Stroke Prevention in Carotid Artery Stenting
Gary Ansel, MD, discusses the goals and challenges of embolic protection, the potential of flow reversal, and how stroke rates have improved over the past decade.
What are the primary goals of neuroprotection during carotid artery stenting (CAS)?
The primary goals of neuroprotection during CAS are to prevent debris from embolizing to the distal vascular bed and causing a stroke while acting as a stable platform from which to deliver the balloon and stent.
What do you feel are the current limitations based on clinical evidence for CAS to date?
The current distal embolic protection devices each have one or more of the following limitations. First, they must pass through the carotid blockage before establishing protection. They have difficulty passing through severely stenotic stenoses and/or significant vessel tortuosity. They also let blood flow through pores that allow some amount of distal embolization, require a landing zone for the device, and have difficulty maintaining wall contact if used in noncircumferential vessels. Lastly, they must be recaptured and removed through the stent.
What has been improved in outcomes since CAS was first introduced?
The biggest change in outcomes since CAS was introduced over a decade ago is primarily centered on the decreased incidence of stroke. Since the early trials with overall stroke rates of approximately 5%, the last few trials have had stroke rates of less than 3%. This decrease may be attributed to several factors including improved device profile, filter efficiency, etc., but the improvement may also be attributed to better patient selection. Just as there are markers for increased surgical risk, there also appears to be markers of increased risk from carotid stenting.,/p>
What will help clinicians to achieve better results?
I think clinicians will continue to achieve better results as experience increases, and we will learn more about what actually leads to strokes both intraprocedurally and after the procedure. As we become more insightful, we may improve our decision-making process as to which protection type, stent type, etc., to use.
Considering the recent Embolic Protection with Reverse Flow (EMPiRE) study results,what role do
you think flow reversal has in helping CAS reach its potential?
The recent proximal protection device results are very encouraging regarding the potential of continuing to lower the patient risk during carotid stent procedures. I feel the addition of this unique approach will increase the number of patients that can be offered a safe procedure. As physicians become more insightful as to which patient populations are best suited for proximal versus distal embolic protection, we will help the field mature.