the CASPER stent were included. Eligibility criteria for stenting included stenosis of ≥70% of the vessel diameter (or ≥50% diameter with ulceration) in symptomatic carotid artery stenosis or ≥80% stenosis in asymptomatic patients at the carotid artery bifurcation or the proximal cervical internal carotid artery. Duplex ultrasound examination was performed before and within 24 hours of implantation as well as at 14 days, and 3, 6, and 12 months.

RESULTS

At the 12-month follow-up visit, moderate in-stent restenosis (ISR) (≥50% and <70%) was detected in three stents (2.8%) and severe (≥70%) ISR in two (1.9%; including one case of stent occlusion). All but the two latter patients remained asymptomatic during the follow-up period. One patient required retreatment for ISR after a minor stroke and another patient with stent occlusion also re-presented with a minor stroke. Multivariable logistic regression was unable to detect any significant factors associated with ISR.

CONCLUSIONS

Duplex ultrasound examination after carotid stenting is a useful tool for patient follow-up and determination of ISR. We found a low incidence of ISR assessed by duplex ultrasound examination at 12 months after CASPER stenting, but further studies are warranted.

Emergency carotid artery revascularization using Casper-RX stent: A single-center experience

BACKGROUND

Casper-RX (MicroVention, Aliso Viejo, California, USA) is a dual-layer closed cell stent recently introduced as a carotid artery revascularization device. Although its effectiveness and safety has been proved in elective cases, there are contradictive results regarding its patency in emergency settings. The purpose of the study is to present our single-center experience with the Casper-RX stent in the emergency interventions.

PATIENTS AND METHODS

Consecutive patients who underwent emergency carotid artery stenting using Casper-RX system with or without additional intracranial thrombectomy between August 2016 and June 2019 at our institution were included. Primary end point was the short-term patency of the carotid stents evaluated before hospital discharge by use of Doppler ultrasonography.

RESULTS

Twenty-nine procedures performed on 28 patients were included in the study. All stents were patent on final angiograms. Acute stent occlusion was observed only in one case (3.4%) with a spontaneous cervical internal carotid artery dissection the day after the procedure. In 26 (89.6%) cases, an additional intracranial thrombectomy was performed with a successful recanalization rate of 96.1%. Seven adverse events occurred peri-/post-procedural: two cases (6.9%) with iatrogenic dissection of distal cervical internal carotid artery during intracranial thrombectomy, two parenchymal hematoma type 2 (6.8%), and three patients (10.3%) developed massive infarction.

CONCLUSION

This study supports the safety and efficacy of the Casper-RX stent in emergency endovascular carotid artery revascularization procedures.

Carotid Artery Stenting Using a Closed-Cell Stent-in-Stent Technique for Unstable Plaque

Purpose: To examine whether carotid artery stenting (CAS) of stenoses with unstable plaque using a closed-cell stent-in-stent technique prevents plaque protrusion. Materials and Methods: Between December 2014 and August 2018, 35 consecutive patients (mean age 75.8 years; 29 men) with carotid artery stenosis (20 symptomatic) and unstable plaque diagnosed by magnetic resonance imaging were prospectively analyzed. Mean diameter stenosis was 83.5%. All CAS procedures were performed with stent-in-stent placement of Carotid Wallstents using an embolic protection device and conservative postdilation. The technical success rate, incidence of plaque protrusion, ischemic stroke rate within 30 days, and new ipsilateral ischemic lesions on diffusion-weighted imaging (DWI) within 48 hours after CAS were prospectively assessed. Follow-up outcomes included the incidences of ipsilateral stroke and restenosis. Results: The technical success rate was 100%. No plaque protrusion or stroke occurred in any patient. New ischemic lesions were observed on DWI in 10 (29%) patients. During the mean 11.6-month follow-up, no ipsilateral strokes occurred. Two (6%) patients developed asymptomatic restenosis recorded as 53% lumen narrowing and occlusion, respectively. Conclusion: CAS using a closed-cell stent-in-stent technique for unstable plaque may be useful for preventing plaque protrusion and ischemic complications.

