Diabetic patients with seriously diseased heart arteries are significantly more likely to survive or avoid future attacks by having them treated with bypass surgery than with artery-opening devices called stents, according to a major new study.
Researchers said a 1,900-patient study found that those randomly assigned to the open-heart operation were 30% less likely to die or suffer a heart attack or stroke within five years, compared with those who underwent the less-invasive treatment to implant a stent.
The findings, presented Sunday at the annual scientific meeting of the American Heart Association, address a long-running controversy over which option offers more benefit to diabetics, whose condition typically makes diseased coronary arteries more complex and difficult to treat.
The study applies especially to patients with diabetes who have disease in more than one vessel—about 20% of the nearly one million patients in the U.S. who undergo one of the procedures each year. While how many of them are currently treated with stents isn't known, many end up with stents, often because they want to avoid open-heart surgery or because their cardiologists deploy stents during the same procedure when they discover the blockages; surgery isn't considered.
Doctors said the results underscore the importance discussing with patients pros and cons of both surgical and stent options before tests to find blockages are done. That way patients would be better informed about their choices.
One likely impact: more diabetics will choose surgery, reducing reliance on stents, whose makers include Medtronic Inc. and Boston Scientific Corp.
"The results are clear," said Valentin Fuster, cardiologist at Mount Sinai School of Medicine in New York and the study's principal investigator. "The results are going to make a change in practice."
The study was also published online Sunday by the New England Journal of Medicine.
Other studies going back as far as 17 years ago have given an advantage to surgery for diabetic patients, but many such trials were either too small to yield robust results, or they were published after advances in technology were seen as rendering the earlier findings obsolete.
For instance, the first study compared bypass surgery and an artery-opening procedure called balloon angioplasty before stents emerged as a major part of angioplasty treatment in the mid-1990s. Then bare metal stents, which were prone to reclogging, were replaced by drug-eluting stents, which reduced the reclogging risk. Meanwhile, the trend in the U.S. for bypass surgery has been to use arteries, especially one from the chest called the left internal mammary artery, as the primary bypass vessels, which are much more durable than veins.
In the new study, called Freedom, all stent patients got drug-eluting stents, while use of arteries instead of veins was encouraged when possible for open-heart patients.
In an editorial accompanying the study, Stanford University cardiologist Mark Hlatky said with the new study, bypass surgery has been associated with improved survival in studies involving more than 4,000 diabetic patients.
"The controversy should finally be settled," he said.
In the earlier studies, the benefits associated with surgery were typically most prominent in avoiding the need for additional procedures to reopen reclogged vessels. The current study, showed clear benefits in reducing risk of death and subsequent heart attacks, researchers said.
During the first months of follow-up in the study, mortality and other problems were higher for bypass patients, reflecting complications around open-heart operations. But by two years, the benefits for surgery were established and they increased over the following three years, Dr. Fuster reported.
After five years, 26.6% of patients treated with stents had either died or suffered a heart attack or stroke, compared with 18.7% of bypass-surgery patients. In addition, 16.3% of stent patients and 10.9% of bypass-surgery patients died while 13.9% of stent patients and 6% of surgery patients suffered a heart attack over the five-year period.
Bypass patients suffered a higher rate of stroke—5.2% vs. 2.4%—than patients treated with stents.
By Ron Winslow, The Wall Street Journal
Reviewed / Posted by: Justin Henson, APRN, FNP-C