title: Urinary albumin:creatinine ratio (ACR) and the prediction of postoperative complications after abdominal aortic aneurysm repair.
abstract: BACKGROUND
  Open repair of abdominal aortic aneurysm (AAA) requires aortic clamping. This results in an ischaemia-reperfusion injury (IRI) which can lead to the development of the systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF). We investigated the use of urinary albumin:creatinine ratio (ACR) as a simple predictor of the development of complications (SIRS) postoperatively.
  
  
  METHODS
  Forty-four patients undergoing elective infrarenal AAA repair and 10 control patients undergoing major abdominal surgery had fresh urine samples taken before, immediately after and 24 h after the procedure. Urinary ACR was calculated on all samples, and daily SIRS scores were calculated for all patients postoperatively. Systemic interleukin-6 (IL-6) levels were measured intraoperatively to measure the cytokine response to surgery.
  
  
  RESULTS
  AAA patients demonstrated a characteristic pattern of ACR levels during the three time points, with a significant increase in the ACR immediately postoperatively and with normalisation by 24 h (P<0.001 Wilcoxon signed ranks test). In comparison, control patients did not demonstrate any changes in their ACR (P=0.45 Wilcoxon signed ranks test) suggesting the increased ACR in AAA patients to occur as a result of IRI. ACR did not correlate with the development of SIRS postoperatively or with the systemic IL-6 response.
  
  
  CONCLUSIONS
  Infrarenal AAA repair is associated with a temporary and reversible renal injury. ACR could not, however, be used as a predictor of complications postoperatively.
authors.affiliation: Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, UK. mgan2@le.ac.uk
authors.forename: M G A
authors.initials: MG
authors.lastname: Norwood
authors.forename: R D
authors.initials: RD
authors.lastname: Sayers
mesh_terms: D000419:Albuminuria / Q000150:complications*; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D016022:Case-Control Studies; D003404:Creatinine / Q000652:urine*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D007432:Intraoperative Period; D007668:Kidney / Q000098:blood supply / Q000502:physiology; D011183:Postoperative Complications / Q000652:urine*; D011184:Postoperative Period; D011300:Preoperative Care; D015424:Reperfusion
chemical_list: D015850:Interleukin-6; D003404:Creatinine