The risk of restenosis in the treatment of coronary artery disease has significantly lessened thanks to the introduction of Drug eluting stent.

Yet, debates on the efficacy and safety of stents in complex lesions or patients have been circulated.

Recently, PCI in multiple lesions is universally performed with the development of effective stents in various kinds in the clinics.

However, a randomized study is rare for multi-vessel coronary artery disease in real procedural environments.

The primary purpose of this study is to evaluate the clinical progress of biolimus A9-eluting stent and zotarolimus-eluting stent in multi-vessel coronary artery disease.

The patients who need multi-vessel stenting with multi-vessel coronary artery disease will be enrolled.Each randomization of the enrolled subjects will be done 1:1 (biolimus A9-eluting stent : zotarolimus-eluting stent). Randomization will be stratified by two factors: Diabetes mellitus and Acute coronary syndrome.Clinical follow-up will occur at the following time points; 1 month, 1 year and 2 years.

Inclusion Criteria:

• patients who need multi-vessel stenting with multi-vessel disease
• patients with signed informed consent

Exclusion Criteria:

• known contraindication to any of the following medications: Aspirin,clopidogrel, heparin, contrast agent, Biolimus or Zotarolimus group
• Cardiogenic shock
• Pregnant women or women with potential childbearing
• End-stage diseases with life expectancy shorter than 2 years
• patients with other Drug eluting stents implanted
• Patients requiring modification of antiplatelet agents for planned major surgery within the first 12 months after the enrollment.