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

<jats:sec><jats:title>Background</jats:title><jats:p>Severity of pulmonary hypertension (<jats:styled-content style="fixed-case">PH</jats:styled-content>) in dogs is related to clinical signs and prognosis.</jats:p></jats:sec><jats:sec><jats:title>Hypothesis/Objectives</jats:title><jats:p>We hypothesized that Doppler echocardiographic (<jats:styled-content style="fixed-case">DE</jats:styled-content>) indices of pulmonary artery pressure (<jats:styled-content style="fixed-case">PAP</jats:styled-content>) and pulmonary vascular resistance (<jats:styled-content style="fixed-case">PVR</jats:styled-content>) are influenced by independent factors that create clinically important variability of <jats:styled-content style="fixed-case">DE</jats:styled-content>‐based estimates of <jats:styled-content style="fixed-case">PH</jats:styled-content> in dogs.</jats:p></jats:sec><jats:sec><jats:title>Animals</jats:title><jats:p>Thirty‐eight client owned dogs with naturally acquired degenerative atrioventricular valve disease and tricuspid regurgitation (<jats:styled-content style="fixed-case">TR</jats:styled-content>).</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>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 [6<jats:styled-content style="fixed-case">MWT</jats:styled-content>], and lateral recumbency after sedation with butorphanol 0.25 mg/kg <jats:styled-content style="fixed-case">IM</jats:styled-content>). Statistical methods included repeated measures <jats:styled-content style="fixed-case">ANOVA</jats:styled-content>, mixed model analysis, and Chi‐squared test of association.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>There was a significant increase in peak <jats:styled-content style="fixed-case">TR</jats:styled-content> flow velocity (<jats:styled-content style="fixed-case">TRFV</jats:styled-content>;<jats:italic> P</jats:italic> < 0.01) after sedation in 78% of dogs, with <jats:styled-content style="fixed-case">TRFV</jats:styled-content> increasing by >0.4 m/s in 42% of dogs, independent of stroke volume. A significant effect of study period on <jats:styled-content style="fixed-case">DE</jats:styled-content>‐estimated <jats:styled-content style="fixed-case">PVR</jats:styled-content> was not found (<jats:italic>P </jats:italic>= 0.15). There were negligible effects of sonographer, body position, and 6<jats:styled-content style="fixed-case">MWT</jats:styled-content> on echocardiographic variables of <jats:styled-content style="fixed-case">PH</jats:styled-content>. Clinically relevant cyclic variation of <jats:styled-content style="fixed-case">TRFV</jats:styled-content> was found. There was an association between estimation of right atrial pressure based on subjective assessment and estimation based on cranial vena cava collapsibility (<jats:italic>P </jats:italic>= 0.03).</jats:p></jats:sec><jats:sec><jats:title>Conclusions and Clinical Importance</jats:title><jats:p>The increase in <jats:styled-content style="fixed-case">TRFV</jats:styled-content> observed with sedation could change assessment of <jats:styled-content style="fixed-case">PH</jats:styled-content> severity and impact prognostication and interpretation of treatment response. Further studies with invasive validation are needed.</jats:p></jats:sec>