- A normal aortic valve opens wide to allow blood to be pumped from the heart to the rest of the body and closes tightly to prevent blood from flowing back into the heart.
- Aortic stenosis is a narrowing or obstruction of the aortic valve that prevents the valve from opening properly, impeding the flow of blood from the heart into the aorta.
- Aortic regurgitation occurs when the aortic valve does not close properly between heartbeats, allowing blood to regurgitate, or spill back, from the aorta into the left ventricle.
The heart has four valves: two on the right side of the heart (the tricuspid and pulmonary valves), and two valves on the left side of the heart (the mitral and aortic valves). Resembling flaps, each valve is made up of segments or leaflets, and each opens and closes so that blood flows through the heart in only one direction. A normal aortic valve has three leaflets that seal tightly together when closed.
During contraction, the aortic valve opens to allow blood to flow from the left ventricle (lower chamber) into the aorta. When the heart relaxes, the aortic valve closes, preventing blood from re-entering the left ventricle.
When aortic valve disease is present, the valve no longer opens or closes properly. The two diseases of the aortic valve are:
- Aortic stenosis is the narrowing or obstruction of the aortic valve that prevents it from opening fully, restricting blood flow from the left ventricle to the aorta. Although the heart may initially be able to compensate, the left ventricle must pump harder, which can eventually cause the heart to thicken and enlarge. Eventually the heart may weaken and begin to fail.
Aortic stenosis is common in the United States, primarily affecting people of advanced age.
- Aortic regurgitation occurs when the aortic valve does not close properly between heartbeats, allowing blood to regurgitate, or re-enter the left ventricle when the chamber relaxes. Also called aortic insufficiency, mild aortic regurgitation may not cause problems, but eventually it can stretch the ventricle and affect its function.
As regurgitation becomes severe, large amounts of blood that re-enters the left ventricle with each heartbeat must be pumped out during the following heartbeat, which strains the left ventricle. If the pumping ability of the left ventricle begins to fail, it will become less able to accept blood as it flows from the atrium, increasing pressure on the left upper chamber and the vessels of the lung resulting in heart failure.