The objective of the study is to assess the superiority of the everolimus-eluting stent (Endeavor Resolute®) compared with the everolimus-eluting stent (XIENCE V®) regarding uncovered stent strut segments.

The mid-term efficacy of drug-eluting stents has been well-established, but there is an ongoing debate on the potential of an increased incidence of late stent thrombosis, particularly after discontinuation of thienopyridine therapy, as well as of delayed onset of restenosis or catch-up phenomenon with permanent polymer-based DES. The extent of strut coverage with reduction of exposed thrombogenic material has been shown to be associated with the inflammatory reaction grade and with the incidence of stent thrombosis. The optical coherence tomography (OCT) is an intravascular imaging modality based on light. The principle is similar to intravascular ultrasound, but due to the much shorter wave length of light, it offers a much better resolution up to 10µm, enabling the exact determination of strut coverage, neointimal thickness, vessel size, presence of dissections, and even the presence of inflammation.

Inclusion Criteria:

• Patients older than age 18 with ischemic symptoms or evidence of myocardial ischemia in the presence of ≥ 50% stenosis located in native coronary vessels.
• Written, informed consent by the patient or her/his legally-authorized representative for participation in the study.
• In women with childbearing potential a negative pregnancy test is mandatory.

Exclusion Criteria:

• Lesion length >16mm requiring a stent length >18mm
• Target lesion located in the left main trunk.
• In-stent restenosis.
• Acute myocardial infarction
• Malignancies or other comorbid conditions (for example severe liver, renal and pancreatic disease) with life expectancy less than 12 months or that may result in protocol non-compliance.
• Known allergy to the study medications: everolimus, zotarolimus, stainless steel or cobalt chrome.
• Inability to take dual antiplatelet therapy for at least 6 months.
• Pregnancy (present, suspected or planned) or positive pregnancy test.
• Previous enrollment in this trial.
• Patient's inability to fully cooperate with the study protocol.