Reevaluating Warm Ischemia Time as a Predictor of Renal Function Outcomes After Robotic Partial Nephrectomy

OBJECTIVE To explore whether variation of warm ischemia time (WIT) is associated with functional and perioperative outcomes following robotic partial nephrectomy (RPN). MATERIALS AND METHODS Six hundred sixty eight patients, each with 2 kidneys, undergoing RPNs for a cT1 tumor were identified from a U.S. multi-institutional database. The associations between WIT, normal excisional volume loss (EVL), and surgical and renal function outcomes, including acute kidney injury at discharge and percent change in eGFR at up to 24 months post-RPN, were evaluated using Spearman's rank correlation test as well as multivariable models controlling for tumor, surgeon, and patient characteristics. RESULTS WIT was weakly correlated with EVL (r = 0.32, P < .001), blood loss (r = 0.34, P < .001), and length of stay (r = 0.35, P < .001). WIT was found to be significantly associated with acute kidney injury at discharge (odds ratio = 6.23; confidence interval 1.52, 30.39). Extended WIT was not found to be significantly associated with renal function decline at 1 year post RPN (P > .05). CONCLUSION Extended WIT is associated with worse perioperative outcomes. While controlling for tumor size and EVL, effects on short-term renal function were still seen after as short as 20 minutes. Efforts to limit warm ischemia time should continue to be implemented during RPN to maximize postoperative renal function. (C) 2018 Elsevier Inc.