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. The aortic valve, like the heart’s pulmonary valve and tricuspid valve, has three semilunar leaflets (cusps) that open and close to regulate blood flow. However, in a small percentage of the world’s population, the valve only contains two leaflets.
What does the aortic valve look like?
The average size of an aortic valve is 2.5-4.5 cm². The three flaps of the valve—the right cusp, the left cusp and the posterior (noncoronary) cusp—attach to the wall of the aorta and a crown-shaped ring called the aortic annulus. Unlike the mitral and tricuspid valves, the aortic valve is not supported by chordae tendineae. The leaflets take on a half-moon or crescent 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 aortic valve serves to regulate blood flowing between the left ventricle (the bottom left chamber) and the aorta (the body’s biggest artery – it supplies the body with oxygen) and to prevent regurgitation as blood is pumped from the left ventricle to the aorta. In normal function, pressure increases in the left ventricle during ventricular systole (contraction of the myocardium of the ventricles). 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 aortic valve closed.
What happens when the aortic valve doesn’t function properly?
If the aortic valve is damaged, defective or 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, the two main types of aortic valve disease. These conditions can arise for other reasons, however; rheumatic fever, marfan’s syndrome, infection (infective endocarditis) and degenerative calcification are well known causes of aortic valve disease.