The aim of this study is to determine whether sodium bicarbonate is superior to sodium chloride in preventing contrast induced nephropathy in diabetic patients undergoing coronary angiography or intervention.

Contrast induced nephropathy (CIN) is a common cause of renal failure associated with prolonged hospitalization, significant morbidity or mortality, and cost. CIN has been reported to account for 10% of hospital acquired renal failure. Several strategies or medications were tried to prevent CIN. Of these, mucomyst and normal saline infusion are effective to prevent CIN. Sodium bicarbonate has shown mixed results from recent randomized trials. Moreover,limited data have been available for preventing CIN in diabetic renal dysfunction undergoing coronary angiography or intervention. Our hypothesis is that addition of sodium bicarbonate will be more efficacious than normal saline in preventing CIN at above situation.

Inclusion Criteria:

• age>18 years, no upper limits
• diabetes treated with insulin or oral hypoglycemic agents
• serum creatinine >=1.1 and
• resting estimated glomerular filtration rate <60ml/min/1.73 square meter

Exclusion Criteria:

• serum creatinine >=8mg/dL
• resting estimated GFR <15ml/min/1.73 square meter
• end stage renal disease on hemodialysis
• multiple myeloma
• uncontrolled hypertension (systolic BP >160mmHg or diastolic BP>100mmHg)
• acute myocardial infarction
• emergent coronary angioplasty or angiography
• recent use of contrast within 2 days
• allergic reaction to contrast
• pregnancy
• allergic to following medication : theophylline, dopamine, mannitol, fenoldopam, N-acetylcysteine