There are four valves that control the flow of blood through the heart and keep it flowing in the right direction. Any of the valves can be affected by problems, but in most cases, it involves the mitral or aortic valves.

A diseased or damaged valve can affect the flow of blood in two ways: –

  • stenosis – the valve does not open fully or becomes stiff, obstructing the flow of blood.
  • regurgitation or valve incompetence – the valve does not close properly, allowing blood to leak backwards.


Both stenosis and regurgitation can put extra strain on the heart.


There are many causes of heart valve disease – it often results from ageing of the heart or may be an abnormality present at birth (eg bicuspid aortic valve). Other underlying conditions may lead to heart valve disease, also infection (infective endocarditits) and rheumatic fever (which is rare these days) can damage the valves.


Mild cases may not need to be treated but if treatment is necessary, this depends on the type of valve disease and how badly the heart is affected. Medicines can help to take the strain off the heart and in more severe cases, heart valve surgery may be carried out: –

  • valve repair – most often used with leaky mitral valves
  • valve replacement – most often used with aortic valves


There are two main types of replacement valves used – mechanical valves and tissue valves. Mechanical valves are designed to last a lifetime but there is a risk that a blood clot may develop on the surface of the valve which means that patients need to take anticoagulants for life. Replacement tissue valves have the disadvantage that they can wear out, so in younger people they may need to be replaced later in life in a repeat operation.

Aortic valve replacement can be performed either through a small hole in the leg blood vessel (transcatheter aortic valve replacement or TAVI) or during cardiac surgery (surgical aortic valve replacement).

We can’t do this without you

Through pioneering research and accessible education, Heart Research UK aims to reduce the number of people developing and dying from heart disease, while improving and extending the lives of those affected.

As a charity, we can only do this with your help.

People with certain types of heart disease have a higher risk of developing serious complications from Covid-19 and there is evidence that the virus can cause damage to the heart.

We must continue to do all we can to prevent and treat heart disease.

To help us fund more research and education, please make a small donation to help ensure we can continue our work, now and in the future.

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