A stent for use in opening blocked arteries in the neck has been approved by The US Food and Drug Administration (FDA). The new stent, manufactured by Guidant Corporation, is intended to prevent stroke by treating blockages in the carotid artery, the main blood vessel leading to the brain, according to an FDA release.

The device-the first of its kind-was approved for use in patients who have had symptoms of a stroke or whose carotid artery is at least 80 per cent blocked, and who are not good candidates for the surgical alternative.

FDA approved the system based on a review of clinical studies of safety and effectiveness conducted by Guidant.

The firm studied use of the carotid stent system in 581 patients at 45 medical centres who either had experienced a stroke or were in danger of having one due to severe blockages in the blood vessels in their neck.

The study showed that the new stent system successfully opened blockages in 92 per cent of patients. When complications from use of the stent were compared to complications reported in the medical literature from patients undergoing surgery, the risk of combined complications of death, stroke and heart attack at 30 days or stroke in the area of the blockage at one year was about 10 per cent compared to 15 per cent for surgery. In addition, the study showed that the stent still allowed blood flow to the brain more than two years after the procedure.

The new system, is inserted during angioplasty, a less invasive procedure in which the stent is threaded up to the neck artery via a catheter inserted in the groin. Patients usually require only local anaesthesia.

The system can be used with a tiny filter that opens like an umbrella. The filter is used to catch and remove the debris that is stirred up during the stenting procedure before it floats to the brain where it can trigger a stroke.

"Carotid stents offer doctors a new, less-invasive option for clearing blocked neck arteries," said Dr. Lester M Crawford, acting FDA commissioner.

Stents, which are small metal mesh tubes, are already approved for use in heart arteries. Currently, blockages in the carotid artery are treated with a surgical procedure called carotid endarterectomy in which surgeons cut into the neck artery to remove the blockage. Patients require general anaesthesia for the procedure.

FDA is requiring Guidant to conduct post-approval studies to confirm the stent's performance in more patients and to assess its long-term safety and effectiveness in preventing strokes.