Using heart ultrasound views to diagnose lung fluid in dogs

Abstract

The objective of this study was to determine whether echocardiographic views adapted for lung evaluation may aid in diagnosis of dyspnea in dogs. Fifteen chronic valvular heart disease (CVHD) dogs without cardiac remodeling, 30 CVHD dogs with cardiac remodeling, 15 CVHD dogs with cardiogenic pulmonary edema and 15 dogs with pulmonary disease were prospectively enrolled. Loop recordings of pericardial-lung ultrasound were gathered during echocardiographic evaluation, and four videos of 4 different adapted views were recorded for each dog. Chest X-rays were used as reference-standard for pulmonary edema and/or disease. The videos were classified based on the number of B- lines as NEGATIVE (0, 1, 2 or 3) or POSITIVE (> 3 or confluent). Accuracy of a POSITIVE classification in identifying pulmonary edema and/or disease was calculated. Multivariate analyses were performed using echocardiographic variables that reflect increased left ventricular filling pressure (LVFP) to distinguish pulmonary edema from disease. Results showed that a POSITIVE classification distinguished dogs with pulmonary edema or disease from asymptomatic CVHD dogs in all four views. The best views were right parasternal short axis at papillary muscle level and long axis 4- chamber view, both with the same sensitivity (86.7%) and a specificity of 95.6% and 82.2%, respectively. Multivariate analyses showed that adding cutoff values of peak E wave > 130, E/IVRT > 2.5 or LA/Ao > 2.0 distinguished pulmonary edema from disease with 100% specificity. In conclusion, echocardiographic views adapted for lung evaluation, in addition to conventional echocardiography, may help identify the cause of dyspnea in dogs.