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Health Sense

Coated Stents Smooth Cardiology Care Recovery

June 17, 2002|JUDY FOREMAN | SPECIAL TO THE TIMES

If you are rushed to an American hospital today with chest pain caused by clogged arteries to your heart, the chances are good that you will get an artery-opening procedure called angioplasty, and the insertion of a tiny, mesh-like device called a stent to keep your arteries open.

If you had the same symptoms in Europe, you'd still get angioplasty, but with an important twist. Instead of a regular stent, you and your physician could opt for a new coated stent that, in addition to keeping arteries open through sheer structural support, releases drugs that combat the inflammatory process that can cause uncoated stents to fill up with scar tissue.

Coated stents will probably be on the U.S. market in the next year or so. And no matter which company gets there first--the leaders are Cordis (a Johnson & Johnson company), Boston Scientific and a joint effort by Guidant Corp. and Cook Inc.--the new stents are likely to revolutionize the way doctors treat heart patients.

Most important, they are expected to reduce dramatically the current 30% to 50% rate at which arteries re-narrow after stenting, a process called restenosis. In fact, some data show an almost unheard-of 100% success rate (meaning zero restenosis) for the drug-delivery stents after two years of follow-up.

"The anticipation is extraordinary in this field," said Dr. Campbell Rogers, director of the cardiac catheterization laboratory at Brigham and Women's Hospital. "The impact of having a new, less-invasive and more effective treatment for coronary artery disease is vast."

The new stents will likely become the preferred option not just for the 1 million or so Americans a year who now get regular stents, but for hundreds of thousands of others currently deemed ineligible because they have too many bad arteries. They may also be used for hundreds of thousands of others with "vulnerable plaques," arteries with fatty deposits that have not yet ruptured.

"If the results of these early trials are confirmed in larger studies, coated stents should significantly reduce the need for coronary artery bypass surgery," says Dr. Sidney C. Smith, chief science officer for the American Heart Assn. and a professor of medicine at the University of North Carolina at Chapel Hill.

Dr. Jesse Currier, associate director of the adult cardiac catheterization lab at UCLA Medical Center, put it even more emphatically: "This is Neil Armstrong, one giant leap for interventional cardiology ... this is a huge, huge quantum leap."

In fact, the biggest downside may turn out to be that financially strapped hospitals could suffer as patients choose the new stents over bypass surgery, a huge money-earner.

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Commonplace as they now are, regular stents have actually been on the U.S. market for only a few years, after two major trials showed that simply placing an uncoated stent into an artery was better than angioplasty alone in reducing the risk of restenosis. (In angioplasty, doctors thread a tube called a catheter up through an artery in the groin to the coronary arteries, then push a button to inflate a balloon to compress the plaque against the artery wall.)

Even though uncoated stents do just fine at keeping artery walls from collapsing, their sheer presence can create new problems, notes Dr. Elazer Edelman, director of the Harvard-MIT Biomedical Engineering Center, a professor of health sciences and technology at MIT and a cardiologist at Brigham and Women's Hospital. The worst possibility is that, immediately after insertion, the stent can trigger blood clots, a process that doctors guard against by giving patients anti-clotting drugs such as aspirin and Plavix. But there's another danger, too, after insertion of a stent. "You're leaving a foreign body behind. Now, as opposed to a single injury from inflating a balloon, you have a rigid, metal object that can trigger a slow, chronic inflammatory process," Edelman says. Indeed, inflammation is now believed to be a root cause of atherosclerosis, the initial formation of plaques, and of restenosis, the re-clogging of arteries during the healing process after angioplasty and stent insertion. Cholesterol, specifically LDL (the "bad" cholesterol) is still a major culprit. But its effects include stimulation of the body's natural inflammatory response to injury--sending immune cells to clean up the area.

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