Resistive index as a predictor of early failure of kidney transplantation

BACKGROUND: Ultrasonography is a simple and noninvasive examination that can be easily performed after renal transplantation because of the lack of toxicity. The resistive index (RI) was measured using Doppler ultrasound at 7 days postoperatively in patients who underwent renal transplantation. The study aimed to determine the risk of graft loss and premature death within 1 year after transplantation. METHODS: This study was conducted from January 2011 to October 2017 and involved 97 patients who underwent renal transplantation at the Chosun University Hospital, Kwangju, Korea. Brain-dead donors were selected. Several parameters were assessed as recipient variables. In addition, postoperative delayed renal function and complications were examined. At 7 days after surgery, the RI was measured in all patients (the mean value of three measurements taken at different positions was used). RESULTS: Of the 97 patients, 40 had an RI of ≥0.8 or greater. Of these, four patients died, and a total of seven developed transplant failure. Logistic regression analysis was conducted to predict the risk of transplant failure and mortality based on complex influences of the relevant variables. The RI showed a relative risk value of 12.711 for transplant failure (P=0.003) and was significantly associated with mortality (P=0.001). CONCLUSIONS: The RI was highly correlated with graft loss and recipient mortality after renal transplantation. Measurement of the RI after renal transplantation may lead to a more aggressive management of high-risk patients, and consequently improve the post-transplantation outcome.