The aorta is the largest artery in the body. It is the main blood vessel that serves as a passageway for oxygen-filled blood to pass from the left side of the heart to be distributed throughout the entire body.
Aortic stenosis may be due to the malformation of the aorta or a defect in the left ventricle. The latter type is also termed as “sub-aortic stenosis” or “sub-valvular aortic stenosis”. There are also rare cases when stenosis or narrowing of the aorta is attributed to a defect in the valve which is located between the aorta and the left ventricle. It functions to prevent the backflow of blood into the left ventricle.
The clinical manifestations of Aortic Stenosis highly depend on the degree of the narrowing of the aorta. Some dogs are lucky enough to inherit only the mild type which can be barely detected while there are unlucky ones which inherit the more serious form. The signs of the condition are manifested as a result of the failure to feed the body the right amount of oxygen which is carried by the blood. Common signs include fainting, poor exercise tolerance, poor growth, or lethargy.
There are some dogs that do not display any of these signs however they often suffer from the secondary effects of a heart which has been pushed to overwork for a longer period of time in order to push blood through a narrow opening. The over-exertion of the heart leads to hypertrophy and the heart grows bigger over time. Dogs suffering from this condition tend to have coughing fits, breathing difficulties, and cardiac arrhythmias. An abnormal heart rhythm (cardiac arrhythmia) occurs when the heart’s size interferes with the normal electrical activity of the heart. Death can eventually follow the manifestation of these signs.
In order to come up with a correct diagnosis, your veterinarian will conduct a thorough physical exam on your dog. The cardiac arrhythmia can easily be detected because of the characteristic heart murmur. Dogs which have inherited the mild form of the disease are usually diagnosed during annual wellness checks particularly during the first year of life.
If the veterinarian can detect the heart murmur, a complete cardiac examination is recommended. Other tests include an echocardiogram (ultrasound of the heart), chest x-rays, and an electrocardiogram. An echocardiogram is the best tool to confirm aortic stenosis.
There is no successful procedure to correct Aortic Stenosis. Dogs suffering from the condition are given supportive treatment in order to lessen the load on the heart.
Regular screening of all dog breeds which are susceptible to the defect should be done before they are allowed to breed. If a dog is diagnosed with Aortic Stenosis, all its siblings and parents should be spayed or neutered to prevent passing on the defect to their offspring.
