Early Postoperative Renal Arterial Resistive Index as a Predictor of Long-Term Graft Dysfunction and Loss in Kidney Transplantation

Abstract

Background:
Renal Doppler ultrasonography is a non-invasive tool for evaluating graft hemodynamics; however, the prognostic threshold of the arterial resistive index (RI) for predicting long-term graft survival requires evaluation.
Objectives: To assess the predictive value of early renal arterial resistive index (RI) for early and late renal allograft dysfunction.
Materials and methods: We analyzed prospective data from 140 renal transplant recipients. Color Doppler ultrasonography with interlobar arterial RI measurement was performed on postoperative days 1, 7, and 3 months. Recipients were followed for 3 years to monitor graft function and graft loss events.
Results: Mean interlobar arterial RI on day 7 post-transplantation was 0.68 ± 0.08. Recipients who developed delayed graft function or chronic graft dysfunction exhibited significantly higher day 7 RI values (0.79 ± 0.06 vs. 0.65 ± 0.04; p < 0.001). A day 7 RI threshold ≥ 0.75 was associated with a 4.2-fold increased risk of 3-year graft loss (OR = 4.22; 95% CI: 1.85–9.62; p = 0.001).
Conclusions: An elevated early intrarenal arterial resistive index (≥ 0.75) serves as a reliable Doppler ultrasound predictor of graft dysfunction and 3-year allograft loss.

Keywords:
Kidney transplantation; resistive index; RI; Doppler ultrasonography; graft dysfunction; allograft loss.