title: Infrarenal aortic-clamping after renal ischaemia aggravates acute renal failure.
abstract: BACKGROUND
  Renal failure is a frequent complication of juxtarenal abdominal aortic aneurysm (JAA)-repair. During this operation, suprarenal aortic-clamping is followed by infrarenal aortic-clamping (below renal arteries) to restore renal flow, while performing the distal anastomosis. We hypothesized that infrarenal aortic-clamping, despite restoring renal perfusion provokes additional renal damage.
  
  
  METHODS
  We studied three groups of rats. After 45min of suprarenal aortic-clamping, group 1 had renal reperfusion for 90min without aortic-clamps (n=7). In group 2, 45min of suprarenal aortic-clamping with a distal clamp on the aortic-bifurcation was followed by 20min of infrarenal aortic-clamping. Renal reperfusion was continued for 70min without aortic-clamps (i.e. 90 min of renal reperfusion; n=8). The sham-group had no clamps (n=7). We measured renal haemodynamics, functional parameters and tissue damage.
  
  
  RESULTS
  On suprarenal aortic-clamp removal, renal artery flow, cortical flow and arterial pressures were higher in group 2 than in group 1. We detected increased tubular brush border damage, luminal lipocalin-2 and 30-60% higher renal protein nitrosylation in group 2 when compared to group 1 (P<0·05). Group 2 showed more release of asymmetrical dimethylarginine (ADMA) from the kidneys in the renal vein, therefore indicating diminished clearing capacity (P<0·001). Arginine/ADMA-ratio, which defines the bio-availability of nitric oxide, tended to be lower in group 2 and correlated with renal flow. Furthermore, there were no significant differences found in creatinine levels and renal leucocyte accumulation between group 1 and 2.
  
  
  CONCLUSIONS
  Additional infrarenal aortic-clamping leads to increased renal damage and oxidative stress, despite adequate perfusion of kidneys after suprarenal aortic-clamping. This study indicates that the clamping sequence used in JAA-repair causes more than simple renal I/R-injury.
authors.affiliation: Department of Surgery, VU University Medical Center (VUmc), Amsterdam, The Netherlands. kakkhee.yeung@gmail.com
authors.forename: Kak K
authors.initials: KK
authors.lastname: Yeung
authors.forename: Milan
authors.initials: M
authors.lastname: Richir
authors.forename: Paul
authors.initials: P
authors.lastname: Hanrath
authors.forename: Tom
authors.initials: T
authors.lastname: Teerlink
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Kompanowska-Jezierska
authors.forename: Renė J P
authors.initials: RJ
authors.lastname: Musters
authors.forename: Paul A M
authors.initials: PA
authors.lastname: van Leeuwen
authors.forename: Willem
authors.initials: W
authors.lastname: Wisselink
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Tangelder
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology* / Q000473:pathology; D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D016022:Case-Control Studies; D003250:Constriction; D003404:Creatinine; D007511:Ischemia / Q000601:surgery*; D007668:Kidney / Q000098:blood supply; D007962:Leukocytes; D011183:Postoperative Complications; D051381:Rats; D012077:Renal Artery / Q000503:physiopathology / Q000601:surgery*; D015424:Reperfusion / Q000009:adverse effects; D014656:Vascular Surgical Procedures / Q000009:adverse effects*
chemical_list: D003404:Creatinine