Safety and Efficacy Study of MGuard Stent After a Heart Attack

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