Risk Factors Identified for Stent Thrombosis

A new study finds that premature interruption of antiplatelet therapy in patients with drug-eluting stents (DES) is the major risk factor for stent thrombosis.

Researchers from the University of Ulsan College of Medicine (Korea) and Asan Medical Center (Seoul, Korea) followed a series of 1,911 consecutive patients with DES implantation. Sirolimus-eluting stents were implanted in 1,545 patients with 2,045 lesions, while paclitaxel-eluting stents were implanted in 366 patients with 563 lesions. Fifteen patients (0.8%) developed stent thrombosis within six hours to 20.4 months of follow up, a rate similar to that reported in clinical trials. Eleven of these patients, representing 0.6% of the cohort, developed late stent thrombosis after a median of 6.1 months, a rate similar to that for bare metal stents. A total of 121 patients experienced complete interruption of antiplatelet therapy and four of these patients (3.3%) developed stent thrombosis.

Premature interruption of antiplatelet therapy, primary stenting in acute myocardial infarction, and total stent length were the independent predictors of stent thrombosis, the investigators found. The results were published in the August 1, 2006, edition of the American Journal of Cardiology.

"In routine clinical practice, antiplatelet drug therapy may be unexpectedly interrupted in patients treated with drug-eluting stents due to non-cardiac surgery, cardiovascular complications causing major bleeding or necessitating surgery, or patient's non-compliance,” said lead author Dr. Seong-Wook Park. "In the current study, the chance of antiplatelet therapy interruption in real practice was higher than expected and it was the most important risk factor for development of stent thrombosis, implying paramount significance of antiplatelet therapy maintenance.”

Antiplatelet therapy, usually aspirin, clopidogrel, or a combination of both drugs, is essential for preventing adverse outcomes after stent implantation. Doctors have recommended that with drug-eluting stents, the length of treatment with these antiplatelet stents should be longer than with conventional bare-metal stents.



Related Links:
University of Ulsan College of Medicine
Asan Medical Center