Drug-Coated Stents Create Clot Risk

While they offer benefits, they may not be appropriate for all heart patients, FDA says

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By Amanda Gardner
HealthDay Reporter

TUESDAY, Dec. 5, 2006 (HealthDay News) -- The once-promising notion that drug-coated stents could help patients with heart disease is now clouded with uncertainty.

Enough so that the U.S. Food and Drug Administration is convening a two-day meeting of experts this week to investigate the safety of the devices, and is doing so even before final information is available on the potential risks of these devices.

"We believe this is a public health issue of such importance that we didn't want to wait until we had every last piece of information and had time to analyze every last piece of information," Dr. Daniel Schultz, director of the FDA's Center for Devices and Radiological Health, explained at a Tuesday press conference. "This is a little departure from the normal way we do things in putting a panel meeting together, but we think that that departure is justified by the nature of this problem and the need to get something moving here."

According to Schultz, some 2 million to 3 million individuals in the United States now carry one of these devices in an artery, with implantations topping 900,000 per year since drug-eluting stents were introduced in 2003-04.

Stents are wire mesh tubes that surgeons use to prop open a blocked artery. The artery in which the stent is placed, however, can become blocked again during a process called restenosis. This re-closure means a repeat surgery.

Drug-eluting stents are coated with a drug that helps keep the blood vessels from re-closing around the device. But while these newer devices have reduced the number of repeat procedures needed, they also carry a heightened risk of potentially fatal thrombosis, or blood clots. According to one estimate, published by Bloomberg News, drug-eluting stents may be causing an extra 2,160 deaths in the United States each year.

"We're still seeing signals where there are problems, but these signals indicate the potential for severe problems," Schultz said.

The stated purpose of the FDA meeting is to weigh the risks and benefits of drug-eluting stents.

Within that framework, the panel of experts will be looking at two main questions: who should or should not get the devices, and what adjuvant therapies are appropriate. The panel's decision is not binding, but the FDA usually follows the recommendations of its advisory committees.

The panel will also be looking at whether or not to impose restrictions on "off-label" use of the devices -- purposes outside those mandated by the agency. "We need to be careful in how we talk about what goes on between an individual patient and an individual doctor, and we need to make sure that patients and doctors have the ability to do what's best for those individuals," Schultz said. "However, as a public health organization, we have the responsibility to make sure that as much information is provided to those doctors and patients to allow them to make those individual decisions using the best possible information."

Existing data on the issue is uneven. Different studies have looked at different populations and different adjunctive therapies, so much so that it's difficult to standardize and compare the evidence.

"We're trying to sort through all of that noise to get to an answer," Schultz said. "We're going to try to look at all of the data together, and see if we can get a unified picture of what's going on with products."

The panel itself, however, is not without its own problems.

Six physicians with financial ties to different heart-device manufacturers are on the panel; the FDA issued conflict-of-interest waivers allowing them to participate.

Schultz defended the composition of the group. "Whether or not waivers were granted or not granted, it was important that we had a panel of individuals who were able to give us objective, non-biased information," Schultz said. "Looking at the entire panel, if you look at that objectively, you will see that we have done a pretty good job of achieving that goal."

The panel is a nonvoting one, but even FDA advisory panels which don't vote are still reviewed by the agency.

"Final determinations regarding any regulatory decisions are still the responsibility of the FDA, so whether or not there's a formal vote I think is really sort of secondary in terms of the importance we place on the opinions of those individuals," Schultz said. "This will give a very distinguished group of individuals a chance to tell us what they really think. We will have to take that information and those opinions and analyze them very carefully to see what, if any, further actions need to be taken."

More information

For more on stents, visit the American Heart Association.

SOURCES: Dec. 5, 2006, teleconference with Daniel Schultz, M.D., director, Center for Devices and Radiological Health, U.S. Food and Drug Aministration; Dec. 4, 2006, Bloomberg News

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