- patients identified at being at risk of contrast induced-AKI (CI-AKI) should have a careful assessment of volume status and receive pre-procedure volume expansion with 0.9% sodium chloride or isotonic sodium bicarbonate if clinically indicated
Contrast-induced acute kidney injury (CI-AKI) secondary to radiological contrast media is uncommon in the general population
- classically occurs within 72 hours of receiving the contrast media and usually recovers over the following five days
- incidence increases significantly in patients with risk factors and is associated with an increased short and long-term mortality
- acute kidney injury results from a combination of afferent arteriolar vasoconstriction and direct toxicity of the contrast media to the tubule epithelial cells
Preventing acute kidney injury in adults having iodine-based contrast media (2):
- encourage oral hydration before and after procedures using intravenous iodine-based contrast media in adults at increased risk of contrast-induced acute kidney injury
- before offering iodine-based contrast media to adults, assess their risk of acute kidney injury but do not delay emergency imaging. Be aware that increased risk is associated with:
- chronic kidney disease (adults with an eGFR less than 40 ml/min/1.73m2 are at particular risk)
- diabetes but only with chronic kidney disease (adults with an eGFR less than 40 ml/ min/1.73m2 are at particular risk)
- heart failure
- renal transplant
- age 75 years or over
- hypovolaemia
- increasing volume of contrast agent
- intra-arterial administration of contrast medium with first-pass renal exposure
- for inpatients having iodine-based contrast media, consider intravenous volume expansion with either isotonic sodium bicarbonate or 0.9% sodium chloride if:
- they are at particularly high risk, for example, if:
- they have an eGFR less than 30 ml/min/1.73m2
- they have had a renal transplant
- a large volume of contrast medium is being used (for example, higher than the standard diagnostic dose or repeat administration within 24 hours)
- intra-arterial administration of contrast medium with first-pass renal exposure is being used
- consider temporarily stopping ACE inhibitors and ARBs in adults having iodine based contrast media if they have chronic kidney disease with an eGFR less than 40 ml/min/1.73m2
- discuss the person's care with a nephrology team before offering iodine-based contrast media to adults on renal replacement therapy, including people with a renal transplant, but do not delay emergency imaging for this
Potentially nephrotoxic medications such as non-steroidal anti-inflammatory drugs and aminoglycosides should be withheld or avoided. Currently there is insufficient evidence to support the routine discontinuation of angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARBs) in stable outpatients (1,2)
Metformin is not nephrotoxic but is exclusively excreted via the kidneys (1,3)
- patients on metformin who develop AKI are at risk of developing lactic acidosis
- advice from the Royal College of Radiologists is that there is no need to stop metformin after receiving contrast if the serum creatinine is within the normal range and/or eGFR > 60 ml/min/1.73m2
- if serum creatinine is above the normal reference range or eGFR is < 60 ml/min/1.73m2, any decision to stop it for 48 hours should be made in consultation with the referring clinician
Notes:
- first-pass renal exposure is when the contrast medium reaches the renal arteries in a relatively undiluted form, for example, through injection into the left heart, thoracic and suprarenal abdominal aorta, or the renal arteries (2)
- patients identified as at high risk of CI-AKI should be discussed with a renal physician to assess the individual risk/benefit to the patient (1)
- recognised that in some patients the risk of CI-AKI is outweighed by the potential benefit from the contrast study
- Renal Association guidance also lists
- atherosclerotic peripheral vascular disease; liver disease; and sepsis as risk factors for contrast induced kidney disease (1)
Reference: