'Drug-Free' Stent Coating Shows Promise
MONDAY, Jan. 21 -- A new kind of coated stent holds promise for overcoming the major problems with these tubes that are inserted to keep arteries open after clot-clearing angioplasty, Italian researchers report.
The new stent is not coated with drugs, like the latest generation in medical use, but with a special polymer designed to prevent thrombosis and restenosis, formation of new clots and buildup of deposits that re-clog the blood vessels, Dr. Corrado Tamburino told the International Symposium of Endovascular Therapy meeting on Monday in Hollywood, Fla.
A trial in which the new stents were inserted in 55 people who underwent angioplasty showed excellent results, said Tamburino, a professor of cardiology at the University of Catania, where the procedures were performed.
"We had no thrombosis, no deaths, no myocardial infarctions [heart attacks] at six months," Tamburino said.
In addition, close examination of the arteries showed re-growth of fatty deposits only in the smallest vessels, Tamburino said. "In large vessels, restenosis was nil," he said.
The results were especially remarkable, because one-third of the stent recipients were diabetic and thus more vulnerable to problems, and all participants got only 30 days of the clot-preventing drug Plavix, he said. Current U.S. recommendations are for six months to a year of Plavix after stent implantation.
The polymer used to coat the stent was developed by CeloNova Biosciences Inc., a Georgia-based biotechnology company. It is designed "to reduce inflammation and immune responses to the stent," Tamburino said.
"A polymer coating with almost no inflammatory action is an interesting concept," said Dr. Ramon Quesada, director of interventional cardiology at the Baptist Cardiac and Vascular Institute of Miami, after he heard Tamburino's report. "There is potentially lower chance of thrombosis."
But it's much too early to start drawing definitive conclusions about the new stents, Quesada said. "These are very preliminary data," he said. "We cannot make too much of it because the numbers in the trial are very small. This is an interesting observation, and we have to see the results of more trials."
Future trials would have to match results of angioplasty using existing drug-coated stents with the new polymer-coated stents, Tamburino said. Such trials would take years to produce definitive information, he said.
"We are going to do three more studies now, a couple in the next two weeks," said Thomas A. Gordy, chief executive officer of CelaNova.
"One study will include 50 to 60 more patients, another will include 20 patients," he said. "Then we will set up registries to include 500 to 600 patients."
The new studies will be done "in multiple centers in Europe," Gordy said. The expanded trials will include tests of the new coated stents against existing stents. Each study will take about six months to complete, he said.
You can learn more about stents from the American Heart Association.
Posted: January 2008
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