Normal Structure of the Heart
Video showing a normal aorta – the tube lighting up red from the upper part of the heart.
What is Aortic Stenosis?
The aorta is the largest artery (blood vessel) in the body. It carries red oxygenated blood from the heart around the body. The connection between the heart and the aorta is guarded by a valve called the aortic valve. Normally it has 3 leaflets and has the appearance of a Mercedes Benz sign. Narrowing of the aortic valve is known as aortic stenosis. Aortic stenosis increases the work of the heart causing the left ventricle (lower pumping chamber) to thicken (known as left ventricular hypertrophy) and potentially eventually fail. Aortic stenosis can be mild, moderate, severe or critical (the latter is an emergency). The narrowing can be at the level of the valve, or above the valve (supravalvar) or below the valve (subvalvar). The valve can be malformed and instead of having 3 leaflets it may only have 2 (bicuspid) or more rarely 1 (monocuspid).
There is a wide spectrum of symptoms and some babies and children will have no symptoms at all and the only indication of a problem may be the detection of a heart murmur. Babies may present with breathing and feeding difficulties, and in the most severe cases, with pallor and shock. Older children may become breathless, tire more easily, and fainting can occur.
A clinical examination will usually reveal a heart murmur. Sometimes a buzzing sensation (a thrill) is felt in the neck or on the chest. An echocardiogram will diagnose aortic stenosis. An ECG will also be performed and often a chest X-ray.
Aortic stenosis may also be diagnosed before birth by fetal echocardiography.
Mild and moderate aortic stenosis is well tolerated and does not require treatment but should be regularly monitored in the outpatient clinic. There is a small possibility of spontaneous improvement with growth. Other cases become more severe with time whilst others remain stable for many years.
Aortic stenosis can be treated either via a keyhole approach with a balloon cardiac catheter (angioplasty) or by open heart cardiac surgery. Each child’s heart is individually assessed to decide which treatment will give the best long-term result.
Balloon cardiac catheter involves a general anaesthetic. A tube, with a deflated balloon, is passed from a blood vessel in the leg to the heart, using X ray guidance. Once the balloon is correctly positioned in the narrowed aortic valve, it is inflated, thereby stretching the narrow opening to enlarge it. This process is repeated a number of times and then the catheter is removed. After this procedure, there may be some leak across the stretched valve but a leaky valve is better tolerated than a very narrow valve. Hospital stay duration depends on the age of the child and their status prior to the procedure. The simplest cases may only require a 1-2 night admission.
There are a number of different open-heart surgery techniques which can be used to treat aortic stenosis. All involve being attached to the cardiac bypass machine. Children are usually in hospital for 5-10 days but longer stays can be necessary particularly for babies. Surgical strategies include surgical repair of the valve, and replacement with a mechanical or tissue valve. A special operation called the Ross operation may be performed. This operation was pioneered at the Royal Brompton Hospital where Dr Naqvi works. It involves replacement of the malformed aortic valve with the child’s own pulmonary valve. Then a donor human tissue valve called a homograft is placed in the position of the removed pulmonary valve. This sounds strange but this technique means that the child’s own valve is positioned in the place of the aortic valve. A child’s own pulmonary valve will usually work much better than a donor one and the aortic valve is the most important heart valve doing the hardest job as the aorta takes blood all around the body.
Dr Naqvi works with an experienced internationally renowned team of nationally audited congenital cardiac surgeons and interventionalists and if needed will refer your child to the one who is best for your child’s heart.
The outlook for children with pulmonary stenosis is excellent in the vast majority of cases. Regular medical follow-up will be required throughout life and after treatment there is still a possibility of the narrowing recurring. Dr Naqvi has cared for many babies and children with aortic stenosis and has followed them up until adulthood. She says “Having aortic does not stop children from having a happy full life.
Those with moderate to severe aortic stenosis will be advised to avoid certain potentially harmful sports but there will usually still be some sports they can enjoy. Over the years I have patients who have had aortic stenosis who after treatment have been in school sport teams and have also had achievements in music and academic exam results.”