The Casper Stent System for carotid artery stenosis

Carotid Artery Stenting With Double-Layer Stent: A Systematic Review and Meta-Analysis

BACKGROUND

Carotid artery stenting (CAS) in the treatment of significant stenosis is a cause of stroke due to both plaque prolapse and cerebral embolization. New types of stents with a double-layer structure have been designed to minimize plaque prolapse and embolization; these double-layer stents (DLSs) should be able to reduce the stroke risk; however, definite data on their performance are scarce in the literature.

METHODS

A systematic search was performed through PubMed, Scopus, and Cochrane Library, according to PRISMA guidelines; all studies on CAS with DLS (Roadsaver/Casper or CGuard) up to January 1, 2022, with a cohort of at least 20 patients were considered eligible. The present meta-analysis was approved and registered on PROSPERO register (CRD42022297512). Patients with tandem lesions or complete carotid occlusion were excluded from the study. The 30-day stroke rate after CAS was analyzed evaluating the preoperative symptomatic status and DLS occlusion. The estimated pooled rate of events was calculated by random effect model and moderators were evaluated.

RESULTS

A total of 14 studies were included in the meta-analysis for a total of 1955 patients. The estimated overall (95% confidence interval [CI]) stroke rate was 1.4% (0.9%-2.2%, I2 = 0%), which was not influenced by the type of DLS used: CGuard 0.8% (0.4%-1.8%, I2 = 0%) versus Roadsaver/Casper 1.5% (0.7%-3.2%, I2 = 0%), p=0.30. The 30-day estimated stroke rate was 1.5% (0.8%-2.9%, I2 = 0%) in asymptomatic and 1.9% (1.0%-3.6%, I2 = 0%) in symptomatic patients, with no influence by moderators. The 30-day DLS occlusion rate was 0.8% (0.4%-1.8%, I2 = 0%). The publication bias assessment identified asymmetry in the asymptomatic populations.

CONCLUSION

The overall 30-day stroke rate in CAS with DLS is low (1.4%), with similar results in symptomatic and asymptomatic patients. Acute occlusion of DLS is rare (0.8%). Further studies are necessary to reduce the publication bias for asymptomatic patients.

CLINICAL IMPACT

CAS with DLS is associated to a low rate of 30-day stroke in both symptomatic (1.9%) and asymptomatic (1.5%) patients. The type of DLS (CGuard or Roadsaver/Casper) did not affect the 30-day stroke rate.

Dual-layered stents reduce cerebral embolism compared with first-generation stents during carotid stenting of high lipid core plaque lesions

BACKGROUND

Periprocedural lipid core plaque (LCP) has been detected in carotid arteries assessed by catheter-based near-infrared spectroscopy (NIRS). High LCP is associated with cerebral embolism after carotid artery stenting (CAS) using a first-generation stent. We aimed to evaluate whether dual-layered stents reduce embolic infarcts in patients with high LCP and change of lipid signal as assessed by NIRS during CAS.

METHODS

Participants comprised 210 consecutive patients undergoing CAS. The study was divided into two distinct periods, with first-generation closed-cell stents used in the earlier period and dual-layered stents used in the later period. NIRS was performed at baseline, after stent implantation, and after balloon post-dilatation to analyze maximal lipid core burden index at minimal luminal area (max-LCBIMLA).

RESULTS

The ipsilateral cerebral embolism rate was significantly lower with dual-layered stents (9%) than with first-generation stents (33%, p<0.001), particularly with highly lipidic lesions (12% vs 60%, p<0.001). On multivariate logistic regression analysis, high LCP and first-generation stent usage were factors related to ipsilateral cerebral embolism (both p<0.001; OR 8.28 (95% CI 3.49 to 19.64) and OR 8.07 (95% CI 2.33 to 27.93), respectively). Max-LCBIMLA decreased significantly after stenting in both groups (both p<0.01) and max-LCBIMLA after balloon post-dilatation was significantly lower with dual-layered stents (22.4±65.6) than with first-generation stents (124.2±208.2; p=0.006).

CONCLUSIONS

Dual-layered stents reduce embolic infarcts in patients with highly lipidic plaque lesions as assessed by NIRS who undergo CAS. Dual-layered stents significantly reduced NIRS-derived lipid signals after stenting.

Procedural embolic protection strategies for carotid artery stenting: current status and future prospects

INTRODUCTION

Carotid artery angioplasty and stenting (CAS) is an established procedure to treat carotid artery stenosis for either primary or secondary prevention of stroke. Randomized clinical trials have shown an increased risk of periprocedural cerebrovascular events with CAS compared with carotid endarterectomy (CEA). Several strategies have been proposed to mitigate this risk, including alternative vascular access site, proximal/distal embolic protection devices, and dual-layer stents, among others.

