What is the aortic valve?
The aortic valve, one of two semilunar valves, is the heart valve that divides the left ventricle and the aorta. It is called the aortic valve because of its location and function in the heart.
Like the heart’s pulmonary valve and tricuspid valve, the aortic valve has three semilunar leaflets (cusps) that open and close to regulate blood flow. However, in a small percentage of people, the valve only contains two leaflets.
Of the four valves in the heart, the mitral valve is the only one that should contain two cusps. In fact, it is commonly referred to as the bicuspid valve.
What does the aortic valve look like?
The average size of an aortic valve is 2.5-4.5 cm². The three leaflets or flaps of the valve – the right cusp, the left cusp, and the posterior cusp (aka the non-coronary cusp) – attach to both the wall of the aorta (the body’s main artery) and a crown-shaped ring called the aortic annulus.
Unlike the mitral and tricuspid valves, aortic valves are not supported by chordae tendineae. The leaflets take on a half-moon shape and overlie three aortic sinuses (sinuses of valsalva).
Each cusp has two free edges, a small fibrous node (nodule of arantius), and a supportive rim (lunula). At the points where the cusps join, there are three small spaces called aortic commissures.
What is the function of the aortic valve? How does it function?
The valve serves to regulate blood flowing between the left ventricle (the heart’s bottom left chamber) and the aorta and prevent regurgitation as blood is pumped from the left ventricle.
In normal function, pressure increases in the left ventricle during ventricular systole. Once it exceeds aortic pressure, the aortic valve opens and blood passes from the left ventricle to the aorta. Then, after systole, left ventricle pressure drops quickly and aortic pressure pushes the valve closed.
What happens when the aortic valve doesn’t function properly?
If the aortic valve of the heart is damaged, defective, or in some way physically abnormal, it can malfunction and cause a number of symptoms and complications.
A common congenital abnormality is a bicuspid aortic valve. Patients with this deformity have an aortic valve that has two cusps instead of three. This makes them more susceptible to aortic stenosis and aortic regurgitation, which are the two main types of aortic valve disease.
These conditions can arise for other reasons, however. Rheumatic Fever, Marfan’s Syndrome, infective endocarditis, and degenerative calcification are well known causes of aortic valve disease.