Diagnostic Value of Echo‐Doppler and Tissue Doppler Imaging in Dogs with Pulmonary Arterial Hypertension

Abstract

Background: Diagnosis of pulmonary arterial hypertension (PAH) relies on Doppler measurement of pulmonic and tricuspid regurgitation (TR). However, these are not always detectable. Hypothesis: Tissue Doppler imaging (TDI), a novel noninvasive ultrasound technique, provides indirect but sensitive and specific assessment of elevated systolic pulmonary artery pressure (SPAP) in dogs. Animals: One hundred and five dogs with TR. Methods: Prospective observational study. Dogs were categorized as presenting normal (group 1, n = 45), mildly increased (group 2, n = 19), or moderately to severely increased (group 3, n = 41) SPAP, based on TR peak velocities (<2.5, 2.5–3.0, and >3.0 m/s, respectively). Ten quantitative echo‐Doppler‐ and TDI‐derived variables were assessed, including the main pulmonary arterial diameter to aortic diameter ratio, pulmonary flow acceleration time, and acceleration‐to‐ejection time ratio, the Tei index of right ventricular function, and 6 longitudinal basal right ventricular TDI variables. Results: A significant correlation was observed between SPAP and each of the 10 tested variables (P < .05). Conventional echo‐Doppler variables were less discriminating than the TDI for predicting increased SPAP. The combined systolic and diastolic right TDI index had the highest sensitivity and specificity (89% and 93% respectively, for a cutoff of 11.8 cm/s) and could discriminate between dogs in group 1 from dogs in group 2. Conclusions and Clinical Importance: TDI provided effective predictors of systolic PAH and demonstrated that both alterations in right‐sided systolic and diastolic myocardial function can occur with mild increases in SPAP.