FRIDAY, May 9 (HealthDay News) -- Stents have become a cornerstone of heart-disease treatment, tiny tools that have extended the lives of millions of patients by maintaining the flow of blood through their arteries.
The wire metal mesh tubes, when inserted following artery-clearing angioplasty procedures, can prop open the artery and ensure a constant supply of blood to the heart and throughout the body.
But stents aren't perfect. Scar tissue causes them to re-close in about one in five patients, requiring a follow-up procedure to remove and replace the stent, lest the patient suffers a heart attack, said Dr. Laura Mauri, an assistant professor of medicine at Harvard Medical School and Brigham and Women's Hospital, in Boston.
New stents that were approved by the U.S. Food and Drug Administration in 2003 are coated with a drug to prevent too much scar tissue from forming. But some research has shown that the drug can increase the risk of too little scar tissue forming and a blood clot appearing in the stent.
"If not enough scar tissue forms to cover the stent, the metal can create a blood clot on its own," said Dr. Jack Tu, a senior scientist at Canada's Institute for Clinical Evaluative Sciences and a professor with the University of Toronto. "It's a fine balance. You want some scar tissue to form around the stent, but you don't want too much to form."
As doctors and scientists continue to pursue ways to improve heart health, the debate over drug-coated stents versus bare-metal stents continues to simmer.
In the latest development, the U.S. Food and Drug Administration announced in December that it is preparing to issue new testing requirements for drug-coated stents. The revised rules, created in response to concerns about stent safety, are expected to be more stringent than current rules. They are expected to specify the numbers of patients on whom new drug-coated stents can be tested and for how long, and to offer a recommended length of time patients should take anti-clotting drugs after receiving a stent.
