Predictive value of the renal resistive index in the immediate postoperative period after kidney transplantation on short- and long-term graft and patient outcomes

Introduction: During the postoperative stay in the intensive care unit after kidney transplantation, the renal resis-tive index (RI) is routinely measured. An increased RI, measured months posttransplant, is associated with a higher mortality. We wanted to investigate the value of the RI immediately posttransplant in predicting both short-and long-term outcome.Methods: We performed a retrospective single-center study. The RI was collected <48 h posttransplant in pa-tients undergoing kidney transplantations between 2005 and 2014. Short-term outcome was evaluated by de-layed graft function (DGF). The long-term endpoints were kidney function and mortality at 30 days, 1 year and 5 years. Results: We included 478 recipients, 91.4% of whom reached the end of the 5-year follow-up. A higher RI < 48 h posttransplant was significantly associated with DGF. This association was particularly strong in patients receiv-ing grafts from donors after brain death and expanded criteria donors. A higher RI also correlated with mortality and death with functioning graft but not with graft failure. After adjustment for confounders, we found an asso-ciation between increased RI and DGF, but not with long-term kidney function or mortality.Conclusion: The RI routinely measured <48 h posttransplant is an independent predictor of short-term kidney function. (c) 2022 Elsevier Inc. All rights reserved.