The study aims to compare a preventive percutaneous coronary intervention (PCI) plus optimal medical treatment (OMT) strategy vs. OMT for treatment of non-functionally significant non-culprit lesions presenting with optical coherence tomography (OCT) findings indicative of vulnerable plaque, in patients with ST-elevation myocardial infarction (STEMI) and multivessel disease.

STEMI patients with multivessel disease planned for invasive evaluation of intermediate lesions (40-69% stenosis) are initially investigated with fractional flow reserve (FFR). Patients with FFR ≤ 0.80 are considered as screening failure and treated with PCI. Patients with FFR > 0.80 are then investigated with optical coherence tomography (OCT). Patients without OCT findings of vulnerable plaque are treated with OMT and included in the OMT registry arm. Patients presenting with OCT characteristics of vulnerable plaque are included in the randomized trial comparing PCI with stent implantation plus OMT versus OMT.

Inclusion Criteria:

• Patients > 18 years.
• Successful revascularization of the culprit lesion in patients undergoing coronary angiography due to ST-segment elevation (> 1mm in > 2 contiguous leads, new left bundle branch block, or true posterior MI with ST depression of >1mm in >2 contiguous anterior leads) in the first 72 hours of the symptom's onset.
• Multivessel coronary disease with non-culprit lesions located in different vessels than the culprit lesion and ranging from 40 to 69% of DS (visual estimated diameter stenosis ) by visual estimate planned for FFR-guided revascularization in staged procedure (>24 hours and <60 days after PCI of the culprit lesion).
• Non-culprit lesions should be suitable for functional assessment with pressure wire and OCT catheter and should be suitable to be treated with a single 2.0 to 4.5 mm EES (everolimus-eluting stent ).
• Subject agrees to not participate in any other clinical trial study for a period of 4 years following the inclusion in the study.
• Informed consent signed.

Exclusion Criteria:

• Inability to provide informed consent.
• Female of childbearing potential (age <50 years and last menstruation within the last 12 months), who did not undergo tubal ligation, ovariectomy or hysterectomy.
• Known intolerance to aspirin, heparin, everolimus, contrast material.
• Unresolved mechanical complication or cardiogenic shock at the staged procedure.
• Non-culprit study lesions located in the left main coronary artery or in coronary vessels with prior coronary revascularization (PCI or by-pass) or with distal vessel occlusion.
• Patients with long, bifurcated, severely angulated or severely calcified non-culprit study lesions non suitable to be treated with a single EES implantation.
• Asthma or known history of bronchial hyper-reactivity.
• Chronic renal dysfunction with creatinine clearance < 45 ml/min.
• Severe comorbidities that in the opinion of the local investigators determine the patient's life expectancy < 4 years.
• Subject is currently participating in another clinical trial that has not yet completed its primary endpoint.