Reduce Bolus Injection of Bivalirudin

Inclusion Criteria: * 1 Age 18 to 80 years old; 2 Medically judge to require coronary angiography; 3 Patients agree to use bivalirudin 4 Patients signe informed consent. Exclusion Criteria: * 1.Cardiogenic shock; 2.Thrombolytic therapy administered before randomization or any anticoagulant administered within 48 hours of randomization; 3.Active or recent major bleeding or bleeding predisposition; 4.Major surgery within 1 month; 5.Clinical syndrome suspicious for aortic dissection, pericarditis, or endocarditis; blood pressure higher than 180/110 mm Hg; 6.Known hemoglobin less than 10 g/dL,platelet count less than 100 × 109/L, aminotransferase level greater than 3 × the upper limit of normal; 7.History of heparin-induced thrombocytopenia; 8.Ellergy to any of the study drugs or devices; 9.Eregnancy or lactation; 10.Any condition making PCI unsuitable or that might interfere with study adherence; 11.Patient unwilling or unable to provide written informed consent 12. Researchers think it is not suitable to participate in this study.