Postangiography Increases in Serum Creatinine and Biomarkers of Injury and Repair.

Background and Objectives: It is unknown whether iodinated contrast causes kidney parenchymal damage. Biomarkers that are more specific to nephron injury than serum creatinine may provide insight into whether contrast-associated AKI reflects tubular damage. We assessed the association between biomarker changes after contrast angiography with contrast-associated AKI and 90-day major adverse kidney events and death.
Design, Setting, Participants, & Measurements: We conducted a longitudinal analysis of participants from the biomarker substudy of the Prevention of Serious Adverse Events following Angiography trial. We measured injury (kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, IL-18) and repair (monocyte chemoattractant protein-1, uromodulin, YKL-40) proteins from plasma and urine samples at baseline and 2-4 hours postangiography. We assessed the associations between absolute changes and relative ratios of biomarkers with contrast-associated AKI and 90-day major adverse kidney events and death.
Results: Participants ( n =922) were predominately men (97%) with diabetes (82%). Mean age was 70±8 years, and eGFR was 48±13 ml/min per 1.73 m ² ; 73 (8%) and 60 (7%) participants experienced contrast-associated AKI and 90-day major adverse kidney events and death, respectively. No postangiography urine biomarkers were associated with contrast-associated AKI. Postangiography plasma kidney injury molecule-1 and IL-18 were significantly higher in participants with contrast-associated AKI compared with those who did not develop contrast-associated AKI: 428 (248, 745) versus 306 (179, 567) mg/dl; P =0.04 and 325 (247, 422) versus 280 (212, 366) mg/dl; P =0.009, respectively. The majority of patients did not experience an increase in urine or plasma biomarkers. Absolute changes in plasma IL-18 were comparable in participants with contrast-associated AKI (-30 [-71, -9] mg/dl) and those without contrast-associated AKI (-27 [-53, -10] mg/dl; P =0.62). Relative ratios of plasma IL-18 were also comparable in participants with contrast-associated AKI (0.91; 0.86, 0.97) and those without contrast-associated AKI (0.91; 0.85, 0.96; P =0.54).
Conclusions: The lack of significant differences in the absolute changes and relative ratios of injury and repair biomarkers by contrast-associated AKI status suggests that the majority of mild contrast-associated AKI cases may be driven by hemodynamic changes at the kidney.
(Copyright © 2020 by the American Society of Nephrology.)