What Practical Factors Guide the Choice of Stent and Protection Device during Carotid Angioplasty?

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).

Embolic protection devices for carotid artery stenting: A network meta-analysis

OBJECTIVES

Carotid artery stenting (CAS) is an alternative treatment option for patients at high risk for carotid endarterectomy (CEA) but has been correlated with increased risk for distal embolization and periprocedural stroke despite the use of adjunctive embolic protection devices (EPD). This study compared four types of EPDs and their intra and periprocedural related complications.

METHODS

A systematic review of the literature was conducted in PubMed/Medline to identify studies that investigated the outcomes of CAS with adjuvant use of EPDs, including Proximal Balloon (PB), Distal Filter (DF), and Distal Balloon (DB) strategy. Continuous flow reversal performed via transcarotid approach by a commercially available device as an embolic protection strategy was intentionally excluded based on its distinct procedural characteristics and lack of availability outside of the United States. This network meta-analysis was performed according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines.

RESULTS

Overall, 45 studies, consisting of 7600 participants satisfied the predetermined search criteria and were included in this network meta-analysis. Overall, 13 studies provided data regarding the number of patients with new ischemic lesions detected in the DW-MRI. DF (OR: 3.15; 95% CI: 1.54-6.44; p = 0.002) and DB (OR: 2.28; 95% CI: 1.58-3.29; p < 0.001) were associated with higher odds of new ischemic lesions compared to PB on DW-MRI imaging. No statistical difference was identified between DB versus DF groups (OR: 1.48; 95% CI: 0.73-2.59; p = 0.317). 36 and 27 studies reported on periprocedural stroke and transient ischemic attack (TIA) rates, respectively, showing similar odds of neurologic adverse events between all three groups.

CONCLUSIONS

PB deployment during CAS is superior to DF and DB in preventing distal embolization phenomena. However, no statistically significant difference in TIA and stroke rate was found among any of the analyzed EPD groups. Further research is warranted to investigate the association of embolic phenomena on imaging after CAS with clinically significant neurologic deficits.

Comparative analysis of CGUARD embolic prevention stent with Casper-RX and Wallstent for the treatment of carotid artery stenosis

Stent protected Angioplasty of extracranial carotid artery stenosis using the dual-layered CGUARD stent is a novel treatment option. In this study we evaluate the feasibility and the safety of the CGUARD in symptomatic and asymptomatic patients in comparison to Casper-RX and Wallstent. This is a multi-center study of consecutive patients treated with the CGUARD, Casper-RX and Wallstent at two German high volume neurovascular centers between April 2017 and May 2018. Patient characteristics, neuroimaging data and angiographic outcome were retrospectively analyzed. The primary end points of the study were acute occlusion of the carotid stent and symptomatic intracerebral hemorrhage (sICH). Carotid artery stenting was performed in 76 patients; of those 26 (34%) were treated with the CGUARD, 25 (33%) with Casper-RX, and 25 (33%) with Wallstent. In 58/76 (76%) cases carotid artery stenosis was symptomatic with a median baseline National Institutes of Health Stroke Scale of 4. Angioplasty and stenting as part of a mechanical thrombectomy for acute ischemic stroke was performed in 25/76 (33%) patients. Baseline patient characteristics were similar between the treatment groups, except for a higher portion of scheduled cases in the Casper-RX group. There were no significant differences in the rate of acute in stent occlusions (CGUARD, 2/26 (8%); Casper-RX, 1/25(4%); Wallstent, 1/25 (4%)) and postinterventional sICH (1/26 (4%), 0/25(0%), 0/25 (0%)). Clinical outcome at discharge did not differ between groups. Treatment of carotid artery stenosis using CGUARD is feasible with a good safety profile comparable to that of Casper-RX and Wallstent.

Prospective multicentre study of carotid artery stenting using the MER™ Stent - the OCEANUS study - 30-day and one-year follow-up results

INTRODUCTION

Constant technological progress in the field of carotid stenting translates into improved short- and long-term results of endovascular treatment. The introduction of a new generation, self-expanding, open-cell stent has provided a new treatment option in endovascular management of carotid stenosis.

AIM

To evaluate 30-day and 1-year clinical outcomes of non-consecutive patients with high risk of carotid endarterectomy, who underwent 5F cylinder-tapered MER™ open-cell carotid stent implantation.

MATERIAL AND METHODS

It was a single-arm, prospective study conducted in four experienced catheterisation centres. The use of embolic protection devices was mandatory. The primary endpoint was stroke in 30-day follow-up. The secondary endpoints were 30-day and 1-year cumulative incidence of death, stroke and myocardial infarction, 1-year target vessel revascularisation, procedural success (residual stenosis ≤ 30%), restenosis rate (%DS ≥ 50%), and Serious Adverse Device Effect (SADE) rate in 1-year follow-up.

