title: Different methods of hilar clamping during partial nephrectomy: Impact on renal function.
abstract: OBJECTIVE
  To evaluate the impact of different hilar clamping methods on changes in renal function after partial nephrectomy.
  
  
  METHODS
  We analyzed the clinical data of 369 patients who underwent partial nephrectomy for a single renal tumor of size ≤4.0 cm and a normal contralateral kidney. Patients were separated into three groups depending on hilar clamping method: non-clamping, cold ischemia and warm ischemia. Estimated glomerular filtration rate was examined at preoperative, nadir and 1 year postoperatively. Percent change in estimated glomerular filtration rate was used as the parameter to assess the renal functional outcome.
  
  
  RESULTS
  Percent change in nadir estimated glomerular filtration rate in the non-clamping group was significantly less compared with the cold ischemia and warm ischemia groups (P < 0.001). However, no significant differences among the groups were noted in percent change of estimated glomerular filtration rate at 1 year (P = 0.348). The cold ischemia group had a similar serial change of postoperative renal function compared with the warm ischemia group. Percent change in 1-year estimated glomerular filtration rate increased with increasing ischemia time in the cold ischemia (P for trend = 0.073) and warm ischemia groups (P for trend = 0.010). On multivariate analysis, hilar clamping (both warm ischemia and cold ischemia) were significantly associated with percent change in nadir estimated glomerular filtration rate, but not in 1-year estimated glomerular filtration rate.
  
  
  CONCLUSIONS
  Non-clamping partial nephrectomy results in a lower percent change in nadir estimated glomerular filtration rate, whereas it carries an estimated glomerular filtration rate change at 1 year that is similar to partial nephrectomy with cold ischemia and warm ischemia. Cold ischemia and warm ischemia provide a similar effect on renal function. Therefore, when hilar clamping is required, minimization of ischemia time is necessary.
authors.affiliation: Department of Urology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
authors.forename: Jeong Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Hwanik
authors.initials: H
authors.lastname: Kim
authors.forename: Minsoo
authors.initials: M
authors.lastname: Choo
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Park
authors.forename: Ja Hyeon
authors.initials: JH
authors.lastname: Ku
authors.forename: Hyeon Hoe
authors.initials: HH
authors.lastname: Kim
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050377:Cold Ischemia; D003250:Constriction; D005260:Female; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007677:Kidney Function Tests; D007680:Kidney Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000379:methods*; D012189:Retrospective Studies; D052096:Warm Ischemia; D055815:Young Adult
keywords: hilar clamping; ischemia time; partial nephrectomy; renal function; renal tumor