Drawbacks of drug-coated stents surfacingSep 13, 2006 | Newsday
Doctors have begun to consider the drawbacks of coated stents, the tiny mesh devices implanted to prop open clogged arteries, in light of emerging studies revealing a risk of blood clots that can lead to heart attacks and strokes.
The era of the coated devices, which are known technically as drug-eluting stents, was ushered in amid fanfare just three years ago as doctors anticipated a more effective way of treating coronary artery disease. Drug coatings thwart the encroachment of immune system cells that can cause blood vessel scarring and replugging. Coated stents replaced bare metal ones, which left the patient vulnerable to re-blockage.
Two reports in today's New England Journal of Medicine document problems with coated stents, suggesting a return to the bare metal type for some newly diagnosed patients.
Last week a team of European doctors at the World Congress of Cardiology in Barcelona reported problems with dangerous blood clots, which appeared several years after patients had been implanted with a drug-coated device. And Boston Scientific, maker of a stent coated with the cancer drug paclitaxel and sold as the Taxus stent, acknowledged that their own data demonstrates a potential for abnormal clotting with the device.
"This is a classic kind of thing," said Dr. David Brown, chief of cardiovascular medicine at Stony Brook University Medical Center. "Every time we have a technological breakthrough, we invent a new disease along with it. In this case, it's late-stage thrombosis ."
Stenting became an option in the 1980s with the development of bare metal devices. In addition to Taxus, the Cypher stent, by Cordis, a division of Johnson & Johnson is coated with sirolimus, which also beats back cellular forces that lead to re-clogging. An estimated 6 million coated stents have been implanted worldwide
Dr. Steven Nissen, president of the American College of Cardiology and chairman of cardiovascular medicine at the Cleveland Clinic, said it's time to conduct a large-scale clinical trial to determine the risk for heart attacks, strokes and death with the coated devices. He underscored that the clinical trials leading to approval of the devices were not long enough.
"It's all about risks and benefits," Nissen said. "In this case, the late-stage thrombosis with drug-eluting stents is an unintended consequence. We're now beginning to get the big picture."
Even though Nissen told Newsday two years ago that stents would become passe as better drug treatments evolved, he said the newly identified problems are not a sign stents are fading out of favor. "These devices are still very important," in the treatment of heart patients, Nissen said.
Both he and Brown say one way to cope with drug-eluting stents is to extend the amount of time patients are on dual blood-thinning therapy aspirin and the drug Plavix. Even though all heart patients must take aspirin for life, they are weaned from Plavix. Patients with drug-coated stents may have to remain on the drugs longer.
"The decline in bypass surgery nationally occurred as a result of better medical therapy, so I don't think we'll see a shift from a percutaneous treatment to a surgical treatment," Dr. Kevin Marzo, chief of interventional cardiology at Winthrop-University Hospital in Mineola, said.