The promising results suggest there would be at least 24,000 fewer deaths, heart attacks and strokes combined annually if every U.S. patient who undergoes angioplasty were treated for one year with Plavix, the researchers said.
"We saw a big benefit," said Dr. Eric Topol of Cleveland Clinic. He helped conduct the research and also works as a consultant for Bristol-Myers Squibb Co. and Sanofi-Synthelabo, which market the drug and paid for the study.
Dr. Robert Bonow, president of the American Heart Association, called the results significant and said if confirmed in other studies, they could lead to changes in current practice.
"It's a big deal," Bonow said.
The study appears in this week's Journal of the American Medical Association and also was to be presented at Monday's session of the AHA's scientific meeting in Chicago.
Plavix, also known as clopidogrel, helps keep blood components called platelets from sticking together and forming clots. The pills are commonly used with aspirin for about one month after an angioplasty.
The study involved 2,116 heart patients aged 62 on average, most of whom underwent a non-emergency angioplasty to open a blocked artery and had a stent implanted to keep the artery from re-closing. Patients were mostly male and white.
Patients took Plavix and aspirin for 28 days after the procedure, which is standard practice. After that, half continued with the combination for a year, and half received a placebo instead, plus aspirin.
After a year, there were 89 deaths, heart attacks and strokes combined in the Plavix patients compared with 122 in the placebo group. That equals a 27 percent risk reduction for the Plavix patients.
The results suggest that with at least 800,000 patients undergoing angioplasties annually, there would be about 24,000 fewer deaths, heart attacks and strokes if they all received the Plavix-aspirin treatment for a year, Topol said.
Plavix is currently recommended for just a month after angioplasty and stenting because that is thought to be the riskiest period for blood clots, Bonow said. Stents are small mesh-like tubes often made of metal and designed to keep an unclogged artery propped open. Exposing blood to the foreign object increases the risk of clots that could cause a heart attack, but tissue gradually grows over the stent and lowers that risk.
The study suggests that using Plavix beyond that initial risky period benefits more than just the stented artery - perhaps also other clogged arteries, Bonow said.
A study published earlier this year in the New England Journal of Medicine suggested that long-term use of Plavix would not be cost-effective because it is much more expensive than aspirin.
Topol said Plavix costs about $80 a month, "which is not trivial," but argued that the benefits found in the study would make the extra cost worth it.
By Lindsey Tanner