In the treatment of coronary heart disease which is the major cause of heart attack, direct mechanical treatment with catheters such as the coronary angiography, coronary balloon intervention and stenting intervention are the mainstay of therapy in recent years. In that procedures, the investigators should use the contrast media, and it may cause kidney toxicity especially in the patients with underlying kidney disease and decreased kidney function. The investigators intended to find out which contrast agent has less kidney toxicity in the catheter based treatment of coronary arterial diseases in patients with underlying decreased kidney function

Iodixanol, a nonionic, dimeric, iso-osmolar contrast medium (IOCM), may be less nephrotoxic than nonionic, monomeric, low-osmolar contrast media (LOCMs) in high-risk patients. We compared the nephrotoxicity of iodixanol with that of iopromide, an nonionic, monomeric LOCM, in patients with renal impairment.

Inclusion Criteria:

• patients who undergo coronary catheterization
• creatinine clearance rates ≤ 60 mL/min using the Cockcroft-Gault formula

Exclusion Criteria:

• pregnancy or lactation
• having received contrast media within 7 days of study entry
• emergent coronary angiography
• acute renal failure or end-stage renal disease requiring dialysis
• history of hypersensitivity reaction to contrast media
• unstable hemodynamic states such as cardiogenic shock, pulmonary edema or needing mechanical ventilation
• multiple myeloma
• parenteral use of diuretics
• use of N-acetylcysteine
• use of metformin or nonsteroidal anti-inflammatory drugs within 48 hours of the procedure