Doppler-derived echocardiographic evidence of pulmonary hypertension in cats with left-sided congestive heart failure

Introduction: Pulmonary hypertension (PH) caused by left-sided congestive heart failure (L-CHF) is common in dogs and contributes to clinical signs and outcome. The aim of this study was to evaluate the prevalence of Doppler echocardiography–derived PH in a population of cats with L-CHF. Animals: The study involved 131 cats with L-CHF and 56 control cats. Methods: The study design is retrospective, observational study. Tricuspid regurgitation velocity, right atrial dimension, right ventricular (RV) dimension and function, RV wall thickness, pulmonary artery (PA) dimension, Doppler-derived systolic time intervals of PA flow, and presence of septal flattening were evaluated. Pulmonary hypertension was considered if tricuspid regurgitation velocity was >2.7 m/s. Results: Tricuspid regurgitation was present in 57/131 (44%) of cats with L-CHF and 24/56 (43%) in control cats based on color flow Doppler. Doppler-derived of PH was identified in 22/131 cats with L-CHF (17%). In 15/22 cats, PH was associated with cardiomyopathy, in 5/22 cases with congenital heart disease, and in 2/22 cases with other causes. Cats with Doppler-derived PH more often had chronic L-CHF, as opposed to acute L-CHF (p<0.05). All cats with Doppler-derived PH had subjectively-assessed right-sided heart enlargement, with larger right atrial and RV diameters (p<0.001), increased RV wall thickness (p<0.05), and higher prevalence of septal flattening (<0.001) and PA enlargement (p<0.05). Conclusions: Pulmonary hypertension identified by Doppler echocardiography is not a common finding in cats with L-CHF. Right-sided heart enlargement, more frequently observed, may raise the suspicion of PH in cats with L-CHF.