The aim of the study is to investigate the efficacy and safety different dose of GPIIb/IIIa inhibitor (tirofiban) in interventional treatment of complex coronary artery disease ,which include bifurcation lesion, left main lesion, multiple vessel disease, intracoronary thrombus, SYNTAX score>26,chronic total occlusion disease. The primary endpoint is all-cause mortality. Secondary endpoints are incidence of major bleeding and the rate of site access complication.

Inclusion Criteria:

• Patients were recruited from those undergoing PCI with a planned placement of an intracoronary stent
• Including patients with unstable angina pectoris, acute coronary syndrome or NSTEMI
• Experienced ischaemic pain at rest
• Lasting 10 minutes and occurring within 7 days before enrollment
• As well as one of the following: ECG changes: New or presumably new ST-segment depression greater than or equal to 0.1 mV (1 mm), or transient (< 30 minutes) ST-segment elevation greater than or equal to 0.1 mV (1 mm) in at least 2 contiguous leads -Abnormal cardiac enzymes within the 24 hours before enrollment, defined as elevated Troponin I defined as elevated Troponin I (above the normal reference -
• High-risk angiographic features :lesion/anatomy related bifurcation lesion, left main lesion, multiple vessel disease, intracoronary thrombus, SYNTAX score > 26 and chronic total occlusion disease.

Exclusion Criteria:

• Increased bleeding risk: ischaemic stroke within the last year or any previous haemorrhagic stroke, tumour or intracranial aneurysm;
• Recent (<1 month) trauma or major surgery (including bypass surgery);
• Active bleeding
• Unexplained clinically significant bleeding, thrombocytopenia (platelet count < 100 x 109/L) or history of thrombocytopenia with GP IIb/IIIa, heparin or enoxaparin therapy
• Angina from secondary causes such as severe uncontrolled hypertension (systolic blood pressure > 180 mm Hg despite treatment)
• Valvular disease, congenital heart disease, hypertrophic cardiomyopathy, - Thrombolytic therapy within preceding 24 hours
• Receiving antiIIb/IIIa therapy
• Creatinine clearance of <30 mL/min