RESULTS

In total 100 patients were recruited for the study, with the majority being males (n = 61). The mean age was 68.3 ±8.2 years, and most of the patients were asymptomatic (n = 56). In 55 (55%) patients direct stenting was performed, with the use of proximal protection devices in 19 (19%) patients. Mean internal carotid artery/common carotid artery stenosis before and after stent implantation was 81.98 ±9.15% and 12.52 ±8.70%, respectively (p < 0.001). Procedural success was achieved in all cases. One ischaemic stroke was observed at 30 days (1%, primary endpoint). At 1-year follow-up two myocardial infarctions and three deaths occurred with no additional stroke.

CONCLUSIONS

The OCEANUS study indicated the safety and efficacy of the MER™ stent during 30-day and 1-year follow-up in both symptomatic and asymptomatic patients. The majority of patients were event-free. However, larger cohort studies are needed to evaluate MER™ stents in detail.

Structural and Hemodynamic Analyses of Different Stent Structures in Curved and Stenotic Coronary Artery

Coronary artery stenting is commonly used for the treatment of coronary stenosis, and different stent structures indeed have various impacts on the stress distribution within the plaque and artery as well as the local hemodynamic environment. This study aims to evaluate the performance of different stent structures by characterizing the mechanical parameters after coronary stenting. Six stent structures including three commercially-shaped stents (Palmaz-Schatz-shaped, Xience Prime-shaped, and Cypher-shaped) and three author-developed stents (C-Rlink, C-Rcrown, and C-Astrut) implanted into a curved stenotic coronary artery were investigated. Structural analyses of the balloon-stent-plaque-artery system were first performed, and then followed by hemodynamic analyses. The results showed that among the three commercially-shaped stents, the Palmaz-Schatz-shaped had the least stent dogboning and recoiling, corresponding to the greatest maximum plastic strain and the largest diameter change, nevertheless, it induced the highest maximum von Mises stress on plaque, arterial intima and media. From the viewpoint of hemodynamics, the Palmaz-Schatz-shaped displayed smaller areas of adverse low wall shear stress (<0.5 Pa), low time-averaged wall shear stress (<0.5 Pa), and high oscillating shear index (>0.1). Compared to the Cypher-shaped, the C-Rcrown and C-Astrut had smaller recoiling, greater maximum plastic stain and larger diameter change, which indicated the improved mechanical performance of the Cypher-shaped stent. Moreover, both C-Rcrown and C-Astrut exhibited smaller areas of adverse low wall shear stress, and low time-averaged wall shear stress, but only the C-Rcrown displayed a smaller area of adverse high oscillating shear index. The present study evaluated and compared the performance of six different stents deployed inside a curved artery, and could be potentially utilized as a guide for the selection of suitable commercially-shaped stent for clinical application, and to provide an approach to improve the performance of the commercial stents.

Outcome of carotid angioplasty with a novel open-cell carotid stent system

BACKGROUND

The choice of carotid stent systems depends primarily on the anatomy of the carotid artery, the lesion morphology, and the patient's risk factors. Design improvements in devices, in terms of crossing profile and the ability to precisely position the stent, may greatly contribute to the procedural success without compromising acute clinical outcomes.

METHODS AND RESULTS

The primary objective of this clinical registry was to evaluate the early safety and efficacy of a novel open-cell carotid stent system in an "all comer" population suitable for carotid artery stenting. The primary end point was the composite of ipsilateral stroke and "all-cause mortality" within 30 days after the procedure. Secondary end points entailed the rates of myocardial infarction and other clinical complications within the first 30 days following the procedure and up to the 6-month follow-up. Unsuccessful placement and/or withdrawal of the delivery system, as well as device-related complications involving the carotid artery and the rate of nonlesion-related embolisms, were evaluated relative to other currently available carotid stents. The 30-day composite death/stroke rate was 2.8% (3 of 106) while the overall stent system performance was similar to commonly used carotid stent systems.

CONCLUSIONS

The utilized open-cell carotid stent system had favorable lesion crossing and positioning characteristics without compromising the 30-day composite death/stroke rate.

Comparison of carotid artery stenting and carotid endarterectomy in patients with symptomatic carotid artery stenosis: a single center study

INTRODUCTION

Carotid artery stenting (CAS) is believed to be an alternative to carotid endarterectomy (CEA); however, recent studies have demonstrated an increase of complications with stenting that does not reflect our experience. We thus wanted to compare the periprocedural and 1-year follow-up outcomes of CAS with those of CEA among patients with symptomatic extracranial carotid stenosis in a population from eastern Turkey.

