Stents, clot-busters improve survival.

To prop open narrowed heart arteries, doctors increasingly are using stainless steel mesh cylinders called stents. When they began employing these permanent inserts routinely several years ago, doctors held out high hopes that the tiny stents could keep blood flowing better than alternative procedures. However, they soon found that stents can jam up with platelets, the blood components responsible for clotting.

Now, researchers report in the Dec. 11 LANCET that the antiplatelet drug abciximab boosts the effectiveness of stents. The results indicate that among heart patients treated with the drug, those receiving a stent are less likely to die during the following year than are patients treated with angioplasty. In that process, a doctor threads a balloon-tipped catheter via blood vessels to a trouble site and opens the vessel by inflating and then removing the balloon.

Researchers tracked 2,399 patients at 63 hospitals in North America for a year after each was treated for moderate heart disease. Of these, 794 received a stent and an infusion of abciximab. Another 809 got a stent and an inert infusion, while 796 others received angloplasty with abciximab but no stent.

Doctors use a catheter to deliver a stent to the narrowed artery. Some patients had to have the artery widened by a balloon first as part of the procedure. All the patients in the study were given heparin and other drugs that inhibit clotting in ways different from how abciximab does it, says study coauthor A. Michael Lincoff, a cardiologist at the Cleveland Clinic Foundation.

After 1 year, only 8 patients given abciximab with a stent had died, compared with 19 of those given a stent without the drug and 17 who received angioplasty and abciximab. Most deaths resulted from cardiac problems.

"These are very exciting results," says cardiologist John A. Bittl of the Ocala (Fla.) Heart Institute. "There's always been this nagging concern that stenting ... was not associated with long-term benefits for the patient. But now, an agent like abciximab seems to make stenting much safer."

The study also sought to detect heart-muscle damage. When doctors perform angioplasty or insert a stent, fragments of blood clots break up and flow downstream. If these pieces lodge in smaller arteries, more blockages result, damaging heart muscle.

Patients getting a stent with abciximab had significantly less heart damage than the other groups. The combination may work because the stent holds open the narrowed vessel while the abciximab keeps downstream particles from causing more blockages, says E. Magnus Ohman, a cardiologist at Duke University Medical Center in Durham, N.C.

Abciximab binds to a substance called glycoprotein IIb/IIIa, which sits on the surface of platelets. By occupying this molecular site, the drug prevents other platelets from latching on and forming a clot, Lincoff says.

A few years ago, physicians inserting stents administered massive doses of heparin and other blood thinners to prevent blockages, but the drugs caused bleeding internally and at the entry site for the catheter carrying the stent. Abciximab allows doctors to use smaller doses of heparin, easing these problems, Ohman says.

Although abciximab is expensive, patient costs in all three groups were comparable because those receiving the drug with a stent had fewer heart problems over the year.