Correlation between color doppler ultrasonographic indices and serum creatinine level before and after renal transplantation

Abstract

Background: The measurement of color Doppler ultrasonographic indices, such as resistive index (RI) can help in the evaluation of a transplanted kidney. This study sought to examine correlation between color Doppler ultrasonographic indices and serum creatinine levels before and after renal transplantation. Methods: A total of 100 patients with end stage renal disease undergoing kidney transplantation were enrolled in this study. Serum creatinine levels was measured before transplantation, on day 5 and at the end of the third month after transplantation. Central and peripheral RI values of the transplanted kidney were also documented on day 5 an month 3 posttransplantation. Results: Creatinine level at the end of third month had positive correlation with central (r=0.27 and p=0.007) and peripheral RI values (r=0.26 and p=0.009) in day 5 after transplantation. There was also a significant positive correlation between the serum level of creatinine at the end of the third month and central (r=0.50 and p<0.001) and peripheral RI values (r=0.50 and p<0.001) at the third month posttransplantation. At an optimal cut-off point of 0.51 for the central RI on fifth day, the sensitivity, specificity, positive predictive value, and negative predictive value for predicting a malfunctioning transplanted kidney were 93%, 30%, 76%, and 64%, respectively. The corresponding values of the peripheral RI on fifth day were 43%, 67%, 75%, and 33%, respectively using an optimal cut-off point equivalent to 0.70. Conclusions: Both peripheral and central RI values on day 5 can be used for predicting malfunctioning transplanted kidney.