title: Urinary [TIMP-2]*[IGFBP7] for early prediction of acute kidney injury after coronary artery bypass surgery.
abstract: BACKGROUND
  Acute kidney injury (AKI) is a common complication after cardiac surgery. Currently, prediction of AKI with classical tools remains uncertain. Therefore, it was the aim of the present study to evaluate two new urinary biomarkers-insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) in patients after coronary artery bypass surgery (CABG).
  
  
  METHODS
  In a prospective cohort study, 60 consecutive patients undergoing isolated on-pump CABG were enrolled. Urine samples collected every 12 h in the postoperative course were analyzed for the product of TIMP-2 and IGFBP7. Urinary output, serum creatinine and estimated glomerular filtration rate (eGFR) were recorded simultaneously. Primary clinical endpoint was the development of AKI stage 2 or 3 according to the classification of the KDIGO within 48 h after surgery.
  
  
  RESULTS
  48 male and 12 female patients with a mean age of 69.61 ± 8.4 years were included. 19 patients developed an AKI (31.6 %), six patients met the endpoint with AKI 2 or 3 (10 %). Urinary [TIMP-2]*[IGFBP7] increased significantly as early as 4 h after CABG in patients with AKI 2/3 (1.83 ± 2.15 vs. 0.23 ± 0.45, p < 0.05) whereas serum creatinine did not increase until 48 h after surgery. The diagnostic accuracy of [TIMP 2]*[IGFBP7] on day one after surgery for the prediction of AKI 2/3 was significantly better (sensitivity 0.89, specificity 0.81, AUC 0.817, 95 % CI 0.622-1.0 SE 0.099, p = 0.022, cut-off 0.817) than for serum creatinine (AUC 0.359, sensitivity 0.50, specificity of 0.52, cut-off value 1.17 mg/dl) and eGFR.
  
  
  CONCLUSIONS
  Urinary [TIMP-2]*[IGFBP7] represents a sensitive and specific biomarker to predict moderate to severe AKI very early after CABG. Analyses from our ongoing larger study are necessary to confirm these findings and probably increase sensitivity and specificity.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. kevin.pilarczyk@imland.de.
authors.forename: Kevin
authors.initials: K
authors.lastname: Pilarczyk
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Michaela.dudasova@uk-essen.de.
authors.forename: Michaela
authors.initials: M
authors.lastname: Edayadiyil-Dudasova
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Daniel.wendt@uk-essen.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wendt
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Ender.demircioglu@uk-essen.de.
authors.forename: Ender
authors.initials: E
authors.lastname: Demircioglu
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Jaroslav.benedik@uk-essen.de.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Benedik
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Daniel.dohle@uk-essen.de.
authors.forename: Daniel Sebastian
authors.initials: DS
authors.lastname: Dohle
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Heinz.jakob@uk-essen.de.
authors.forename: Heinz
authors.initials: H
authors.lastname: Jakob
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, West German Heart and Vascular Center Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany. Fabian.dusse@uk-essen.de.
authors.forename: Fabian
authors.initials: F
authors.lastname: Dusse
keywords: Acute kidney injury; Biomarker; CABG; Cardiac surgery; Coronary artery bypass surgery; IGFBP7; Insulin-like growth factor-binding protein 7; TIMP-2; Tissue inhibitor of metalloproteinases-2