Birth defect. Sometimes a person is born with a bicuspid aortic valve that has two flaps instead of the normal three. Over time, the valve becomes damaged and calcium builds up. As the valve narrows, less blood can flow through it.
Infection.Rheumatic fever can cause scar tissue to build up at the edges of the valve. Rheumatic fever is not common now. But if you had it as a child, your risk of aortic valve stenosis may be increased.
Artificial valve. Aortic valve disease also may develop in an artificial aortic valve that is made from human or animal tissue.
Other things that increase the risk for aortic valve stenosis include: