Split Renal Function in Patients with Renal Masses: Utility of Parenchymal Volume Analysis versus Nuclear Renal Scans.

To evaluate the utility of parenchymal volume analyses (PVA) for estimation of split-renal function (SRF) in patients with renal masses. SRF is important for deciding about partial versus radical nephrectomy (PN/RN) and assessing risk for developing severe chronic-kidney disease after surgery. For renal donors PVA is routinely used to estimate SRF, but the utility of PVA for the more complex renal mass population remains undefined.

All patients (n=374) with renal tumors and normal contralateral kidney managed with PN (2010-2018) with preoperative/postoperative nuclear-renal scans (NRS) and cross-sectional imaging were analyzed. Parenchymal-volumes were measured by freehand-scripting or software analysis. Concordance between ipsilateral estimated-glomerular filtration rate (eGFR) values based on SRF from NRS versus PVA were evaluated by Pearson-correlation and Bland-Altman plots. Parallel analysis of all 155 patients managed with RN at our center (2006-2016) with preoperative NRS and imaging was also performed.

For PN, median age and tumor size were 62 years and 3.4cm, respectively. Median preoperative ipsilateral parenchymal volume and eGFR were 181cm3 and 36.9ml/min/1.73m2 , respectively. Parenchymal volumes estimated by free-hand scripting versus software analyses correlated strongly (r=0.98, p<0.001). Preoperative ipsilateral eGFR based on SRF from PVA versus NRS also correlated strongly (r=0.94, p<0.001). Ipsilateral eGFR saved after PN correlated strongly with parenchymal volume preserved (all r>0.60); however, the correlation was much stronger when ipsilateral eGFRs were based on SRF from PVA rather than NRS (z-statistic=3.15, p=0.002). For RN patients, preoperative eGFR in the contralateral kidney based on SRF from PVA versus NRS also correlated strongly (r=0.87, p<0.001).

PVA has utility for estimation of SRF in patients with renal masses, even though this population is older and more comorbid than renal donors, and the tumor(s) can complicate the analysis. PVA can be obtained by software-analysis from preoperative cross-sectional imaging and thus readily incorporated into routine clinical practice.

BJU international. 2020 Jan 23 [Epub ahead of print]

Yunlin Ye, Hajime Tanaka, Yanbo Wang, Rebecca A Campbell, Diego Aguilar Palacios, Molly E DeWitt-Foy, Furman A Mahmood, Mohamed Eltemamy, Erick M Remer, Jianbo Li, Steven C Campbell

Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH.