The results, which appear in the Dec. 20 issue of the journal Circulation: Journal of the American Heart Association, could give physicians the green light to attempt an artery-opening procedure called stenting on diabetics who also suffer from coronary disease. Stenting involves a surgeon placing a small metal cylinder permanently inside a clogged coronary artery, which supplies blood to the heart muscle. Clogged coronary arteries can lead to heart attacks.
Two-thirds of diabetics have heart or blood vessel disease -- a rate so high that diabetes is considered one of the major risk factors for coronary artery disease, along with smoking, high blood pressure, and a family history of the disease.
In recent years, physicians had chosen to perform bypass surgery on diabetics rather than conduct stenting and another artery-opening procedure called balloon angioplasty. That's because several studies had shown that, compared to nondiabetics, diabetics face an increased risk of heart attack and clogged arteries after angioplasty, and researchers worried that the same would be true of stenting.
But drug researchers had also been working to overcome this problem. They thought that blood-thinning drugs, similar to aspirin but more powerful, could reduce the risk of clogged coronary arteries and thereby reduce the risk of heart attacks. Such drugs keep blood cells called platelets from clumping and forming blood clots, which can block blood flow to the heart and cause a heart attack.
Researchers at several medical centers combined efforts to test the effect of one promising blood-thinning drug, Reopro (abciximab), in both diabetic and nondiabetic patients. The study, called the EPISTENT trial, was designed to see whether the drug could improve the outcome in patients who undergo stenting. Earlier results from the study showed that the drug helped prevent blood clots in nondiabetic patients who received stents, but did not prevent their arteries from clogging gradually with cholesterol plaque over a period of months.
But the results were different for diabetics.
The researchers compared the outcomes of 156 diabetics who received a stent and the drug with 173 who received a stent and a placebo. Reopro cut the death rate in half in the patients who received it. After six months, 12.7% of the stented patients who had received the placebo had died or suffered a heart attack, compared to only 6.2% of those who received stent and Reopro.
The drug also prevented the patients' arteries from clogging up over a period of months. Only about half as many needed additional procedures to clear out their arteries.
"The use of [Reopro] with the stent essentially neutralized the excess risk among diabetics as compared with nondiabetics for long-term death and repeat [procedures]," study co-author A. Michael Lincoff, MD, tells WebMD. Lincoff is an associate professor of medicine at the Cleveland Clinic in Ohio.
Other experts agree that the drug could help diabetics who undergo coronary artery procedures.
"It does represent a potential advance for diabetics who are dealing with coronary artery disease," says Leroy Rabbani, MD, director of coronary care at Columbia Presbyterian Medical Center. However, patients who have narrowing of all three coronary arteries would still be better off with a heart bypass, he says. Rabbani was not involved in the study, which was funded by Centrocor Inc. and Eli Lilly and Company, the producer and distributor, respectively, of Reopro.
Spencer King, MD, director of interventional cardiology at Emory University of Medicine, calls the findings a "technical innovation." King, who was not involved in the study, says, "I think it's a fascinating finding, but it needs independent confirmation."