Drug-eluting stents (DES) reduce restenosis rates compared to bare-metal stents. Most trials using DES enrolled selected patient and lesion subtypes, and primary endpoint focused on angiographic metrics or relatively short-term outcomes. When DES are used in broader types of lesions and patients, important differences may emerge in long-term outcomes between stent types, particularly the incidence of late stent thrombosis. PROTECT is a randomized, open-label trial comparing the long-term safety of the zotarolimus-eluting stent and the sirolimus-eluting stent. The trial has enrolled 8,800 patients representative of those seen in routine clinical practice, undergoing elective, unplanned, or emergency procedures in native coronary arteries in 196 centers in 36 countries. Indications for the procedure and selection of target vessel and lesion characteristics were at the operator's discretion. Procedures could be staged, but no more than 4 target lesions could be treated per patient. Duration of dual antiplatelet therapy was prespecified to achieve similar lengths of treatment in both study arms. The shortest predefined duration was 3 months, as per the manufacturer's instructions. The primary outcome measure is the composite rate of definite and probable stent thrombosis at 3 years, centrally adjudicated using Academic Research Consortium definitions. The main secondary end points are 3-year all-cause mortality, cardiac death, large nonfatal myocardial infarction, and all myocardial infarctions. This large, international, randomized, controlled trial will provide important information on comparative rates of stent thrombosis between 2 different DES systems and safety as assessed by patient-relevant long-term clinical outcomes.