Echocardiographic characteristics of dogs with pulmonary hypertension secondary to respiratory diseases

Evaluation of Plasma Nitric Oxide and Serum Endothelial Nitric Oxide Synthase in Pulmonary Hypertensive Dogs: A Clinical and Echocardiography Investigation

Nitric oxide (NO), an endogenous vasodilator, has been proposed as a biomarker for pulmonary hypertension (PH) in humans. NO is synthesized by endothelial nitric oxide synthase (eNOS). Alterations in NO/eNOS have not been studied in dogs with PH. We assessed alterations in NO and eNOS in the blood of dogs with PH (n = 17) and healthy dogs (n = 10) and analyzed their correlations with echocardiographic parameters. The results showed significantly higher plasma NO and serum eNOS levels in dogs with PH compared with healthy dogs. Dogs with PH and ascites (n = 11) had significantly lower plasma NO levels than those without ascites (n = 6) and presented a decreasing eNOS trend. In dogs with PH, plasma NO was positively correlated with left ventricular hemodynamics, right ventricular compliance, and pulmonary distensibility, but was negatively correlated with pulmonary vascular resistance and right cardiac remodeling. Serum eNOS was positively correlated with the main pulmonary artery diameter. Increments in NO/eNOS reflected compensatory responses to cardiovascular changes in PH. These compensations were downward in the advanced stages. Other factors may also impact NO/eNOS compensation. Although the role of NO/eNOS as biomarkers for PH in dogs remains equivocal, they may indicate compensatory consequences of cardiovascular alterations.

Comparative Echocardiographic Evaluation of Right Pulmonary Artery Dimensions and Right Pulmonary Artery Distensibility Index in Dogs with Heartworm Disease

Canine cardiopulmonary dirofilariosis or heartworm disease (Dirofilaria immitis), is a globally spread vector-borne disease [...].

The echocardiographic pulmonary to left atrial ratio: A noninvasive variable for the hemodynamic classification of pulmonary hypertension in dogs

BACKGROUND

Hemodynamic classification of pulmonary hypertension (PH) has important clinical implications. However, only a few echocardiographic variables have been used to hemodynamically classify PH in dogs.

OBJECTIVE

To evaluate the echocardiographic pulmonary to left atrial ratio index (ePLAR) in dogs with PH.

ANIMALS

Forty-six dogs with intermediate to high probability of PH.

METHODS

Cross-sectional study. Variables were compared between dogs with precapillary PH [PrePH (n = 24)] vs postcapillary PH [PostPH (n = 22)], and with combined PH [CombPH (n = 14)] vs isolated PH [IsoPH (n = 8)] 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.

RESULTS

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 = .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.

CONCLUSIONS AND CLINICAL IMPORTANCE

ePLAR can be considered a valid noninvasive variable to hemodynamically classify PH in dogs with an intermediate to high probability of PH. Assessment of ePLAR can be useful in the therapeutic management of PH in dogs.