But experts tell WebMD it's still too soon to tell whether study patients treated with drug-coated stents will get the same long-term benefits as those who undergo surgery. A trend toward the more frequent use of drug-coated stents -- in patients with more complex heart disease -- already has reversed direction.
Even so, the finding offers hope that some patients with seriously blocked arteries may be able to avoid open-chest surgery.
The study compared outcomes for 799 patients treated with drug-coated stents to outcomes for 799 matched patients treated with coronary artery bypass grafts. The study, sponsored by stent maker Cordis J&J, included researcher James M. Wilson, MD, cardiology program director at St. Luke's Episcopal Hospital and Texas Heart Institute in Houston.
"When we look at an important outcome measure -- whether you live or die -- at three years the procedures look pretty similar," Wilson tells WebMD. "But we are still in the early days on this endpoint of survival."
Drug-Coated Stents vs. Bypass Surgery
Wilson notes that his team did an earlier study comparing bare-metal stents with bypass surgery.
"In the first year of that study, it looked like you were better off with a stent than with a bypass," he says. "But at three years, it was a dead heat. And now, after nine years, it's clear that surgery was better for long-term survival. So here we are at three years for drug-coated stents vs. bypass -- now they look equal, but we reserve judgment."
Nine percent of the drug-coated stent recipients died vs. 6.6% of those who had bypass surgery. Statistically speaking, these death rates are not significantly different. But it's an ominous trend, suggests Prediman K. Shah, MD, who is director of cardiology at the Atherosclerosis Research Center at Cedars-Sinai Medical Center and professor of medicine at UCLA.
"The three-year outcome is 9% of [stent] patients died -- almost 50% more than bypass patients who died," Shah tells WebMD. "So the trend is not in favor of drug-coated stents. ... I am not reassured by any of this."
Another study finding surprised Wilson. Because they don't require surgery, stent procedures are supposed to be much safer than bypass surgery. But the study showed that patients who got drug-coated stents had at least as many complications as bypass patients.
"When we tried to tackle the tougher patients -- those with greater risk, like the typical patient sent to bypass surgery -- our complication rate went up," Wilson says. "We can no longer say we are safer with stents than with bypass at the time of procedure."
Shah and Wilson agree that early stent complications are much more likely in patients with more advanced, more complicated disease. Shah says such complications are unlikely when doctors use stents as approved by the FDA.
Researchers presented the study today at the American Heart Association's Arteriosclerosis, Thrombosis, and Vascular Biology Annual Conference in Chicago.
Side Effects Compared
Cholesterol plaque-laden arteries eventually narrow -- a life-threatening condition called atherosclerosis.
Using a catheter inserted into an artery, interventional cardiologists push a balloon-like device into narrowed coronary arteries (the coronary arteries supply the heart muscle with blood). They then carefully inflate the balloon to widen the artery. After this process, called balloon angioplasty, stents may be used to keep the artery propped open.
About a third of the time, bare-metal stents clog back up. Newer stents carry a drug coating that prevents clogging. But drug-coated stents have their own problems. The most serious one is that, once in a while, they cause a blood clot to form in the opened artery. This can lead to a fatal heart attack - sometimes years after the stent is put in.
It's a rare event. But anyone who gets a drug-coated stent has to take powerful anticlotting drugs for at least a year. This means that bare-metal stents are still the best choice for some patients.
"Time was, 90% of these patients got drug-coated stents. Now we're down to about 50% to 60%. That is a big drop," Shah says. "Some estimate the correct proportion should be 30% to 40% of stenting should be with drug-coated stents, and the rest with bare-metal stents."
For other patients -- especially those with blocked coronary arteries very close to the aorta (the main artery from the heart) or those with multiple blockages in major coronary arteries -- bypass is the best choice.
And many patients will do better with no procedure at all. Cardiologists are getting better and better at treating patients with an aggressive combination of drugs that prevent heart disease from getting worse.
How does a patient decide?
"Medical management is just as good as stenting in patients with chronic, stable heart disease," Shah says.
"The time where a stent is appropriate is where the heart disease severity doesn't greatly imperil your medium-term risk of dying of coronary artery disease," Wilson says. "This takes an honest discussion between the doctor and the patient. The doctor says, 'I can do this, but my chance of causing a heart attack is X.' Some patients will say to go ahead. Others will say, 'Whoa, let's try beta-blockers and aspirin and cholesterol-lowering drugs for awhile and see if I really need a procedure.'"