Orlando, Fla. ? A new blood thinner proved better than Plavix, one of the world’s top-selling drugs, at preventing heart problems after procedures to open clogged arteries, doctors reported Sunday. But the new drug also raised the risk of serious bleeding.

People given the experimental drug, prasugrel, were nearly 20 percent less likely to suffer one of the problems in a combined measure – heart attack, stroke or heart-related death – than those given Plavix, a drug that millions of Americans take to prevent blood clots that cause these events.

However, for each heart-related death that prasugrel (PRASS-uh-grell) prevented, compared with Plavix, almost one additional bleeding death occurred.

“There is a price to pay” for greater effectiveness, Dr. Deepak Bhatt, a Cleveland Clinic cardiologist, wrote in an editorial accompanying the results, which were published online by The New England Journal of Medicine and presented at an American Heart Association conference in Florida.

Still, many doctors said that on balance, the new drug comes out ahead, and offers great promise as a more potent alternative to Plavix, which costs $4 a day and does not work for some patients.

“I’m encouraged by the results” and think prasugrel should win Food and Drug Administration approval because it so dramatically cuts non-fatal heart attacks, said the Cleveland Clinic’s Dr. Steven Nissen, a frequent government adviser.

Doctors can sort out who might benefit from it, such as diabetics, and who might face too much bleeding risk to use it, like the elderly, people who previously had strokes and those with kidney problems, he said.