Major study of carotid stents may help local medical device makers

Local medical device companies, including Boston Scientific Corp., Lumen Biomedical Inc. and ev3 Inc. in Plymouth, Minn. may benefit from a major government-funded study that concludes carotid stents are equally safe and effective as surgery to unblock clogged neck arteries.

The long-awaited results from the Carotid Revascularization EndarterectomyVersus Stenting Trial (CREST), led by a Mayo Clinic researcher, will hopefully persuade federal officials to expand reimbursement of the stent, allowing Minnesota device makers to grab a bigger piece of the $65 million carotid stent market in the United States.

The medical device industry has been carefully watching the CREST study, the largest randomized trial of its kind, that compared surgery (endarterectomy) to stenting in patients at high risk for stroke who displayed both symptoms and no symptoms. During surgery, doctors cut into the vessel wall and removes the plague. With stents, doctors insert a balloon catheter, inflate the balloon to expand the artery, and then implant a stent to keep the walls open.

The CREST study, which enrolled 2,500 patients, found stents were just as good as surgery in preventing long-term strokes and heart attacks with stents slightly outperforming surgery in patients 69 years and younger, and surgery edging stents in patients older than 70 years.

However, the study found that in the 30 days after treatment, the stent group reported a 4.1 percent rate of stroke versus 2.3 percent in the surgery group. But the stent group had a lower rate of heart attacks (1.1 percent) than the surgery patients (2.3 percent).

“We found that the two procedures were similar with regard to the study’s primary endpoint —overall incidence of stroke, heart attack and death,” Dr. Thomas G. Brott, the lead author of the study and professor of neurology and director for research at the Mayo Clinic campus in Jacksonville, Fla., said in a statement. “We also found that the rates of these events were low and that safety for patients with and without symptoms was as good as any reported in any randomized carotid intervention trial.”

“For the present, stenting offers a reasonable alternative to carotid artery surgery,” Brott said. “For younger patients, carotid stenting appears to be a very useful tool.”

For years, the medical community has debated the merits of traditional surgery versus relatively new stent therapy. American studies have favored the stent while European trials offered less favorable judgments on the technology.

“It’s gone back and forth,” said Dr. David Tubman, director of interventional neuroradiology at Abbott Northwest Hospital in Minneapolis.

But CREST is significant for two reasons, Tubman said: CREST was primarily funded by the National Institute of Neurological Disorders and Strokes, which gives it more credibility that previous company sponsored trials. CREST is much larger than older studies–critics tend to dismiss those trials as being too small to produce meaningful data, he said.

With 2,500 people, “that’s a lot of patients,” Tubman said. “Now we are seeing some real data. It was a well-conducted study.”

Currently, the Centers for Medicare and Medicaid Services (CMS) offers reimbursement for a limited pool of high risk, symptomatic patients. In 2007, CMS rejected Abbott Vascular’s petition to expand coverage to asymptomatic patients and “conventional” patients, those with a lower risk for heart attack or stroke.

The limited reimbursement has hamstrung U.S. sales of carotid stents. But medical device officials hope the CREST study combined with Food and Drug Administration approval of Abbott’s Acculink stents for conventional patients will prod CMS to expand coverage to a wider patient market.

That could help ev3, which makes the Protege Rx Carotid Stent, and Lumen Biomedical, which makes FiberNet, a catheter-based system that removes debris from the carotid artery.

With its Carotid Wallstent, Boston Scientific, whose cardiovascular operations are based in Maple Grove, Minn. controls about 10 percent ($6.5 million) of the U.S. market and 40 percent ($14 million) of the European market. Boston Scientific officials say they hope CREST will boost U.S. carotid stent sales and help the company to better challenge market leaders Abbott and Johnson & Johnson.