Prediction of allograft function in pre-transplant kidneys using sound touch elastography (STE): an ex vivo study

Abstract

Abstract Background The purpose of the study was to evaluate renal quality and predict posttransplant graft function using ex vivo sound touch elastography (STE). Methods In this prospective study, 106 donor kidneys underwent ex vivo STE examination and biopsy from March 2022 to August 2023. The mean stiffness of the superficial cortex (STEsc), deep cortex (STEdc), and medulla (STEme) was obtained and synthesized into one index (STE) through the factor analysis method. Additionally, 100 recipients were followed up for 6 months. A random forest algorithm was employed to explore significant predictive factors associated with the Remuzzi score and allograft function. The performance of parameters was evaluated by using the area under the receiver operating characteristic curve (AUC). Results STE had AUC values of 0.803 for diagnosing low Remuzzi and 0.943 for diagnosing high Remuzzi. Meanwhile, STE had an AUC of 0.723 for diagnosing moderate to severe ATI. Random forest algorithm identified STE and Remuzzi score as significant predictors for 6-month renal function. The AUC for STE in predicting postoperative allograft function was 0.717, which was comparable with that of the Remuzzi score (AUC = 0.756). Nevertheless, the specificity of STE was significantly higher than that of Remuzzi (0.913 vs 0.652, p < 0.001). Given these promising results, donor kidneys can be transplanted directly without the need for biopsy when STE ≤ 11.741. Conclusions The assessment of kidney quality using ex vivo STE demonstrated significant predictive value for the Remuzzi score and allograft function, which could help avoid unnecessary biopsy. Critical relevance statement Pre-transplant kidney quality measured with ex vivo STE can be used to assess donor kidney quality and avoid unnecessary biopsy. Key Points STE has significant value for diagnosing low Remuzzi and high Remuzzi scores. STE achieved good performance in predicting posttransplant allograft function. Assessment of kidney quality using ex vivo STE could avoid unnecessary biopsies. Graphical Abstract

Keywords

• Donor Kidney
• Sound touch elastography
• Allograft function
• Remuzzi score