title: Preoperative Renal Volume: A Surrogate Measure for Radical Nephrectomy-Induced Chronic Kidney Disease.
abstract: OBJECTIVE
  Surgically induced chronic kidney disease (CKD) has been found to have less impact on survival as well as function when compared to medical causes for CKD. The aim of this study is to evaluate whether preoperative remaining kidney volume correlates with renal function after nephrectomy, which represents an individual's renal reserve before surgically induced CKD.
  
  
  METHODS
  A retrospective review of 75 consecutive patients (29.3% females) who underwent radical nephrectomy (RN) (2000-2010) was performed. Normal side kidney parenchyma, excluding renal vessels and central sinus fat, was manually outlined in each transverse slice of CT image and multiplied by slice thickness to calculate volume. Estimated glomerular filtration rate (eGFR) was determined using the Modification of Diet in Renal Disease equation. CKD is defined as eGFR < 60 mL/min/1.73 m(2).
  
  
  RESULTS
  Mean preoperative normal kidney parenchymal volume (mean age 55 [SD 13] years) is 150.7 (SD 36.4) mL. Over median follow-up of 36 months postsurgery, progression to CKD occurred in 42.6% (n = 32) of patients. On multivariable analysis, preoperative eGFR and preoperative renal volume <144 mL are independent predictors for postoperative CKD. On Kaplan-Meier analysis, median time to reach CKD postnephrectomy is 12.7 (range 0.03-43.66) months for renal volume <144 mL but not achieved if renal volume is >144 mL.
  
  
  CONCLUSIONS
  Normal kidney parenchymal volume and preoperative eGFR are independent predictive factors for postoperative CKD after RN and may represent renal reserve for both surgically and medically induced CKD, respectively. Preoperative remaining kidney volume may be an adjunct representation of renal reserve postsurgery and predict later renal function decline due to perioperative loss of nephrons.
authors.affiliation: 1 Department of Urology, National University Health System , Singapore, Singapore .
authors.forename: Fiona Mei Wen
authors.initials: FM
authors.lastname: Wu
authors.affiliation: 1 Department of Urology, National University Health System , Singapore, Singapore .
authors.forename: Melissa Hui Wen
authors.initials: MH
authors.lastname: Tay
authors.affiliation: 2 Saw Swee Hock School of Public Health, National University of Singapore , Singapore, Singapore .
authors.forename: Bee Choo
authors.initials: BC
authors.lastname: Tai
authors.affiliation: 3 Investigational Medicine Unit, National University Health System , Singapore, Singapore .
authors.forename: Zhaojin
authors.initials: Z
authors.lastname: Chen
authors.affiliation: 1 Department of Urology, National University Health System , Singapore, Singapore .
authors.forename: Lincoln
authors.initials: L
authors.lastname: Tan
authors.affiliation: 1 Department of Urology, National University Health System , Singapore, Singapore .
authors.forename: Benjamin Yen Seow
authors.initials: BY
authors.lastname: Goh
authors.affiliation: 1 Department of Urology, National University Health System , Singapore, Singapore .
authors.forename: Lata
authors.initials: L
authors.lastname: Raman
authors.affiliation: 1 Department of Urology, National University Health System , Singapore, Singapore .
authors.forename: Ho Yee
authors.initials: HY
authors.lastname: Tiong
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000601:surgery*; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D007680:Kidney Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000009:adverse effects*; D009929:Organ Size; D011184:Postoperative Period; D057234:Preoperative Period; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed