Definition of Aortic Stenosis
Aortic stenosis, also called subaortic stenosis or “SAS,” is a narrowing of the front part of the aorta, which is the artery that carries oxygenated blood out of the heart. In dogs, aortic stenosis is usually hereditary. Occasionally, it is caused by a bacterial infection of the aorta or the upper left heart valve, which is the doorway between the heart and the aorta. When the aorta is constricted, blood backs up inside the heart, making it work harder than normal to pump blood and maintain proper blood pressure throughout the body. This extra strain causes the walls of the left heart chamber to thicken and lose elasticity. Unfortunately, aortic stenosis is fairly common in dogs. It usually is congenital, which means it is present at birth. However, symptoms of the condition may not show up for several years. Some affected dogs never develop noticeable signs and simply die unexpectedly.