Renal Function is Associated with Nephrometry Score After Partial Nephrectomy: A Study Using Diethylene Triamine Penta-Acetic Acid (DTPA) Renal Scanning

Purpose. The aim of this study was to evaluate the effect of renal tumor anatomical characteristics on renal function change after partial nephrectomy using the scoring systems and the glomerular filtration rate (GFR) estimated from diethylene triamine penta-acetic acid (DTPA) scans. Methods. Patients who underwent DTPA renal scans before and after partial nephrectomy from January 2009 to December 2011 were identified retrospectively. The anatomical characteristics of renal tumors were standardized using the RENAL, PADUA and C-index scoring systems. Associations between scoring systems and change in GFRs were evaluated using a correlation coefficient. Predictors of GFR change and postoperative new-onset chronic kidney disease (CKD) after partial nephrectomy were assessed. Results. A total of 185 patients with a mean tumor size of 2.6 cm (median 2.3, range 0.5-10) were identified. Mean ischemia time was 21.5 min. The last DTPA renal scan was performed at a mean follow-up duration of 23.3 months after surgery, and the mean decrease in GFR was 8.1 ml/min. By multivariable analysis, preoperative GFR (beta = -039; p < 0.001), RENAL complexity score (beta = -5.32; p < 0.001), and C-index complexity (beta = -5.19; p < 0.001) were independent predictors of decreased GFR on DTPA. Of 175 patients in whom preoperative estimated GFR (eGFR) was > 60 ml/min/1.73 m(2), CKD developed in 14 (8 %) patients after surgery. Independent factors predicting new-onset CKD were preoperative eGFR (odds ratio [OR] 0.91; p = 0.047), age (OR 1.13; p = 0.003), and diabetes (OR 5.10; p = 0.038). Conclusions. Although each scoring system describing the complexity of renal tumors correlates with change in GFR after partial nephrectomy, RENAL and C-index score were significantly predictive of GFR reduction.