WEDNESDAY, May 25, 2005 (HealthDay News) -- A major long-term study of patients treated for coronary artery disease finds that those who undergo bypass surgeries do much better than those who have an artery-widening procedure involving a stent -- a wire-mesh tube used to prop open blocked vessels.
The study of more than 37,000 people treated for coronary artery disease in New York state between 1997 and 2000 found the death rate for patients with blockages in three cardiac arteries to be a third lower for those who underwent bypass surgery than those receiving stents.
The death rate for people with two blocked arteries was 24 percent lower with bypass surgery, the researchers added. And they noted that 7.8 percent of arteries receiving stents closed again within three years, compared to just 0.3 percent of arteries operated on in bypass patients.
The study results appear in the May 26 issue of the New England Journal of Medicine.
The findings challenge the results of the carefully controlled, randomized trials that have long been regarded as the gold standard in this area of research, said lead investigator Edward L. Hannan, chairman of the department of health policy management and behavior at the University of Albany, N.Y.
"The results are essentially different from those of the controlled trials," Hannan said. "For the most part, the randomized trials have not found significant differences in outcome between the two procedures."
Several reasons might explain the difference between the results shown in the new study and those of the previous trials, Hannan said.
"First, the [original] trials are based on a very small number of patients, so it takes huge differences to come up with a statistically significant difference," he said. On the other hand, Hannan said, his team's study involved "very large numbers. Second, randomized trials are very restrictive, excluding a lot of patients for a variety of reasons, so what is reported in the trials is not reflective of what goes on in the real world.
"Also, patients in the trials are followed very carefully. If the cardiologist finds chest pains, the patient is immediately given treatment to avert problems. In the real world, you don't have people who are following you like that," he added.
According to Hannan, these fundamental differences reveal a "downside of clinical trials that a lot of people don't admit to."
But Dr. Bernard J. Gersh, author of an accompanying editorial in the journal and a professor of medicine at the Mayo Clinic College of Medicine, strongly defended the value of controlled trials.
By their nature, Gersh acknowledged, controlled trials are different from real-life practice. "Any such trial includes only patients who are suitable for both procedures," he said. "Otherwise you could not ethically do the trial. We have always known that patients in randomized trials who are too sick [for stent implants] go to surgery at once."
And that is what happens in the real world, Gersh said, as cardiologists use their clinical judgment to select the best treatment, based on a patient's condition.
"What we find in this real-world study is that sicker patients appear to benefit more from surgery, while the less-sick group does as well with PCI [artery-widening stents] as with surgery," Gersh said.
The current study shows that evidence from controlled trials "goes hand in hand with clinical judgment," he said. In other words, "[Each] physician needs to take this evidence and apply it to the individual patient."
Treatments for coronary artery disease, starting with lifestyle changes, are described by the National Heart, Lung, and Blood Institute.