No increase in Kidney Injury Molecule-1 and Neutrophil Gelatinase-Associated Lipocalin excretion following intravenous contrast enhanced-CT.

Objectives: To analyze kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (N-GAL) excretion post-intravenous contrast enhanced-CT (CE-CT) in patients with chronic kidney disease (CKD).

Methods: Patients were enrolled in a trial on hydration regimes to prevent contrast-induced acute kidney injury (CI-AKI). Blood and urine samples were taken at baseline, 4 - 6, and 48 - 96 h post CE-CT. Urinary KIM-1 and N-GAL values were normalized for urinary creatinine levels, presented as medians with 2.5 - 97.5 percentiles.

Results: Of the enrolled 511 patients, 10 (2%) were lost to follow-up. CI-AKI occurred in 3.9% of patients (20/501). Median KIM-1 values were 1.2 (0.1 - 7.7) at baseline, 1.3 (0.1 - 8.6) at 4 - 6 h, and 1.3 ng/mg (0.1 - 8.1) at 48 - 96 h post CE-CT (P = 0.39). Median N-GAL values were 41.0 (4.4 - 3,174.4), 48.9 (5.7 - 3,406.1), and 37.8 μg/mg (3.5 - 3,200.4), respectively (P = 0.07). The amount of KIM-1 and N-GAL excretion in follow-up was similar for patients with and without CI-AKI (P-value KIM-1 0.08, P-value N-GAL 0.73). Neither patient characteristics at baseline including severe CKD, medication use, nor contrast dose were associated with increased excretion of KIM-1 or N-GAL during follow-up.

Conclusion: KIM-1 and N-GAL excretion were unaffected by CE-CT both in patients with and without CI-AKI, suggesting that CI-AKI was not accompanied by tubular injury.

Key Points: • KIM-1 and N-GAL excretion were unaffected by intravenous contrast-enhanced CT (CE-CT). • Patient or procedure characteristics were not associated with increased KIM-1 or N-GAL excretion. • Performance of CE-CT in CKD patients is likely to be safe.