Health
Normally, blood passes from the left lower chamber of the heart, called the left ventricle, through the aortic valve into the main artery of the body, the aorta.
If the aortic valve becomes narrowed, or stenosed, the blood flow through it is reduced and the heart has to work harder to pump blood to the body.
Aortic stenosis is more common in men. It can be present at birth but is more likely to occur in older people.
In young people from developed countries the most likely cause of aortic stenosis is a congenital heart abnormality.
In older people it's commonly caused by a build-up of calcium deposits on the valve.
In the past, rheumatic fever was a common cause of aortic stenosis.
If the aortic stenosis is mild, there may be no symptoms at all, or tiredness may be the only symptom. If the stenosis is greater, other symptoms may include chest pain and/or breathlessness during exertion, palpitations, dizziness and fainting, especially during exertion.
Heart failure may develop, causing symptoms that include tiredness, breathlessness and fluid retention in the legs, for example.
It's important to treat streptococcal infections with antibiotics to reduce the risk of rheumatic fever, which can cause aortic stenosis, from developing.
People with aortic stenosis are advised to take antibiotics before some invasive investigations (such as bladder cystoscopy) and surgical procedures to reduce the risk of heart valve infection (endocarditis).
Some people with aortic stenosis are also recommended to take antibiotics before dental treatments for the same reason.
Mild aortic stenosis is usually treated with medication, such as diuretics or ACE-inhibitors, to lessen the symptoms of heart failure.
In more severe cases, a balloon may be inflated in the valve to widen it, called a balloon valvuloplasty, or the valve may be widened or replaced during open heart surgery.
In the UK, aortic valve stenosis is the most common heart valve disorder requiring valve replacement.