Clinical implications of hepatic structure and function evaluation based on vibration-controlled transient elastography and liver maximum function capacity test in patients with nonalcoholic fatty liver disease

Background and aims: Transient elastography [vibration-controlled transient elastography (VCTE)] noninvasively guides risk stratification in patients with nonalcoholic fatty liver disease (NAFLD). Patients with nonalcoholic steatohepatitis (NASH) and fibrosis can be identified using the FAST-score. The liver maximum function test (LiMAx) could be helpful in more precise risk stratification. This pilot study evaluated VCTE, FAST-score, and LiMAx in NAFLD patients.

Methods: NAFLD patients prospectively underwent VCTE and LiMAx. The cutoffs for high fibrosis risk were 9.3/9.6 kPa (M/XL-probe) and 331 dB/m for steatosis. A FAST-score greater than 0.67 was used to identify patients with NASH and LiMAx values below 315 μg/kg/h for impaired liver function.

Results: In total, 57 NAFLD patients (BMI 32 ± 6 kg/m2; 60% diabetes) were included. High risk for fibrosis and steatosis was observed in 26/57 and 28/57 cases, respectively. Overall, 19/57 patients presented impaired liver function. However, 14/26 of patients with a high risk for fibrosis had impaired liver function compared to 5/31 of those without (P = 0.0026). Similarly, 12/18 patients at high risk for NASH had impaired liver function compared to 7/39 without (P < 0.001). The subgroup with diabetes had a liver stiffness a factor of 1.8 higher, FAST-score was 0.13 higher and LiMAx values were 66 μg/kg/h lower compared to nondiabetics.

Conclusion: There is a significant correlation between the functional liver capacity (LiMAx) and the structural liver assessment by VCTE. In cases with high liver stiffness or FAST-score, low LiMAx results may identify NAFLD patients at risk for disease progression and reduce the risk of false-positive categorization.