Contrast-enhanced echocardiographic assessment of left ventricular wall measurements in cats

Introduction/Objectives Hypertrophic cardiomyopathy (HCM) is defined by increased left ventricular wall thickness (LVWT), making accurate measurement essential. Contrast-enhanced echocardiography (C-ECHO) improves myocardial border delineation. We aimed to evaluate whether C-ECHO provides more reliable LVWT measurements in cats compared to standard echocardiography (S-ECHO). Animals, Materials and Methods Forty-five cats (32 with LVWT <6 mm; 13 with LVWT ≥6 mm) were prospectively enrolled. Two-dimensional right parasternal short-axis images were acquired before and after contrast administration (Sonovue 0.05 mL/kg (0.04–0.14 mL/kg)). Septal and posterior wall thickness were measured using both modalities. Agreement and reliability were assessed using Bland-Altman analysis, Kappa statistics, and intraclass correlation coefficients (ICC). Results left ventricular wall thickness was greater with S-ECHO than C-ECHO (maximal LVWT 5.0 mm (2.8–9.5 mm) vs. 4.2 mm (2.5–8.9 mm), P<0.0001). On average, LVWT measured by S-ECHO was 0.61 mm greater than that obtained by C-ECHO. Agreement between S-ECHO and C-ECHO for HCM diagnosis was only moderate (Kappa 0.50). Bland-Altman analysis showed fixed biases and wide 95% limits of agreement (LoA) for LVWT (septum: bias 0.8 mm, LoA -0.7-2.3 mm; posterior wall: bias 0.4 mm, LoA -1.1-2.0 mm). Contrast-enhanced echocardiography demonstrated higher measurement reliability (ICC 0.99 vs. 0.96). Study limitations A low–mechanical index preset was not used; and measurements were not timed using an ECG. Conclusions Standard echocardiography seems to overestimate LVWT compared to C-ECHO, consistent with findings reported in human studies. Contrast-enhanced echocardiography improves measurement reliability. These findings support its use to enhance HCM assessment in cats.