This is an abnormality of the outlet of the left side of the heart, due to narrowing just below the outlet (aortic) valve. The narrowing may be mild in some patients and may not require treatment at all. However in some cases it may get worse with time and if this happens the heart has to work very hard to pump blood through the narrowing. If severe, it is a serious problem and can even cause death.
Usually a simple ultrasound scan is all that is necessary to make the diagnosis. An ECG (a simple electrical recording of the heart’s activity) can also be helpful. Other, more complicated tests to take detailed X-Ray pictures of the heart (cardiac catheterisation) may be necessary in some cases. It is important to have regular visits to the outpatient clinic to make sure the narrowing doesn’t get worse as time goes by. Some patients may have other abnormalities of the heart, such as a leaky outlet (aortic) valve which will also need to be watched as time goes by.
If the narrowing becomes severe surgery is necessary to try to relieve the narrowing. This is a major operation which involves opening the heart (after its function is taken over by the bypass machine) and trying to cut out the tissue causing the narrowing. It is often a difficult operation because the narrowing is very close to the inlet and outlet valves of the heart and these valves can be damaged during surgery. It is almost always possible to make the narrowing much better, but it is not possible to remove it completely, so the heart is never completely normal even after a successful operation.
All heart operations are serious and carry some risk of death or major complications such as permanent brain damage, kidney damage or lung complications such as pneumonia. For subaortic stenosis the risk of dying at operation is small (about 1 in 100) and the risk of brain damage is also small (probably around 1 in 100). There is also a small risk (around 1 in 50) of the heart’s electrical system being damaged at operation; if this happens the child’s heart rate will be much slower than normal and a further operation is required to implant a pacemaker to make the heart beat faster. The results of surgery for subaortic stenosis in Leeds are, we believe, excellent when compared with other centres in the UK and abroad.
After the operation
Most children are in hospital for about a week after their operation, although it may be longer than this if there are complications. Most children have medicines to take at home after leaving hospital but these are usually only necessary for a month or so. Visits to the outpatient clinic will be necessary after the operation.
The long term future
Most patients with repaired subaortic stenosis will lead normal active lives after their operation and the only limitation we usually recommend is to avoid competitive sport or physical activities which involve really hard exercise (such as playing squash).
In some patients (particularly if surgery is required when a child is very young) subaortic
stenosis may come back again as the child grows and this can occasionally require further surgery. Regular review in outpatients is very important even if the patient appears well.
General advice for the future
It is probably best to avoid really hard physical exercise even after a successful operation - your cardiologist will give you specific advice for your child. All patients with subaortic stenosis will be at risk of infection in the heart (called endocarditis), both before and after surgery. Such infections may be caused by infections of the teeth or gums or even by routine treatment at the dentist. It is important to visit the dentist regularly and to remind the dentist at each visit of the heart abnormality. You will be given an information card to help you with this. Ear or body piercing and tattooing are best avoided as they also carry a small risk of infection which may spread to the heart.
How to interpret the survival funnel plots
These graphs show the national average survival after specific procedures for treating congenital heart disease. The national average is shown as a horizontal grey line. Two control limits are shown; a warning limit (Green line, 98%) and an alert limit ( Red line 99.5%). Unit performances are shown as identifiable coloured symbols. If a unit's symbol is above the green line then the performance is no different from the national average. If a unit’s survival rate is below the warning limit, their performance will be closely monitored in subsequent years. If a unit’s survival rate is below the alert limit, an investigation into possible reasons and remedial actions will be launched by the appropriate professional and regulatory bodies.