Medical Edge Newspaper Column

Should Cardiac Stents Be Removed?

November 26, 2007
Dear Mayo Clinic:
With the recent controversy about drug-coated stents, should I talk to my doctor about removing my stent?

Answer:
While we continue to learn more about the risks associated with these medical devices, drug-coated or drug-eluting stents are considered safe for the vast majority of patients. Neither the Food and Drug Administration nor any medical organization has suggested that patients should consider having drug-coated stents removed or replaced, because stents are an important part of medical treatment that improves symptoms and can prolong life for millions of patients with heart disease.

Stents are metal mesh tubes varying in length from 8 to 33 millimeters. Doctors insert stents into coronary arteries after performing angioplasty, a procedure where partially or completely blocked arteries are opened, usually with a small balloon. Stents help prevent recurrent blockage of the artery, which could require a second procedure to open the arteries. Without stent placement, about 30 percent of arteries become blocked again. There are two categories of stents: bare-metal stents, which have been used for more than 15 years, and the newer drug-eluting stents. The drug-eluting stents have been in the news recently.

The drug-eluting stents are coated with medication that helps prevent scar tissue growth, a problem that sometimes occurs with bare-metal stents. There's no dispute that drug-coated stents are better than bare-metal stents at preventing recurrent blockages. About 20 percent of patients with bare-metal stents experience tissue growth that reblocks the arteries. For patients with drug-eluting stents, that risk is cut by more than half.

Recent studies have raised questions about whether drug-eluting stents are riskier in other ways. While the studies aren't conclusive and don't all agree, here's what seems to be the consensus:

• The risk of subsequent death or heart attack is about the same for both types of stents.
• Both types of stents are associated with a very small overall risk of blood clots (a frequency of less than 1 percent a year), which can occur within the stent and potentially cause blockage of the artery.
• Regarding the risk of stent-generated blood clots, for patients with bare-metal stents, the risk seems to be highest within three months after the angioplasty. For patients with drug-eluting stents, studies seem to indicate that the risk is highest more than a year after the stent placement. This late risk of blood clots is still very low, less than 1 percent per year after the first year.

As a result of these studies, the American Heart Association and several other medical professional groups are now encouraging doctors to keep patients with drug-eluting stents on medications to reduce the risk of blood clots for a year or more. Patients shouldn't discontinue these medications, which include aspirin and clopidogrel (Plavix), without consulting a cardiologist.

— David Holmes Jr., M.D., Cardiology, Mayo Clinic, Rochester, Minn.