AREAS COVERED

This review provides a general overview of current embolic protection strategies for CAS. The phases of the procedure which can affect the early risk of stroke and how to reduce it with novel techniques and devices have been discussed.

EXPERT OPINION

Innovations in device technologies have dramatically improved the safety and efficacy of CAS. To minimize the gap with surgery, a thorough, patient-oriented approach should be pursued. Endovascular technologies and techniques should be selected on an individual basis to address unique lesion characteristics and vascular anatomies. Meticulous pre-procedural planning, both clinical and anatomical, is needed to assess the embolic risk of each procedure. Only by having an in-depth understanding of the wide range of available endovascular devices and techniques, the operator will choose the most appropriate strategy to optimize CAS results.

Carotid Artery Stenting: Applications and Technical Considerations

PURPOSE OF THE REVIEW

To examine current understanding of diverse etiologies of extracranial carotid disease, including clinical and imaging manifestations as well as treatment approaches.

RECENT FINDINGS

Increasing availability of advanced cerebrovascular imaging modalities continues to elucidate atherosclerotic and nonatherosclerotic carotid steno-occlusive disease as a common culprit of cerebral ischemia. Individualized treatment strategies targeting each etiologic subset would optimize preventive measures and minimize recurrence of cerebral ischemia.

SUMMARY

Ischemic stroke is a prominent cause of mortality and long-term disability worldwide. The magnified effect of carotid disease warrants constant and close inspection.

Contralateral Stenosis and Echolucent Plaque Morphology are Associated with Elevated Stroke Risk in Patients Treated with Asymptomatic Carotid Artery Stenosis within a Controlled Clinical Trial (SPACE-2)

BACKGROUND

Asymptomatic carotid artery stenosis (ACS) has a low risk of stroke. To achieve an advantage over noninterventional best medical treatment (BMT), carotid endarterectomy (CEA) or carotid artery stenting (CAS) must be performed with the lowest possible risk of stroke. Therefore, an analysis of risk-elevating factors is essential. Grade of ipsilateral and contralateral stenosis as well as plaque morphology are known risk factors in ACS.

METHODS

The randomized, controlled, multicenter SPACE-2 trial had to be stopped prematurely after recruiting 513 patients. 203 patients were randomized to CEA, 197 to CAS, and 113 to BMT. Within one year, risk factors such as grade of stenosis and plaque morphology were analyzed.

RESULTS

Grade of contralateral stenosis (GCS) was higher in patients with any stroke (50%^ECST vs. 20%^ECST; p=0.012). Echolucent plaque morphology was associated with any stroke on the day of intervention (OR 5.23; p=0.041). In the periprocedural period, any stroke was correlated with GCS in the CEA group (70%^ECST vs. 20%^ECST; p=0.026) and with echolucent plaque morphology in the CAS group (6% vs. 1%; p=0.048). In multivariate analysis, occlusion of the contralateral carotid artery (CCO) was associated with risk of any stroke (OR 7.00; p=0.006), without heterogeneity between CEA and CAS.

CONCLUSION

In patients with asymptomatic carotid artery stenosis, GCS, CCO, as well as echolucent plaque morphology were associated with a higher risk of cerebrovascular events. The risk of stroke in the periprocedural period was increased by GCS in CEA and by echolucent plaque in CAS. Due to small sample size, results must be interpreted carefully.

[Asymptomatic carotid artery stenosis - treatment recommendations]

For the asymptomatic carotid stenosis, defined as an atherosclerotic carotid stenosis without neurological symptoms for more than 6 months, there are in contrast to a symptomatic carotid stenosis still no reliable treatment recommendations. Possible therapy recommendations based on current data are presented below.

Casper Versus Precise Stent for the Treatment of Patients with Idiopathic Intracranial Hypertension

Purpose

We hypothesized that due to its specific characteristics, the Casper^TM RX carotid stent (CP) might be particularly suitable for venous sinus stenting (VSS) in patients with idiopathic intracranial hypertension (IIH). To test this theory, we compared it to the commonly used Precise Pro RX^TM stent (PP).

Methods

A total of 15 patients with IIH (median age 28.7 years) were reviewed retrospectively. Technical aspects as well as peri- and postinterventional complication rates were examined in patients treated with CP (n = 10) and the PP (n = 5). Improvements in cerebrospinal fluid opening pressure (CSF OP), transstenotic pressure gradient (TSPG) and clinical symptoms were also assessed.

