Prediction of contrast-induced acute kidney injury by early post-procedural analysis of urinary biomarkers and intra-renal Doppler flow indices in patients undergoing coronary angiography

Background: The study was designed to evaluate the applicability of combined assessment of urinary biomarkers and intra-renal Doppler flow indices for the prediction of contrast-induced acute kidney injury (CI-AKI) after coronary angiography/percutaneous coronary interventions (CA/PCI). Methods: This prospective observational study covered 95 consecutive patients with coronary artery disease subject to elective or urgent CA/PCI. Doppler intra-renal flow indices were assessed before and 1 h following CA/PCI. Urine samples were collected within 24 h before and 6 h after CA/PCI and assayed for urinary interleukin-18 (IL-18), liver-fatty acid-binding protein (L-FABP), and kidney injury molecule-1 (KIM-1) using ELISA method. CI-AKI was defined as >= 50% relative or >= 0.3 mg/dL absolute increase of serum creatinine concentration at 48 h post-procedurally. Results: CI-AKI was confirmed in nine patients (9.5%). CI-AKI onset was associated with significantly higher urinary KIM-1 at 6 h (P = 0.003) and Delta KIM-1 concentrations (P = 0.001), and urinary IL-18 at 6 h (P = 0.014) and Delta IL-18 concentrations (P = 0.012), however, L-FABP and Delta L-FABP levels were comparable in both groups. Receiver operating characteristic curve analysis denoted that post-procedural IL-18 levels at 6 h >89.8 pg/mg (AUC = 0.75, P = 0.007), KIM-1 at 6 h >0.425 ng/mg (AUC = 0.81, P = 0.001), renal resistive index (RRI) at 1 h >0.73 (AUC 0.88; P < 0.0001), and renal pulsatility index (RPI) at 1 h >0.86 (AUC = 0.86; P < 0.0001) predicted CI-AKI onset. Logistic regression analysis of postoperative predictors revealed that IL-18 and RRI were independent predictors of CI-AKI onset (AUC = 0.96; P < 0.0001). Conclusions: Joint assessment of early post-procedural urinary biomarkers and Doppler renovascular parameters aids early diagnosis of CI-AKI in patients undergoing coronary interventions.