Sodium Bicarbonate Infusion at Low Concentration to Reduce Kidney Insufficiency by Angiographic Non-iodinated Contrast Media

INTERVENTION: administer 154 mEq/L of sodium bicarbonate intravenously, as a bolus of 3 mL/kg/hr for 1 hour before coronary angiography, followed by an infusion of 1 mL/kg/hr for 6 hours after coronary angiography administer 0.9% saline intravenously at 1 mL/kg/hr for 12 hours before through 12 hours after coronary angiography CONDITION: Contrast‐Induced Nephropathy PRIMARY OUTCOME: the incidence of contrast‐induced nephropathy within 2 days of coronary angiography SECONDARY OUTCOME: the incidence of adverse events, the change of glomerular filtration rate in one year and the occurrence of clinical events within one year of coronary angiography INCLUSION CRITERIA: individuals with moderate renal insufficiency (serum creatinine concentration exceeding 1.2 mg/dL within 3 months) who are scheduled for coronary angiography