This is a brief overview of information related to FDA’s approval to market this product. See the links below to the Summary of Safety and Effectiveness Data (SSED) and product labeling for more complete information on this product, its indications for use, and the basis for FDA’s approval.
Product Name: Exponent® Self-Expanding Carotid Stent with Over-the-Wire (OTW) Delivery System
Exponent® Self-Expanding Carotid Stent with Rapid-Exchange (RX) Delivery System
PMA Applicant: Medtronic Vascular, Inc.
Address: 3576 Unocal Place, Santa Rosa, CA 95403 USA
Approval Date: October 23, 2007
Approval Letter: http://www.accessdata.fda.gov/cdrh_docs/pdf7/p070012a.pdf
What is it? The Exponent® Self-Expanding Carotid Stent with Over-the-Wire (OTW) Delivery System and the Exponent® Self-Expanding Carotid Stent with Rapid-Exchange (RX) Delivery System are used to re-open stenotic (narrowed) regions of the carotid arteries in the neck which supply blood to the brain. They consist of two components, the stent and the delivery system. The stent is an implant constructed of nitinol (nickel-titanium alloy) tubing, laser-cut into a mesh shape. The stent is mounted onto the delivery catheter: a long, thin, tube-like device.
Carotid stents are typically used in conjunction with embolic protection devices: catheter-mounted filters or balloons that are placed near the treatment site to capture bloodclots or plaque debris that may break off from the blockage during the stenting procedure.
How does it work? The Exponent® Self-Expanding Carotid Stent Systems are inserted during angioplasty (a less invasive procedure than surgery), in which the stent is threaded up to the carotid artery via a catheter inserted in the groin.
- The embolic protection device is inserted into the vessel in the groin and advanced up to the blood vessel in the neck where there is blockage.
- The embolic protection device is deployed, whereby the device is activated so that it will capture debris generated during the stenting procedure.
- After the embolic protection device is deployed, the physician uses the same wire to advance the Exponent® stent to the blocked area.
- The stent is then allowed to come out of the catheter and opens automatically over the blockage.
- The catheter is removed, and the embolic protection device is removed next, along with any pieces of debris that were trapped.
When is it used? The Exponent® Self-Expanding Carotid Stent with OTW or RX Delivery System is used in patients who:
- have had a stroke and at least a moderate (≥ 50%) blockage in the blood vessels of the neck, or
- who have not had a stroke but have a very tight (≥ 80%) blockage in the vessels of the neck.
Patients should also have either medical problems or body abnormalities that would put them at a high risk if they had the surgical alternative (called carotid endarterectomy).
What will it accomplish? The stent is supposed to open blockages in the blood vessel in order to prevent future strokes. In a clinical study involving 399 patients, the risk of death, stroke and heart attack at 30 days or any stroke in the area of the blockage at one year was similar to the rate of complications reported in literature from patients undergoing surgery. In addition, the study showed that the stent still allowed blood flow to the brain more than one year after the procedure.
When should it not be used? Stents should not be used in patients who:
- cannot take blood thinners,
- have bleeding disorders, such as hemophilia,
- who are allergic to the nitinol material the stent is made from
- who have blockages at the beginning of the neck artery, or
- who have problems preventing the catheter from getting to the blockage.
Additional information: The Summary of Safety and Effectiveness and labeling will be available at: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cftopic/pma/pma.cfm?num=p070012