• Press Center
• Press Release Archive
• Media Kit
• SAAAVE Act Campaign
• Press Releases from 2008 Annual Meeting
• JVS Press Releases
• SVS Position Statements
• Contact Us

Carotid artery stenting (CAS) is a commonly used alternative to carotid endarterectomy in patients with carotid artery disease who are thought to be at risk for stroke. To learn how different CAS devices impact patient outcomes, researchers studied the theoretical difference in closed vs. open-cell stents as well as eccentric vs. concentric embolic protection devices (filters which aim to prevent particles from moving through the bloodstream to the brain during implantation of the stent). 

“Closed-cell stents and eccentric filter devices were predominately used in this study and performed better in the short term in symptomatic patients or those with echolucent lesions,” said Joseph Hart, MD, lead author and now assistant professor of vascular surgery, University of Rochester School of Medicine and Dentistry in Rochester, N.Y. The study, performed while Dr. Hart was studying carotid stenting with Dr. Marc Bosiers and his team at AZ Sint Blasius in Dendermonde, Belgium, was presented at the 60th Annual Meeting of the Society for Vascular Surgery.

“In a study of 709 patients, 701 were considered a technical success,” said Dr. Hart. “There were more adverse events within 30 days with the open cell stent. Closed-cell stents cover a greater percent of the vascular wall in the stented region and have less free (uncovered) cell area. The closed-cell stents have greater potential to scaffold and support fractured plaque and keep material that could embolize to the brain, or cause small clots, away from the moving blood. Also, the paper noted that complex hematologic factors might also contribute to the apparent superiority of closed-cell stents in this series. Therefore we would recommend them for symptomatic patients.”

There also were more adverse events within 30 days with concentric filters. “Some data suggest that eccentric filters are superior to concentric filers for transient ischemic attack (TIA) prevention of particle capture,” said Dr. Hart.“We postulate the better wall apposition in the distal internal carotid artery (ICA) due to axial flexibility may account for this.”

He added that concentric filter wires might pull it away from the wall and filter when used in a person whose anatomy has curves. Suboptimal position of the concentric filter within the distal ICA beyond the lesion being treated may lead to incomplete embolic protection. However, floating eccentric filters are potentially more prone to complete wall apposition, thus improved embolic protection. Our researchers believe eccentric filters should be used in symptomatic patients undergoing CAS.

A subset of patient, lesion or procedure-related variables were analyzed for an association with occurrence of stroke, death or TIA. Overall combined rates of stroke, death or TIA in this study was 3.7 percent at 30 days.  Results at 30 days, one year and three years for overall rates of stroke or death were 1.4 percent, 6 percent and 15.1 percent and restenosis rates were 0.2 percent, 0.9 percent and 5.6 percent (respectively). There was no difference in rates of restenosis between symptomatic and asymptomatic patients. After analyzing basic risk factors, the only significant condition was hypercholesterolemia. All patients were monitored by a number of neurological evaluations before, during the CAS procedure and at follow-up.

Researchers examined the impact of 30-day stroke, death and TIA for various risk factors. Severe abnormally slow heart rate and low blood pressure resulted in transient brain muscle activity and even neurologic deficits.   Neurologic deficit, even following a period of hypotension with bradycardia, were recorded as a TIA. It should be noted, said Dr. Hart, that similar events may be masked under general anesthesia, particularly if EEG monitoring is not utilized or fails to indicate such activity.

“Carotid stenting is here to stay,” said Dr. Hart. “Although the decision to use it for patients is highly individualized, it is likely that it will be used on even more patients in the future because of the less invasive nature of the procedure.”

With study limitations alternative explanations for data does exist. Researchers believe a prospective trial is necessary prior to conclusive resolution that device characteristics under consideration here materially impact patient outcome. As an alternative to prospective trial, it would be possible to consider meta-analysis of the existing trial data to further examine this question without incurring the expense and logistical difficulties of a formal trial