Two carotid stenting trials show results comparable to AHA guidelines

Two carotid stenting trials examining patient outcomes demonstrated results that are comparable to guidelines established by the American Heart Association (AHA) for patients treated with carotid artery surgery.

The results of these studies were presented today at the Cardiovascular Research Foundation's 19th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium by William A. Gray, M.D., FACC, associate professor of clinical medicine at Columbia University College of Physicians and Surgeons and director of Endovascular Services at the Center for Interventional Vascular Therapy at NewYork-Presbyterian Hospital/Columbia University Medical Center in New York. Dr. Gray is the director of Endovascular Services at the Cardiovascular Research Foundation.

An interim analysis of patients treated with carotid stents in Abbott's CAPTURE 2 (Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events) and EXACT (Emboshield and Xact Post Approval Carotid Stent Trial) post-marketing trials, which enrolled 4,111 patients in over 150 sites, demonstrated 30 day patient outcome results consistent with longstanding AHA guidelines for patients with a severe carotid stenosis but who do not have symptoms. These guidelines recommend that rates of complications for carotid artery surgery to prevent stroke be less than 3 percent for patients without symptoms of stroke (asymptomatic) and 6 percent for patients with symptoms of stroke (symptomatic).

“In these two well-conducted carotid artery stenting studies, carotid stenting has achieved outcomes comparable guidelines established for patients who undergo carotid surgery, and has done so in a population of patients who are at high risk for experiencing adverse events from surgery,” said Dr. Gray. “This is a significant report because this is the first time that these guidelines have been achieved by any revascularization therapy in a large, multi-center examination of such patients, and although the guidelines were established for surgery (before stenting was practiced), there are no comparable surgical results in this group of patients.”

In 1998, the American Heart Association published its 30 day outcome guidelines in Circulation for patients treated with carotid artery surgery. These guidelines were based on the observed stroke and death rates in patients with carotid artery disease who had undergone surgery, called carotid endarterectomy, to treat their condition. The guidelines were based on studies of surgery in patients who did not have excessive risks for anesthesia, etc., but left unanswered what the best therapy is for patients for whom surgery was risky. These two studies are the first demonstration of a therapy providing stroke prevention (carotid artery stenting) in these patients and they provide an option to those facing difficult decisions regarding the risks of surgery.

The CAPTURE 2 study included 1,987 patients and utilized Abbott's ACCULINK(tm) Carotid Stent System and ACCUNET(tm) Embolic Protection System. The EXACT study included 2,124 patients and utilized Abbott's Xact(r) Rapid Exchange Carotid Stent System and Emboshield BareWire(tm) Rapid Exchange Embolic Protection System. The key objective of both trials was to determine whether carotid stenting could be performed safely in the real-world clinical setting by physicians with varying levels of experience. The primary endpoints were death, stroke and MI at 30 days. The demographics of patients in both trials were similar.

The 30-day composite endpoints of stroke and death for patients in the CAPTURE 2 and EXACT studies were:

• 3.1 percent and 3.0 percent combined stroke and death in CAPTURE 2 and EXACT patients without symptoms under age 80
• 6.0 percent and 7.3 percent combined stroke and death in CAPTURE 2 and EXACT patients with symptoms under age 80
• 3.8 percent and 4.0 percent stroke and death within 30-days of treatment for the combined patient populations