Ulf Nyman1 & Joanna Ahlkvist2 & Peter Aspelin3 & Torkel Brismar3,4 & Anders Frid5 & Mikael Hellström6 & Per Liss7 & Gunnar Sterner8 & Peter Leander1 & on behalf of the Contrast Media Committee of the Swedish Society of Uroradiology and in collaboration with the Swedish Society of Nephrology (GS) and the Swedish Society of Diabetology (AF)
European Society of Radiology 2018
Aside-by-sidecomparisonofupdatedguidelinesregardingcontrastmedium-inducedacutekidneyinjury(CI-AKI)fromtheSwedish Society of Uroradiology (SSUR) and the European Society of Urogenital Radiology (ESUR) is presented. The major discrepancies include a higherglomerular filtration rate (GFR) threshold as a risk factorfor CI-AKI and for discontinuation of metformin by SSUR, i.e., < 45 ml/min versus < 30 ml/min/1.73 m2 by ESUR, when intravenous or intra-arterial contrast media (CM) with second-pass renalexposureisadministered.SSURalsocontinuestorecommendconsiderationoftraditionalnon-renalriskfactorssuchasdiabetes and congestive heart failure, while ESUR considers these factors as non-specific for CI-AKI and does not recommend any consideration. Contrary to ESUR, SSUR also recommends discontinuation of NSAID and nephrotoxic medication if possible. Insufficient evidence at the present time motivates the more cautionary attitude taken by SSUR. Furthermore, SSUR expresses GFR thresholds in absolute values in ml/min as recommended by the National Kidney Foundation for drugs excreted by glomerular filtration, while ESUR uses the relative GFR normalised to body surface area in ml/min/1.73 m2. CM dose/GFR ratio thresholds established for coronary angiography/interventions are also applied as recommendations for CM-enhanced CT by SSUR, since SSUR regards coronary procedures as a second-pass renal exposure of CM with no obvious difference in the incidence of AKI compared with IV CM administration. Finally, SSUR recommends reducing the gram-iodine dose/GFR ratio from < 1.0 in patients not at risk to < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation.
• The more cautionary attitude taken by SSUR compared with that of ESUR is motivated by insufficient evidence regarding risk for contrast medium-induced acute kidney injuries (CI-AKI).
• SSUR recommends that absolute and not relative GFR should be used when dosing drugs eliminated by the kidneys such as contrast media.
• According to SSUR the gram-iodine dose/GFR ratio should be < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation.
From the article
Recent retrospective propensity score-matched controlled studies indicate that the risk of contrast medium- induced acute kidney injury (CI-AKI) after intravenous (IV) contrast media (CM) may have been overestimated. This has motivated the American College of Radiology (ACR), The Royal Australian and New Zealand College of Radiologists (RANZCR)  and the Contrast Media Safety Committee of the European Society of Urogenital Radiology (ESUR)] to lower the CI-AKI risk threshold to 30 ml/min/1.73 m2 at CM-enhanced computed tomography (CT) and omit non- renal risk factors in their updated guidelines. However, an extensive systematic literature review initiated by the Radiological Society of the Netherlands concluded that the level of evidence from these retrospective controlled studies is low. The Contrast Media Committee of the Swedish Society of Uroradiology (SSUR) fears that lowering the CI- AKI risk threshold based on insufficient evidence may Blet the genie out of the bottle^ and has therefore adapted a more conservative attitude in its updated guidelines . The guide- lines also differ in certain other aspects including principles for estimating GFR and the use of GFR to maximise CM doses. The aim of this report is to compare the SSUR guide- lines side by side with the ESUR guidelines, which in many respects are similar to those of ACR and RANZCR, and to present the arguments for the SSUR posi- tion where the standpoints differ.
Summary and conclusions
The major discrepancies regarding the CI-AKI guidelines be- tween SSUR and ESUR include that SSUR
• has a higher GFR threshold as a risk factor for CI-AKI and for discontinuation of metformin, i.e. < 45 ml/min (SSUR) in connection with IV CM administration or IA CM administration with second-pass renal exposure while ESUR has < 30 ml/min/1.73 m2,
• includes traditional non-renal risk factors such as diabetes and congestive heart failure, while ESUR considers them non-specific for CI-AKI,
• recommends discontinuation of NSAID and nephrotoxic medication if possible, while ESUR does not,
• expresses GFR thresholds in absolute values in ml/min while ESUR uses relative GFR in ml/min/1.73 m2 and
• has the same CM dose/GFR ratio thresholds for coronary angiography/interventions and CM-enhanced CT and recommends keeping the gram-iodine dose/GFR ratio < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation.
Insufficient evidence and the unreliability of estimated GFR lie behind the more conservative attitude expressed by SSUR about when a patient should be considered at risk of CI-AKI and a prophylactic regimen should be instituted. Thus, there is a strong need for further prospective studies. Approaches to studying CI-AKI may include careful prospec- tive analysis of the aetiology of PC-AKI in individual cases, restricting propensity score matching to patients receiving CM with various CM dose/GFR ratios at different GFR levels or performing prospective controlled studies in patients for ex- ample with malignant disease scheduled for routine tumour surveillance without and with CM-enhanced CT, but with a week’s interval.
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