Initial Clinical Results and In Vitro Testing of the New CGuard MicroNet-Covered "One-Size-Fits-All" Carotid Stent

Purpose: To evaluate a MicroNet-covered stent designed for the carotid artery with the new ability to adjust to different vessel diameters. Materials and Methods: Thirty consecutive patients (mean age 72.1±7.7 years; 26 men) with symptomatic stenosis (86.3%±6.4%) of the internal carotid artery were treated with the new self-adjusting nitinol stent, which has a self-expanding, open-cell design covered by an outer conformable layer (MicroNet). The only stent used was the "One-Size-Fits-All" CGuard stent with lengths of 30 or 40 mm. In bench testing, the chronic outward force of the One-Size-Fits-All stent was determined with a segmented head radial force test device. The stent was deployed directly into the test device at a diameter of 5.0 mm, and the chronic outward force was measured up to 10.0 mm, the maximum expansion of the stent. Results: The stent was successfully implanted in all 30 patients without periprocedural complications, including no neurological events within 30 days. The chronic outward force normalized by stent length demonstrated a near-equivalent radial force outcome: The stent displayed only a minor difference between the minimal radial force at 9.0 mm (0.195 N/mm) and the maximal radial force at 5.5 mm (0.330 N/mm). Conclusion: The new self-adjusting, MicroNet-covered stent has high conformability combined with an almost equivalent radial force at expansion diameters ranging from 5.5 to 9.0 mm. The first clinical results demonstrate that the new One-Size-Fits-All stent can be safely implanted in internal carotid arteries with reference diameters within this range.

Cumulative incidence of restenosis in the endovascular treatment of extracranial carotid artery stenosis: a meta-analysis

OBJECTIVE

To assess the cumulative incidence of restenosis and stroke after stenting for cervical carotid artery stenosis.

METHODS

We reviewed PubMed, ScienceDirect, and Scopus and included all studies reporting restenosis after stenting. The cumulative incidence of restenosis at 6 and 12 months was calculated. We also estimated the cumulative incidence of ipsilateral stroke within 30 days after stenting. Random effect meta-analysis and meta-regression were performed using relevant study level covariates. Sources of heterogeneity were investigated.

RESULTS

Among 7765 records, 40 studies were selected. 15 943 patients and 16 337 carotid arteries were considered. The overall pooled cumulative incidence of restenosis >50% at 12 months was 5.7% (95% CI 3.8% to 8.6%), >70% at 12 months was 5.2% (95% CI 3.3% to 8.2%), >50% at 6 months was 3.9% (95% CI 2.2% to 6.8%), and ipsilateral stroke within 30 days after stenting was 1.6% (95% CI 1.0% to 2.5%) without association with the use of an embolic protection device. We did not identify any relevant source of heterogeneity of the cumulative incidence of restenosis >50% at 12 months. Mean age explained 80.9% (R²=80.9%, p=0.01) of heterogeneities of restenosis >70% at 12 months. The presence of hostile neck explained 53.9% (R²=53.9%, p=0.03) of heterogeneities of restenosis >50% at 6 months.

CONCLUSION

This meta-analysis showed a low cumulative rate of restenosis at 12 months and ipsilateral stroke within 30 days after stenting. Older patients and those with hostile neck present a lower risk of in-stent restenosis. The use of an embolic protection device was not associated with a lower risk of stroke.

Evaluating the effectiveness and safety of the carotid Casper-RX stent for tandem lesions in acute ischemic stroke

INTRODUCTION

A new generation of carotid artery stents that use a dual micromesh layer to reduce embolic events during carotid artery stenting has recently been introduced. We aimed to analyze the effectiveness and safety of the new Casper-RX stent in patients experiencing acute ischemic stroke with large vessel intracranial occlusion associated with a tandem lesion (another carotid occlusion or severe stenosis).

METHODS

We retrospectively analyzed all consecutive patients treated with carotid Casper-RX stents from our stroke registry. We analyzed clinical, angiographic, and neuroimaging data. Endpoints included acute intra-stent thrombus formation, stent occlusion prior to hospital discharge, 3 month modified Rankin Scale score (mRS), and symptomatic intracranial hemorrhage.

RESULTS

21 patients were included: 10 patients had tandem carotid occlusions and 11 patients had severe carotid stenosis, 8 of whom had a hemodynamically significant stenosis. We observed acute in-stent thrombus formation in 11 patients. No stent occlusion occurred prior to hospital discharge. We report no stroke recurrence at 3 months but symptomatic intracranial hemorrhage in two patients. mRS score at 3 months was 0-2 (favorable) for 15 patients (71%), 3-5 for 3 patients, and 6 for 3 patients.

