Poor correlation of 2D shear wave elastography and transient elastography in Fontan-associated liver disease: A head-to-head comparison

Background and Aims: Fontan-associated liver disease (FALD) is a long-term complication of the Fontan procedure. Guidelines recommend elastography, but the utility of transient elastography (TE) and two-dimensional shear wave elastography (2D SWE) is unknown. We aimed to evaluate the relationship between TE and 2D SWE in FALD.Methods: This prospective cohort study included 25 patients managed in a specialist clinic between January 2018 and August 2021. Trained clinicians performed 2D SWE (GE Logiq-E9) and TE (FibroScan 503 Touch) on the same day under the same conditions. Laboratory, echocardiography, and imaging data were collected. The atrioventricular systolic-to-diastolic duration (AVV S/D ratio) was calculated as a measure of cardiac diastolic function.Results: We analyzed 40 paired measurements. Median age was 22 years. Median liver stiffness measurement (LSM) was 15.4 kPa (12.1-19.6) by TE and 8.0 kPa (7.0-10.3) (P = 0.001) by 2D SWE. There was weak correlation between the modalities (r = 0.41, P = 0.004). There was no correlation between time since Fontan and LSM by TE (r = 0.15, P = 0.19) or 2D SWE (r = 0.19, P = 0.13). There was no difference in LSM irrespective of whether sonographic cirrhosis was present or absent by TE (17.4 kPa [15.9-23.6] vs. 14.9 kPa [12.0-19.4], respectively, P = 0.6) or 2D SWE (9.0 kPa [2.8-10.5] vs. 8.0 kPa [6.7-10.1], P = 0.46). There was no correlation between AVV S/D ratio and LSM by TE (r = 0.16, P = 0.18) or 2D SWE (r = 0.02, P = 0.45).Conclusions: In FALD, TE and 2D SWE are poorly correlated. LSM by either modality was not associated with known risk factors for liver fibrosis or Fontan function. Based on these data, the role of elastography in FALD is uncertain.