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A drug-releasing stent placed in the blocked artery below the knee might re-establish blood flow, new research shows.
Critical limb ischemia, the most severe form of peripheral arterial disease (PAD), causes more than 100,000 leg amputations in the United States each year. Now, researchers from Mount Sinai Medical Center in New York City say insertion of a stent can prevent many of these amputations.
"Traditional balloon angioplasty is plagued by high incidence failure, restenosis [recurrence] and inability to elevate the patient's symptoms," said lead researcher Dr. Robert A. Lookstein, associate director of Mount Sinai's division of interventional radiology.
But placing a stent in the affected artery during angioplasty greatly improves these problems, Lookstein added. The drug-eluting stent keeps the narrowed artery open and releases a medication for several weeks after implantation, preventing the artery from closing again, he said.
"Patients with the least severe form of the [severe] disease, those with pain at rest, as well as the patients with minor skin infection of their legs, were able to avoid major amputation," he said.
But some patients with severe disease and those with gangrene still lost a limb, said Lookstein, who was scheduled to present the finding Monday at the Society of Interventional Radiology's annual meeting in Tampa, Fla.
For the study, Lookstein's team followed 53 patients with critical limb ischemia who had a total of 94 drug-eluting stents implanted to treat leg arteries that would not stay open after angioplasty alone. These are the same stents commonly used to open blocked coronary arteries.
The treatment was effective in all the patients, the researchers said.
A year after the procedure, 81.8 percent of the stented arteries were still open, allowing blood to flow freely, the researchers found. And, over an average of 17 months' follow-up, fewer than 10 percent of the patients required a major amputation, Lookstein noted.
"These results show that when angioplasty doesn't work, this is an excellent option," Lookstein said. "Patients should know that if angioplasty fails, there are treatment options that offer excellent outcomes."
Dr. Juan Pablo Zambrano, an assistant professor of clinical medicine at the University of Miami Miller School of Medicine, said a downside of stent insertion is the need to take blood-thinning drugs for at least a year after surgery.
"The current recommendations for drug-eluting stents require taking antiplatelet drugs for one year," Zambrano said. This is usually a combination of a drug like Plavix and aspirin, he said.
Not taking them greatly increases the chances of clotting in the stent, which can cause a thrombosis (a blood clot), and the likelihood that a clot will break loose and travel to the heart or lungs, Zambrano said.
"If you leave these patients without treatment, you get very early amputations," he said. "If you can change the fate of the disease by stenting those vessels and keeping them open for longer, then you are going to have a significant impact," he said.
About 10 million Americans suffer from peripheral arterial disease, but only one in four is diagnosed and treated, according to background information with the study. The condition results from plaque build-up, which hardens in the arteries, blocking and reducing blood flow to the legs, arms, brain and other organs.
Bypass surgery, the standard treatment to open an artery, isn't an option for many patients because of other medical problems, Lookstein said. He said their results show that stent insertion is as effective as bypass surgery.
The alternative is angioplasty, which involves threading a catheter through the artery and inflating a balloon at the tip of the catheter to open the vessel. But arteries below the knee often close up again after angioplasty.
Those patients would be candidates for a stent in the artery, Lookstein said.
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SOURCES: Robert A. Lookstein, M.D., associate director, division of interventional radiology, Mount Sinai Medical Center, New York City; Juan Pablo Zambrano, M.D., assistant professor, clinical medicine, University of Miami Miller School of Medicine; March 15, 2010, presentation, Society of Interventional Radiology annual meeting, Tampa, Fla.