Stents get safer

Orville Ackerman felt like someone was sitting on his chest.

Alarmed, he wasted no time getting to the emergency room. A few days later, Ackerman, a Winter Texan, became one of the first Rio Grande Valley recipients of a new type of drug-coated stent designed to keep open a partly blocked artery in his heart. The stent stopped his chest pain, he said, and has made a heart attack much less likely, according to doctors.

"I feel excellent," said Ackerman, 84, who was diagnosed with chronic chest pain and now is undergoing cardiac rehabilitation. "I'm in no pain whatsoever."

The device, the Endeavor stent, is the first drug-coated stent approved by the U.S. Food and Drug Administration in four years. Medicated stents have been under scrutiny in recent years because of studies suggesting that patients who receive them might be at greater risk of developing dangerous blood clots.

Some local doctors think this new, "next-generation" stent will prove safer than earlier versions. Others say it's just too early to tell.
"In trials, it certainly looks better than the first-generation stent," said Dr. Charles Mild, a Harlingen cardiologist. "I think more physicians are going to be comfortable with it and use it more commonly."

A handful of patients at Valley Baptist Medical Center-Harlingen have received the new stent, and more will follow, local cardiologists said.

A stent is a tiny cylinder, made of metal mesh, that is threaded into a blocked blood vessel along with a small balloon. When the balloon is inflated to clear the blockage, the stent expands "like a Chinese finger trap," according to Mild.

The stent stays in place after the balloon is removed, and acts as a scaffold to keep the vessel open, according to the FDA.
The problem with ordinary metal stents is that scar tissue tends to form in the vessel around the stent, causing it to clog up again for about 20 percent of people, Mild said.

"When stents first came out 10 years ago, that was the Achilles' heel," Mild said. "The body tends to reject a foreign body ... and any time you injure tissue, you get scar formation. That scar slowly grows over time and can totally block the blood vessel."
Drug-coated stents seemed to be the solution when they hit the market a few years ago. These devices release medication to stop the formation of scar tissue in the vessel and prevent re-clogging, cardiologists say.

Then some studies suggested that, in rare cases, people who had received the drug-coated stents had a higher incidence of heart attacks or death than patients who received ordinary metal stents. The risks were especially high when the stents were used for reasons other than mild artery disease or chest pain.

The medicated stent did its job well, stopping scar tissue from forming, but that created a new problem, Mild said.
"If you stop scar formation, you stop blood vessels from healing themselves," he said. "So a blood clot would form at the (stent) site, and there were no cells to deal with the clot."

One researcher, at Columbia University, estimated that 1 in 500 patients who receive drug-coated stents could be at risk for developing blood clots.

After some researchers and physicians' groups sounded an alarm, the FDA in 2006 convened an advisory panel to examine the issue. The agency concluded that when the devices were used in approved cases, such as in mild artery disease, the risk of heart attack or death was slight compared to metal-only stents. The picture is less clear when it comes to using the devices for more complex diseases, the panel said, and agreed the issue needed further study.

When approving the Endeavor device in February, the FDA said that, for this device, the blood-clot risk appeared to be no greater than with metal-only stents. The device's manufacturer, Medtronic, will follow its trial patients for five years to assess the risk, the FDA said in a press release.

Mild is convinced the new device "has the advantages of a drug-eluting stent without the disadvantages."
"We currently think it's a safer stent," he said.

Other local hospitals are using the new stent as well.

Doctors Hospital at Renaissance began using the device on Thursday, confirmed Chico Meyer, director of cardiovascular services. Physicians at the hospital also still use the other drug-coated stents, depending on the patients' needs, he said.

Meyer said he thought it was too soon to determine whether the newer stent was safer than other drug-coated devices.

Doctors at Valley Regional Medical Center in Brownsville elected not to use the new device right now because they've had good results with the older drug-coated stents, said Matt Caldwell, chief nursing officer.

A McAllen cardiologist, who asked not to be identified, said he'd start using the device soon, but he didn't necessarily think it was safer than other drug-coated stents.

Overall, however the benefits of all drug-coated stents outweigh the risks, the cardiologist said.

"Ninety percent of my stents are drug-eluting stents, and the benefits are tremendous," he said. "They are safer than metal stents."

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Melissa McEver covers health and environment issues for Valley Freedom Newspapers. She is based in Harlingen and you can reach her at (956) 430-6252.