title: Ipsilateral renal function preservation after robot-assisted partial nephrectomy (RAPN): an objective analysis using mercapto-acetyltriglycine (MAG3) renal scan data and volumetric assessment.
abstract: OBJECTIVE
  To objectively assess ipsilateral renal function (IRF) preservation and factors influencing it after robot-assisted partial nephrectomy (RAPN).
  
  
  METHODS
  Our database was queried to identify patients who had undergone RAPN from 2007 to 2013 and had complete pre- and postoperative mercapto-acetyltriglycine (MAG3) renal scan assessment. The estimated glomerular filtration rate (eGFR) for the operated kidney was calculated by multiplying the percentage of contribution from the renal scan by the total eGFR. IRF preservation was defined as a ratio of the postoperative eGFR for the operated kidney to the preoperative eGFR for the operated kidney. The percentage of total eGFR preservation was calculated in the same manner (postoperative eGFR/preoperative eGFR × 100). The amount of healthy rim of renal parenchyma removed was assessed by deducting the volume of tumour from the volume of the PN specimen assessed on pathology. Multivariable linear regression was used for analysis.
  
  
  RESULTS
  In all, 99 patients were included in the analysis. The overall median (interquartile range) total eGFR preservation and IRF preservation for the operated kidney was 83.83 (75.2-94.1)% and 72 (60.3-81)%, respectively (P < 0.01). On multivariable analysis, volume of healthy rim of renal parenchyma removed, warm ischaemia time (WIT) > 30 min, body mass index (BMI) and operated kidney preoperative eGFR were predictive of IRF preservation.
  
  
  CONCLUSIONS
  Using total eGFR tends to overestimate the degree of renal function preservation after RAPN. This is particularly relevant when studying factors affecting functional outcomes after nephron-sparing surgery. IRF may be a more precise assessment method in this setting. Operated kidney baseline renal function, BMI, WIT >30 min, and amount of resected healthy renal parenchyma represent the factors with a significant impact on the IRF preservation. RAPN provides significant preservation of renal function as shown by objective assessment criteria.
authors.affiliation: Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Homayoun
authors.initials: H
authors.lastname: Zargar
authors.forename: Oktay
authors.initials: O
authors.lastname: Akca
authors.forename: Riccardo
authors.initials: R
authors.lastname: Autorino
authors.forename: Luis Felipe
authors.initials: LF
authors.lastname: Brandao
authors.forename: Humberto
authors.initials: H
authors.lastname: Laydner
authors.forename: Jayram
authors.initials: J
authors.lastname: Krishnan
authors.forename: Dinesh
authors.initials: D
authors.lastname: Samarasekera
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stein
authors.forename: Jihad H
authors.initials: JH
authors.lastname: Kaouk
mesh_terms: D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000033:anatomy & histology / Q000502:physiology*; D007677:Kidney Function Tests / Q000379:methods; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000379:methods*; D009929:Organ Size; D011184:Postoperative Period; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D065287:Robotic Surgical Procedures; D017263:Technetium Tc 99m Mertiatide
chemical_list: D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide
keywords: functional outcome; nephron-sparing surgery; renal function preservation; renal scan; robot-assisted partial nephrectomy