Pulmonary hypertension (PH) in dogs is confirmed echocardiographically using a combination of Doppler-derived pressure estimates and supporting structural indices, with treatment indicated when clinical signs are present or when PH severity reaches intermediate-to-high probability thresholds.

The ACVIM consensus defines PH by increased pressure within the pulmonary vasculature and requires comprehensive evaluation integrating signalment, clinical signs, echocardiographic parameters, and ancillary diagnostics — no single measurement is sufficient alone.Journal of Vete… Right heart catheterization remains the gold standard for direct pulmonary arterial pressure and pulmonary capillary wedge pressure measurement, but is impractical in dogs due to anesthetic risk in severe cardiorespiratory disease; transthoracic echocardiography is the diagnostic test of choice in clinical practice.Journal of Vete…+1

The primary echocardiographic pressure estimate is the tricuspid regurgitation pressure gradient (TRPG), derived from the tricuspid regurgitation jet velocity. An estimated systolic pulmonary arterial pressure (sPAP) ≥47 mmHg identifies dogs with significantly shorter survival times compared to those with sPAP <47 mmHg (median 9 days versus a substantially longer survival; P = 0.001), and at this cutoff the TRPG carries a sensitivity of 0.78 and specificity of 0.63 for predicting non-survival in dogs with respiratory disease-associated PH.The Veterinary… The CT pulmonary trunk-to-aorta diameter ratio correlates moderately with TRPG (r = 0.61) and is significantly elevated in moderate and severe PH compared to normal dogs, but does not differ significantly between normal dogs and those with mild PH; an elevated ratio on thoracic CT should prompt follow-up echocardiography.Veterinary Radi…

Hemodynamic classification into precapillary versus postcapillary PH is essential before initiating pulmonary vasodilator therapy. Precapillary PH arises from increased pulmonary vascular resistance with normal pulmonary capillary wedge pressure and encompasses respiratory disease/hypoxia, thromboembolic disease, parasitic disease, congenital shunts, and idiopathic pulmonary arterial hypertension.Journal of Vete…+1 Postcapillary PH results from elevated pulmonary venous pressure secondary to left-sided heart disease — most commonly myxomatous mitral valve disease — and can progress to combined pre- and postcapillary PH with secondary pulmonary vascular remodeling.Journal of Vete…+2 Echocardiographic distinction relies on left atrial dimension, with left atrial enlargement supporting postcapillary origin; the pulmonary-to-left atrial ratio has been evaluated as a noninvasive index to differentiate these hemodynamic subtypes.Journal of Vete… This distinction is clinically critical: phosphodiesterase-5 inhibitors (PDE5i) such as sildenafil are potentially contraindicated in isolated postcapillary PH because they may exacerbate pulmonary edema.Journal of Vete…

Supporting echocardiographic indices of PH include the main pulmonary artery-to-aorta diameter ratio (MPA/Ao), right ventricular acceleration time-to-ejection time ratio (AT/ET), pulmonary insufficiency gradient, and right ventricular structural changes including hypertrophy, dilatation, and dysfunction.Veterinary Radi…+2 The normalized right pulmonary artery minimum diameter (RPAmin_N) demonstrates higher diagnostic accuracy and less measurement variability for PH detection than MPA assessment alone, and complementary use of this parameter is recommended.Journal of Vete… Three-dimensional echocardiographic right ventricular end-diastolic volume indexed to body weight (EDVn) is significantly higher in dogs with PH (2.5 mL/kg) compared to healthy controls (1.8 mL/kg), and 2D global and free-wall right ventricular longitudinal strain measurements detect decreased right ventricular function with advantages over conventional indices.Journal of Vete…

NT-proBNP is a validated noninvasive biomarker for detecting and monitoring PH severity. In dogs with heartworm disease, a NT-proBNP cutoff of 1524.8 pmol/L detects moderate-to-severe PH with a sensitivity of 99% and specificity of 87%; baseline NT-proBNP is significantly higher in dogs with PH compared to those without PH (2038 ± 1671 pmol/L versus 583 ± 185 pmol/L, P < 0.001).Parasites and V… NT-proBNP concentrations correlate positively with parasite burden and clinical sign severity in heartworm-associated PH, and decline progressively during adulticide treatment in dogs with PH while remaining stable in those without PH.Parasites and V…

The six ACVIM classification groups guide the diagnostic workup and direct treatment toward the underlying cause: Group 1 (pulmonary arterial hypertension), Group 2 (left heart disease), Group 3 (respiratory disease/hypoxia), Group 4 (pulmonary emboli/thrombi/thromboembolism), Group 5 (parasitic disease — Dirofilaria and Angiostrongylus), and Group 6 (multifactorial or unclear mechanisms).Journal of Vete…+1 In dogs with bronchomalacia, echocardiography is recommended as a screening tool given the high prevalence of intermediate-to-high probability PH in this population.Journal of Vete… In dogs with Angiostrongylus vasorum infection, mild-to-severe pulmonary arterial hypertension is diagnosed in 58.8% of naturally infected dogs, and echocardiographic findings suggestive of PH can be the initial diagnostic pointer toward angiostrongylosis.Topics in Compa…

Treatment with PDE5 inhibitors is indicated when PH is clinically evident, and PDE5 inhibitor administration is the sole independent predictor of survival in dogs with respiratory disease-associated PH (hazard ratio 4.0, P = 0.02).The Veterinary… Sildenafil decreases pulmonary artery pressure gradient and improves quality of life in dogs with clinically evident PH.Journal of the… In right-to-left shunting patent ductus arteriosus, surgical correction is contraindicated once shunt reversal has occurred, and sildenafil is prescribed on a lifelong basis for PH management alongside periodic phlebotomy for polycythemia.Journal of the… For Group 4 pulmonary thrombosis, antithrombotic treatment is first-line, with pulmonary vasodilators added when pulmonary circulation does not improve sufficiently; beraprost sodium (BPS) at 15 µg/kg has been reported as a treatment for PH in dogs, dilating both pulmonary and systemic vasculature.Journal of Vete…

Would you like the specific sildenafil dosing protocol and monitoring approach for dogs with confirmed precapillary PH?