The goal of this study is to demonstrate the superiority of the MGuard™ stent over commercially-approved bare-metal (BMS) /drug-eluting stents (DES) in achieving better myocardial reperfusion in primary angioplasty for the treatment of acute ST-elevation myocardial infarction (STEMI).

Inclusion Criteria

• 18 years of age
• ST-segment elevation (more than 2mm in more than contiguous leads)
• MI with symptom onset less than 12h
• The patient is willing to comply with specified follow-up evaluations
• Signed ICF
• Single de novo lesion in the target (culprit) vessel
• Target lesion maximum length is 33 mm (by visual estimation)
• Reference vessel diameter must be more than 3.0 to less than 4.0 mm by visual estimation
• Randomization should occur as soon as Presence of TIMI 2 or 3 before randomization Exclusion Criteria
• Pregnant or nursing patients
• Left Bundle Branch Block (LBBB), paced rhythm, or other Electrocardiogram (ECG) abnormality
• Impaired renal function
• Prior coronary artery bypass graft surgery
• Bleeding diathesis
• Contraindication to aspirin
• cardiopulmonary resuscitation
• Cardiogenic shock
• chronic warfarin anticoagulation
• LVEF less than 20%
• other medical illness
• participation in another investigational drug or device study that has not reached its primary endpoint
• Left main coronary artery disease with 50% stenosis
• Ostial target lesion
• Failure to visualize vessel anatomy distal to the culprit lesion
• Moderate to heavily calcified target lesion or vessel
• excessive tortuosity
• bifurcation with a side branch more than 2.0 mm in diameter
• A significant (greater than 50%) stenosis proximal or distal to the target lesion is present that cannot be covered by same single stent
• Diffuse disease distal to target lesion with impaired runoff
• Any prior stent proximal to the target lesion, or within 10 mm distal of the target lesion
• PCI of another lesion performed within 6 months before the index procedure
• Target lesion located in a saphenous vein graft