Clinical utility of shear wave speed and dispersion slope measured by shear wave elastography for the assessment of hepatic congestion in dogs with cardiac disease.

INTRODUCTION/OBJECTIVES: Right-sided heart failure (RHF) elevates central venous pressure, causing hepatic congestion. Two-dimensional shear wave elastography (2D-SWE) measures shear wave speed (SWS) and dispersion slope (DS), reflecting tissue viscoelasticity and viscosity. The aim was to investigate associations between hepatic SWS and DS and RHF in dogs and evaluate clinical utility. ANIMALS, MATERIALS AND METHODS: One hundred client-owned dogs with cardiac disease were prospectively classified into RHF (n = 27) and non-RHF (n = 73) groups based on ascites. Hepatic SWS and DS were measured using 2D-SWE. Congestion and cardiac function were assessed via caudal vena cava short-to-long diameter ratio (CVC SD/LD), right atrial area index (RAA index) and left ventricular outflow tract velocity-time integral (LVOT-VTI). Associations between elastography and echocardiographic variables were analysed, and diagnostic performance for RHF was evaluated. RESULTS: Both SWS and DS were significantly higher in RHF dogs (SWS: 1.79 [1.63-2.38]; DS: 16.40 [15.55-19.83]) than non-RHF dogs (SWS: 1.31 [1.25-1.37]; DS: 12.5 [11.0-13.5]; P<0.001) and were moderately correlated with CVC SD/LD, RAA index and LVOT-VTI. Receiver operating characteristic analysis showed DS had the highest area under the curve. Multiple regression analysis indicated SWS was associated with CVC SD/LD and LVOT-VTI, while DS was associated with CVC SD/LD and RAA index. STUDY LIMITATIONS: It is a single-centre study without histopathologic confirmation. CONCLUSIONS: Hepatic SWS and DS measured are promising non-invasive markers for RHF in dogs. In particular, DS is more specific for hepatic congestion, while SWS reflects both congestion and low cardiac output-related changes.