New Dual-Layer Carotid Stent Reduces Cerebral Embolism

November 04, 2021

In patients undergoing carotid artery stenting, use of a new-generation dual-layer stent significantly reduced periprocedural cerebral embolism compared with a conventional stent, in a new randomized study.

Furthermore, cerebral embolism throughout 48 hours to 30 days post-stenting was abolished by the dual-layer MicroNet-covered stent, while it was ongoing with the conventional single-layer stent.

"These results provide, for the first time, level 1 evidence for MicroNet-covered stent cerebral embolism prevention in carotid artery stenting that extends throughout the stent healing period. This may influence decision making in carotid revascularization," the authors conclude.

The study was published online November 8 in JACC: Cardiovascular Interventions.

The authors, led by Andrey Karpenko, MD, E.N. Meshalkin National Medical Research Center, Novosibirsk, Russia, explain that long-term clinical outcomes of randomized trials demonstrate equipoise between carotid artery stenting and surgical management (carotid endarterectomy) of carotid atherosclerosis.

Carotid artery stenting using first-generation (single-layer) stents showed an early excess of (mostly minor) strokes, and this has been used as an argument against using stenting as the first-line interventional treatment, they note.

With first-generation carotid stents, serial brain imaging shows that cerebral embolism may be ongoing after removal of the intraprocedural neuroprotection device, translating into new postprocedural ipsilateral cerebral lesions.

These events have been related to the atherosclerotic plaque prolapse through the stent struts, leading to plaque/thrombus embolism, a phenomenon that is not eliminated with the conventional closed-cell stent design. Effective plaque insulation has thus become a leading challenge, they state.

They report that the MicroNet-covered stent (CGuard, InspireMD) has been designed to minimize plaque prolapse, and imaging studies have demonstrated minimized cerebral embolism with this stent, while clinical series have shown low stroke rates and elimination of postprocedural events. However, conclusive evidence for reduced cerebral embolism with the MicroNet-covered stent is lacking, they note.

For the current study, 100 consecutive patients were randomly assigned to filter-protected carotid stenting using a conventional stent (Acculink, Abbott Vascular) or the CGuard MicroNet-covered device.

The primary endpoint was at least 50% reduction in ipsilateral diffusion-weighted magnetic resonance imaging (DW-MRI) lesion average volume 48 hours postprocedure.

Results showed that 82 (total volume, 18,212 mm3) diffusion-weighted magnetic resonance imaging postprocedural cerebral lesions occurred in 26 Acculink-treated patients and 45 lesions (total volume, 3930 mm3) in 25 CGuard-treated patients, a 78.4% reduction.

New cerebral lesion average volume was 171 mm3 with the Acculink stent vs 73 mm3 with the CGuard stent (P = .017) per affected patient and 222 mm3 vs 84 mm3 per lesion (P = .038).

In lesion-affected patients, the average sum of lesion volumes was 701 mm3 with the Acculink stent and 157 mm3 with the CGuard device (P = .007). The Acculink significantly increased the risk for multiple (≥ 5) cerebral lesions (relative risk, 7.8; P = .021).

At 30 days, new permanent lesion prevalence was 3:1 (P < .001), with a total permanent lesion volume of 7474 mm3 with the Acculink stent vs 574 mm3 with the CGuard stent, a 92.3% reduction. There were six new ipsilateral lesions in the Acculink group vs zero in the CGuard group (P = .030).

Two postprocedural ipsilateral ischemic strokes (both minor) occurred in the Acculink arm within 30 days of the procedure compared with zero strokes in the CGuard arm.

The authors note that DW-MRI is the most powerful tool for the detection of focal brain ischemia in the acute stage, and DW-MRI lesion burden with carotid revascularization is an established index of clinical stroke risk.

The proportion of patients with at least one periprocedural ipsilateral DW-MRI lesion was similar between the study stent arms (Acculink, 52%; CGuard, 48%). The authors note that carotid-revascularization–related cerebral embolism is multifactorial, and it is only in part amenable to correction with an antiembolic stent.

"Robust Scientific Evidence"

In an accompanying editorial, Eugenio Stabile, MD, and Donato Gerardi, MD, Azienda Ospedaliera Regionale San Carlo, Potenza, Italy, say that stroke is still the "Achilles' heel" of carotid percutaneous revascularization, and procedural improvement is needed to minimize peri- and postprocedural embolization risk.

They note that a new generation of dual-layer, mesh-covered carotid stent systems are now being developed that allow the device to trap and exclude thrombus and/or plaque debris to prevent embolic events from the target lesion.

They describe the current trial as "robust scientific evidence" that has been added to the available data on carotid stenting with dual-layer stents.

"We praise the investigators for the effort made in this well-conducted trial comparing the use of a dual-layer stent with a conventional stent...providing unique and useful clinical information," the editorialists write.

They point out some limitations, such as the single-center design of the trial, conducted at a high-volume institution, by very experienced operators (two operators, each with > 500 carotid stenting procedures, performing the interventional procedure and assisting each other), which they say is "hardly comparable with real-world practice."

They also note that the choice of the comparator — an open-cell stent with the largest free-cell area, which is known to be associated with a significant increase in stroke risk at 30 days — could potentially have affected the results in favor of the dual-layer stent.

The editorialists also report that a previous comparison between the dual-layer stent and a closed-cell stent showed no significant differences on 72-hour DW-MRI, but this study enrolled a low-risk asymptomatic population, whereas in the current study 1 in 4 patients were symptomatic.

"Considering the equipoise between carotid artery stenting and surgery with respect to long-term outcomes, the reduction of periprocedural complications and in particular the risk for stroke in patients undergoing stenting is the main objective of research in this area," Stabile and Gerardi comment.

"The technological progress of devices used in carotid artery stenting (i.e., embolic protection devices, dual-layer stents) seems to progressively improve outcomes; new-generation stents such as dual-layer stents could potentially offer the final optimization of carotid artery stenting compared with carotid endarterectomy, but large-scale studies are needed," they conclude.

The study was an investigator-initiated study supported by the E.N. Meshalkin National Medical Research Center and Jagiellonian University Medical College. Senior author Piotr Musialek is a proctor, an advisory board member, and a consultant for Abbott Vascular, InspireMD, and Medtronic. All other authors and the editorialists have disclosed no relevant financial relationships.

JACC Cardiovasc Interv. 2021;14:2377-2387. Full text, Editorial

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