The aortic valve is located between the left ventricle of the heart and the aorta, which is the largest artery in the body. The aorta supplies blood throughout the body. Aortic stenosis (AS) is a narrowing of the aortic valve that could block blood flow from the heart and cause a back-up of flow and pressure in the heart and to the lungs. AS can range from mild to severe.

The main causes of AS include:

  • A birth defect of the aortic valve, which normally has three cusps:
    • A two-part aortic valve becomes stenotic with progressive wear and tear
    • An aortic valve that has only one cusp or has stenosis from birth
  • Progressive hardening and calcification of the aortic valve with age
  • Scarring of the aortic valve caused by rheumatic fever—rare