Bypass tops stents in diabetics with diseased arteries
LOS ANGELES (Reuters) - Diabetics with more than one diseased artery fared significantly better if they underwent bypass surgery than those who received drug coated stents following artery clearing procedures to improve blood flow to the heart, according to data from a five-year study presented on Sunday.
After five years, the bypass group had a lower combined rate of heart attacks, strokes and deaths of 18.7 percent versus 26.6 percent for the stent group in the 1,900-patient study funded by the U.S. National Institutes of Health.
The result was deemed to be highly statistically significant, researchers said.
Previous studies had demonstrated the superiority of bypass surgery over the use of bare metal stents - tiny mesh tubes used to prop open cleared arteries. Researchers suspected that newer stents coated with drugs to prevent reclogging might negate some of the bypass advantage, but that turned out not to be the case.
"The advantages were striking in this trial and could change treatment recommendations for thousands of individuals with diabetes and heart disease," said Dr. Valentin Fuster, from Mount Sinai School of Medicine in New York, who presented the findings at the American Heart Association scientific meeting in Los Angeles.
There was a higher incidence of stroke in bypass patients -- 5.2 percent versus 2.4 percent. Stroke is a known risk of the surgical procedure in which a piece of a healthy blood vessel from another part of the body is grafted on to re-route blood flow around a blocked heart artery.
But deaths from any cause were significantly lower with bypass surgery than those who received artery clearing angioplasty and a drug eluting stent - 10.9 percent compared with 16.3 percent. There were also twice as many heart attacks among diabetics in the stent group within five years - 99 vs 48, which Fuster called "very significant."
More than one million bypass surgeries or stenting procedures are performed in the United States each year and some 25 to 30 percent of those involve diabetics with multiple diseased arteries, researchers said.
If the results of this study alter clinical practice, it could eat into lucrative profits of the companies that sell drug coated stents, such as Abbott Laboratories, Boston Scientific Corp and Medtronic Inc. Boston Scientific and Johnson & Johnson supplied the stents used in the study, but J&J has since exited the stent business.
Dr. David Williams of Brigham and Women's Hospital in Boston, who was not involved in the study, called the results "very convincing."
"I think the (treatment) guidelines will recognize this and I do think it will be adopted," he said.
However, Fuster cautioned that longer term follow-up of patients was necessary.
"We always want to know how long the effects last," he said. "The gap could begin to close or the results could get better and better."
"Patients are doing this with or without our permission" so it's important to test, said Dr. John G. Harold, president-elect of the American College of Cardiology and a doctor at Cedars-Sinai Heart Institute in Los Angeles. He said at least two of his patients had suffered heart failure after getting chelation in Mexico.
Dr. Gary Gibbons, director of the National Heart, Lung and Blood Institute, which funded the study with the National Center for Complementary and Alternative Medicine, called it "a first step" and urged caution about results that suggest "a marginal benefit."
This chelation seemed safe in this study, where steps were taken to minimize complications and exclude people likely to suffer them, he said. "Further research needs to be done before this can join the mainstream of cardiovascular care."
Other experts questioned the results, especially because 60 more people in the group getting dummy infusions withdrew from the study than in the group getting chelation. Usually, more people in a treatment group drop out because of side effects, said Dr. Christie Ballantyne, a Baylor College of Medicine heart specialist. To find the opposite is "a red flag" that suggests those who got dummy treatments found that out and decided to drop out.
"There's something funky going on here," Ballantyne said. "It raises questions about study conduct," especially since a difference of one or two people or complications could have nullified the small overall benefit researchers reported.
Dr. Clyde Yancy, a Northwestern University cardiologist and a former Heart Association president, agreed.
"It's funny business," he said. "I've never seen a study in which one in five people withdrew consent."
The study's leader, Dr. Gervasio Lamas of Mount Sinai Medical Center in Miami, said: "The trial needs to be taken for what it is — a step towards future investigation."
It initially aimed to enroll 2,400 people in the United States and Canada but recruitment lagged and the goal was reset to 1,700.
In 2008, a group of scientists published a long article criticizing the trial, saying participants had not been warned that others had died from chelation. More than half of the doctors running the study make money by selling chelation treatments — a conflict of interest, they complained.
Investigations by the Office for Human Research Protections and the Food and Drug Administration found that several doctors doing the study had been accused of poor practices by state medical boards or involved in insurance fraud, and at least three were convicted felons. That did not prevent them from doing federal research, the government decided, and let the study go on after corrective steps. By that time, 1,500 participants had already been enrolled