• Development of contrast-induced nephropathy, CIN, defined as an increase in serum creatinine of 25% or more from pre-intervention baseline to within 48-72 hours after administration of the radiographic contrast.
  

• Group mean change in serum creatinine
  
• Days in hospital within the week post contrast
  
• Requirement for dialysis
  
• Atheroembolic events
  
• Major adverse cardiovascular events
  
• Death
  

A decline in kidney function after contrast is associated with prolonged hospital stay, adverse cardiac events, and higher mortality both in hospital and in the long term. Deliberate administration of fluids is recommended to reduce the risk of contrast nephropathy. However, data to support specific recommendations are lacking and the optimal fluid regimen remains unclear.

It has been hypothesized that alkalinization of tubular fluid might be beneficial by reducing pH dependent free radical levels. A recent trial found a lower frequency of creatinine rise > 25% within two days of contrast with a 7 hour infusion of isotonic sodium bicarbonate than with saline infusion (Merten GJ, JAMA 2004). However, it remains to be proven that bicarbonate is superior as this trial has a number of methodological flaws.

Comparison: IV 1/6 M sodium bicarbonate OR IV 0.9% saline, each isotonic fluid given at the same rate of sodium administration (3.25 ml/Kg over 1 hour pre-contrast, followed by 1.1 ml/Kg/hr for 6 hours for bicarbonate; 3.5 ml/Kg over 1 hour pre-contrast, followed by 1.2 ml/Kg/hr for 6 hours for saline). Total infusion time 7 hours (for both). Maximum rate of fluid permitted is that for a body weight of 110 Kg. Intra-vascular iso- or low-osmolality contrast in the minimal dose needed to complete the required imaging.

Inclusion Criteria:

• Booked for cardiac or other non-renal arteriography
• Pre-existing reduced kidney function: Serum Creatinine >= 1.3 & <= 4 mg/dl (female gender) or >= 1.5 & <= 5 mg/dl (male gender)
• Age > 18 years

Exclusion Criteria:

• GFR MDRD estimate < 15 ml/min/m2
• End-stage renal disease already on dialysis
• Known current Acute Kidney Failure with serum creatinine rise of > 0.5 mg/dl within 24 hours
• Pulmonary edema - current or within 48 hours
• Clinically relevant ascites, edema or other fluid overload
• Uncontrolled hypertension (> 165 mmHg systolic, or > 105 mmHg diastolic)
• Hemodynamically unstable patient requiring IV nitroglycerine, or IV fluid or inotropes for blood pressure support
• Emergency (unplanned) angiography
• IV contrast procedure
• Exposure to iodinated radiocontrast within 3 days prior to study
• Prior anaphylactoid reaction to contrast
• Planned administration of N-acetylcysteine
• Planned administration of dopamine, fenoldopam or mannitol
• Current pregnancy