Aortic valve: Aortic valve is located at the root of the aorta between the aorta and the left ventricle. It prevents backflow (regurgitation) of oxygenated blood from aorta to the left ventricle when the latter relaxes (diastole) after contraction (systole). Aortic valve is a semilunar valve with three cusps, which close in diastole.
Diseases of aortic valve
Birth defects of aortic valve
Normally aortic valve has three cusps or leaflets. In a small percentage of individuals it can have just two cusps. Then it is known as ‘bicuspid aortic valve‘. In very rare cases there is only a single cusp. Then it is known as ‘unicuspid aortic valve‘. Unicuspid valves usually have a very small orifice and the babies are quite symptomatic in early life. Bicuspid valves function fairly well in early life, but get progressively damaged as age advances. Later on they become either leaky (aortic regurgitation) or obstructive (aortic stenosis) or a combination of the two (aortic stenosis with regurgitation). Abnormal valves are also prone for infections of the valve (endocarditis).
Degenerative aortic valve disease
As age advances, aortic leaflets gradually gets damaged and becomes obstructive or rarely leaky. Degenerative aortic valve disease with aortic stenosis is the commonest valvular heart disease in the very elderly in developed countries.
Rheumatic aortic valve disease
Rheumatic fever is a disease affecting heart valves, mostly seen in developing countries and occasionally in some regions of developed countries. Aortic valve is the second commonest valve affected in rheumatic fever, the most commonly affected being mitral valve. During an acute attack of rheumatic fever, it produces leakage of the valve. In the long term it can produce leaky valve, obstructed valve or a combination of leak and obstruction.
The valve can also be damaged by infections or associated birth defects of the heart like ventricular septal defect. Ventricular septal defect is seen in the wall between the lower chambers of the heart. The defect causes a lack of support for the valve from the lower side and the valve sometimes becomes progressively leaky.
How do you know when the valve is damaged?
Mild degrees of damage to the valve may not be detected until an ultrasound study of the heart (echocardiogram) is done for some other reason. More severe degrees may be picked up on routine physical examination by a doctor as it causes additional heart sounds known as ‘heart murmurs‘. Still more severe cases may produce symptoms like breathlessness on exertion or at rest, chest pain on exertion or unduly prominent heart beats (palpitation). Very severe forms can cause giddiness and fall (syncope) or heart failure.
What can we do if the valve is severely damaged?
Severe damage to the valve can produce heart failure, which can be treated with medicines. In some cases it may be necessary to repair the valve by an operation or remove the diseased valve and replace it with an artificial valve. Currently there are advanced techniques like TAVI (transcatheter aortic valve implantation) in which an artificial valve can be implanted using specially made tubes introduced through the groin without surgery.