The Source for Neurovascular News and Education

June 06, 2020


Embolic protection is important, even if it does not appear to affect stroke risk, one expert says.


Carotid artery stenting (CAS) is associated with a low cumulative incidence of restenosis at 12 months and ipsilateral stroke at 30 days, according to a meta-analysis published online recently in the Journal of NeuroInterventional Surgery. Somewhat surprisingly, the analysis also found no association between use of an embolic protection device and a reduced risk of stroke, but an expert emphasized to Neurovascular Exchange that it remains an important component of CAS.


Despite the fact that the meta-analysis yielded no link between embolic protection and stroke, Frank J. Veith, MD (NYU Langone Medical Center, New York, NY, and Cleveland Clinic, OH), maintains that protection remains important.


Commenting on the results for NVX, he said: “The overwhelming data are that, even if the stroke rate is not decreased—and that of course is controversial—unprotected CAS does result in perhaps asymptomatic small infarcts in the brain which, even if they do not qualify as a stroke, are not good things. The overwhelming recent evidence would suggest that embolic protection is an important addition to CAS.”


Pierre Clavel, MD (CHU Limoges, France), and colleagues performed the meta-analysis by combining data from 40 studies that comprised 15,943 patients (16,337 carotid arteries) who underwent CAS. Overall, the pooled cumulative incidence of restenosis and ipsilateral stroke were both low.


Outcomes of Stenting


Pooled Cumulative Incidence (95% CI)

12-Month > 50% Restenosis

5.7% (3.8%-8.6%)

12-Month > 70% Restenosis

5.2% (3.3%-8.2%)

6-Month > 50% Restenosis

3.9% (2.2%-6.8%)

30-Day Ipsilateral Stroke

1.6% (1.0%-2.5%)


There were no relevant sources of heterogeneity for the cumulative incidence of restenosis > 50% at 12 months. For > 70% restenosis at 12 months, however, mean age explained 80.9% of heterogeneities across studies (R2 = 80.9%, P = 0.01), with older patients tending to have lower risk. In addition, the presence of hostile neck explained 53.9% of heterogeneities in restenosis for > 50% at 6 months (R2 = 53.9%, P = 0.03), with lower risk seen in studies of a higher prevalence of this anatomy.


In the studies where embolic protection was used systematically, the pooled cumulative incidence of ipsilateral stroke within 30 days was 0.9% (95% CI 0.4%-2.2%). Similarly, in the subgroup of studies with no embolic protection device, the pooled cumulative incidence of ipsilateral stroke within 30 days was 1.2% (95% CI 0.3%-4.0%). There was no statistically significant difference in the incidence of stroke between these subgroups.


Clavel and colleagues note, however, that the use of a protection device was not randomly assigned in the studies, “and we cannot eliminate the potential bias that a protection device might have been preferentially used in challenging cases or associated with other clinical characteristics that may have affected clinical outcomes. This finding needs to be confirmed in a prospective randomized trial with and without the use of a protection device for carotid stenting.”


Veith said the findings come as no surprise to him. “We know that the incidence of restenosis after CAS and [carotid endarterectomy] is low,” he explained. “Even when it occurs, it probably has very little significance. It does not cause much of a problem in most instances. It does not [usually] need to be retreated because it’s a relatively benign condition.”


He anticipates that the most important development in this arena will be the increasing use of transcarotid artery revascularization (TCAR). Veith pointed out, however, that determining which patients with carotid artery stenosis actually require surgical revascularization, particularly if they are asymptomatic, remains an important clinical question.



Clavel P, Hebert S, Saleme S, et al. Cumulative incidence of restenosis in the endovascular treatment of extracranial carotid artery stenosis: a meta-analysis. J Neurointervent Surg. 2019;Epub ahead of print.



Clavel and Veith report no relevant conflicts of interest.