Effect of Body Position, Exercise, and Sedation on Estimation of Pulmonary Artery Pressure in Dogs with Degenerative Atrioventricular Valve Disease

Background Severity of pulmonary hypertension (PH) in dogs is related to clinical signs and prognosis. Hypothesis/Objectives We hypothesized that Doppler echocardiographic (DE) indices of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are influenced by independent factors that create clinically important variability of DE‐based estimates of PH in dogs. Animals Thirty‐eight client owned dogs with naturally acquired degenerative atrioventricular valve disease and tricuspid regurgitation (TR). Methods Dogs were prospectively enrolled, and target variables were acquired during 4 echocardiographic study periods (lateral recumbency, standing, lateral recumbency after a 6‐minute walk test [6MWT], and lateral recumbency after sedation with butorphanol 0.25 mg/kg IM). Statistical methods included repeated measures ANOVA, mixed model analysis, and Chi‐squared test of association. Results There was a significant increase in peak TR flow velocity (TRFV; P 0.4 m/s in 42% of dogs, independent of stroke volume. A significant effect of study period on DE‐estimated PVR was not found (P = 0.15). There were negligible effects of sonographer, body position, and 6MWT on echocardiographic variables of PH. Clinically relevant cyclic variation of TRFV was found. There was an association between estimation of right atrial pressure based on subjective assessment and estimation based on cranial vena cava collapsibility (P = 0.03). Conclusions and Clinical Importance The increase in TRFV observed with sedation could change assessment of PH severity and impact prognostication and interpretation of treatment response. Further studies with invasive validation are needed.