Amid growing concern about drug-coated heart stents, the Food and Drug Administration convened a panel late last week to consider the latest data on the devices.
The bottom line was decidedly mixed.
As The Early Show medical correspondent Dr. Emily Senay explained Monday, a stent is a tiny metal device that's inserted in a blood vessel that leads to the heart, in order to prop the vessel open and keep blood flowing freely. The stent is placed at the end of a catheter with which it's moved through the body until it arrives at the narrowed artery. After a process called angioplasty has expanded the artery to maximum capacity, the stent is opened up, and left there, to keep the artery open.
When stents were introduced in 1994, they were made of bare metal, Senay continued. Over time, a certain number of patients who received them saw their arteries re-narrow, as scar tissue grew over the stents and back into the path of the flowing blood. So a new kind of stent was introduced three years ago. It's coated with a drug that inhibits the growth of the scar tissue.
And, Senay pointed out, it's the drug-coated stents that are causing concern now. Recent data suggest that, in at least a small number of patients, blood clots may start forming over time, around and inside the stent. Those clots can choke off the blood supply in the artery, leading to a sudden heart attack, and potentially, to death.
So, the FDA panel met in Washington to look at the potential danger.
Its conclusions about the drug-coated stents were mixed.
In about 40 percent of the situations in which the stents are used, the blockage involves just one artery, and the patient's heart is not significantly damaged. That's what the FDA envisioned when it approved the use of stents. And in those cases, the panel says the benefits of the stents outweigh any clotting danger.
But the remaining 60 percent are cases where multiple arteries are blocked, the patient has already suffered a serious heart attack, or other complications are involved. In these more complex cases, the panelists say they're not confident the benefits outweigh the risk of blood clots.
To minimize the clotting risk In patients who have the drug-coated stents, it is standard procedure to take aspirin and the anticoagulant drug Plavix for several months after the stents are placed. The panel recommends now that these medications be continued for at least a year. There's some thought that indefinite use of anticoagulants might even be needed, but the panel isn't going there yet.
As for patients who are considering stents, especially those whose cases are more complex, we may see a return to more heart bypass surgery as a result of the panel's opinion, according to Senay. Ironically, bypass surgery is the procedure that stenting largely replaced. When multiple stents have been placed, panelists found the danger to the patient increases with each additional stent. But multiple bypasses apparently present no more risk of complications than single bypasses.
So, Senay observes, in many cases where multiple arteries need repair, bypass surgery may become the preferred method again.
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