In a recent fine report in The American Journal of Cardiology , Shin et al described the results of an observational study testing the optimal duration of dual-antiplatelet therapy after the implantation of first-generation drug-eluting stents (DES) and concluded that the benefit of clopidogrel use beyond 6 months after DES implantation is questionable.

We believe that this statement is too strong and could mislead the community of clinical and interventional cardiologists. First, although corroborated by a strong statistical method, this was not a randomized controlled clinical trial but an observational study with only 163 patients in the nonclopidogrel group and an ambitious composite primary end point (death, myocardial infarction, and stent thrombosis), usually reserved for larger studies. Moreover, the nonclopidogrel population was at lower risk for adverse events (there were fewer acute coronary syndromes and multivessel diseases and fewer deployed stents, and the patients had higher left ventricular ejection fractions), so their better prognosis may have contaminated the ischemic end point that proved to be comparable with that observed in the clopidogrel group. Finally, there is substantial evidence showing that prolonging the use of clopidogrel for even >12 months in DES-treated patients who are not prone to bleeding, especially (but not only) in high-risk patients, is safe and reasonable. For example, a recent study published in this journal found that prolonged dual-antiplatelet treatment with aspirin and clopidogrel for 24 months led to fewer episodes of very late stent thrombosis (2% vs 0%, p = 0.03) in comparison to a 12-month regimen.

It is also worth mentioning the recent report Goy et al, whose results of a 5-year follow-up study of patients who had received Cypher stents (Cordis Corporation, Miami Lakes, Florida) showed a 3.6% cumulative incidence of stent thrombosis, 90% of which occurred >1 year after implantation and after the discontinuation of dual-antiplatelet therapy. Newer generation DES seem to have reduced the incidence of stent thrombosis and late adverse ischemic events, and further studies regarding optimal antiplatelet treatment are advocated, but the patients in Shin et al’s study were implanted with first-generation DES and the follow-up was limited to 2 years.

Although the study is interesting and the report well written, we believe that its conclusion is somewhat too strong and insufficiently corroborated by scientific evidence.