Aortic stenosis (AS) is a narrowing of the aortic valve. This valve controls the flow of blood from the heart to a large artery called the aorta. The aorta carries the blood to the rest of the body.

Aortic stenosis can interfere or block the flow of blood from the heart to the rest of the body. It could also cause a back-up of blood into the heart and lungs. AS can range from mild to severe.

Heart Chambers and Valves
heart anatomy
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The aortic valve is normally made up of three cusps that open and close together. In babies, AS is caused by a birth defect of the aortic valve that may result in:

  • One cusp that can not open as fully as three cusps
  • Two cusps that are damaged
  • Cusps that are partly closed or do not open correctly due to thickness

The aortic valve can also be damaged by infection or injury to the valve.