Patients with drug-eluting stents should take dual antiplatelet medication for at least one year after stent placement, according to a new advisory released by multiple US societies including the American Heart Association and American College of Cardiology. The advisory is available in the journals Circulation and Journal of the American College of Cardiology.

Clopidogrel and ticlopidine are in the drug class called thienopyridines. Thienopyridines and aspirin are routinely started before stent insertion to reduce the chance of in-stent thrombosis.

“Despite this benefit, antiplatelet therapy is sometimes prematurely discontinued within the first year after stent implantation,” the advisory warned.

According to the authors, discontinuation of antiplatelet therapy too early after a stent is placed is the leading independent predictor of stent thrombosis. “Death rates due to presumed or documented stent thrombosis range from 20 percent to 45 percent,” the advisory reported.

"We want to alert patients and healthcare professionals that this is a serious medical issue; they shouldn’t even think about stopping antiplatelet therapy because it could result in heart attack or death,” said Cindy Grines, MD, chair of the advisory writing committee and a cardiologist at William Beaumont Hospital in Royal Oak, Mich.

“If a physician, dentist or surgeon feels that stopping these medicines is absolutely necessary, the patient’s cardiologist should be consulted, and the medications should be re-started as soon as possible. Patients are advised to postpone elective procedures if the physician or dentist doing it isn’t comfortable with continuing antiplatelet medicine.”

Grines noted the importance of taking both medications - aspirin plus a thienopyridine -or dual antiplatelet therapy, which is most effective for preventing stent thrombosis. This is particularly true for patients receiving drug-eluting stents, for which the risk of thrombosis remains high for at least one year compared with one-to-three months for bare metal stents.

Research cited in the advisory showed stent thrombosis occurred in up to 29 percent of patients who discontinued antiplatelet therapy early. In a study of 500 patients who received drug-eluting stents after myocardial infarction, the death rate over the next 11 months was 7.5 percent for those who stopped taking their prescription thienopyridine medication compared with 0.7 percent for those who continued therapy. Another study of 652 patients with drug-eluting stents found that discontinuing clopidogrel was associated with a 30-fold greater risk of stent thrombosis.

“Patients should receive appropriate antiplatelet therapy according to existing practice guidelines wherever possible,” said Raymond J. Gibbons, MD, American Heart Association president. “This will usually require patients taking both aspirin and a thienopyridine (most commonly clopidogrel) for periods of up to at least one year after stenting and aspirin indefinitely. Patients should not discontinue either aspirin or the thienopyridine within the first year without consulting their treating cardiologist.”