During the prenatal period, the unborn puppy develops an important blood vessel called the ductus arteriosus, which connects the pulmonary artery of the lungs to the aorta of the heart. The dusctus arteriosus is necessary in maneuvering the blood circulation so that it bypasses the fluid-filled fetal lungs and goes directly through the pumping heart to deliver oxygen throughout the rest of the body. However, when the puppies are born and they start to breathe on their own, the cardiovascular system undergoes a change where the lungs are no longer filled with fluid but with air and it now requires the oxygenation from the blood pumped by the heart. Hence, the ductus arteriosus should naturally close off and blood should travel normally throughout the body, but these don’t occur with patent ductus arteriosus (PDA). This leads to a serious and possibly fatal complication where the heart gets overwhelmed from the backwards shunting of blood that was supposed to go through the pulmonary artery of the lungs and then at the same time trying to circulate oxygenated blood throughout the whole body. The puppy’s heart may be able to cope, but only for a short period of time because the puppy will eventually have heart enlargement leading to heart failure.
You may ask why your Labrador has this terrible condition and the answer will be in his or her genes. Patent ductus arteriosus is a congenital and hereditary condition which is three times more likely to affect female dogs than male dogs.
As it is congenital, detection should be found early at birth but it can be confirmed by the veterinarian. You may notice several signs with your Labrador puppy, like shortness of breath, coughing, and loss of energy in short exercises. However, dogs with patent ductus arteriosus are often asymptomatic and these symptoms only appear when the heart has already been damaged. That is why it is very important to have your puppy medically examined a few days or a week after his or her birth to determine any cardiac or any other problems.
The first sign of a patent ductus arteriosus are heart murmurs which vets can detect in a routine check-up. But in order to know the extent of the problem, further tests has to be conducted such as x-rays and ECGs to observe the blood flow between the pulmonary artery and aorta.
Once the Labrador is diagnosed with PDA, the only route to treatment is through invasive surgery. Currently, there are two options: (1) thoracotomy and (2) catheter based occlusion. Thoracotomy is an open-chest, close-heart surgery which was the traditional way of closing the ductus arteriosis by way of stitching. General anesthesia is administered and the dog may be discharged after a few days.
The catheter based occlusion is the minimally invasive choice, where they insert a self-expanding plug into the ductus arteriosus, called the Amplatzer canine ductal occlude, through a jugular or femoral vein to close it off from within. The dog may be discharged the next day after the procedure.
Post-operative procedures include removal of sutures from the thoracotomy a week after surgery and another echocardiogram check-up a couple of months to check for any recurring or underlying problems.
If the condition is detected and addressed early, the general prognosis is that your Labrador will live a healthy and normal life. If not, the condition could lead to permanent heart damage which will require long-term medical examinations and cardiac medications to manage long-standing problems. Furthermore, if your dog is inflicted with this problem it should not be used for further breeding and its siblings have to be screened carefully before breeding, too. This is a serious condition that all pet-owners should be aware of as early as possible so take the necessary precautions and medical examinations to prevent your pet from suffering.