Valvular disease

Today we’re going to talk about valvular disease. The heart has four valves, two atrioventricular valves that separate the atria from the ventricles, and two semilunar valves, one in the aorta and one in the pulmonary artery. All of these valves can become diseased. Now currently in the UK, most of the valvular diseases associated with the aged, where less than 1% of the under-45s have valvular disease. But over the age of 75, this rises to over 13%. And there are currently about a million people over 65 living with valvular disease.

About 70% of all cases of valvular disease occur to the mitral valve or the bicuspid valve on the left side of the heart, slightly under 30% to the aortic valve, and just under 5% to the valves on the right side of the heart. The abnormality may be a stenosis, which normally results in a narrowing of the aperture of the valve, or it can be a prolapse that results in incomplete closure of the valve. This causes the valve to leak and not be able to perform its function very well. With the mitral valve, the aperture size should be between four and six centimetres.

When the aperture size drops below 1 centimetre, this can significantly increase the left atrial pressure, and this can feed through to increase the pulmonary pressure. This can cause congestion and breathlessness. Initially, this will be felt only in response to exercise. But as the disease progresses, the symptoms will start to become present even at rest. The aortic valve can also become diseased, and the most common condition is aortic stenosis, in which the aperture size of the aortic valve is significantly decreased. This can occur as a result of calcification, which occurs in response to the normal ageing process, or as a result of an infection.

When the aperture size of the aortic valve becomes sufficiently small, this can significantly overload the heart because the heart has to work much harder to pump blood to the systemic circulation. With time, this causes the heart to enlarge or undergo what is called hypertrophy. This is similar to what occurs to skeletal muscle when it’s trained as a result of going to the gym. So the heart increases in size and has to work a lot harder to pump blood through the aortic valve. With time, if the condition is not dealt with, then the heart will become fatigued and undergo heart failure. The main treatment option for valvular disease is either valvular repair or valve replacement.

If this is done early enough, then this will give the heart a chance to recover. However, if the disease has progressed sufficiently before the surgery takes place, then the heart may not have the ability to recover.