Development and evaluation of a composite echocardiographic score for predicting pulmonary hypertension severity in dogs.

Abstract

BACKGROUND: Tricuspid regurgitation peak velocity (pTRV) is commonly used to estimate pulmonary arterial systolic pressure in dogs but is not always obtainable. Echocardiographic changes may suggest pulmonary hypertension (PH) probability, but not all of them equally reflect severity. HYPOTHESIS/OBJECTIVES: Develop a composite echocardiographic score predicting pTRV in dogs. ANIMALS: Client-owned dogs (n&#xa0;=&#xa0;118) undergoing echocardiography for various cardiorespiratory reasons. METHODS: Multicenter retrospective study of dogs with identifiable tricuspid regurgitation. Echocardiographic findings were categorized into 6 a priori variables consisting of structural and flow-related abnormalities. Variable weighting was explored using regression analysis and cut-off scores were established for predicting pTRV &#x2265; 3.4 and&#xa0;&#x2265;&#xa0;4.3&#xa0;m/s using receiver operating characteristic (ROC) curves, and the predictive performance of the PH score also was assessed. Correlations between PH score and pTRV were analyzed, and intra- and interrater measurement reliability was evaluated. RESULTS: A final weighted PH score (25-point) incorporated semiquantification of right ventricular (RV) wall thickening (0/1/2 points), RV dilatation (0/2/4/6), right atrial (RA) enlargement (0/2/4/6), pulmonary artery enlargement (0/2/4/6), interventricular septal flattening (0/2/4), and midsystolic notching of RV outflow (0/1). In dogs without severe left atrial enlargement (LAE), 89% of cases were correctly stratified (area under the curve [AUC], 0.95), whereas performance was limited in dogs with postcapillary PH and marked LAE. Five-fold cross-validation identified final recommended thresholds of 3 (predicting pTRV &#x2265; 3.4&#xa0;m/s) and 9 (pTRV &#x2265; 4.3&#xa0;m/s). The PH score correlated with pTRV (rs&#xa0;=&#xa0;0.88, P&#xa0;<&#xa0;.001) and showed excellent intra- and inter-rater agreement (intraclass correlation coefficient [ICC]&#xa0;>&#xa0;0.95). CONCLUSIONS AND CLINICAL IMPORTANCE: The PH score may serve as a complementary tool for evaluating PH in dogs, particularly in those without severe LAE.