The analysis of three pivotal stenting vs surgery trials also found no impact of cerebral embolic protection devices on adverse events.
Results of a pooled analysis of randomized, controlled trials suggest that stent design is a major factor in the risk of procedural stroke or death with carotid artery stenting (CAS). Both events were less likely to occur with closed-cell than with open-cell stents, and filter protection devices did not mitigate this risk.
“Interventionalists should take into account these findings when selecting devices to use for carotid stenting,” Martin M. Brown, MD (UCL Institute of Neurology, London, England), a co-author of the study, told Neurovascular Exchange. However, he also noted that further research is needed to establish the safest technique for carotid stenting.
Brown said that one explanation for the apparent lack of benefit of protection devices is that they cause as many strokes from initial insertion across the stenosis or damage to the distal carotid artery as they prevent by capture of embolic material during stent insertion.
“Another possible explanation is that protection devices do reduce the rate of stroke, but in this study the more experienced interventionalists were more likely to stent without a protection device, and more experienced interventionalists were less likely to cause emboli,” Brown said. “The results could also be explained by selection of patients, such that high-risk patients were stented with protection and low-risk patients were stented without protection.”
Scaffolding Effect Implicated
The study, which was led by Fritz Wodarg, MD (University Hospital Kiel, Germany), was published online April 19, 2018, ahead of print in the Journal of NeuroInterventional Surgery.
To compare outcomes of different stent types, the researchers pooled data from 1,557 patients enrolled in three large randomized trials comparing stenting with endarterectomy for symptomatic carotid stenosis (EVA-3S, SPACE, and ICSS). The primary outcome was procedural stroke or death within 30 days.
Most of the 962 procedures were performed with a closed-cell stent compared with open-cell (61.8% vs. 38.2%). Among those who received open-cell stents, the rate of procedural stroke or death was 10.3% vs 6.0% for closed-cell stents (P = 0.002).
When discussing this result, Brown stated that “the scaffolding effect of open-cell stents holding atheromatous plaque in place is less” and that atheromatous debris might be more likely to extrude through the larger cells and embolize, causing stroke.
Brown added that anatomical features and operator experience with the type of stent being used are important factors to take into account when choosing a stent type, but when other factors are equal, the results of this study support the use of open-cell stents.
With more than 60% of patients in the three trials undergoing procedures where a protection device was used, the primary outcome occurred in 8.0% of those treated with protective stenting and 7.1% of those treated without (P = 0.67).
The study also identified several factors that significantly increased risk for procedural stroke of death, including increasing age, increasing severity of the qualifying events, patients with a history of stroke, and those with increasing level of functional disability at randomization. However, the effect of stent design remained robust after adjusting for these variables.
Sources:
Wodarg F, Turner EL, Dobson J, et al. Influence of stent design and use of protection devices on outcome of carotid artery stenting: a pooled analysis of individual patient data. J NeuroIntervent Surg. 2018;Epub ahead of print.
Disclosures:
The authors report no relevant conflicts of interest.
