BACKGROUND: The influences of
antiplatelet therapy discontinuation on the risk of
stent thrombosis and long-term clinical outcomes after
drug-eluting stent implantation have not yet been addressed adequately. METHODS AND RESULTS: In an
observational study in Japan, 2-year outcomes were assessed in 10 778 patients undergoing sirolimus-eluting
stent implantation. 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. CONCLUSIONS: Discontinuation of both
thienopyridine and
aspirin, but not discontinuation of
thienopyridine therapy only, was associated with an increased risk of
stent thrombosis. Landmark analysis did not suggest an apparent clinical benefit of
thienopyridine use beyond 6 months after sirolimus-eluting
stent implantation.
