S1228 EUS-Guided Shear Wave Elastography Appears to Be More Accurate Than Transient Elastography in Predicting Liver Fibrosis Staging in Patients With Obesity

Abstract

Introduction: Transient elastography (TE) is a non-invasive clinical tool used to assess liver stiffness measurement (LSM) and can be correlated to liver fibrosis staging. Obesity can make elastography challenging to perform due to increased abdominal wall thickness, with high failure rates for TE. Fibroscan XL probes have lower failure rates, though it is unclear if readings are reliable or correlate well with liver biopsies. EUS guided shear wave elastography (EUS-SWE) can potentially circumvent this limitation, as liver parenchyma via EUS can be visualized under a thin subcentimeter gastric or duodenal wall, which does not change appreciably with body habitus. We aim to determine whether TE or EUS-SWE correlate better with liver biopsy fibrosis staging for patients with obesity. Methods: A retrospective chart review was performed for patients with obesity at a single tertiary hospital from Dec 2021 to May 2022. Patients with obesity (BMI≥30) with LSM concerning for advanced fibrosis (F3 or F4) were referred for EUS-SWE and EUS guided liver biopsy, both of which performed in the left liver lobe. LSM (reported in kPa) were correlated with fibrosis staging on liver biopsy and were considered accurate if they fell within cutoff ranges: kPa ≤7 = F0-1, kPa 7-8 = F2, kPa 8-12 = F3, and kPa >12 = F4. No established cutoffs exist for EUS-SWE, so stiffness values were compared to that for TE on which were closer to TE cutoff ranges. Results: 12 consecutive patients with obesity underwent TE, EUS-SWE, and EUS guided liver biopsy. The mean age was 55.3 [range 18-69], 9 (75%) were females, and mean BMI was 44.9 [range 30.2-67.8]. LSM ranged from 9.1 to 41.9 kPa. Only 2 (17%) patients’ TE results correlated accurately with liver fibrosis staging on biopsy; see Table. Assuming similar fibrosis staging cutoff ranges for TE, EUS-SWE accurately downgraded 8 (67%) patients and demonstrated no change for 4 (33%) patients. EUS-SWE was closer to biopsy LSM cutoffs for 9 (75%) patients, while TE was more accurate in only 1 (8%) patient. Conclusion: In this small cohort of patients with obesity with possible advanced fibrosis, TE appeared to overdiagnose fibrosis stage, while EUS-SWE appeared to downgrade LSM appropriately for patients who were overdiagnosed. Larger cohort studies are ongoing to allow proper interpretation of EUS-SWE stiffness values and compare its utility and accuracy to TE. Table 1. - Individual patient data with basic demographics, transient elastography data, EUS shear wave elastography data, and data comparison and analysis Patient # Age Gender BMI TE LSM Value (kPa) Fibrosis Staging Based on TE Cutoff Fibrosis Stage on Biopsy (TE cutoffs) TE LSM as Compared to Fibrosis Staging on Biopsy EUS-SWE Stiffness (kPa) Closer to Biopsy Cutoffs? TE vs EUS-SWE How Did EUS-SWE Compare to TE via Fibrosis Staging ? 1 58 Female 62.4 9.1 F3 F0 (kPa≤7mmHg) Overstaged 5 EUS-SWE Downgraded 2 68 Female 39 9.9 F3 F0 (≤7) Overstaged 4.9 EUS-SWE Downgraded 3 59 Female 32.6 9.4 F3 F0 (≤7) Overstaged 6.3 EUS-SWE Downgraded 4 63 Female 32.8 15.7 F4 F0 (≤7) Overstaged 7.3 EUS-SWE Downgraded 5 48 Male 67.8 41.9 F4 F0 (≤7) Overstaged 7.3 EUS-SWE Downgraded 6 63 Female 38 9.4 F3 F0 (≤7) Overstaged 2 EUS-SWE Downgraded 7 56 Male 43.6 9.6 F3 F3 (8-12) Appropriate Stage 10.5 EUS-SWE No Change 8 18 Female 61.1 34.6 F4 F2 (7-8) Overstaged 19.6 EUS-SWE Downgraded 9 53 Female 32.6 20.5 F4 F4 (≥12) Appropriate Stage 21.7 Same No change 10 55 Male 34.9 12.2 F4 F2 (7-8) Overstaged 12.2 Same No Change 11 53 Female 30.2 14 F4 F3 (8-12) Overstaged 15.2 TE No Change 12 69 Female 64.1 14.7 F4 F2 (7-8) Overstaged 10.2 EUS-SWE Downgraded