Introduction

In the last decade, percutaneous coronary intervention (PCI) with drug-eluting stents (DES) has largely replaced PCI with bare-metal stents (BMS) due to their superior antirestenotic properties. However, the optimal duration of dual antiplatelet therapy (DAPT) with aspirin and a thienopyridine after DES implantation remains unknown. With early-generation DES, it was shown that premature discontinuation of DAPT [<3 months for sirolimus-eluting stents (SES) and <6 months for paclitaxel-eluting stents (PES)] strongly predicts stent thrombosis (ST) [1, 2]. Moreover, additional safety concerns arose from observational reports on increased risks of late (30 days to 1 year) and very late (>1 year) ST compared to BMS [3]. These late thrombotic events were hypothesized to be due to delayed vessel healing [4] and have led many to promote longer durations of DAPT for DES. In fact, current guidelines from American societies recommend DAPT for at least 12 months [5], while the European Society of Cardiology recommends 6–12 months after DES implantation [6]. These recommendations, however, were not based on any strong prospective randomized data, but rather on consensus opinion derived from earlier trials involving thienopyridine dosing strategies [7, 8] and observational studies suggesting lower death and myocardial infarction (MI) rates with prolonged DAPT [9, 10]. Moreover, prolonging DAPT increases bleeding risks [11], and post-PCI bleeding leads to deleterious long-term outcomes [12]. Hence, uncertainty exists regarding DAPT duration in the absence of solid clinical evidence while striking a balance between reducing ST and increment bleeding risk.