What is a heart valve disease?
Our heart contains 4 valves. 2 of the valves contribute to the blood circulation, pumping the blood from the heart and out into the body from the right and left chamber of the heart. The remaining 2 valves help guide the blood from the two atriums down into the chambers of the heart. The objective of the heart valves is to guide the blood through the heart and out into the body. As with regular ‘valves’, heart valves can be damaged to a degree where they lose their density and become ‘insufficient’, thus being unable to open and close sufficiently.
Usually, a cardiac valve disorder occurs either in the mitral valve or the aortic valve, and it is referred to as stenosis (narrowing of the heart valve) or as insufficient (leaky heart valve). If the issue is a narrowed and leaky heart valve, which is often the case with children, the condition is referred to as aortic valve disease. A leaky heart valve cannot keep the blood between the chambers, the aorta or the pulmonary artery separated, which means that the blood runs back as the valve does not function optimally.
How is heart valve disease treated today?
Currently, aortic valve disease is treated with 1 of the following 3 operations:
Plastic surgery
- Plastic surgery is a treatment which is usually chosen for younger children, but it requires another operation after a number of years.
Ross operation
- An operation, where the aortic valve is removed. Afterwards, the child’s own pulmonary artery is inserted. The missing pulmonary heart valve is regenerated by inserting an artificial blood vessel, containing a valve. The artificial blood vessel can either be from humans or from calves. The benefit of inserting the pulmonary artery valve is that it will adjust to the growth of the child. However, as the artificial blood vessel will become calcified, this method either requires a so-called ‘angioplasty’ or a replacing of the blood vessel after a number of years.
Replacing the aortic valve with an artificial valve
- A form of operation, where the aortic valve is either replaced by a metal valve or a valve made of dead tissue. The benefit of this operation is that you never have to replace a metal valve. The drawback, however, is that many children are too young to have a metal valve in adult size implanted, and therefore the metal valve will need replacing when the children grow older. A replacement operation is also associated with the risk of developing blood clots as the implanted metal valve may contain congealed blood.
How does the new treatment work?
American scientists are currently researching the possibilities of developing a heart valve which can grow in line with the child. The new heart valve consists of a pipe-like structure, which in its centre contains a biodegradable substance. The biodegradable core will then metabolise over time, which causes it to expand, after which it can adjust to the growth of the child. The speed of which the core is metabolised is calculated using a mathematical model. So far, the new ‘growth adjustment valves’ have only been tested on pigs, which means that it will be a bit longer before the treatment is offered to children if it turns out to be a safe treatment alternative to the current treatments.
References:
1: https://hjerteforeningen.dk/alt-om-dit-hjerte/hjerte-kar-sygdomme/hjerteklapsygdom/
3: Feins EN, Lee Y, O’Cearbhaill ED, Vasilyev N V, Shimada S, Friehs I, et al. A growth accommodating implant for paediatric applications. Nat Biomed Eng. 2017
