During the postoperative stay in the critical care unit that followed kidney transplantation, the renal resistive index (RI) was evaluated consistently. It was shown that a higher RI was associated with a higher mortality risk in the months following the transplant. For a study, researchers sought to determine the predictive significance of the RI immediately after post-transplant for both short- and long-term outcomes. They conducted a retrospective, single-center investigation. The RI was obtained less than 48 h post-transplant in kidney transplant recipients between 2005 and 2014. Evaluation of short-term outcomes was based on delayed graft function (DGF). The long-term objectives were renal function and mortality at 30 days, 1 year, and 5 years. Investigators enrolled 478 beneficiaries, of whom 91.4% completed the 5-year follow-up. Less than 48 hours after transplant, a higher RI was substantially linked with DGF. This association was especially clear in patients who had gotten grafts from brain-dead donors and donors who fulfilled a wider range of requirements. A greater RI was also related to mortality and death in patients with functioning grafts, but this connection was not found in individuals who had failed grafts. After correcting for confounding variables, they identified a correlation between greater RI and DGF. Still, they did not find a connection between higher RI and long-term kidney function or death. An independent factor that predicted short-term renal function was the RI measured within less than 48 hours after the transplant.