Contrast-Induced AKI Prevention (ACR/NKF)

Algorithm Steps

1. ▶

   Start

   Contrast Study Planned

   Patient to receive iodinated contrast media

   1. ●

      Action

      Assess Kidney Function

      Check eGFR (within 3-6 months if stable)

      • Use CKD-EPI 2021 equation
      • If AKI suspected, use most recent creatinine
      • Consider point-of-care creatinine if urgent
      1. ◆

         Decision

         eGFR-Based Risk

         Stratify CI-AKI risk by kidney function

         • Low risk: eGFR ≥45 (IV) or ≥30 (IV without risk factors)
         • Moderate risk: eGFR 30-44
         • High risk: eGFR <30 or AKI or dialysis-dependent
         1. ●

            Action

            Low Risk (eGFR ≥45)

            Minimal CI-AKI risk with IV contrast

            • IV contrast: Proceed without specific prophylaxis
            • Intra-arterial with renal first-pass: Consider if eGFR ≥30
            • Encourage oral hydration if able
            • No nephrotoxin hold needed routinely
            1. ●

               Action

               Proceed with Contrast

               Implement prevention protocol

               • Pre-hydration: NS 1 mL/kg/hr × 6-12h (or 3 mL/kg × 1h if urgent)
               • Use iso-osmolar (iodixanol) or low-osmolar contrast
               • Minimize volume (contrast/eGFR ratio <3.7)
               • Post-hydration: Continue 6-12h
               • Hold nephrotoxins (NSAIDs, aminoglycosides)
               • Hold metformin for 48h or until Cr stable
               1. ●

                  Action

                  Post-Contrast Monitoring

                  Assess for CI-AKI development

                  • Recheck creatinine at 48-72h post-contrast
                  • CI-AKI definition: SCr rise ≥0.3 mg/dL or ≥50% within 48-72h
                  • Most cases self-limited, peak at 3-5 days
                  • Resume metformin if creatinine stable
                  • Nephrology follow-up if CI-AKI develops
                  1. ✓

                     Outcome

                     No CI-AKI

                     Creatinine stable at 48-72h

                  2. ✓

                     Outcome

                     CI-AKI Developed

                     Supportive care, avoid repeat contrast, nephrology if severe

         2. ●

            Action

            Moderate Risk (eGFR 30-44)

            Prophylactic measures recommended

            • IV hydration: 1-1.5 mL/kg/hr NS starting 3-12h pre-procedure
            • Continue 6-12h post-procedure
            • Use lowest contrast volume possible
            • Consider iso-osmolar contrast
            • Hold metformin day of procedure
            1. ◆

               Decision

               Benefit vs Risk Assessment

               Is contrast study essential?

               • Clinical urgency of diagnosis
               • Alternative imaging modalities
               • Patient preference and goals of care
               • Discuss with radiology
               1. ●

                  Action

                  Defer/Alternative Imaging

                  Avoid contrast if possible

                  • Non-contrast CT may suffice
                  • MRI with gadolinium (different risk profile if eGFR ≥30)
                  • Ultrasound
                  • Nuclear medicine studies
                  • Reassess need for contrast study
         3. ⚠

            Warning

            High Risk (eGFR <30 or AKI)

            Significant CI-AKI risk - careful assessment

            • Consider alternative imaging (non-contrast CT, MRI, US)
            • If contrast essential: Nephrology consult
            • Aggressive IV hydration protocol
            • Minimize contrast volume (<100 mL or <4 mL/kg)
            • Use iso-osmolar or low-osmolar contrast
            • Consider N-acetylcysteine (evidence weak)
            1. ●

               Action

               Dialysis-Dependent

               Different considerations for ESRD on HD

               • Not at risk for CI-AKI (no kidney function to protect)
               • Proceed with contrast if indicated
               • Coordinate with dialysis schedule
               • No need for emergent dialysis post-contrast
               • Timing dialysis around contrast does not reduce risk