Antiplatelet Therapy and Stent Thrombosis After Sirolimus-Eluting Stent Implantation

Dr Marco Valgimigli

Although premature discontinuation of antiplatelet therapy is reported to be the most powerful predictor of stent thrombosis (ST) and adverse cardiovascular outcomes the relative contribution of discontinuation of either aspirin or thienopyridine on ST rates has not been addressed adequately. although premature discontinuation of antiplatelet therapy is reported to be the most powerful predictor of stent thrombosis (ST) and adverse cardiovascular outcomes the relative contribution of discontinuation of either aspirin or thienopyridine on ST rates has not been addressed adequately.

The j-Cypher registry is a physician-initiated prospective, multicenter observational study in Japan enrolling consecutive patients undergoing sirolimus-eluting stent implantation. In this observational study, 2-year outcomes were assessed in 10 778 patients.
Data on status of antiplatelet therapy during follow-up were collected prospectively. Incidences of definite stent thrombosis were 0.34% at 30 days, 0.54% at 1 year, and 0.77% at 2 years.

Thienopyridine use was maintained in 97%, 62%, and 50% of patients at 30 days, 1 year, and 2 years, respectively. Patients who discontinued both thienopyridine and aspirin had a significantly higher rate of stent thrombosis than those who continued both in the intervals of 31 to 180 days, 181 to 365 days, and 366 to 548 days after stent implantation (1.76% versus 0.1%, P=0.001; 0.72% versus 0.07%, P=0.02; and 2.1% versus 0.14%, P=0.004, respectively).

When discontinuation of aspirin was taken into account, patients who discontinued thienopyridine only did not have an excess of stent thrombosis in any of the time intervals studied. Adjusted rates of death or myocardial infarction at 24 months were 4.1% for patients taking thienopyridine and 4.1% for patients not taking thienopyridine (P=0.99) in the 6-month landmark analysis.

Conclusion

Authors concluded that discontinuation of both thienopyridine and aspirin, but not discontinuationof thienopyridine therapy alone, was associated with an increased risk of ST. Landmark analysis did not suggest an apparent clinical benefit of thienopyridine use beyond 6 months after SES implantation.