PDA

PDA

What is patent ductus arteriosus (PDA)?

At birth, mammals must adapt from living in a fluid environment (the amniotic fluid) and acquiring oxygen through the mother's blood, to breathing air and acquiring oxygen through their own lungs. The ductus arteriosus is very important in the adaptation process. This is a small communicating blood vessel between the pulmonary artery (which carries blood to the lungs), and the aorta (which carries blood to the rest of the body). Before birth, most of the blood from the fetal heart bypasses the fetal lungs via the ductus arteriosus. The lungs gradually become functional fairly late in fetal development. At birth, the blood supply from the mother is of course cut off, the dog (or other mammal) begins breathing on its own, and blood flow through the ductus arteriosus decreases dramatically. Within a few days, the ductus closes off completely.

Where the ductus does not close, the dog is left with a patent ductus arteriosus (PDA). The extent to which this affects the dog depends on the degree of patency, or opening, of the ductus.

How is PDA Treated?

Treatment consists of an operation that is done as soon as possible after diagnosis. The operation requires general anesthesia and an incision in the chest (thoracic surgery). The PDA is located and closed with a surgical suture. In some referral centers, the PDA may be closed using special catheterization techniques, where the chest is not opened, but these are still considered experimental.

There is no benefit to delaying surgery. In fact, the chance of a dog developing heart failure or suffering irreversible damage to the heart muscles only increases with passing time. One should not wait for signs to develop. Should signs (coughing, difficult breathing) already be present, a brief period of medical treatment may be needed to stabilize the puppy's condition before surgery. Following surgery, medications are given to control post-operative pain. After a 1 to 3 day post-operative hospital stay, the dog is released to your care at home.

What is the Prognosis for Dogs with PDA?

The prognosis is very good if surgery is performed early. With prompt recognition and surgical repair there is a 92 to 95% success rate. Following successful surgery, the dog should live a normal life. Unless there are complications from other heart defects, or heart failure has already developed, there is rarely a need for any future medicine or exercise limitations. Without surgery, about 60% of the dogs diagnosed with PDA will die within one year of diagnosis. Of course, there may be special circumstances that can influence the prognosis in an individual case. Any concerns or questions should be discussed with your veterinarian.

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