A person with aortic stenosis has abnormal narrowing of the aortic valve.

A normal aortic valve allows blood to flow from the heart, into the aorta. The aortic valve closes to prevent the backflow of blood from the aorta into the heart.

The narrowing interferes with the flow of blood from the left ventricle into the aorta. Aortic stenosis places stress on the heart, as it works to overcome the narrowed passageway.