This study was performed to evaluate the role of renal resistive index (RI) in the diagnosis of acute rejection after successful renal transplantation. In a prospective study from Jan. 2006 to Aug. 2007 , 101 renal transplantation (mean age of 39 years , 74 male and 25 female) were performed in our center. Resistive index measured in all patients by doppler sonography 3 days, 7 days and at 1 , 3, 6 months and at the time of graft dysfunction (increase of more than 1 mg/dl in creatinine level) after operation. All measurements were done by a single sonographist and under the same condition. The normal limit of RI presumed to be less than 0.70. Statistical analysis was done by T-test in SPSS soft-ware computer program. Thirty-three episodes of acute rejection in 27 patients (32%) , 10 high blood level of cyclosporine in 8 patients, 5 episodes of ischemic tubular necrosis (ATN) and 3 episodes of renal artery thrombosis detected in case of graft dysfunction in these patients. Mean RI was 0.606 +/- 0.065 (0.45-0.75) in normal graft function group. Mean RI was 0.866 +/- 0.083 (0.69-1.1) in rejection group (p<0.05). In 32 episodes of rejection resistive index were higher than normal (> 0.70) and in one episodes the RI were in normal limit. Normal RI detected in patients with history of another episode of rejection. Mean RI was 0.642 +/- 0.060 (0.56-0.72) (p>0.05) in ATN group. Only one patient with ATN had RI mildly elevated (0.72) and the others had normal RI. Mean RI was 0.622 +/- 0.056 (0.49-0.69) (p>0.05) in high blood cyclosporine level group. None of the patients with high serum level of cyclosporine had elevated RI. Only 2 patients had mild elevation of RI in-spite of normal graft function (0.75 and 0.73 ). Both these patients had post transplant diabetes mellitus (PTDM). Resistive index was significantly higher in patients with acute rejection and not elevated in patients with ATN or cyclosporine toxicity after renal transplantation. RI measurement is a non-invasive diagnostic method which provides flow-metric quantitative parameters for the hemodynamic assessment of the renal transplant with a certain sensitivity.
Volume : 6
Issue : 4
Pages : 53
Urology Research Center,Sina Hospital, Tehran University Of Medical Sciences, Tehran, Iran