What is pulmonic stenosis (PS)?

Pulmonary valve stenosis, or pulmonic stenosis (PS), in dogs is one of the most common congenital heart diseases that is caused by a malformation of the pulmonic valve. This interferes with blood flow from the heart to the lungs. The valve, which is located between the right ventricle and the pulmonary artery, becomes thickened or partially fused, narrowing the area around the valve. This malformation increases pressure and obstructs blood flow. As a result, the strain on the right ventricle increases. This condition is caused by genetics and is more prevalent in small-breed dogs, such as brachycephalic breeds or terriers. It may also be accompanied by other congenital and structural heart diseases. Treatment options depend on the results of a cardiac function evaluation and may include medication, surgery, or interventional procedures.

Causes of pulmonic stenosis in dogs

The cause of pulmonary valve stenosis in dogs has not been accurately identified yet, but evidence leads experts to believe it is a congenital (present at birth) malformation.

Breeds prone to pulmonic stenosis:

• English Bulldogs
• Boxers
• Samoyeds
• Terriers (Fox terriers, Scottish terriers, West Highland white terriers, Airedale Terrier, etc.)
• Labrador Retrievers
• Miniature Schnauzers
• Chihuahuas
• Miniature Pinschers
• Mastiffs
• Beagles

Symptoms of pulmonary valve stenosis (PS) in dogs

Symptoms of pulmonary artery stenosis in dogs vary, depending on the degree of stenosis. In mild cases, there may be no signs of disease during the first months or years of life, and the dog may even live without major problems throughout life. However, in moderate to severe stenosis, blood flow to the lungs is reduced and arrhythmia or congestive heart failure may occur. This can result in symptoms such as fatigue, decreased exercise tolerance, fainting (especially during exercise or excitement, and even death.

When to see a vet for pulmonic stenosis in dogs

If symptoms such as sudden fatigue, exercise intolerance, or fainting appear during exercise or excitement, this may indicate severe stenosis or a possibility of other heart diseases. It is recommended that you visit a hospital for an accurate diagnosis for the best prognosis.

How to manage pulmonic stenosis at home

Pulmonary valve stenosis in dogs is a disease that requires professional treatment, especially if the narrowing is severe enough to cause symptoms. There is no cure for this congenital heart defect and requires treatment to assist in controlling the disease through veterinary treatment.

Diagnosis of pulmonic stenosis (PS) in dogs

A veterinarian may first ask the owner about any typical symptoms of pulmonary valve stenosis, such as fatigue, exercise intolerance, and fainting, including when they occur and how often.

Depending on the symptoms present, the following tests may be conducted to help differentiate from other diseases:

• Physical examination

  Auscultation is crucial when suspecting heart disease. It can detect heart murmurs and arrhythmias. Additionally, an enlarged jugular vein can be confirmed as well as the presence or absence of fluid buildup can be determined through palpation. Other congenital heart diseases, such as patent ductus arteriosus (PDA), atrial septal defect (ASD), and ventricular septal defect (VSD), may also cause cyanosis which can be determined through physical examination.

• X-ray

  Symptoms such as coughing and shortness of breath can also appear in other respiratory-related diseases, in addition to heart disease, and X-rays can help differentiate between them. Additionally, the size of the heart can be evaluated through chest radiography. In the case of pulmonary valve stenosis, a marked enlargement of the right side of the heart may be observed.

• Electrocardiogram (ECG)

  An electrocardiogram, or ECG, is an evaluation of the electrical activity of the heart. This is done by attaching electrodes to the body. ECGs are used to determine the presence and classify the type of arrhythmia. In the case of pulmonic stenosis, an ECG can confirm evidence of an enlarged right ventricle and right atrium, such as a deepening of the S wave and a high P wave.

• Echocardiography

  The most useful method for diagnosing heart disease in dogs is through understanding the structure of the heart. Echocardiography allows for various evaluations of the heart's structure and function, such as detecting the presence and degree of stenosis, analyzing blood flow patterns, measuring velocity and pressure differences, and determining myocardial wall thickness.

  With pulmonary valve stenosis, there may be dilation of the pulmonary artery beyond the site of the stenosis, thickening of the right ventricular wall, or dilatation of the right atrium. In addition, pressure in the right ventricle may increase and impact the left ventricle. Measuring the velocity and pressure difference of the blood passing through the pulmonary artery valve can help determine the severity of a dog’s pulmonic stenosis. A pressure difference of 50 to 80 mmHg or higher indicates moderate to severe stenosis, and treatment options can be determined based on this value.

• Blood tests

  In general, blood tests such as a complete blood count, a serum chemistry test, and an electrolyte test are performed to evaluate the possibility of side effects and to check the overall condition of the body when prescribing medicine after a diagnosis of heart disease. Although not often used in pulmonary artery stenosis, depending on the situation, biomarkers that can detect changes in levels in the presence of heart diseases, such as proBNP or Troponin I, may be used for testing.

How to treat pulmonic stenosis in dogs

In cases of mild pulmonary artery stenosis without any clinical symptoms, likely, it will not cause significant health issues. As such, only regular monitoring is necessary and no treatment may be required. However, if clinical symptoms are present and the stenosis is moderate to severe, your pet’s symptoms and test results will be used to create a treatment plan that is specific to your pet’s condition.

You can expect the following treatment methods for dogs diagnosed with pulmonary valve stenosis:

• Movement restriction

  Restricting movement can help minimize the heart's work, along with a calm and stress-free environment that does not excite your dog.

• Medication

  In general, drug treatment can only help to alleviate the symptoms caused by pulmonic stenosis. Rather than treating the disease itself, beta-blockers may be prescribed to keep the heart from beating too fast and control arrhythmias. If congestive heart failure has occurred, drugs such as diuretics can be used to reduce fluid retention in the heart or lungs.

• Interventional procedures and surgical procedures

  To fundamentally solve pulmonary valve stenosis, various surgical techniques and minimally invasive therapies, such as balloon catheterization, can be used to widen the affected area. However, these procedures and surgeries may not be widely available, so it is important to consult with a specialist.

Prognosis for pulmonary valve stenosis

The prognosis for pulmonary valve stenosis may vary depending on the severity of the stenosis. If the narrowing is not severe, the dog can live a normal lifespan. However, it is still possible if proper treatment and management are not provided, symptoms can worsen or even lead to sudden death, depending on the severity of the stenosis.

Prevention of pulmonic stenosis in dogs

Since pulmonary valve stenosis is considered a congenital heart disease, it is not possible to prevent it. Early detection and management through regular checkups is the best course of action in preventing conditions from worsening. Additionally, if your dog is diagnosed with a genetic disease, such as pulmonic stenosis, it is recommended that you avoid breeding to prevent passing it on to future offspring.

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