Transient elastography: a new noninvasive diagnostic tool for assessment of chronic allograft nephropathy

Abstract

Purpose: Chronic allograft nephropathy (CAN) is the most common cause of kidney allograft failure. Protocol biopsies remain the "gold standard" in CAN recognition. However, renal allograft biopsies have numerous limitations. It is an invasive procedure connected with risk of complications, patient discomfort, and sampling errors. The aim of our study was to investigate the usefulness of transient elastography (TE) for the assessment of kidney allograft fibrosis in renal transplant recipients (RTRs).

Methods: In this cross-sectional study, we involved 52 RTRs. Renal allograft stiffness was used to assess its fibrosis by using transient elastography (Fibroscan, Echosense, Paris, France). In 23 patients with a deterioration of graft function, percutaneous renal allograft biopsy was performed closely around the time of TE.

Results: We have found that the renal allograft stiffness was highly negatively correlated with estimated glomerular filtration rate (eGFR) (r = -0.640; p < 0.0001). However, renal allograft stiffness showed a statistically significant difference between patients who had an eGFR > 50 ml/min per 1.73 m(2) and patients with eGFR < 50 ml/min per 1.73 m(2) (28 ± 2.7 vs. 33.9 ± 5.5 kPa; p = 0.0003). Also, there was a highly positive correlation between renal allograft stiffness and extent of interstitial fibrosis on renal biopsy (r = 0.727; p = 0.0001).

Conclusion: According to our results, parenchymal stiffness obtained by TE reflects interstitial fibrosis. Therefore, TE provides the opportunity for noninvasive screening of CAN.