The value of intrarenal resistive index in delayed graft function after kidney transplantation.

Abstract

Background: For patients with chronic kidney disease (CKD), it is crucial to detect delayed graft function (DGF) promptly after kidney transplantation; however, the application value of ultrasound as a non-invasive monitoring method has not yet been studied. Therefore, our study compared the ultrasound results between a DGF group and a normal graft function (NGF) group to explore the application value of ultrasound-related parameters, especially renal resistive index (RI), in diagnosing DGF.

Methods: This was a single-center retrospective study. We analyzed the clinical data of patients who underwent kidney transplantation at West China Hospital of Sichuan University from 1 July 2019 to 1 April 2023, and collected all patients' demographic information, clinical test results, and ultrasound parameters on Doppler ultrasound (DUS). According to the definition of DGF, all patients were divided into either the DGF group or the NGF group.

Results: Our study enrolled 225 patients (DGF group, n=115; NGF group, n=110), including 153 men and 72 women, with a mean age of 38.4±11.6 years. Compared with the NGF group, the body mass index (BMI), serum urea nitrogen (SUN), serum creatinine (SCr), cystatin C (Cys-C), and uric acid (UA) in the DGF group were significantly higher, and the albumin (ALB) and estimated glomerular filtration rate (eGFR) in DGF group were lower (P<0.05). The results of ultrasound parameters' comparison showed that the renal RI of the DGF patients was significantly higher compared with that of the NGF patients (P<0.05), and the renal artery RI measured ≥48 hours after kidney transplantation was higher than that measured <48 hours (P<0.05). Additionally, the area under the curve (AUC) of the RI measured ≥48 hours after kidney transplantation was generally larger, which revealed significantly better performance for DGF.

Conclusions: Increased RI may be a predictor to indicate the occurrence of DGF, which can help clinicians in early recognition of DGF and improve long-term graft survival.