Recent developments for drug-eluting stents

May 10 2007

Drug-eluting stents -- small metal tubes used to prop open clogged arteries -- have been garnering headlines.

In an interview in the May issue of Mayo Clinic Women's HealthSource, Abhiram Prasad, M.D., a Mayo Clinic cardiologist, puts recent developments in perspective.

Introduced in 2003, drug-eluting stents help prevent recurrence of artery narrowing (restenosis), by slowly releasing medication that may help reduce plaque build up. With the previous generation of stents, bare-metal type, about 20 percent of patients needed a second angioplasty procedure to prop open the artery because of restenosis. With drug-eluting stents, the risk of restenosis is 5 percent. The use of drug-eluting stents now accounts for 90 percent of all stent usage.

Recent evidence has highlighted the risk of blood clots forming due to drug-eluting stents, a condition known as stent thrombosis. That risk has always been present for all stents, says Dr. Prasad. “One thing that is different about drug-eluting stents is that the risk of stent thrombosis appears to be present for a longer time than with bare-metal stents.” With bare-metal stents, the risk of blood clots typically is largely gone after the first year.

That's because the tissue grows over the bare-metal stents more quickly. With drug-eluting stents, the drug coating decreases tissue growth. This prevents restenosis - a good feature - but also makes clot formation more likely beyond the first year after stent replacement.

While stent thrombosis is a serious concern, it's also rare, says Dr. Prasad. And the overall risk of serious complications such as clots, heart attacks or death is very low and is the same as for bare-metal and drug-eluting stents.

No medical device is perfect. Patients need to discuss pros and cons of every option with their doctor to make an informed decision. After a stent procedure, it's important to follow a doctor's recommendation regarding blood-thinning medications to reduce the risk of blood clots.