Negative on biosensors

Wed Oct 18, 2006 5:42pm ET

By Gene Emery

BOSTON (Reuters) - Propping open clogged arteries with little mesh tubes called stents is more likely to cause strokes than the old-fashioned method of simply cleaning out the arteries surgically, a French study showed on Wednesday.

Stents were found to be so dangerous that just over a year ago, the team led by Jean-Louis Mas of Sainte-Anne Hospitals in Paris stopped enrolling volunteers in the study, begun in November 2000, because of risks from the stent technique.

The work, published in The New England Journal of Medicine, reflects international efforts to determine the best treatment for clearing clogged carotid arteries -- the most common cause of the strokes suffered by over 700,000 Americans each year.

Based on results from 30 medical centers in France, the Mas team found that at the one-month mark, 9.6 percent of 247 stent recipients had died or suffered a stroke, against 3.9 percent of 257 who received the surgery, known as endarterectomy.

"One additional stroke or death resulted when 17 patients underwent stenting rather than endarterectomy," they said.

Of the strokes in the stent group, 71 percent took place on the day of the procedure. In the surgery group, 33 percent of the strokes occurred on the first day.

The team decided it would be unethical to continue using stents in the patients, whose arteries were at least 60 percent blocked and who had already had symptoms of a stroke.

Such symptoms can include confusion, vision changes, difficulty speaking and a sudden weakness, numbness or coordination problems in a hand or arm, even if temporary.

Stenting did offer some benefits, the researchers found. The risk of nerve damage was just 1 percent for stenting versus nearly 8 percent for surgery, and surgery patients usually spent an extra day in the hospital.

UNDER SCRUTINY

The study coincides with troubling times for the $6 billion global market for stents, which once implanted stay in the artery permanently to improve the flow of blood to the heart muscle and relieve symptoms such as chest pain.

The devices have come under scrutiny amid studies suggesting drug-eluting stents may raise the risk of blood clots months after they are implanted.

Medical device-maker Boston Scientific Corp., for example, has seen its stock hover near four-year lows this month following safety concerns that have sharply slowed sales of stents and implantable heart defibrillators.

Other studies, however, give conflicting results on the two techniques.

Johnson & Johnson's 300-patient SAPPHIRE trial released results two years ago that showed the stroke rate after stenting was 3.6 percent, less than half what it was in the Mas study, known as EVA-3S.

But the 2004 results may have made stenting look safer because 70 percent of the patients had never had symptoms before their treatment, and surgery for them tends to be less risky, the Mas team said.

In an editorial in the journal, Anthony Furlan of the Cleveland Clinic, said that, for now, the only patients who should be getting stents are those who have stroke symptoms, have an artery that is at least 70 percent blocked, and who face a high risk from surgery.

Several experiments assessing both treatments are still under way in the United States and Europe.