Pulmonary Hypertension
Pulmonary hypertension is defined as high blood pressure within the vessels of the lungs. Primary pulmonary hypertension (meaning not resulting from another disease process) is rare in veterinary medicine and is diagnosed by ruling out all other causes of pulmonary hypertension.
Most common causes of pulmonary hypertension in dogs include:
Chronic lung disease and low blood oxygen concentration
- Chronic bronchitis (COPD)
- Pulmonary fibrosis (scarring of the lung tissue)
- Obstruction of the blood vessels
- Pulmonary thromboembolism (PTE, blood clot to the lungs) - Typically dogs with PTEs have another disease process that predisposes them to spontaneously forming blood clots within the body. These processes most commonly include a recent history of major trauma, Cushing’s disease, protein-losing intestinal or kidney disease, and cancer.
- Heartworm disease - Obstruction by the worms themselves and reaction of the blood vessels to the worms’ presence.
- Cancer
- Long-standing left-sided heart disease and heart failure
- Degenerative mitral valve disease
- Dilated cardiomyopathy
Clinical signs and physical exam findings common in pulmonary hypertension patients:
- Coughing
- Changes in breathing – increased respiratory rate and/or effort
- Exercise intolerance
- Fainting (syncope)
- Heart murmur
- Abnormal lung sounds (crackles +/- wheezes)
- Cyanosis of the tongue or mucous membranes (blue/purple color to the tongue or gums)
- Signs of right-sided congestive heart failure (most commonly free abdominal fluid)

The speed of the tricuspid valve leak can be used to estimate lung pressures.

Color-compare image showing severe right heart enlargement and moderate tricuspid regurgitation.

Short axis view of the ventricles showing severe right ventricular dilation and flattening of the septum.
High blood pressure in dogs is often treatable so your dog can lead a normal life. Talk to a board-certified dog cardiologist about a diagnosis and treatment.
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