Over the last year, it's been rare to utter the word "stent" without at least thinking "thrombosis," an uncommon but serious complication that's been on the minds of interventional cardiologists and patients alike.
At the 30th Annual Scientific Sessions of the Society for Cardiovascular Angiography and Interventions (SCAI), an international panel of experts shared their perspective on both the causes of stent thrombosis, or blood clot formation, and the latest research on its prevention.
The symposium is the most recent of several proactive steps SCAI has taken in addressing concerns about stent thrombosis. Others include testimony before the Food and Drug Administration Circulatory System Devices Advisory Panel and release of a clinical alert advising physicians on practical steps for reducing the risk of this potentially life-threatening late complication.
"The issue of stent thrombosis, especially late stent thrombosis after placement of a drug-eluting stent, is critically important," said Gregory J. Dehmer, M.D., FSCAI, a co-moderator of the session and SCAI'S president. "Interest continues to be extremely high on this timely topic."
Drug-eluting stents are metallic mesh tubes that prop open narrowed arteries in the heart while slowly releasing a medication to prevent the build-up of scar tissue inside the stent. These tiny devices have been very successful in preventing renarrowing, or restenosis, of the coronary arteries, reducing its rate by 40-60 percent compared to bare metal stents. However, several recent analyses that tracked patient outcomes for four to five years after stent placement showed that blood clots were slightly more likely to form inside drug-eluting stents than inside bare metal stents. It is not yet clear how large the difference in risk is, but available data suggest that each year drug-eluting stents hike the risk of late stent thrombosis by about 0.2 percent over bare metal stents. When this occurs, the patient may suffer a heart attack or even die.
The annual meeting symposium will address several key topics related to stent thrombosis, including subacute thrombosis, occurring within a few days of stent implantation; late thrombosis, occurring months or years after stent implantation; and comparisons among drug-eluting stents.
In addition, speakers will focus on the possible causes of stent thrombosis. One common culprit is early discontinuation of double anticlotting medication, typically consisting of aspirin and clopidogrel. A substantial number of patients stop taking anticlotting medication before they should. Today, patients who are treated with drug-eluting stents are advised to continue anticlotting medications for at least 1 year. If it appears they cannot continue therapy for that long, many interventional cardiologists are choosing to implant a bare metal stent instead.