The aortic valve (from the word aorta, from the Greek aortê, meaning large artery), also called semilunar or sigmoid valve, is a valve located at the level of the heart and separating the left ventricle from the aorta.
Anatomy of the aortic valve
Location of the aortic valve. The aortic valve is located at the level of the heart. The latter is divided into two parts, left and right, each having a ventricle and an atrium. From these structures emerge various veins and arteries including the aorta. The aortic valve is placed at the origin of the aorta at the level of the left ventricle. (1)
Structure. The aortic valve is a valve with three cusps (2), that is to say having three points. The latter are formed by a lamina and folds of endocardium, the inner layer of the heart. Attached to the arterial wall, each of these points constitutes a valve in the shape of a half-moon.
Physiology / Histology
Blood path. Blood circulates in one direction through the heart and the blood system. The left atrium receives oxygen-rich blood from the pulmonary veins. This blood then passes through the mitral valve to reach the left ventricle. Within the latter, blood then passes through the aortic valve to reach the aorta and be distributed throughout the body (1).
Opening / closing the valve. The opening and closing of the aortic valve depends on the pressure differences between the left ventricle and the aorta (3). When the left ventricle is filled with blood from the left atrium, the ventricle contracts. The pressure within the ventricle increases and causes the aortic valve to open. The blood will then fill the valves, having the consequence of closing the aortic valve.
Anti-reflux of blood. Playing an important role in the passage of blood, the aortic valve also prevents the backflow of blood from the aorta to the left ventricle (1).
Valvulopathie. It designates all the pathologies affecting the heart valves. The course of these pathologies can lead to a change in the structure of the heart with dilation of the atrium or the ventricle. Symptoms of these conditions can include a heart murmur, palpitations, or even discomfort (4).
- Aortic insufficiency. Also called valve leakage, this valve disease corresponds to improper closing of the aortic valve causing blood to flow backwards to the left ventricle. The causes of this condition are varied and can include age-related degeneration, infection or endocarditis.
- Aortic stenosis. Also called aortic valve narrowing, this valve disease is one of the most common in adults. It corresponds to an insufficient opening of the aortic valve, preventing the blood from circulating well. The causes can be varied such as age-related degeneration, infection or endocarditis.
Medical treatment. Depending on the valve disease and its progression, different drugs may be prescribed, for example to prevent certain infections such as infective endocarditis. These treatments can also be specific and intended for associated diseases (5).
Surgical treatment. In the most advanced valve disease, surgical treatment is frequently performed. Treatment can be either aortic valve repair or the replacement and placement of a mechanical or biological valve prosthesis (bio-prosthesis) (4).
Examination of the aortic valve
Physical examination. First, a clinical examination is performed in order to observe the heart rate in particular and to assess the symptoms perceived by the patient such as shortness of breath or palpitations.
Medical imaging exam. A cardiac ultrasound, or even a doppler ultrasound can be performed. They can be supplemented by a coronary angiography, a CT scan, or an MRI.
Electrocardiogramme d’effort. This test is used to analyze the electrical activity of the heart during physical exertion.
Charles A. Hufnagel, American surgeon of the 20th century, was the first to invent the artificial heart valve. In 1952, he implanted, in a patient suffering from aortic insufficiency, an artificial valve formed of a metal cage with a silicone ball placed in its center (6).