Patent Ductus Arteriosus (PDA)

What is a Patent Ductus arteriosus (PDA)?

A patent ductus arteriosus is a congenital heart defect in which there is an irregular transmission of blood between two of the major arteries in the heart. In the normal fetus, the blood by-passes the lungs through the “ductus arteriosus” because the lungs are not active and do not oxygenate the blood. When most puppies or kittens are born, the ductus arteriosus closes. A “patent” ductus arteriosus (PDA) means that this vessel remains open and blood gets re-circulated through the heart, making the heart work overtime and eventually leading to heart failure. In some cases, the blood flow reverses, causing a portion of blood that has not been oxygenated by the lungs to flow to the body. A variety of signs can be seen in animals with PDA, including lethargy, fast breathing and cough. Small and toy breed dogs are predisposed to this condition; however, dogs and cats of any breed and size can be affected. The majority of dogs and cats with PDA have a very loud heart murmur that can be heard when your veterinarian listens to the animals chest.

Pre-Op Work Up

A preoperative work up will be performed on your pet to confirm the diagnosis of PDA. Thoracic x-rays will be performed in order to see the size of the heart and whether there is fluid build up in the lungs. An echocardiogram (sonogram of the heart) will also be performed to assess how well the heart is working and to visualize the PDA. Based on this work up and physical examination, we will determine if treatment should be pursued and which treatment would be recommended.


Once the PDA is closed, most dogs and cats will enjoy a long, normal life without further heart problems.

What does treatment invovle?

One option for the treatment of a PDA is surgery. The procedures are performed by our board-certified surgeons. Through an icision between the ribs, the PDA is identified, gently isolated and closed using permanent suture. For some dogs and cats, surgery is the only option available for PDA closure.

Collaboratively with our Cardiology and Radiology services, we also offer minimally invasive interventional therapy. This involves placement of small occluders within the abnormal vessel that will cause the vessel to close. This is accomplished through a catheter in the neck or leg. This procedure avoids the need for open-chest surgery and likely results in a shorter stay in hospital. However, some animals are too small or the shape of the abnormal vessels is such that this procedure is not possible.

Post Operative Care

While complication rates are low, your pet will require close monitoring and supportive care in our intensive care unit for 2-3 days post-operatively, even when surgery is short and uneventful. Patients are carefully monitored by our specialized ICU staff 24 hours a day.

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