Validez diagnóstica del índice de resistividad en pacientes trasplantados renales con disfunción del injerto: correlación histológica

Objective

To estimate the diagnostic validity of the resistance index (RI) in renal transplant patients with graft dysfunction, using the histopathological findings as gold standard.

Material and methods

A retrospective review was performed on the biopsies of 85 patients with renal graft dysfunction. Patients were grouped according to the histological findings: normal findings, acute rejection, chronic rejection, and other findings. The RI was assessed by Doppler ultrasound, considering values of < .55 and > .75 as pathological, and were analyzed along with the findings in the biopsy. Sensitivity, specificity, positive predictive value and negative predictive value of RI were assessed. The mean RI was compared between patients with normal and abnormal pathological findings.

Results

The RI was normal in 59 patients, and pathological in 26. The RI showed a specificity of 72.73% and a high positive predictive value of 88.46% in patients with graft dysfunction. There was no statistically significant difference (P = .196) in the RI between patients with normal and pathological histopathology in the biopsy.

Conclusion

Despite its low sensitivity, the RI is reliable in detecting an abnormal parameter when its value is outside the reference range. However the performing a biopsy is still required to determine the cause of the kidney disease.