WASHINGTON — Diabetics suffering from clogged arteries to the heart appear to have a significantly better chance of survival if they undergo bypass surgery instead of angioplasty, another popular technique for this problem, a major international study has shown.
The unexpected findings showed that, after five years, drug-dependent diabetics randomly assigned bypass surgery experienced a 19% death rate, compared with 35% in those who underwent angioplasty, a non-surgical procedure, officials at the National Institutes of Health said Thursday.
The results from this group of patients "really stood out," said Dr. Michael Horan, director of the heart division of the NIH's National Heart, Lung and Blood Institute, which funded the study. "We . . . are convinced this is real."
Members of a special board monitoring the study, who met Sept. 13, thought the results so compelling that they issued a "clinical alert" to the nation's physicians. The alert recommends bypass surgery over standard angioplasty for diabetics on drug therapy who have multiple vessel coronary blockages and are first-time candidates for either procedure.
"This is an important finding for a big population," said Dr. Frank Vinicor, president of the American Diabetes Assn.
The results showed no difference between the two procedures either in the non-diabetic population or in diabetics who were not taking medication for their diabetes. Both groups experienced a 9% death rate five years after undergoing either procedure.
Diabetes is a major risk factor for coronary heart disease, which is the nation's leading killer of men and women. There are an estimated 14 million Americans with diabetes, about half of them undiagnosed. About 65% of all diabetics die of some form of heart or blood vessel disease. Put another way, diabetics have a twofold to fourfold higher risk of heart disease than non-diabetics. Of the estimated 7 million known diabetics, about 85% are on drug therapy, either oral medicine or insulin to control blood sugar, according to the American Diabetes Assn.
The study is the largest random clinical trial to compare bypass surgery and angioplasty, and the first to report on the outcome of these procedures among diabetic patients.
"The results should provide helpful guidelines for physicians treating diabetics with multi-vessel disease," said Dr. Sidney C. Smith Jr., president of the American Heart Assn. and chief of cardiology at the University of North Carolina at Chapel Hill. "This important study also serves to point out the need for additional research to understand ways to better control and treat diabetes."
