Applicability and Results of Liver Stiffness Measurement and Controlled Attenuation Parameter Using XL Probe for Metabolic-Associated Fatty Liver Disease in Candidates to Bariatric Surgery. A Single-Center Observational Study

Purpose: Patients with morbid obesity are at high risk of liver fibrosis due to metabolic-associated fatty liver disease. Data on liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) by vibration-controlled transient elastography (VCTE, FibroScan®) XL probe for liver fibrosis and steatosis assessment in morbid obesity are needed.

Materials and methods: LSM and CAP were measured in candidates to bariatric surgery at a single center during 12 months. In patients who underwent an intraoperative liver biopsy, we compared LSM and CAP with histology findings. Comorbidities, body mass index, type of surgery, and infections after surgery were collected and analyzed.

Results: Of the eighty-three patients assessed by XL probe, 49 (59%; female in 63%, BMI 42.6 ± 5.1 kg/m²) had a valid LSM and CAP measurement. LSM was 7.0 ± 3.9 kPa and CAP 329 ± 57 dB/m. In the 14 patients undergoing intraoperative liver biopsy, all had steatosis (severe in 50%), 6 (43%) had NASH (NAS ≥ 5), and 4 (29%) showed significant or bridging fibrosis. LSM accurately discriminated between patients with and without significant or severe fibrosis (AUROC 0.833) and CAP well-identified patients with or without ≥S2 steatosis (AUROC 0.896). Nine of 49 patients (18%) tested positive for significant/severe fibrosis by LSM (cut-off 8.9 kPa).

Conclusion: Applicability of LSM and CAP by XL probe in patients candidate to bariatric surgery was moderate. However, when technically successful, their reliability to diagnose severe steatosis and fibrosis related to MAFLD was good.