METHODS

The hospital records of all patients who underwent carotid artery revascularization were retrospectively reviewed. Patients were divided into two groups based on the type of carotid revascularization performed, namely CEA or CAS. Comparisons were made with respect to 30-day and 1-year outcomes of transient ischemic attack (TIA), myocardial infarction (MI), stroke, and all-cause death rates. Composite endpoints for both groups were also analyzed.

RESULTS

Thirty-two CEA and 33 CAS procedures were performed for symptomatic occlusive carotid disease. Baseline characteristics were similar between both groups except for the incidence of diabetes mellitus. No significant differences were found with respect to 30-day mortality, MI, and neurologic morbidity endpoints for CEA and CAS procedures. In the postprocedural 1-year follow-up, only TIA was observed to be significantly higher in the CAS group; the other endpoints did not differ significantly. One-year composite endpoints did not differ between both groups (log-rank P = 0.300).

CONCLUSION

In our trial of patients with symptomatic carotid artery stenosis, no significant difference could be shown in periprocedural outcomes, postprocedural outcomes except TIA, and in composite endpoints between the CEA and CAS groups. CAS is a safe and efficacious alternative for the treatment of symptomatic carotid artery stenosis.

Evaluation of carotid stent scaffolding through patient-specific finite element analysis

After carotid artery stenting, the plaque remains contained between the stent and the vessel wall, moving consequently physicians' concerns toward the stent capability of limiting the plaque protrusion, that is, toward vessel scaffolding, to avoid that some debris is dislodged after the procedure. Vessel scaffolding is usually measured as the cell area of the stent in free-expanded configuration, neglecting thus the actual stent configuration within the vascular anatomy. In the present study, we measure the cell area of four different stent designs deployed in a realistic carotid artery model through patient-specific finite element analysis. The results suggest that after deployment, the cell area change along the stent length and the related reduction with respect to the free-expanded configuration are functions of the vessel tapering. Hence, the conclusions withdrawn from the free-expanded configuration appear to be qualitatively acceptable for comparative purposes, but they should be carefully handled because they neglect the post-implant variability, which seems to be more pronounced in open-cell designs, especially at the bifurcation segment. Even though the investigation is limited to few stent designs and one vascular anatomy, our study confirms the capability of dedicated computer-based simulations to provide useful information about complex stent features as vessel scaffolding.

The role of embolic protection devices during carotid stenting prior to cardiac surgery in asymptomatic patients: empty filters?

OBJECTIVES

The purpose of this study was to analyze the debris captured in the distal protection filters used during carotid artery stenting (CAS).

BACKGROUND

CAS is an option available to high-risk patients requiring revascularization. Filters are suggested for optimal stroke prevention during CAS.

METHODS

From May 2005 to June 2007, filters from 59 asymptomatic patients who underwent CAS were collected and sent to a specialized laboratory for light-microscope and histological analysis. Peri- and postprocedural outcomes were assessed during 1-year follow-up.

RESULTS

On the basis of biomedical imaging of the filter debris, the captured material could not be identified as embolized particles from the carotid plaque. On histological analysis the debris consisted mainly of red blood cell aggregates and/ or platelets, occasionally accompanied by granulocytes. We found no consistent histological evidence of embolized particles originating from atherosclerotic plaques. Post-procedure, three neurological events were reported: two (3.4%) transient ischemic attacks (TIA) and one (1.7%) ipsilateral minor stroke.

CONCLUSION

The filters used during CAS in asymptomatic patients planned for cardiac surgery often remained empty. These findings may be explained by assuming that asymptomatic patients feature a different atherosclerotic plaque composition or stabilization through antiplatelet medication. Larger, randomized trials are clearly warranted, especially in the asymptomatic population.

Carotid artery surgery: back to the future

In this study we performed 548 carotid revascularizations between 2006 and 2008 at the Department of Vascular Surgery of the A.Z. Sint-Blasius, Dendermonde, Belgium - a high-volume experienced center for carotid artery stenting (CAS). In 2006, our 30-day complication rates were 3.21 and 1.51% for symptomatic and asymptomatic patients, respectively. At that time, CAS represented approximately 86% of all cases we performed. However, the publication of the results of EVA-3S and SPACE studies drove us to reconsider our treatment allocation algorithm. In 2007 and 2008, CAS procedures only accounted for 43% of all carotid procedures, which was a result of strict patient selection with comorbidities and high-risk lesions assessment, especially in symptomatic patients. Our current 30-day stroke/death rates are 1.24% for symptomatic patients and 0.53% for asymptomatic ones, which reflects that correct patient selection is the key to maintain CAS as a valuable alternative to carotid endarterectomy.