Stents keep clogged leg arteries open

Flexible nickel-titanium mesh tubes may be more effective than standard treatment in helping blood flow through arteries in the thighs that are clogged by heart disease, a study in The New England Journal of Medicine shows.

The mesh tubes, known as nitinol stents, could provide a better treatment option to patients who suffer extreme leg pain from the disease and who are at risk of limb amputation.

These stents are designed to bend, twist and even regain their shape after being crushed, unlike conventional stainless steel stents.

A team at the Medical University of Vienna, led by Martin Schillinger, found that patients with the nitinol stents could walk further on a treadmill and had less of a chance of having the tubes clog up again.

In the first year after the mesh tube was implanted, researchers found that only 37 percent of the 51 volunteers suffered new blockage.

At the same time, 63 percent of the 53 volunteers who had their arteries reopened by a procedure called angioplasty, in which a balloon is inserted into and then expanded in a blocked artery, developed more clogging.

Physicians generally recommend using angioplasty first, but it usually does not lead to a long-term improvement.

Doctors can also perform bypass surgery, a more complicated surgical procedure, or use stainless steel stents to repair the problem. But the stainless steel stents often break because the leg muscles surrounding the artery move so much.

The risk of breakage of the nitinol stents was just 2 percent in the first year, the study found.

The study used two brands of nitinol stents made by Guidant, which was recently acquired by Boston Scientific. Four of the 10 investigators have ties to Boston Scientific.

In an editorial in the Journal, Alan Hirsch of the University of Minnesota said the Schillinger study is not definitive because it only followed patients for a year and did not include people who were treated without surgery. Patients sometimes get better on their own.

"The relative risk and benefit, durability, and cost of each potential therapy and the patient subgroups that are mostly likely to benefit from each therapy have not been defined," he added.