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Anterior (frontal) view of the opened heart White arrows indicate normal blood flow
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Base of ventricles exposed by removal of the atria
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The is one of the
Valves of the
Heart . It lies between the
Left Ventricle and the
Aorta .
The aortic valve has three cusps. When the aortic valve is open, the normal size of the
Orifice is 3-4 cm².
During ventricular
Systole ,
Pressure rises in the left ventricle. When the pressure in the left ventricle rises above the pressure in the aorta, the aortic valve opens, allowing
Blood to exit the left ventricle into the aorta. When ventricular systole ends, pressure in the left ventricle rapidly drops. When the pressure in the left ventricle decreases, the aortic pressure forces the aortic valve to close. The closure of the aortic valve contributes the A
2 component of the second
Heart Sound (S
2).
There are a number of diseases that can affect the aortic valve.
The most common
Congenital abnormality of the heart is the
Bicuspid Aortic Valve . In this condition, instead of three cusps, the aortic valve has two cusps. This condition is often undiagnosed until later in life when the person develops symptomatic aortic stenosis. Aortic stenosis occurs in this condition usually in patients in their 40s or 50s, an average of 10 years earlier than can occur in people with congenitally normal aortic valves.
Aortic valve replacement means that a patient's aortic valve is replaced by a different valve. The aortic valve can be affected by a range of diseases and require aortic valve replacement. The valve can either become leaky (
Regurgitant or insufficient) or stuck partially shut (
Stenotic ). Aortic valve replacement currently requires open heart surgery. Research is being done now on to develop valves that can be implanted using a
Catheter without open
Heart Surgery . There are two basic types of artificial heart valve, mechanical valves and tissue valves. Tissue heart valves are usually made from animal tissues, either animal heart valve tissue or animal pericardial tissue. The tissue is treated to prevent rejection and to prevent calcification.
There are alternatives to animal tissue valves. In some cases a human aortic valve can be implanted. These are called
Homograft s. Homograft valves are donated by patients and harvested after the patient expires. The durability of homograft valves is probably the same for porcine tissue valves. Another procedure for aortic valve replacement is the
Ross procedure or pulmonary
Autograft . The Ross procedure involves going to surgery to have the aortic valve removed and replacing it with the patient's own pulmonary valve. A pulmonary homograft (a
Pulmonary Valve taken from a cadaver) is then used to replace the patients own pulmonary valve.