Results

Stent delivery was easier and more successful with the CP than the PP (difficult/failed stent delivery 0.0% versus 57.1%) and consequently achieved with less attempts (≥ 2: 0.0% versus 40.0%). No severe peri- or postinterventional complications or instances of in-stent thrombosis and/or stenosis were observed during follow-up. Improvement of CSF OP and TSPG immediately after VSS as well as at 6‑month follow-up was comparable between the CP and PP group. Both groups showed substantial and similar decreases in intensity and frequency of headache. Almost all patients with other IIH-related symptoms showed either improvement or complete resolution of those symptoms after VSS. All patients who were available for interview (n = 12/15) reported a substantial improvement in quality of life.

Conclusion

VSS using the CP seems to be safe and effective. The CP may reduce the risk of difficult or failed stent delivery in patients with challenging intracranial venous anatomy.

Supplementary Information

The online version of this article (10.1007/s00062-021-01024-2) contains supplementary material, which is available to authorized users.

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.

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.

Internal Carotid Artery Dissection Treated with C-Guard Stent

Internal carotid dissection is the most common cause of stroke in the young population. Stroke, the presence of a pseudoaneurysm, and decreased artery lumen with cerebral flow impairment are indications for treatment. Medical therapy with antithrombotic drugs and endovascular therapy with stenting are the main available options. The C-Guard stent is an open cell mesh-covered dual layer stent that has been mainly used in cases of internal carotid artery stenosis with a post-operative reduction in stroke incidence. Thus, we present two cases of internal carotid artery dissections of the cervical segment treated with the open cell dual-layer C-Guard stent without complications.

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.

Complication Rates Using CASPER Dual-Layer Stents for Carotid Artery Stenting in Acute Stroke : A 3-Year Single Center Experience

BACKGROUND AND PURPOSE

The number of acute and early stent occlusions after emergency stenting of the internal carotid artery (ICA) in patients with tandem lesions is unclear and only mentioned in a small number of publications, ranging from 0-20%. A recent article by Yilmaz et al. reported a high rate of acute in-stent occlusions of 45% within 72 h after deployment of CASPER dual layer stents.

METHODS

All patients with acute ischemic stroke treated with a CASPER stent between August 2014 and April 2018 were retrospectively evaluated for occlusion rates, periinterventional medication and early complications. A total of 66 patients, 45 with tandem pathologies and 21 with proximal ICA stenosis only were enrolled.

RESULTS

Thrombotic complications occurred in 16 out of 66 patients (24%) and hemorrhagic complications in 8/66 (12%) and 15 of the 16 thrombotic complications and 7/8 symptomatic intracranial hemorrhages (sICH) occurred in patients with tandem lesions and accessory intracranial thrombectomy. Of the patients with sICH five were treated in a prolonged or unknown time window. In patients with intraprocedural thrombotic complications ultrasound imaging showed patent stents in 13 of the 14 patients CONCLUSIONS: The CASPER stent system showed a high technical success rate in patients with acute stroke. The number of patients with sICH was not higher than the numbers reported in the published literature despite the early use of Gp IIb/IIIA inhibitors, whereas the number of thrombotic complications was smaller than that reported in recent studies. The majority of sICH occurred in patients treated because of tandem lesions in an unknown or prolonged time window.

Acute thromboses and occlusions of dual layer carotid stents in endovascular treatment of tandem occlusions

PURPOSE

To evaluate the occurrence and risk factors of acute in-stent thrombosis or stent occlusion in patients with tandem occlusions receiving intracranial mechanical thrombectomy and emergent extracranial internal carotid artery stenting with a dual layer carotid stent.

METHODS

Multicenter retrospective data collection and analysis of stroke databases of seven comprehensive stroke centers from three European countries.

RESULTS

Overall, 160 patients (mean (SD) age 66 (12) years; 104 men (65%); median (IQR) baseline NIHSS 14 (9-18); IV lysis, n=97 (60.6%)) were treated for a cervical carotid artery occlusion or stenosis using a CASPER stent (MicroVention), and received mechanical thrombectomy for an intracranial occlusion between April 2014 and November 2018. During the procedure or within 72 hours, formation of thrombus and complete occlusion of the CASPER stent was observed in 33/160 (20.8%) and in 12/160 patients (7.5%), respectively. In 25/33 (75.8%) and in 9/12 patients (75%), respectively, this occurred during the procedure. No statistically significant difference was observed between patients with and without thrombus formation with regard to pre-existing long term medication with anticoagulants or intraprocedural administration of heparin, acetylsalicylic acid (ASA), or heparin and ASA. Favorable early neurological outcome was similar in patients with (n=15; 45.5%) and without (n=63; 49.6%) thrombus formation at the CASPER stent.

CONCLUSION

Acute thrombosis or occlusion of CASPER stents in thrombectomy patients receiving emergent extracranial internal carotid artery stenting for tandem occlusions were observed more often during the procedure than within 72 hours of follow-up, were less frequent then previously reported, and showed no impact on early neurological outcome.

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.