Microalbuminuria Predicting CIAKI After CAG

Inclusion Criteria: * Patients with eGFR≥30ml/min and without macroalbuminuria undergoing CAG. Exclusion Criteria: * Pregnancy * Lactation * Allergic history of contrast media * Having been received contrast media within 7 days * Use of nephrotoxic medications within 7 days * eGFR \<30 ml/min, macroalbuminuria (ACR \>300 mg/g) * Renal transplantation, emergent coronary angiography * Cardiogenic shock, pulmonary edema * Use of intra-aortic balloon pump (IABP) or mechanical ventilation * Multiple myeloma and other malignant tumor * Life expectancy less than 12 months