Drug-Eluting Stents: Do They Cause Blood Clots?

If you have coronary artery disease, you may have a stent in one or more of your coronary arteries.

Stents are small, mesh-like metal tubes that are inserted through a small incision near your groin and threaded up into your coronary arteries. Once in place, stents expand, pushing plaque against the arteries’ outer walls and thus opening the arteries where they were blocked.

Drug-eluting stents (DES) are stents that contain time-released medication that may reduce the chance that arteries will become blocked over time by restenosis, which is scar tissue formation inside of the stent. Studies have shown that DES decrease the frequency of stent restenosis from 15 or 20 percent for unmedicated stents (known as Bare metal stents (BMS)) to approximately 5-7 percent, thereby preventing future heart catheterizations, angioplasties and bypass surgeries.

However, recent data suggests that DES may actually heighten the risk of a second type of stent complication: the formation of blood clots inside the stent (known as stent thrombosis). The data shows that there may be a small but significant increase in the rate of death and heart attack due to thrombosis in patients treated with DES.

The Food and Drug Administration (FDA) monitors the use of DES. While the new data is of interest to the FDA and raises important questions, they do not have enough information yet to draw conclusions. It’s unclear, for example, what causes drug-eluting stent thrombosis, how often it occurs, under what circumstances it occurs, or what the risk of occurrence is in a given patient. At this time, FDA believes that coronary DES remain safe and effective when used for FDA-approved indications.

If you have been treated with DES or may be in the near future, ask your cardiologist about their risks and benefits. Extended treatment with anti-clotting medications such as Plavix and aspirin may be an appropriate counter measure. As always, patients with coronary artery disease should be on a daily aspirin which shouldn’t be stopped without the advice of their cardiologist.