CI-AKI: PREVENTION

• Extremely important
• Development of CI-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 <60 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

If eGFR <60 mL/min

• Interpret eGFR with caution as it may underestimate the severity of renal impairment in patients at the extremes of age and body size with
• severe malnutrition, paraplegia, tetraplegia, known skeletal muscle disease
• rapidly changing renal function
• Review need for use of contrast
• Discuss suitability of alternative media with radiologist and consultant in charge of patient’s care
• vascular imaging may be possible using CO₂ as alternative contrast medium
• use of iso-osmolar contrast medium and reduced volumes may reduce risk
• to maximise image quality and reduce contrast dose, a sodium chloride 0.9% flush should be used by imaging department

All patients

• Review medication and, where clinically appropriate, omit potentially nephrotoxic drugs on day of scan. See Modifiable risk factors
• Ensure adequate oral intake
• If patient nil-by-mouth or unable to drink adequately, give IV fluids before angiography
• if nil-by-mouth for planned anaesthesia, patient to drink clear fluids until 2 hr before anaesthesia

Additional measures for high-risk patients

• High risk patients
• inpatients with eGFR <60 mL/min requiring any iodinated contrast
• outpatients with eGFR <60 mL/min requiring intra-arterial contrast media
• outpatients with eGFR <30 mL/min for any iodinated contrast scan
• Hydration with IV fluids is important in prevention of CIN
• 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
• prolonged regimes using IV sodium chloride 0.9% 12 hr pre- and post-contrast at a minimum of 1 mL/kg/hr is acceptable. Therefore, if patient already on IV fluid replacement with sodium chloride 0.9%, this is acceptable as prevention for CI-AKI
• Omit/reduce diuretics on day of scan
• If patient is on metformin and has eGFR ≤50 mL/min, omit it on day of scan
• do not re-instate it for 48 hr afterwards

Requesting imaging with contrast medium

• Indicate baseline serum creatinine or eGFR on the request

Patient acutely sick/unstable

• If serum creatinine (eGFR) has changed since the request was made, notify imaging department
• Ensure up to date result requested

• 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