7 Healthcast: Stents and blood clots

But now the newest models, coated with drugs, are under the government microscope.

It's estimated more than six million people have received drug-eluting stents, tube-like props coated with medicines, as an extra measure to prevent arteries from clogging.

Now the FDA is examining the safety of the coated stents.

Research suggests that there a risk of clotting one to three years after they are implanted.

"We did find a higher rate of stents clotting up with longer-term follow-up with drug coated stents versus bare metal stents," Dr. Deepak Bhatt, of the Cleveland Clinic, said.

According to federal statistics, late stage clotting happens in three to four out of every 1,000 patients. The Cleveland Clinic researchers say that while such findings raise a red flag, they should not trigger panic.

"So the absolute risk to an individual patient is quite low, unless of course you happen to be that patient," Dr. Bhatt said. "It's not an altogether trivial issue, but should not be the cause for panic among either patients or their physicians."

A statement by the American Heart Association highlights research suggesting that poor patient compliance with follow-up drug therapy, either blood thinners or long-term aspirin therapy, plays a role. A FDA committee will review all the research and decide whether further study or new warnings are needed.

It's estimated that stents are implanted in 650,000 Americans a year.

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