In a person with aortic stenosis, the aortic valve no longer opens completely - that is, the valve becomes partially obstructed. This means the heart must work much much harder than normal to eject blood. Over time, the heart begins to fail.
What causes aortic stenosis?
Degeneration and calcification. The most common cause of aortic stenosis is, essentially, “wear and tear.” In some individuals, with the passage of time the aortic valve begins to degenerate, and when this happens calcium accumulates on the valve, creating irregular, rock-like deposits. These calcium deposits infringe on the valvular opening, causing a narrowing of that opening, or aortic stenosis.Bicuspid aortic valve. About 1% of all males are born with a bicuspid aortic valve. (That is, their aortic valves, which are supposed to have three cusps, have only two.) Bicuspid valves are especially prone to developing degeneration and calcification, and thus aortic stenosis. Men with aortic stenosis due to bicuspid valves develop symptoms in their 40s and 50s. In contyrast, patients whose degenerative aortic stenosis develops on normal, tricuspid valves begin to have symptoms two or three decades later.
Rheumatic heart disease. Fifty years ago, rheumatic heart disease was the leading cause of aortic stenosis in the developed world. With the advent of antibiotics, rheumatic fever has become relatively uncommon, and so has rheumatic aortic stenosis.
Congenital aortic stenosis. While aortic stenosis associated with bicuspid aortic valves is, strictly speaking, a form of congenital aortic stenosis, it is generally classified with the degenerative aortic stenoses. Included in the congenital category are various malformations of the aortic valve itself, as well as obstructive membranes or muscular growths that form above or below the actual aortic valve. These congenital lesions appear in much younger people than the non-congenital aortic stenoses (usually in children, or occasionally in young adults), and these young patients are more prone to sudden death than older patients with aortic stenosis.
How is aortic stenosis diagnosed?
Doctors become suspicious of aortic stenosis when patients complain of symptoms (shortness of breath, reduced exercise tolerance, chest pain, lightheadedness, or blackout spells), and by examining the heart (and noting the presence of a heart murmur – caused by the blood being forced through the narrow opening of the aortic valve - or an extra heart sound, called the “S4 gallop”).Once the doctor becomes suspicious of aortic stenosis, the diagnosis can be easily confirmed or ruled out by an echocardiogram.
It is important for doctors to remember that "classic" symptoms of aortic stenosis may not appear in elderly patients, so it is not uncommon for aortic stenosis to be missed in these patients until it becomes very risky to perform corrective surgery. It must especially be remembered that old age does not cause shortness of breath, chest pain, or blackout spells. These symptoms always need a thorough medical evaluation.
