title: The incidence and risk factors of acute kidney injury after hepatobiliary surgery: a prospective observational study.
abstract: BACKGROUND
  Although intraperitoneal surgery is a major operation associated with postoperative acute kidney injury (AKI), the incidence, risk factors, and long-term renal outcome are not well known. We aimed to determine the risk factors and 6 months renal outcome in patients with clinical or subclinical AKI after hepatobiliary surgery. We also assessed the validity of urine neutrophil gelatinase-associated lipocalin (NGAL) in the early detection of AKI or prediction of renal outcome.
  
  
  METHODS
  This prospective observational study enrolled patients with normal renal function who underwent hepatobiliary surgeries. Urine and serum samples were collected for NGAL measurement.
  
  
  RESULTS
  Among 131 patients, 10 (7.6%) developed postoperative AKI. Urine NGAL at 12 h postsurgery was the most predictive parameter for the diagnosis of AKI (cutoff, 92.85 ng/mL). With the cutoff value, subclinical AKI was diagnosed in 42 (32.1%) patients. Patients with clinical AKI and those with subclinical AKI were assigned to the AKI group. The AKI group had significantly higher model for end-stage liver disease and sodium (MELD-Na) score, lower albumin level, and longer hospital stay after surgery than the non-AKI group. Older age and higher MELD-Na score were independent risk factors for the development of postoperative AKI. At 6 months postsurgery, the estimated glomerular filtration rate (eGFR) in the AKI group was significantly lower than that in the non-AKI group, although the baseline eGFR was not different. In multiple linear regression analysis, the maximum urine NGAL level during 24 h postsurgery, intraoperative fluid balance, and having liver transplantation were significantly associated with a poor 6 months renal outcome.
  
  
  CONCLUSIONS
  Urine NGAL was useful in the early diagnosis of postoperative AKI as well as in predicting the 6 months renal outcome after hepatobiliary surgery. A considerable proportion of patients developed subclinical AKI, and these patients showed worse renal outcome compared with the non-AKI group.
authors.forename: Eunjung
authors.initials: E
authors.lastname: Cho
authors.forename: Sun-Chul
authors.initials: SC
authors.lastname: Kim
authors.forename: Myung-Gyu
authors.initials: MG
authors.lastname: Kim
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Korea University Anam Hospital, 5Ka, Anam-Dong, Sungbuk-Gu, Seoul 136-705, Korea. sang-kyung@korea.ac.kr.
authors.forename: Sang-Kyung
authors.initials: SK
authors.lastname: Jo
authors.forename: Won-Yong
authors.initials: WY
authors.lastname: Cho
authors.forename: Hyoung-Kyu
authors.initials: HK
authors.lastname: Kim
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology* / Q000652:urine; D000209:Acute-Phase Proteins / Q000652:urine; D000419:Albuminuria / Q000453:epidemiology; D001662:Biliary Tract Surgical Procedures; D015415:Biomarkers; D017558:Elective Surgical Procedures; D005919:Glomerular Filtration Rate; D006498:Hepatectomy; D006801:Humans; D015994:Incidence; D007902:Length of Stay / Q000706:statistics & numerical data; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood / Q000652:urine; D008103:Liver Cirrhosis / Q000601:surgery; D008113:Liver Neoplasms / Q000556:secondary / Q000601:surgery; D016031:Liver Transplantation / Q000706:statistics & numerical data; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000097:blood / Q000652:urine; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins