MP63-02 HOW A DONOR NEPHRECTOMY POPULATION CAN HELP CLARIFY THE EFFECTS OF WARM RENAL ISCHEMIA DURING PARTIAL NEPHRECTOMY

Abstract

INTRODUCTION AND OBJECTIVES: The most important modifiable risk factors for kidney function after partial nephrectomy (PN) are the quantity of parenchyma removed and the length of warm ischemia time (WIT) although the relative importance of these two factors has been debated. In this study, the effects of WIT on renal function were investigated by comparing PN patients to completely healthy patients undergoing donor nephrectomy (DN). METHODS: A retrospective review was performed of 119 PN and 250 DN patients at a single academic institution. Baseline characteristics, WIT, and follow-up serum creatinine (sCr) at discharge, 1- 7months and at last follow-up were compared. Estimated GFR (eGFR) was calculated using sCr and the Modification of Diet on Renal Disease (MDRD) formula. Data was analyzed using the Mann-Whitney U and Chi-square tests as appropriate. RESULTS: The DN patients were younger (37.5 vs. 60.8; p<0.01), had lower BMI (26.6 vs. 30.9; p<0.01), lower ASA scores (p<0.01) and higher preoperative eGFR (101.7 vs. 78.4; p<0.01). In the PN cohort, the median tumor size was 3.6 cm and mean WIT was 27.8 minutes. DN patients were found to have greater eGFR decline upon discharge (-42.7% vs. -1.5%, p<0.01), at 1-7 mos postoperatively (-36.9% vs. -6.4%; p<0.01) and at the latest followup (-36.3% vs. -2.4%; p<0.01). The percentage decrease in eGFR was also significantly greater in donor nephrectomy patients than partial nephrectomy patients with WIT > 30 minutes at all time points including discharge (-42.7% vs. -4.1%; p<0.01) at 1-7 mos (-36.9% vs. -3.8%; p<0.01) and at latest follow-up (-36.3% vs. -6.9%; p<0.01). CONCLUSIONS: Despite being younger and healthier, the donors had a much greater decrease in GFR than all PN patients including those with > 30 min WIT. This dramatic benefit of partial nephrectomy compared with radical nephrectomy in all patients emphasizes the benefit to GFR derived from renal parenchymal preservation. Surgeons should utilize warm renal ischemia when indicated if it facilitates the preservation of renal parenchyma.