Introduction

Partial nephrectomy aims to maintain renal function by nephron sparing. However, the functional change of contralateral kidney remains to be known. We evaluated the functional change in contralateral kidney using DTPA renal scan and determined the predicting factors of contralateral kidney function after partial nephrectomy.

Methods

From 2001 to 2012, 699 patients underwent partial nephrectomy and we performed DTPA renal scan before and after surgery in all patients to assess the exact renal function of each kidney. Patients were divided into 3 groups according to initial contralateral glomerular filtration rate (GFR) (group 1: <30ml/min/1.73m2, group 2: 30~45ml/min/1.73m2, and group 3: ≥45ml/min/1.73m2). We evaluated separate renal functions using DTPA up to 5 year after surgery. Logistic regression analysis was used to identify the factors associated with increased GFR of contralateral kidney. Kaplan-Meier method was used for overall survival. Median follow-up period was 45.1 month.

Results

Patients of group 1 were older age (64.2±9.8 vs 55.0±11.0 vs 48.0±9.5, p<0.001), more hypertension history (59.5% vs 39.3% vs 20.9%, p<0.001), worse American society of anesthesiologists (ASA) score (≥2; 94.0% vs 89.5% vs 80.2%, p<0.001), and shorter ischemic time (19.9±8.0 vs 22.3±8.7 vs 22.8±8.9, p=0.025) among three groups (respectively). Tumor size, resected weight, RENAL nephrometry score and ischemic type were not different among three groups (p=0.293, p=0.255, p=0.582 and p=0.967, respectively). The mean ipsilateral GFR changes were -7.5%, -1.6%, and -21.2% in group 1, 2, and 3, respectively and contralateral GFR changes were 33.9%, 19.9%, and 7.3% in group 1, 2, and 3, respectively at 5 year after partial nephrectomy. On multivariable analysis, ASA score (OR 0.54, 95% confidence interval [CI] 0.31-0.92 p=0.0277) and preoperative contralateral GFR (OR 0.97, 95% CI 0.95-0.99 p=0.0011) were the significant predictive factors for increased GFR of contralateral kidney within 5 years. 5 year overall survival rates were 86.1%, 93.1% and 97.4% in group 1, 2, 3, respectively.

Conclusions

Contralateral kidney compensated for the functional loss of ipsilateral kidney. The increase of GFR in contralateral kidney is more prominent in healthy patients with decreased contralateral renal function.

Funding

none