Patent Ductus Arteriosus (Blood Vessel Malformation on the Heart) in Dogs

  • Occurrence: very rare
  • Location of illness: Chest
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Patent Ductus Arteriosus (PDA) is a congenital heart defect in dogs in which the ductus arteriosus, a blood vessel that normally closes at birth, remains open, leading to abnormal blood flow circulation between the aorta and the pulmonary artery.

The most important facts at a glance

Patent ductus arteriosus (PDA) is a heart condition in dogs in which an important blood vessel that should close after birth remains open. During fetal development, the ductus arteriosus bypasses the lungs because the fetus receives oxygen through the placenta. After birth, the lungs should expand and this vessel should close. In dogs with PDA, however, it remains open, leading to mixed blood and overloading the heart. This can lead to heart failure in the long term. The exact cause is unclear, but genetic factors are significant, and certain breeds such as Poodles and Shepherds are more commonly affected. Symptoms range from heart murmurs and reduced exercise tolerance to Respiratory distress. For diagnosis, the veterinarian uses clinical examinations, echocardiograms, and X-rays. Treatment is usually surgical by closing the vessel, which significantly improves the prognosis. Medications can be used temporarily to relieve symptoms. Early diagnosis and treatment are crucial for the prognosis. Prevention focuses on responsible breeding practices and avoiding risk factors during pregnancy. Regular follow-up examinations ensure the heart health of operated dogs. A balanced diet for the pregnant bitch can reduce the risk of heart defects.

Causes

The ductus arteriosus is an important blood vessel in fetuses that bypasses the lungs because the unborn animal’s oxygen needs are met by the placenta. After birth, when the lungs take over the function of oxygen supply, this vessel should close. The closure is triggered by the increase in blood oxygen levels and the decrease in prostaglandins, natural chemical messengers.

In dogs with PDA, however, this channel remains open, leading to a mixture of oxygen-rich and oxygen-poor blood. This overloads the heart, especially the left atrium and left ventricle, as they have to process more blood than usual. In the long term, this can lead to heart failure.

The exact cause of a patent ductus arteriosus is not fully understood, but genetic factors play a significant role. Certain dog breeds, such as the Poodle, Shepherd, and Cavalier King Charles Spaniel, have a higher predisposition, indicating a hereditary component. Environmental factors during pregnancy, such as infections or malnutrition, may also increase the risk.

Symptoms

Rare symptoms:

Dogs with a patent ductus arteriosus can have a variety of symptoms, depending on the size of the defect and the amount of blood being shunted. In many cases, symptoms are visible in the first weeks or months of life.

The most common signs include reduced exercise tolerance, rapid breathing, Cough, and growth retardation. On physical examination, a characteristic heart murmur, known as a “machinery murmur”, can be heard, which is caused by the turbulent flow of blood through the patent ductus.

In severe cases, dogs may also show signs of heart failure, such as Respiratory distress, abdominal dropsy, or fainting spells. Untreated, the condition can ultimately lead to heart enlargement and life-threatening complications.

Diagnosis

The diagnosis of patent ductus arteriosus often begins with a thorough clinical examination, during which the characteristic heart murmur is detected. An experienced veterinarian can then order further diagnostic tests to confirm the diagnosis and assess the extent of the problem.

An echocardiogram (ultrasound of the heart) is the method of choice to visualize the patent ductus arteriosus and assess its effects on the heart. It allows visualization of blood flow and heart structure and provides important information about the size and function of the heart.

In addition, chest X-rays can be taken to assess the size of the heart and the condition of the lungs. Electrocardiograms (ECG) can also be performed to detect any Cardiac arrhythmia.

Therapy

Treatment of patent ductus arteriosus in dogs is surgical in most cases. The procedure involves ligating or closing the open vessel to stop the abnormal blood flow. This can be done either through traditional surgery or through a minimally invasive procedure using a catheter.

Surgical closure has a high success rate and can significantly improve the prognosis of the affected dog. The decision on the exact procedure depends on several factors, including the size of the dog, age, severity of the defect, and the surgeon’s experience.

In some cases, especially when surgery is not immediately possible, medications can be used to control symptoms and support heart function. These medications may include diuretics, ACE inhibitors, and cardiac glycosides, which help reduce the strain on the heart.

Prognosis and follow-up care

The prognosis for dogs with patent ductus arteriosus depends heavily on timely diagnosis and treatment. With early detection and successful surgical correction, many dogs can live a normal, healthy life.

Untreated, the course is often unfavorable, as the continuous strain on the heart can lead to progressive heart failure and ultimately to Death. Therefore, it is crucial to recognize and treat the defect as early as possible.

Dogs that undergo successful surgery usually have a very good quality of life, and many experience no further heart problems. However, regular follow-up examinations are important to monitor heart health.

Prevention

Since patent ductus arteriosus is often genetic, prevention is primarily aimed at avoiding breeding affected animals. It is important to educate breeders and owners about the risks and the genetic component, especially in predisposed breeds.

Screenings and genetic tests can help identify carriers and affected dogs to prevent the defect from being passed on to future generations. Responsible breeding practices can help reduce the incidence of this malformation in the dog population.

In addition, avoiding risk factors during pregnancy, such as stress, infections, and malnutrition, can help reduce the risk of congenital heart defects. A balanced and nutritious diet for the pregnant bitch can support the healthy development of the fetuses.

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