Most people who have
aortic valve stenosis are born with a normal, healthy
aortic valve but develop
aortic stenosis late in life. Aging and calcium buildup cause the leaflets of
the valve to thicken and harden, preventing the valve from opening properly.
Typically, stenosis develops slowly over many years.
Some people may develop aortic stenosis after having rheumatic fever as a child. It usually takes 30 to 40
years after a case of rheumatic fever for aortic stenosis to develop. Rheumatic
fever has been rare in the United States since the 1970s.