FRIDAY, March 20 (HealthDay News) -- A major international study
pinpoints which people with major heart artery blockages would be better off
having bypass surgery than artery-opening angioplasty.
"Bypass surgery is preferable for people with diabetes and older patients," said
Dr. Mark Hlatky, professor of health research and policy and cardiovascular
medicine at Stanford University and lead author of a report published online in
The Lancet. "We used 65 as the cutoff point and, as age went up, so did the
benefit of bypass surgery."
Hlatky led a group that looked at survival data on almost 8,000 people treated
in 10 trials worldwide. Overall, the death rate over an average of nearly six
years was almost the same for those who had bypass surgery (15 percent) and
those who had what is formally called percutaneous coronary intervention, or PCI
(16 percent).
But analysis showed that people with diabetes were 30 percent less likely to die
if they had bypass surgery rather than PCI. People 65 and older who had bypass
surgery had a mortality rate of 20 percent, compared with 24 percent for PCI.
The study is a prime example of the relatively new approach called comparative
effectiveness research, Hlatky said. Most controlled trials look at the effects
of giving a treatment and giving no treatment, he said. The new approach is to
determine the most effective treatment "so that we can tailor the treatment to
individuals," Hlatky said.
The U.S. government has allocated $1.1 billion of the economic stimulus package
to fund comparative effectiveness research in hopes of getting the maximum
effect from dollars spent on health care.
His study pioneered in several ways, Hlatky said. Rather than looking at the end
results of published studies, it pooled data on individual participants in those
studies -- an idea proposed in 1995 by Stuart Pocock of the London School of
Hygiene and Tropical Medicine and senior author of the report.
The studies analyzed in the new report were done before the use of drug-coated
stents, the flexible tubes implanted after PCI, had become common. But Hlatky
noted that that did not affect the conclusions of the report.
"Every comparison of coated stents and bare-metal stents has shown no difference
in mortality," he said. "The difference is in the number of repeat procedures
required."
Some cardiologists have been reluctant to perform bypass surgery, because it
carries more immediate risk than PCI. The study found a 1 percent incidence of
complications from bypass procedures, compared with half of 1 percent for PCI.
But Hlatky said that difference is overwhelmed by the long-term survival data.
"We know you have a higher risk upfront," he said. "You are willing to take that
risk if you know the longer outcome is more favorable."
The diabetes finding "is not terribly surprising," said Dr. L. David Hillis,
chairman of the department of medicine at the University of Texas Health Science
Center in San Antonio. Studies reporting improved survival with surgery in
diabetics were published as long as 10 years ago, and the U.S. National Heart,
Lung, and Blood Institute is starting a study to confirm those findings, Hillis
said.
He described the reported benefit of surgery in older people as "somewhat
surprising, because you would think that, as people grow older, the risk of
surgery goes up -- so this is the opposite of what you would predict."
But the definition of "old" in the new study provides one possible explanation,
Hillis said. "There were almost no patients over the age of 75," he said. "They
are talking about people ages 65 to 75. There were no really very old people in
the study."
Another possible explanation is that older people are likely to have more
extensive blockage of the heart arteries, and surgery is always better in such
cases, Hillis said.
