FDA Approves Carotid Stent For High-Risk Endarterectomy

By Elizabeth Mechcatie

A second carotid stent system has been approved by the Food and Drug Administration for patients with carotid artery disease who are at high risk for carotid endarterectomy and meet certain criteria.

The Xact carotid stent, a self-expanding nitinol stent manufactured by Abbott Laboratories, was approved by the FDA last month for use with an embolic protection filter (the Emboshield Embolic Protection System) to capture emboli during the stenting procedure. Abbott has agreed to implement a training program and to provide updates at least once a year to physicians who use the device on the long-term follow-up of patients and postmarketing studies, which will include information about death, stroke, and MI rates in treated patients, according to the FDA approval letter.

This is the second carotid stent system to be approved; the first, manufactured by Guidant Corp., was approved in August 2004. Several others are under review at the FDA.

The Xact stent is intended for use in patients who are symptomatic and have 50% or more carotid stenosis on ultrasound or angiography, or in patients who are asymptomatic and have 80% or more stenosis, located between the origin of the common carotid artery and the intracranial segment of the internal carotid artery, according to the FDA. The stent is contraindicated in patients who cannot take anticoagulants or antiplatelet therapy, or who have uncorrected bleeding disorders or lesions in the ostium of the carotid artery.

On the basis of evidence from preclinical and clinical studies, the Xact stent system "provides a safe, effective, and durable method" for treating carotid stenosis in patients at high risk for endarterectomy, the FDA concluded in a summary of safety and effectiveness.

In a prospective, nonrandomized study of 305 patients in the United States and Australia with an anatomical risk factor and/or comorbidity that put them at risk for endarterectomy, and who were symptomatic and had 50% or more stenosis, or were asymptomatic with 80% or more stenosis, treatment of the target lesion was considered successful in 295 patients (97%). At 30 days, 269 patients (88%) had "overall procedural success," defined as residual stenosis less than 50% when the procedure was completed and no major adverse events (stroke, death, or MI) at 30 days. Almost 93% had not experienced a major adverse event (death, stroke, or MI) at 30 days, one of the primary end points. Another primary end point, the composite rate of the 30-day major adverse event and ipsilateral strokes at 1 year, was 8.5%.

At 12 months, 99% of patients had not required repeat vascularization and restenosis occurred in 5% at 6 months after the procedure, according to the FDA. Within 30 days of the procedure, there were three deaths, 21 strokes, and 109 procedural complications.

The company has agreed to conduct postmarketing studies, including an evaluation of safety and effectiveness lasting for 3 years after implantation in at least 305 patients, according to the approval letter.