Clinical and histologic predictors of renal function decline after laparoscopic partial nephrectomy

Background and Purpose: Clinical and surgical factors predict renal function decline after laparoscopic partial nephrectomy (LPN). Additional histopathologic predictors may be found in the specimen's nonneoplastic tissue but were not studied. This study investigated the significance of histologic findings in addition to other known predictors of renal function after LPN. Patients and Methods: Data of 150 patients who underwent LPN was analyzed. Renal function changes (median follow-up 15 months) were correlated with perioperative and histopathologic parameters. Three histopathologic features were evaluated and graded in the nonneoplastic parenchyma: Glomerulosclerosis, arteriosclerosis (AS), and interstitial fibrosis/tubular atrophy. Estimated GFR (eGFR) and percent decline on postoperative day 1 (POD1) and at the last follow-up were measured. Results: Median eGFR percent decline at POD1 and last follow-up was -17 and -10, respectively (P<0.001). New-onset ≥stage III chronic kidney disease developed in only 7% of the patients. Three factors independently predicted POD1 eGFR decline: Artery and vein clamping vs artery only clamping (P=0.002), male sex (P=0.015), and larger tumor (P=0.02). Long-term loss of renal function was associated with POD1 eGFR decline (P=0.002) and the percentage of AS (P=0.01). The study limitations include a retrospective analysis leading to variability in the follow-up length and a small size cohort. Conclusions: LPN is associated with a favorable renal function outcome in most patients. Pathologic findings in the nonneoplastic tissue, in addition to clinical parameters, can be used to predict which patients are more likely to experience renal function impairment.