CONCLUSIONS

In the present series, we frequently observed clot formation during the procedure with Casper-RX stents, which required periprocedural intravenous infusion of anticoagulant and antiplatelet treatment. This motivated us, in the absence of a prospective randomized controlled study demonstrating the non-inferiority of micromesh dual layer stents compared with the single layer design, to discontinue using this stent type in acute stroke requiring carotid angioplasty.

The Casper Stent System for carotid artery stenosis

Purpose

To report the results of a retrospective analysis of prospectively collected data evaluating the safety and efficacy of a double layer stent engineered for carotid artery occlusive disease.

Methods

Between January 2014 and February 2017, 138 patients (25.4% women; median age 71 years) underwent Casper stent implantation for carotid artery stenosis. Eligibility criteria included stenosis >70% of vessel diameter (or >50% diameter with ulceration) in symptomatic patients or asymptomatic patients with >80% stenosis at the carotid bifurcation or in the proximal internal carotid artery. For all procedures, a distal embolic protection device was used. The primary endpoint was the rate of 90 day major adverse neurological events, defined as minor stroke, major stroke, or death by independent neurological assessment.

Results

Stent deployment was completed successfully in all cases without documented technical failure. There were no adverse neurological events or mortalities within 90 days. One thromboembolic occlusion of a small distal branch of the anterior cerebral artery occurred during the procedure and resolved with systemic recombinant tissue plasminogen activator administration. New ischemic lesions, all clinically silent, were seen in 6.5% of patients on post-procedure cerebral MRI.

Conclusion

The Casper carotid stent demonstrated safety and efficacy in the treatment of carotid stenosis, with no technical failures and no adverse neurological events seen throughout the 90 day follow-up period. Its double layer structure seems to combine adequate plaque scaffolding with high vessel adaptability.

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.

Mesh-covered (Roadsaver) stent as a new treatment modality for symptomatic or high-risk carotid stenosis

Introduction

Prevention of periprocedural stroke has a crucial role in carotid artery stenting (CAS) procedures.

Aim

To assess retrospectively 30-day safety and effectiveness of 41 procedures of internal and common carotid artery stenting using the Roadsaver double nitinol layer micromesh stent in 40 non-consecutive patients with symptomatic or high-risk carotid artery stenosis.

Material and methods

The patients were men (n = 31) and women (n = 9); mean age was 67.8 ±7.9 years. Femoral access was used in 39 cases, whereas radial access was used in 2. Proximal (n = 27) or distal (n = 14) embolic neuroprotection was used.

Results

The Roadsaver stents (nominal diameter 7, 8 or 9 mm, length 25 or 30 mm) were implanted successfully in all cases. One minor stroke occurred after common carotid artery intubation with a guiding catheter (before stent deployment) and one transient postprocedural ischemic attack (TIA) of the ipsilateral cerebral hemisphere was observed. Internal/common carotid artery stenosis severity was evaluated by duplex Doppler. Maximal peak systolic velocity (PSV) before CAS was in the range: 2.0–7.0 m/s, mean: 3.9 ±1.0 m/s, at 24–48 h after stenting mean PSV was 1.1 ±0.4 m/s (p < 0.05), and at 30 days 1.1 ±0.3 m/s (p < 0.05). Maximal end-diastolic velocity (EDV) was 0.85–3.5 m/s, mean 1.4 ±0.5 m/s, at 24–48 h after stenting mean EDV was 0.3 ±0.1 m/s (p < 0.05), and at 30 days 0.4 ±0.1 m/s (p < 0.05). No restenosis or thrombosis was observed. Angiographic stenosis decreased from 82.9 ±9.1% (range: 61–97%) to 19.3 ±7.3% (range: 0–34%) (p < 0.05).

Conclusions

The CAS using the Roadsaver stent seems to be safe and effective. Further studies involving larger patient populations and longer follow-up are needed.

Transcervical access, reversal of flow and mesh-covered stents: New options in the armamentarium of carotid artery stenting

In the last 25 years, the very existence of carotid artery stenting (CAS) has been threatened on a number of occasions. The initial disappointing results that even lead to the discontinuation of an early randomized controlled trial have improved considerably with time. Novel devices, advanced stent and equipment technology, alternative types of access and several types of filters/emboli protecting devices have been reported to reduce stroke/death rates during/after CAS and improve CAS outcomes. The present review will provide a description of the various technology advances in the field that aim to reduce stroke and death rates associated with CAS. Transcervical access, reversal of flow and mesh-covered stents are currently the most promising tools in the armamentarium of CAS.

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.