MP68-03 THE HEALTHIER THE PATIENT, THE LONGER THE ISCHEMIA

Abstract

INTRODUCTION AND OBJECTIVE: Ischemia time [IT] during partial nephrectomy (PN) is among the greatest determinant of acute kidney injury (AKI). Whether this association is affected by preoperative risk of AKI has never been investigated. We aimed to assess the interaction between preoperative risk of AKI and IT on the probability of AKI during PN. METHODS: Data of 944 patients treated with on-clamp PN for cT1 renal masses between 2013 and 2016 were extracted from the RECORd2 prospective multicentre database. AKI was defined according to the RIFLE criteria. We estimated the preoperative risk of AKI according to age, baseline estimated glomerular function rate (eGFR), clinical stage, PADUA score and surgical approach. The coefficients from multivariable model were used to build a nomogram for the prediction of AKI. Classification and regression tree (CART) analysis identified patients at “high” and “low” risk of AKI. Finally, we plotted the probability of AKI over IT stratified by preoperative risk of AKI. RESULTS: Overall, median (interquartile range) age at surgery and preoperative eGFR were 64 (54, 72) years and 87 (73, 101) mL/min/1.73 m2, respectively. Median warm IT was 15 (12, 20) minutes. A total of 235 (25%) patients experienced AKI after surgery. At multivariable analysis, age (odds ratio [OR] 1.03; p<0.0001), preoperative eGFR (OR 1.02; p=0.003), clinical T1b stage (OR 1.88; p=0.0002) and higher PADUA score (OR 1.20; p=0.007) were associated with increased risk of AKI. Conversely, laparoscopic (OR 0.47; p=0.011) and robotic (OR 0.39; p<0.0001) surgery had lower probability of AKI compared to open surgery. According to the first split at CART analysis, patients were categorized as “high” and “low” risk of AKI having a probability greater or smaller than 40%. For low risk patients, the probability of AKI in case of less than 10 vs more than 20 minutes of ischemia was 13% and 28%, respectively (absolute risk increase: 15%). By contrast, the risk of AKI for high risk patients who had less than 10 vs more than 20 minutes of ischemia was 31% and 77% respectively (absolute risk increase: 45%; Figure 1). CONCLUSIONS: In patients treated with partial nephrectomy functional harm related to ischemia is highly dependent on baseline risk of AKI. Appropriate surgical planning should include the assessment of individual risk of functional damage.Source of Funding: On behalf of the RECORD 2 Investigators. None.