Partial nephrectomy aims to maintain renal function by nephron sparing; however, functional changes in the contralateral kidney remain unknown. We evaluate the functional change in the contralateral kidney using a diethylene triamine penta-acetic acid (DTPA) renal scan and determine factors predicting contralateral kidney function after partial nephrectomy. A total of 699 patients underwent partial nephrectomy, with a DTPA scan before and after surgery to assess the separate function of each

more »

... ney. Patients were divided into three groups according to initial contralateral glomerular filtration rate (GFR; group 1: Ͻ30 ml·min Ϫ1 ·1.73 m Ϫ2 , group 2: 30 -45 ml·min Ϫ1 ·1.73 m Ϫ2 , and group 3: Ն45 ml·min Ϫ1 ·1.73 m Ϫ2 ). Multiple-regression analysis was used to identify the factors associated with increased GFR of the contralateral kidney over a 4-yr postoperative period. Patients in group 1 had a higher mean age and hypertension history, worse American Society of Anesthesiologists score, and larger tumor size than in the other two groups. The ipsilateral GFR changes at 4 yr after partial nephrectomy were Ϫ18.9, Ϫ3.6, and 3.9% in groups 1, 2, and 3, respectively, whereas the contralateral GFR changes were 10.8, 25.7, and 38.8%. Age [␤: Ϫ0.105, 95% confidence interval (CI): Ϫ0.213; Ϫ0.011, P Ͻ 0.05] and preoperative contralateral GFR (␤: Ϫ0.256, 95% CI: Ϫ0.332; Ϫ0.050, P Ͻ 0.01) were significant predictive factors for increased GFR of the contralateral kidney after 4 yr. The contralateral kidney compensated for the functional loss of the ipsilateral kidney. The increase of GFR in contralateral kidney is more prominent in younger patients with decreased contralateral renal function.