Impact on Delayed Graft Function of the Renal Resistive Index in the Immediate Postoperative Period After Kidney Transplantation: A Cohort Analysis.

Abstract Background The renal resistive index (RI) is routinely used for the clinical monitoring of renal transplant patients in the early postoperative period. It is a noninvasive method that allows us to detect microvascular changes in intrarenal blood flow. The aim of this study was to determine whether the RI measured in the immediate post-transplant phase during intensive care unit admission can be used to predict delayed graft function (DGF). Patients and Methods We performed a retrospective study in 1 tertiary care academic center. We measured the RI by Doppler ultrasonography within the first 2 days after kidney transplant. We included 446 transplant recipients who were transplanted between 2005 and 2014. Short-term outcome was studied by the 22 DGF definitions. Results Of the 446 kidney transplant recipients, 279 (62.6%) were men, with a median age of 55 years (interquartile range, 46-63 years). Median RI was 0.62 (interquartile range, 0.55-0.70). Depending on the definition used, DGF was present in 4.4% to 54.0% of recipients. We found that RI was associated with DGF; most of the available DGF definitions were associated with a significantly higher RI. Conclusions DGF was associated with an increased RI already within the first 2 days after kidney transplant.