WASHINGTON (AP) _ Patients fitted with drug-coated stents to open their choked arteries face a small but significant risk of forming blood clots, but the danger of death or heart attack associated with the devices remains unknown, health officials said Tuesday.
The increased risk is in comparison to bare-metal stents and emerges a year or more after surgery. It applies to patients given stents made by Boston Scientific Corp. and Johnson & Johnson, the Food and Drug Administration said.
The FDA has convened a two-day meeting of outside experts this week to discuss safety issues associated with the devices, formally known as drug-eluting stents.
The miniature lattice-shaped tubes are coated with drugs that slowly dissolve _ or elute _ into the bloodstream to prevent regrowth of tissue that can clog arteries anew.
Labels on the two types of drug-coated stents now sold in the United States recommend patients take baby aspirin and the blood-thinner Plavix for either three or six months, depending on the manufacturer, following surgery.
Multiple studies have suggested the risk of blood clots, heart attack and death rises in patients who stop taking those drugs early. The FDA, in documents released ahead of the Thursday-Friday meeting, said it is unknown how long patients should remain on the drugs to prevent life-threatening clots from forming.
Nor are the long-term risks of treatment with Plavix known, the FDA said. The drug, also known as clopidogrel, can cause major bleeding.
The FDA said the risk of blood clotting applies to the drug-coated stents when used as labeled. However, the agency acknowledges that more than 60 percent of the stents are likely implanted in types of patients not studied during the trials of the devices that led to their approval _ a so-called off-label use.
Doctors now implant stents in about 650,000 Americans a year. Of those, 80 percent or more are the drug-coated kind.
There is less reclogging of the arteries in patients given drug-eluting stents compared to those with the bare-metal versions.