MONDAY, Nov. 5 (HealthDay News) -- For a subset of heart patients who are both diabetic and have more than one clogged artery, bypass surgery appears to outperform the use of artery-widening stents, a major new trial finds.

The study adds more evidence that bypass is the preferred approach for this type of patient, according to experts discussing the findings Sunday at the annual meeting of the American Heart Association in Los Angeles.

"This has the potential to change clinical practice," said Dr. Alice Jacobs, director of the Cardiac Catheterization Laboratory and interventional cardiology at Boston Medical Center. In her commentary, she said the results of the new trial "add to the consistent evidence base supporting coronary artery bypass grafting as the preferred strategy for patients with diabetes and multi-vessel coronary heart disease."

The findings were also published online Nov. 4 in the New England Journal of Medicine.

In bypass surgeries, doctors reroute blood flow around a blocked artery using a grafted vessel taken from another part of the body. In stenting, doctors use a catheter to insert a thin metal mesh tube called a stent into the artery, to prop it open.

Bypass has typically outperformed stenting in trials done in the past, but some experts thought that was only because older stents tended to re-close too often. Over the past decade, new drug-eluting stents have been developed that work better at preventing vessel reclosure.

According to Jacobs, the new trial's launch "was fueled by the contention that drug-eluting stents would negate the advances of [bypass]."

But the trial, funded by the U.S. National Heart, Lung, and Blood Institute, found that even with the use of drug-eluting stents, bypass still came out on top -- at least for very sick, diabetic heart patients.

The study included 1,900 such patients, 83 percent of whom had at least three clogged vessels. Patients averaged about 64 years of age and 71 percent were men.

The research was led by Dr. Valentin Fuster, director of Mount Sinai Heart at the Mount Sinai School of Medicine, in New York City. He and his colleagues randomly assigned the patients to receive either bypass surgery or the placement of a drug-eluting stent. The researchers then tracked patient outcomes for about five years.

Bypass remains "the preferred method" of keeping arteries flowing for diabetic heart patients, Fuster said at an AHA press briefing Sunday. For example, at five years, the rate of a combination of events such as death from any cause, nonfatal heart attack or nonfatal stroke was 26.6 percent among those receiving stents versus 18.7 percent for those who got bypass, Fuster said.

The five-year rate of heart attack was about 14 percent for patients receiving stents, but just 6 percent for those who had undergone bypass.

There was only one downside to getting bypass: a slight bump up in the odds for a stroke, from 2.4 percent over five years for those who got a stent to 5.2 percent for patients who underwent bypass.

Jacobs said the impact of a study like this could be important.

"In the United States alone, we know that nearly 1 million coronary revascularization procedures are performed yearly, and 35 percent of these are performed in patients with diabetes," she said at the press briefing. "We also know that there's a higher incidence of adverse outcomes in patients with diabetes undergoing revascularization."

But what about the relative costs of the two procedures? A second study, also presented at the AHA meeting, found that over the long term, bypass beat stenting in that regard as well.

In a sub-analysis of data from of the Fuster-led trial, Elizabeth Magnuson and colleagues found that even though upfront costs for bypass were higher, over the long term health-care dollars were saved, because fewer patients suffered new heart attacks or needed new operations to re-open arteries.

"Our results demonstrate that bypass surgery is not only beneficial from a clinical standpoint, but also economically attractive from the perspective of the U.S. health care system," Magnusson, director of health economics and technology assessment at Saint Luke's Mid-America Heart Institute in Kansas City, said in an AHA news release.

But one other expert stressed that heart disease care is never a one-size-fits-all affair.

The new trial "was limited to patients with diabetes and multi-vessel disease, which likely is a different type of patient from those with multi-vessel disease who don'thave diabetes," Dr. David Williams of Brigham and Women's Hospital, Boston, said at the press briefing.

He believes there may be many patients without diabetes, but with multi-vessel disease, "for whom bypass surgery offers no apparent benefit over [stenting]."

Dr. David Friedman is chief of heart failure services at Plainview Hospital in Plainview, N.Y. He said that a patient's input is also key to decisions about cardiovascular care.

"I do factor in patient preference, which tends to be for the up-front, less invasive stenting approach," he said. But Friedman also agreed that opting for bypass may mean fewer repeat surgeries down the line.

More information

Learn more about common procedures to unblock arteries at the American Heart Association.