# Transient elastography measurements of the liver and transplanted kidney in patients with AA amyloidosis: a cross-sectional comparative study

## TL;DR

This study explores the use of FibroScan to measure liver and kidney stiffness in patients with AA amyloidosis and compares results with other groups.

## Contribution

The study introduces FibroScan as a potential non-invasive tool for detecting liver and kidney involvement in AA amyloidosis.

## Key findings

- Liver stiffness was significantly higher in AA amyloidosis and AL amyloidosis patients compared to healthy controls.
- Kidney stiffness was significantly higher in patients with recurrent amyloidosis in transplanted kidneys.
- FibroScan showed comparable liver stiffness in FMF patients with and without amyloidosis.

## Abstract

To evaluate the utility of elasticity imaging techniques, such as transient elastography (FibroScan), in assessing the liver and transplanted kidney in patients with AA amyloidosis (AA-A). This study was conducted in patients with AA-A, while patients with immunoglobulin light chain amyloidosis (AL-A), Familial Mediterranean Fever (FMF) without amyloidosis, and healthy controls (HC) were included as comparison groups for liver stiffness (LS) measurements. Additionally, kidney stiffness (KS) was measured in renal transplant recipients (RTRs) with transplants due to AA-A or other causes of chronic renal failure. LS evaluations were performed in 65 patients with AA-A, 14 with AL-A, 20 with FMF, and 27 with HC. LS (kPa) was significantly higher [median (IQR)] in patients with AA-A [6.4 (5.4)] and AL-A [9.8 (11)] compared to HC [4.7 (1.7)] (p < 0.001). However, the difference between AL-A and AA-A was not statistically significant. LS values were comparable in FMF-AA patients with [6.8 (6.6)] and without [5.7 (3.6)] liver involvement, and FMF patients without amyloidosis [7.15 (4.6)]. The median KS values were comparable in 19 AA-A and 16 disease controls. However, KS values were significantly higher in patients with recurrent amyloidosis in the transplanted kidney [29.3 (18.9)] compared to those without recurrence [10.9 (7.7)] (p = 0.003). In our study, increased liver stiffness measurements were observed in patients with AA-A, AL-A, and FMF compared to HC. Transient elastography using FibroScan appears to be a promising non-invasive tool for assessing liver involvement in AA-A and may aid in detecting recurrence of amyloidosis in transplanted kidneys. Further studies are needed to validate the utility of FibroScan in evaluating the involvement of the liver and kidneys in patients with AA-A.

The online version contains supplementary material available at 10.1007/s00296-025-05906-3.