The aortic valve allows oxygen-rich blood to flow from the heart to the aorta. It prevents the blood from flowing back from the aorta into the heart when the pumping chamber relaxes.
Bicuspid aortic valve is present at birth (congenital). An abnormal aortic valve develops during the early weeks of pregnancy, when the baby's heart develops. The cause of this problem is unclear, but it is the most common congenital heart disease. It often runs in families.
The bicuspid aortic valve may not be completely effective at stopping blood from leaking back into the heart. This is called aortic regurgitation. The aortic valve may also become stiff and not open up as well, causing the heart to have to pump harder than usual to get blood past the valve (aortic stenosis). The aorta may become enlarged with this condition.
This condition is more common among males than females.
A bicuspid aortic valve often exists in babies with coarctation of the aorta and other diseases in which there is a blockage to blood flow on the left side of the heart.