April 16, 2012 -- A stent that helps keep clogged heartarteries open, then resorbs, appears safe, according to a new study.
The study was small, with 50 patients. The follow-up lasted 10 years.
The results are called ''excellent'' by researcher Kunihiko Kosuga, MD, PhD, director of cardiology at Shiga Medical Center for Adults in Moriyama City, Japan.
One patient died of heart-related causes during the study follow-up. Rates of major complications, including heart attacks, were similar to those for metal stents in use now.
The research is published in the journal Circulation.
The biodegradable stents will eventually replace the current metal stents, Kosuga predicts. A U.S.-based expert says the study findings are positive. However, he doesn't expect the new stents to be on the market anytime soon. "The timeline for U.S. approval would be at least five or six years," says Kirk Garratt, MD, an interventional cardiologist and clinical director of interventional cardiovascular research at Lenox Hill Hospital in New York.
Other companies are already developing biodegradable stents.
More than a million procedures using heart stents are done annually in the U.S. To open the vessel, doctors perform angioplasty. They insert a balloon-tipped catheter into the artery. A stent is collapsed to a tiny diameter and put over the balloon.
When the catheter gets to the blockage, the balloon is inflated to open the vessel. The stent expands and locks into place. The scaffold it forms holds open the vessel.
Clots can form in the stent. Most metal stents are coated with drugs to reduce the risk of clots.
Patients are also typically put on aspirin and take a blood-thinning drug, such as clopidogrel (Plavix), for a time, then typically remain on aspirin for life.
Biodegradable Stents: Study Details
Kosuga's team followed 44 men and six women. The average age was 61. Together, they got 84 stents.
The new stent is made of a cornstarch-based material called poly-l-lactic acid. It completely resorbs in about three years, the researchers found.
The researchers looked for adverse events, such as clots within the stent area. They looked at re-narrowing of the vessels and deaths from heart disease and other causes.