Utilizzo dell’indice ecocardiografico ePLAR per la classificazione emodinamica dell’ipertensione polmonare nel cane

Pulmonary hypertension (PH) is characterized by abnormally high pulmonary arterial pressure (PAP). Hemodynamically, PH is classified into 2 main groups, precapillary (PrePH) resulting from abnormalities on the arterial side of the pulmonary vascular system and postcapillary (PostPH), secondary to pulmonary venous congestion. Postcapillary PH can be further classified into isolated PH (IsoPH) and combined pre- and postcapillary PH (CombPH). Isolated PH is characterized by increased PAP with normal pulmonary vascular resistance (PVR). In contrast, CombPH is characterized by structural changes in the pulmonary vasculature caused by chronic and progressive congestion of the pulmonary capillaries and veins, which increase PVR. Hemodynamic classification of PH has important clinical implications. However, only a few echocardiographic variables have been used to hemodynamically classify PH in dogs. The aim of this study was to evaluate if the Echocardiographic Pulmonary to Left Atrial Ratio index (ePLAR) could differentiate PrePH from PostPH and IsoPH from CombPH in dogs. Forty-six dogs with intermediate to high probability of PH were classified in PrePH (n=24) and PostPH group (n=22). Dogs of the PostPH group were further classified in IsoPH (n=8) and CombPH subgroups (n=14). Age, sex, body weight, heart rate and echocardiographic parameters, including ePLAR values, were compared between groups using the t-, Mann-Whitney, Pearson's Chi, or Fisher's exact test. The receiver operating characteristic curve and Youden index were used to identify the optimal ePLAR cutoff value to differentiate among the groups, intraclass correlation coefficients (ICC) were used to determine the reliability of measurements. The mean (SD) ePLAR of the PrePH was higher than that of the PostPH group [0.36 (0.13) vs 0.26 (0.09), respectively; P = 0.005]. The median (interquartile range) ePLAR of the CombPH was higher than that of the IsoPH subgroup [0.29 (0.24-0.38), vs 0.20 (0.16-0.23), respectively; P = .001]. The best cutoff value of ePLAR for identifying IsoPH was <0.245 [AUC at cutoff point = 0.86; sensitivity (95% confidence interval [CI]) = 0.71 (0.47-0.95); specificity (95% CI) = 1 (0.76-1)]. The ICC analysis indicated a high degree of reliability. The results showed that ePLAR is a simple and valid echocardiographic parameter that can be used to hemodynamically classify PH in dogs with an intermediate to high probability of PH. The assessment of ePLAR can assist clinicians in selecting the most appropriate treatment for dogs with PH an intermediate to high probability of PH.