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Doctor helps develop drug-coated stent to prevent arterial scar tissue

A federal medical advisory panel in Washington, D.C., has given the go-ahead to a device developed in the lab of a Portland cardiologist that promises to greatly advance the treatment of clogged arteries.

Dr. Andrew Carter, director of interventional cardiology research at Providence Heart Institute in Portland, was among the heart specialists testifying before the panel, which makes recommendations to the federal Food and Drug Administration.

The FDA wants more information about the device, called a 'drug-coated stent,' before giving its final approval. But the agency almost always follows its advisory panel's recommendations, Carter said.

He expects the stent to be available for patients undergoing angioplasty in the first quarter of 2003.

'It's been very satisfying,' said Carter, who has worked on the stent for more than eight years.

The stent, a microscopic-size, wire-mesh tube that releases a small amount of medication into the artery, 'should substantially improve the long-term functioning of patients with heart disease,' said Carter, a lead investigator in clinical trials that tested the stent on heart patients.

'It should eliminate a large portion of their time away from work and bring patients an improved quality of life,' he said.

FDA approval of the stent, besides offering patients a significant advance in heart disease treatment, will bring more attention Ñ and research dollars Ñ to the Providence Heart Institute, Carter said.

'It helps us a tremendous amount to maintain a very competitive edge,' he said.

The institute, based at Providence St. Vincent Medical Center in Southwest Portland, has generated at least $2 million in research revenue and has secured research agreements with a number of national medical-device manufacturers since he arrived a year ago, Carter said.

The drug-coated stent attracting all of this money and attention represents a vast improvement over the bare-metal stents commonly used in treating clogged coronary arteries.

The tiny metal stents serve as a kind of scaffolding, stretching and keeping arteries open. The stent developed by Carter and his colleagues is covered with a medication called sirolimus, an antibiotic used to prevent organ transplant rejection.

Once this stent is implanted, the drug goes to work to prevent scar tissue from reclogging the arteries, a process called restenosis.

About 20 percent to 30 percent of the 1 million patients who each year undergo angioplasty, the technique used to clear clogged arteries, suffer restenosis Ñ usually from scar tissue that grows at the site of the implanted stent.

'That has been a major limitation of (bare-metal) stents, that some patients will come back for additional treatment, maybe another angioplasty or radiation therapy or bypass surgery,' Carter said.

Drug-coated stents eventually should replace bare-metal stents and should keep patients from returning for more treatment, Carter said.

They also are likely to greatly reduce the need for riskier bypass surgery, he said.

Results of clinical trials testing the drug-coated stents, first in Europe and Latin America and then in the United States, were impressive. In the European-Latin

American study, not one patient who received a drug-coated stent had a recurrence of scar tissue blocking the artery's flow.

A study involving 1,100 heart patients enrolled in the U.S. study showed a 75 percent reduction

in the number of heart patients

experiencing reclogged arteries, according to information from the stent's maker, Cordis Corp., a division of Johnson & Johnson that will market the device.

Cordis is the major financial backer of Carter's research.

The drug-coated stent was approved for marketing in Europe last April and has been available in Europe, Asia and New Zealand since then.

Cordis is the first company to receive the FDA panel's approval for a drug-coated stent. Other companies, such as Boston Scientific Corp. in Massachusetts and Guidant Corp. in Indiana, are working on similar stents that use different drugs.

An osteopath and cardiologist, Carter came to the Providence Heart Institute last year from Stanford University Medical Center in Stanford, Calif., where he worked on the sirolimus-coated stent.

He brought his research with him when he came to Portland to work with his friend and colleague, Dr. Kenton Gregory, a cardiologist and director of the Oregon Laser Medical Center, which also is based at Providence. Gregory and Carter are partners in a practice called Northwest Heart Care, based at St. Vincent.

Carter, who also is a senior scientist at the laser center, said he is working with the other companies to see if their versions of the drug-coated stent are as effective as the one Cordis is making.

He said he will not receive royalties from its marketing and distribution.

'I don't have any financial relationships of that nature,' he said. 'I am a researcher, not a manufacturer. My objectives are different.'

The Providence Heart Institute has research agreements with a number of device manufacturers, 'which gives us an opportunity to be involved in this kind of research,' Carter said.

'By virtue of our ability to prove that medication can be put on a stent and improve the way the body heals, this research has implications for other aspects of health care,' he said. 'I think this (research) will spill over into other areas of treating both vascular and nonvascular diseases.'

More information is available online at www.providence.org/Oregon/health_resource_centers/Heart_Disease_Center/DrugCoatedStents.htm