title: Factors affecting renal function after open partial nephrectomy-a comparison of clampless and clamped warm ischemic technique.
abstract: OBJECTIVE
  To analyze factors impacting postoperative renal function after open partial nephrectomy using both the clampless and clamped warm-ischemic technique.
  
  
  METHODS
  We studied a cohort of patients who underwent clamped partial nephrectomy (n = 164) and clampless partial nephrectomy (n = 64) from March 2002 to March 2009 with ≥ 12-months follow-up. Clamped partial nephrectomy used hilar occlusion before resection. Clampless partial nephrectomy used focal radio frequency coagulation to facilitate hemostasis before resection, nonischemic dissection/resection with hydro-dissection, or sharp resection after local compression. Demographics, tumor characteristics/RENAL nephrometry scores, perioperative variables, and complications were compared between the two methods. Multivariable analysis was performed to identify factors predicting de novo estimated glomerular filtration rate <60.
  
  
  RESULTS
  Patient characteristics were similar between groups. Mean RENAL score was greater in clamped (6.9) vs clampless (6.4, P = .026); complications (P = .430) and urine leaks (clampless partial nephrectomy 3.1% vs clamped-PN 7.3%, P = .360) were similar. Mean warm ischemia time (min) was 24.5 for clamped partial nephrectomy. De novo estimated glomerular filtration rate <60(%) at last follow up was 13.5 (clamped) vs 3.1 (clampless) (P = .071). Multivariable analysis of the entire cohort revealed increasing body mass index (OR 1.1, P = .042) and RENAL score (OR 1.71, P = .002) as being independently associated with development of postoperative de novo estimated glomerular filtration rate <60. Multivariable analysis of the clamped subgroup demonstrated increasing body mass index (OR 1.12, P = .028), RENAL score (OR 1.56, P = .010), and ischemia time (OR 1.15, P = .042) as independent factors associated with de novo estimated glomerular filtration rate <60.
  
  
  CONCLUSIONS
  Body mass index and RENAL score were factors predictive of development of de novo estimated glomerular filtration rate <60 after partial nephrectomy, with increasing warm ischemia time also being predictive in clamped partial nephrectomy patients. Further investigation and long-term functional data are requisite.
authors.affiliation: Division of Urology, Department of Surgery, University of California, San Diego School of Medicine, La Jolla, CA 92093-0987, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Kopp
authors.forename: Reza
authors.initials: R
authors.lastname: Mehrazin
authors.forename: Kerrin
authors.initials: K
authors.lastname: Palazzi
authors.forename: Wassim M
authors.initials: WM
authors.lastname: Bazzi
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Patterson
authors.forename: Ithaar H
authors.initials: IH
authors.lastname: Derweesh
mesh_terms: D000328:Adult; D000368:Aged; D016063:Blood Loss, Surgical; D015992:Body Mass Index; D003250:Constriction; D005260:Female; D005919:Glomerular Filtration Rate; D006488:Hemostasis, Surgical; D006801:Humans; D007668:Kidney / Q000503:physiopathology* / Q000601:surgery*; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009392:Nephrectomy / Q000009:adverse effects / Q000379:methods*; D059351:Organ Sparing Treatments; D051436:Renal Insufficiency, Chronic / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D052096:Warm Ischemia / Q000009:adverse effects / Q000379:methods*