The contrast induced kidney toxicity has been known to affect the mortality and morbidity in the patients undergoing coronary angiography. But the mechanism and therapeutic strategy for it is not well known. Nowadays, it is reported that the N-acetylcysteine may have preventive effects for contrast induced kidney toxicity with its antioxidant effects.The statins have been reported to have many other effects other than the lipid lowering effect-including antioxidant effect, so we hypothesized that the antioxidant effect of simvastatin may prevent the contrast induced kidney toxicity.

The simvastatin may prevent the contrast agent induced acute renal failure in the patients with underlying renal insufficiency who is undergoing the coronary angiography. The effect may derive from the antioxidant function of simvastatin.

Inclusion Criteria:

• Angina patients
• Patients who is required the coronary catheterization
• creatinine clearance rates ≤60 mL/min using the Cockcroft-Gault formula Patients who undergo coronary catheterization
• Age of 19 or over 19

Exclusion Criteria:

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