This study will compare clinical outcomes of immediate stent implantation with deferred stent implantation(4-10days after primary angiography) for patients presented with acute myocardial infarction due to left main coronary artery occlusion.

Primary percutaneous coronary intervention for patients presented with acute myocardial infarction caused by left main coronary artery occlusion is associated with significantly higher mortality and risks of major cardiac adverse events. Deferred stent implantation may improve prognosis of primary PCI through reducing distal embolization and no-reflow phenomenon. There is no randomized clinical trial focuses on the effect and outcome of deferred stent implantation on primary PCI for left main coronary artery occlusion in contrast with conventional strategy.

This prospective, multicenter, randomized trial is aimed to compare immediate stenting with deferred stenting for LM-AMI with 30 centers in China involved. We hope to determine whether deferred stenting is superior to conventional strategy for primary PCI of AMI caused by left main coronary artery occlusion in improving long-term clinical outcomes and cardiac function.

Inclusion Criteria:

• Clinical diagnosis of acute myocardial infarction occured within 12 hours
• Left main coronary artery occlusion confirmed by angiography
• Left main coronary artery occlusion (TIMI flow 0,1 or 2) confirmed by primary angiography, TIMI flow grade 3 achieved after pretreatment of thrombus aspiration or balloon dilatation

Exclusion Criteria:

• Life expectancy less than 1 years
• Cardiogenic shock
• Chronic kidney disease, stage 4 by KDOQI(GFR<30ml/min)
• Contraindications to aspirin or other anti-platelet drugs
• Allergy to contrast agent, rapamycin or paclitaxel
• Patients who are included in other ongoing trials
• Pregnant female