Limited impact of warm ischemic threshold for partial nephrectomy in the robotic surgery era: A propensity score matching study.

OBJECTIVES To evaluate the association between extended (≥30 min) warm ischemic time and renal function in patients undergoing robot-assisted partial nephrectomy. METHODS This multi-institutional study retrospectively recruited 1131 patients who underwent robot-assisted partial nephrectomy. Patients were classified into shorter (<30 min; n = 1038) and longer (≥30 min; n = 92) groups based on the ischemic time required, and 1:2 propensity score matching was used to minimize selection bias. The perioperative outcomes, including acute kidney injury and trifecta attainment, and mid/long-term renal function were assessed before and after matching. RESULTS Patients in the longer group had tumors with a significantly larger diameter and RENAL nephrometry score. The decline in the nadir of the estimated glomerular filtration rate was significantly greater in the longer than the shorter group in the unmatched and matched cohorts (-16.2 vs -5.5%, P < 0.001; 15.5 vs -9.5%, P = 0.003, respectively). A higher incidence of acute kidney injury (9.8 vs 2.6%, P = 0.002) was observed in the longer group before matching, whereas the difference was comparable after matching. Before matching, the decline in estimated glomerular filtration rate at 6 months postoperatively was greater (-8.2 vs -5.1%, P = 0.005) and trifecta attainment was lower (50.0 vs 63.5%, P < 0.001) in the longer group. However, the differences were comparable for both the parameters between the groups in the matched cohort. CONCLUSIONS While extended warm ischemia during robot-assisted partial nephrectomy can be demanded in case of large and complex tumors, its impact on postoperative renal function is limited.