Patent Ductus Arteriosus (PDA) in Dogs
Definition of Patent Ductus Arteriosus
The ductus arteriosus is a normal fetal blood vessel connecting the aorta and the pulmonary artery. This allows the blood of unborn puppies to bypass their non-functioning lungs; they get oxygen from their mother. The ductus arteriosus should close shortly before or just after birth, once a puppy takes its first breaths and its lungs inflate. In puppies with a patent ductus arteriosus (“PDA”), this channel stays open. PDAs are considered genetic, although they may be influenced by environmental, infectious, nutritional, pharmaceutical and toxicological factors. PDAs make the heart work too hard. The left heart chambers stretch, reducing blood flow from the heart. Affected dogs tire easily, become weak and lethargic, cough, have trouble breathing and have stunted growth. Many develop seizures and fainting episodes. Left untreated, PDAs will contribute to congestive heart failure and are almost always fatal. They are among the most common congenital heart defects in dogs.
Arterial shunts are normal in fetal animals (including people), but they should close within a short time of birth. A patent ductus arteriosus is one of the most common congenital heart defects in dogs (congenital defects are those which are present at birth). Unfortunately, little is known about why PDA develops so frequently in domestic dogs. It may be influenced by a number of factors or combinations of factors, including environmental, infectious, nutritional, pharmaceutical and/or
Signs of patent ductus arteriosus (PDA) in domestic dogs can take years to develop, but some dogs show mild signs from this disorder as early as one year of age. It is critical to detect PDA as early in a dog’s life as possible, because this congenital defect is almost always surgically correctable. Surgery has a much better chance of success if the PDA is detected before the onset of congestive heart failure or other
Patent ductus arteriosus is usually diagnosed during a routine physical examination of a young dog showing no overtly abnormal clinical signs. PDA shunts cause a continuous heart murmur that is louder and then softer at identifiable phases of the heart cycle. A skilled veterinarian can detect this murmur when listening to the heart through a stethoscope. This murmur often can be felt by placing the palm of a hand behind the dog’s left elbow; the
Fortunately, patent ductus arteriosus (“PDA”) is one of the congenital canine conditions that is highly treatable – in fact, surgically correctible – in most affected dogs. The therapeutic goal is to occlude or tie off the shunt defect and thereby restore normal blood flow between the right and left heart chambers. This treatment it is extremely effective in young animals that have not yet deteriorated to the point of congestive heart failure. Dogs that have