COMPARISON OF ELASTOGRAPHY OF ALLOGRAFT WITH BIOCHEMICAL AND RADIOLOGICAL PARAMETERS IN KIDNEY TRANSPLANT RECIPIENTS

Introduction:

 Chronic renal allograft injury affects graft function which is investigated through graft biopsy, a procedure associated with risks and complications. Hence, the need for non-invasive methods such as elastography. This study aims to evaluate the effectiveness of elastography in measuring renal fibrosis in renal allograft recipients and to compare it with serum creatinine, estimated glomerular filtration rate (eGFR), and resistivity index (RI).

Methods:

This prospective cohort study included 39 renal transplant recipients between August 2018 and April 2020. Inclusion criteria encompassed adult patients (≥18 years) who provided informed consent, while patients undergoing en-bloc or multiorgan transplants were excluded. Data collected included demographic information, laboratory tests (serum creatinine, urea), and radiological assessments (elastography and RI) at two time points: before discharge post-transplant and at six months. Elastography was performed using an Acuson S3000 ultrasound system, utilizing Acoustic Radiation Force Impulse technology. Shear wave velocity (SWV) measurements were taken in a 10mm x 6mm region of interest in triplicate, with the mean SWV value used for analysis. RI was measured via colour doppler technology. Immunosuppressive regimens included steroids, tacrolimus, and mycophenolate mofetil, with tacrolimus levels monitored and adjusted. Data were analyzed using SPSS version 25.0. Continuous variables were expressed as mean ± standard deviation and categorical variables as percentages. Paired t-test assessed differences between baseline and follow-up measurements. Correlations between variables were examined, with significance set at p < 0.05.

Results:

The cohort had an average age of 43.62 years, with a male predominance (89.7%). Baseline serum creatinine averaged 1.44 mg/dl, e-GFR was 67.86 ml/min/1.73 m², and elastography readings averaged 2.81 m/s. The most common native kidney disease was presumed chronic interstitial nephritis. Induction agents included antithymocyte globulin (14 patients) and basiliximab (22 patients). The majority of donors were female (69.23%), with 71.79% being living donors. Follow-up data showed that baseline and six-month measurements of e-GFR, RI, and elastography were statistically similar with no significant changes in these parameters over six months. Elastography demonstrated limited positive predictive value (PPV) and negative predictive value (NPV) for e-GFR and RI(Image 1 and 2). Elastography showed a positive but non-significant correlation with serum creatinine(Image 3) and a negative correlation with e-GFR(Image 4). No significant correlation with RI was observed(Image 5).Scatter plots and ROC analysis indicated that elastography had lower sensitivity and specificity compared to RI and serum creatinine(Image 6).

Conclusions:

Elastography did not exhibit a reliable correlation with renal fibrosis in renal allograft recipients. Although there was a trend toward a positive correlation with serum creatinine and a negative correlation with e-GFR, these findings were not statistically significant. Elastography did not correlate with RI and had limited predictive value for renal function. Limitations included that it was a single centre study, with a small cohort, non availability of protocol biopsy and short duration of follow up.

This abstract was submitted at the Indian Society of Nephrology South Zone congress in 2022. 

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.