Evaluation of liver fibrosis using Transient Elastography in non-alcoholic steatohepatitis (NASH) patients

Purpose: The purpose of this study was to assess by Transient Elastography (TE) the severity and dynamics of liver fibrosis in NASH patients.

Material and methods: We conducted a prospective study on 890 NASH patients, diagnosed based on: ultrasound examination (“bright liver” with posterior attenuation); biological tests (increased aminotransferases level); no history of alcohol abuse; negative viral hepatitis B or C markers. In each patient ten liver stiffness measurements (LSM) were performed, either with M (3.5 MHz) or XL (2.5 MHz) probe. Reliable measurements were defined as: median value of 10 LSM with a success rate SR≥60% and an interquartile range IQR< 30%. Using the cut-offs proposed by Wong (1), NASH patients were divided into 3 categories: < 7.9kPa (absence of severe fibrosis); values ranging between 7.9 kPa and 9.6 kPa (“gray zone” in which biopsy is recommended) and > 9.6kPa (severe fibrosis).

Results: Out of 890 patients, reliable measurements by either probe were obtained in 76.5%. Older age, female gender and higher BMI were associated with unreliable TE measurements. The analysis of liver fibrosis distribution was performed in 681 NASH patients with reliable LSM. Using the proposed cut-offs, 69.5% of the patients did not have severe fibrosis, 11.5% had F≥2 fibrosis being in the “gray zone” and 19% had severe fibrosis. In 49 patients the dynamics of fibrosis was evaluated. Over a period of at least 2 years, fibrosis progression was observed in 12.2%, 75.6% had stable fibrosis, and 12.2% had an improvement in fibrosis stage.

Conclusions: Approximately 20% of NASH patients had LSM compatible with severe fibrosis, therefore LS assessment should be performed systematically in NASH patients.

Reference: [1] Wong WV et al. Diagnosis of Fibrosis and Cirrhosis Using Liver Stiffness Measurement in Nonalcoholic Fatty Liver Disease Hepatology 2010 Feb; 51 (2): 454 – 62