Stents are wire-mesh tubes that keep arteries open after balloon angioplasty. But there's a problem with the lifesaving devices. Over time, they tend to develop new blockages. Doctors call this "restenosis."
Within six months of implantation, 20% to 40% of stents become blocked. For people with diabetes, it's an even worse problem. New stent blockages occur within six months in 32% to 66% of patients with diabetes.
Help is on the way. The diabetes drug Avandia -- a member of the "glitazone" drug class -- reduced the stent-blockage rate from 38.2% to 17.6% in a study of 83 diabetes patients with coronary artery disease. The report comes from a research team led by Donghoon Choi, MD, PhD, of Yonsei University College of Medicine in Seoul, Korea. It appears in the November issue of Diabetes Care.
And this type of drug may do more than simply keep stents open.
"Because most diabetes patients with coronary artery disease also are at high risk for [blocked arteries] ... the [glitazone] class will be a relatively safe and important modality not only for preventing an in-stent restenosis but also for inhibiting any undiscovered and [widespread] atherosclerotic process," Choi and colleagues write.
In an editorial accompanying the study, Vivian A. Fonseca, MD, of Tulane University in New Orleans, and colleagues, note that glitazone drugs promise to lessen the high rate of heart disease in people with diabetes.
"These findings confirm the benefits seen with other [glitazone drugs] following angioplasty," Fonseca and colleagues write.
They note that the drugs' effects on the heart are not directly linked to their ability to make the body more sensitive to insulin. Instead, this class of drugs may inhibit excess cell growth within the stent that can lead to stent blockage. The study also showed that compared with patients taking other types of diabetes medications, patients taking Avandia had lower blood markers of inflammation, an important process in the development of atherosclerosis and plaque buildup.
And there are some downsides to glitazones. The first member of this drug class, Rezulin, was withdrawn from the market in 2000 after it turned out to cause serious liver damage. While Avandia and its cousins don't have such serious liver side effects, they do cause weight gain and water retention.
Many diabetes patients have serious congestive heart failure. Because of their side effects, glitazones cannot be given to such patients.