• Extremely important
• Development of contrast associated acute kidney injury (CA-AKI) is associated with:
• permanent renal impairment in up to 30% of patients
• a greater than five-fold increase in mortality
• prolonged hospital stay

Risk factors

Fixed (non-modifiable)

• Pre-existing renal insufficiency
• eGFR <45 mL/min increases risk significantly
• Diabetes mellitus
• Aged >75 yr
• Congestive cardiac failure
• New York Heart Association (NYHA) Class 3–4 or ejection fraction <49%
• Acute myocardial infarction
• Cardiogenic shock
• Renal transplantation
• Cirrhosis of the liver
• Myeloma

Modifiable risk factors

• Volume of contrast medium used
• Hypotension/volume depletion/sepsis
• Intra-aortic balloon pump
• Anaemia and blood loss
• ACE inhibitors
• Diuretics
• Nephrotoxic antimicrobials
• NSAIDs
• For other medication, check BNF

• When requesting imaging procedures that may require use of intravascular (particularly intra-arterial) contrast media, indicate baseline serum creatinine or eGFR on the request
• If patient acutely sick, notify imaging department if serum creatinine (eGFR) has changed since the request was made and ensure up to date result requested

If eGFR ≤30 mL/min

• Review carefully with a consultant/SpR radiologist and consultant in charge of patient the risk versus benefit of iodinated contrast and suitability of alternative media
  • vascular imaging may be possible using CO₂ as alternative contrast medium
  • use of iso-osmolar contrast media and reduced volumes may reduce risk
  • use sodium chloride 0.9% flush in the imaging department to maximise image quality and reduce contrast dose

eGFR >30 mL/min

• Ensure adequate oral intake
• Only if patient nil-by-mouth or unable to drink adequately, give IV fluids before angiography ensuring adequate hydration
• Patients who are nil-by-mouth for planned anaesthesia to drink clear fluids until 2 hr before anaesthesia
• Review medication and, where clinically appropriate, omit potentially nephrotoxic drugs (see Modifiable risk factors above and BNF) on day of scan
• To proceed with IV contrast where the eGFR is >30 mL/min but <45 mL/min, the protocolling radiologist documents eGFR in the CRIS comments with the precautionary measures required

eGFR ≤30 mL/min or acute kidney injury

• Omit/reduce diuretics on day of scan
• If patient is on metformin and has eGFR ≤30 mL/min, omit it on day of scan and do not reinstate it for 48 hr afterwards

Fluid management for patients with eGFR ≤30mL/min or AKI

• If patient already on intravenous fluid replacement with sodium chloride 0.9% this is acceptable as prevention for CA-AKI
• If time allows, intravenous sodium chloride 0.9% 12 hr pre- and 12 hr post-contrast at a minimum of 1 mL/kg/hr is acceptable

OR

• Give sodium bicarbonate 1.26% 3 mL/kg (actual body weight) IV over 1 hr pre-contrast, followed by sodium bicarbonate 1.26% 1 mL/kg/hr IV for 6 hr post-contrast
  • If sodium bicarbonate 1.26% polyfusor not available, sodium bicarbonate 1.4% can be substituted

• After procedure, daily monitoring of renal function for 48–72 hr

• If further exposure to contrast agents required, because of need for repeat/additional procedure, and patient has no major risk factors, delay exposure for >48 hr
• if major risk factors present, delay for >72 hr