Early Renal Resistive Index Measurement as a Predictor of Delayed Graft Function and Clinical Outcomes in Renal Transplantation

Introduction Delayed graft function (DGF) is a relatively common and clinically important complication after renal transplantation, with potential implications for graft and patient outcomes. Renal allograft resistive index (RI), assessed via Doppler ultrasonography, may provide a noninvasive method for identifying patients at increased risk of DGF. This study is aimed at evaluating early postoperative RIs and their association with DGF and other posttransplant complications at our center. Methods This retrospective cohort study was conducted from September 15, 2020, to January 3, 2025 at the Kidney and Pancreas Transplant Center of a tertiary care hospital. The study included all patients who underwent Doppler ultrasonography within the first postoperative week. Relevant clinical data, including donor and recipient characteristics as well as transplantation details, were retrieved from electronic medical records. Data were analyzed using SPSS Version 26. Results Of the 171 subjects included in the study, DGF was seen in 91 (53.2%) subjects. The average RI was significantly higher in subjects with DGF (0.78 ± 0.16) compared with those without DGF (0.70 ± 0.15; p = 0.005). The receiver operating characteristic analysis for average RI had an AUC of 0.64 (95% CI: 0.55–0.74; p = 0.005), with an optimal cutoff value of 0.67. At this threshold, the sensitivity was 70.15%, and specificity was 53.70%. RI was also higher in failed allografts (0.87 ± 0.20) versus nonfailed (0.74 ± 0.15; p = 0.022). Conclusion An elevated resistive index was associated with delayed graft function and allograft failure but demonstrated modest discriminative performance. RI may provide supportive clinical information when interpreted alongside other posttransplant parameters.