Off-clamp and on-clamp robotic-assisted partial nephrectomy in ischemia-sensitive patients: a multicenter propensity score-matched study (RAPN OFF-CLAMP study - UroCCR 187)

BACKGROUND: The aim of this study was to assess the real impact of ischemia during robotic-assisted partial nephrectomy (RAPN) in high-risk patients, this study focused on ischemia-sensitive populations such as those with a solitary kidney (SK) or chronic kidney disease (CKD), who may benefit from off-clamp (OfC) nephron-sparing surgery.METHODS: We retrospectively analyzed all RAPN cases performed at 16 centers of the UroCCR network (2011-2024), in patients with a SK or stage 3b CKD (eGFR≤45 mL/min/m2). Patients were prospectively enrolled in the UroCCR project after signed consent. Our cohort was divided into two subgroups of SK and CKD. A propensity score matching adjusted on preoperative eGFR and RENAL score was used in SK subgroup and on baseline creatinine in CKD subgroup. We compared OfC RAPN and on-clamp RAPN (OnC) in terms of perioperative outcomes. Our main objective was to assess post-operative evolution of renal function.RESULTS: Among 251 RAPN, 144 were performed OnC and 107 OfC. After matching, OfC SK had less eGFR variation between pre-operative level and day 1 (-19.5 vs. -27.6 mL/min/1.73 m2; P=0.001) or discharge (-6.7 vs. -15.0 mL/min/1.73 m2; P=0.001). This difference was no longer observed beyond 3 months. SK operated OfC presented less AKI at day 1 and at discharge (67.6% vs. 86.8%; P=0.01). They were discharged significantly more often at D0/D1, with a lower length of stay (3.4 vs. 6.4 days; P=0.001). There was no significant difference in terms of complications, bleeding, locoregional recurrence and positive margins. We found no significant difference in the CKD subgroup.CONCLUSIONS: OfC RAPN offers significant short-term functional advantages in ischemia-sensitive patients with a solitary kidney. By avoiding warm ischemia, the OfC approach reduces the incidence of acute kidney injury and shortens hospital stays, without increasing surgical morbidity or compromising oncologic outcomes.