DRUG SHOWN TO ENHANCE ANGIOPLASTIES.

Byline: Daniel Q. Haney Associated Press 

A clot-blocking drug may allow doctors to perform angioplasties with greater success, a study found.

Angioplasty - which uses little balloons to pry open clogged heart arteries - is a highly effective way of relieving chest pain. It is used on 400,000 Americans annually. But it has one major drawback: About 40 percent of the time, the arteries close up again within a few months.

One answer to this problem is the stent, a tiny wire coil that is left inside the artery after the balloon is removed. When all goes well, it props the blood vessel open.

The stent reduces reclogging by about one-third. However, clots sometimes form around the stent, raising a small but troubling risk of heart attacks. Blood thinners given to prevent this complication may in turn trigger dangerous bleeding.

As a result, many doctors have been reluctant to use stents. However, a German study in Thursday's issue of the New England Journal of Medicine shows that a combination of aspirin and the drug Ticlid, made by Hoffman-LaRoche, dramatically reduces the risk of heart attacks and other complications in stent recipients.

The study was conducted by Dr. Albert Schomig and others from the Technical University in Munich. It was partially financed by Johnson & Johnson, which makes stents, and Siemens Medical Systems and Scimed-Boston Scientific, which make angioplasty equipment.

Ticlid works by inhibiting blood platelets, the cells that play a critical role in forming clots.

In the study, 257 stent patients were randomly assigned to take either aspirin and Ticlid or aspirin plus two blood thinners - heparin and a form of warfarin.

After one month, 6 percent of the blood thinner patients had either died from cardiac causes, suffered a heart attack or required bypass surgery or another angioplasty. By comparison, these things happened to fewer than 2 percent of Ticlid users.

Particularly notable was an 82 percent lower risk of heart attacks among the Ticlid patients.

A second study in the journal by Ethan J. Weiss and colleagues from Johns Hopkins University in Baltimore underscored the role of platelets in heart disease.

The researchers looked at common variations in a gene that makes a platelet protein and found that one was linked to heart attacks.

The gene contains the code for making a substance called glycoprotein IIb/IIIa, which influences the way platelets form blood clots.About 20 percent of Americans carry at least one copy of a particular form of this gene.