Urinary renalase concentration in patients with preserved kidney function undergoing coronary angiography.

Abstract

The purpose of the study was to evaluate urinary renalase concentration before and after coronary angiography/percutaneous coronary interventions (CA/PCI) in patients with coronary artery disease (CAD) and preserved kidney function and verify its potential application as contrast-induced acute kidney injury (CI-AKI) diagnostic marker. This prospective study comprised 95 consecutive patients (69.5% men; median age 65years) with CAD submitted to elective or urgent CA/PCI. Data regarding 128 clinical variables were obtained. Urine samples were collected on admission and 6h after CA/PCI and tested for urinary renalase using ELISA method, which was expressed as renalase-to-creatinine ratio. The CI-AKI diagnosis was based on ≥50% relative or ≥0.3mg/dl absolute increase of serum creatinine concentration 48h following the procedure. Nine patients developed CI-AKI (9.5%). In comparison to baseline values, urinary renalase-to-creatinine ratio significantly decreased 6h following CA/PCI, (2843.6 vs.1540.7ng/mg,P<0.0001). Nine patients developed CI-AKI (9.5%).The reduction of renalase level was profound both in CI-AKI (2709.7 vs. 1585.7ng/mg, P=0.007) and non-CI-AKI group (2814.9 vs.1561.8ng/mg, P<0.0001). There was a trend towards a greater relative decrease of urinary renalase in CI-AKI group (-57.3 vs.-41.8%, P=0.10). Univariate analysis revealed that both pre- and post-procedural urinary renalase did not predict CI-AKI onset; however, absolute decrease of renalase below 25 percentile was a predictor of CI-AKI (OR=5.4, 95% CI:1.3-21.9, P=0.027). Urinary renalase concentration is reduced in the aftermath of CA/PCI, which may be related to CI-AKI development. Further studies are warranted to elucidate the role of urinary renalase as a CI-AKI diagnostic marker.