These devices, which slowly leach medication into blood vessels to keep them from squeezing shut after procedures to remove blockages, have revolutionized heart care so much in the last few years that studies now are aimed at finding which ones work best for which patients — not whether they work at all.
They are vastly better than the plain old metal stents that were standard just a few years ago. Results on the new ones are so good that more and more patients are being successfully treated with them and avoiding a more drastic alternative — heart bypass surgery.
Two are on the market — Boston Scientific Corp.'s Taxus stent, and Cypher, made by Cordis Corp., a Johnson & Johnson company.
"Both devices have made remarkable progress" in treating heart disease, said Dr. Gregg Stone, a cardiologist at Columbia University Medical Center, who was not involved in the comparison studies.
New studies on stents were presented Sunday at an American College of Cardiology conference in Orlando. They showed that benefits apparently last for years, and that even very big blockages in very small vessels — some nearly two inches long — can be fixed with such stents, sometimes using overlapping ones.
The devices work so well that when an older stent clogs, it's better to put a new drug-coated one inside it than to treat the problem with radiation as has been done in the past, one study found.
Competitors also are being developed that could help cut the price of these devices. One novel type even dissolves in the body once its job is done.
"It's looking very good," Dr. Gerald Fletcher, a Mayo Clinic cardiologist, said of the evidence for drug-coated stents. "The benefit is going to be substantial in the long term."
Clogged arteries can cause a heart attack. One solution is open-heart bypass surgery, in which blood vessels from elsewhere in the body are used to create detours around blockages.
A less drastic treatment is angioplasty, in which a tiny balloon is snaked through blood vessels to blockages and inflated to flatten them. Nearly a million of these are done each year in the United States, and in most cases, a stent is placed to keep the artery from squeezing shut again.
But even these reclogged about one-fourth of the time until drug-coated ones came along and cut the rate to around 5 percent. The Cypher and Taxus stents use radically different drugs, and it hasn't been known which is better.
The first big comparison study showed that eight months after treatment, rates of heart attacks, strokes and repeat procedures were similar with both stents. The study involved 1,353 patients in Europe, Latin America and Asia, and was reported Dr. Marie-Claude Morice of Institut Cardiovasculaire Paris Sud in France. It was sponsored by Cypher's maker, Cordis.
A different study led by doctors with no ties to Cordis showed Cypher clearly outperformed Taxus in 250 diabetics, whose arteries are more prone to reclogging. Problems were two to three times more frequent among those who got Taxus stents.
"These results would push us to select the Cypher stent for diabetic patients," said Dr. Adnan Kastrati of Deutsches Herzzentrum, a medical center in Munich, Germany.
Other research confirmed the effectiveness of both stents two and three years after treatment. Nearly nine out of 10 stents used in the United States now are drug-coated, and two out of three are Taxus stents.
Meanwhile, Medtronic Inc. reported that its experimental drug-coated stent, Endeavor, outperformed plain metal stents in tests on 1,197 patients. The company hopes to sell it in Europe soon and to seek U.S. approval later this year.
Finally, the first human tests of Biometrik's experimental dissolving stent were reported. Five people received the device last July, and "absorption seems to occur within the first four weeks as planned," said Dr. Raimund Erbel of University Clinic in Essen, Germany.
Competition should make drug-coated stents more affordable, said Dr. Samin Sharma, co-director of the Cardiovascular Institute at Mount Sinai Medical Center in New York. They used to cost more than $3,000, sell for around $2,300 now, and could drop to less than $2,000, he said.
By Marilynn Marchione