Description
In the normal heart the right side pumps blood to the lungs which is a relatively easy task, whilst the left side has the more difficult job of pumping blood all around the body. As a result the pressure in the left ventricle (pumping chamber) is generally about four times that in the right ventricle, and the wall of the left ventricle is thicker than that of the right.

Many defects that involve holes in the septum (central wall) allow blood to flow (shunt) from the high pressure left side of the heart to the lower pressure right side. This results in an increase in the pressure on the right, and causes too much blood to be pumped to the lungs. The body's natural reaction to this, is to constrict (narrow) the blood vessels in the lungs in an effort to limit this excess blood flow.

Over a period of time, this narrowing of the pulmonary (lung) arteries causes a thickening in the surrounding muscle due to the increased workload, and also the closure of smaller lung arteries. These changes reduce the blood flow into the lungs, and increase the pressure needed by the right ventricle to pump blood into the lungs to be oxygenated.

As the pressure increases, there is less left to right shunting (blood flow) within the heart, and eventually the pressure is such that the shunt is reversed, i.e., right to left shunting occurs. This process is called Pulmonary Vascular Disease, and ultimately results in low oxygen levels and therefore cyanosis (blueness) and increased haemoglobin levels in the blood of the patient.

It is the damage caused by prolonged pulmonary hypertension that generally prohibits late repair of cardiac defects. As children with Down's Syndrome have a propensity to develop Pulmonary Vascular Disease due to the fact that they tend to have larger holes in the heart, fewer small lung arteries and smaller airways, surgical repair is generally carried out fairly early in life, although timing will vary depending on the exact heart defect.

Special attention should be paid to treating obstructed breathing (e.g. inhalations, nose drops, antibiotics, ENT surgeon), as long term obstruction may aggravate the condition. The rate of development of pulmonary hypertension depends on the nature and size of the defect, but varies greatly from child to child, even between those with the same cardiac problem. Routine checks that your child has at clinic appointments, such as an echocardiogram, help the cardiologist to monitor your child's pulmonary artery pressure.

Treatment
In a young child with abnormally elevated pressure in the pulmonary artery, surgery is often considered too dangerous, but pulmonary artery handing (pa banding/banding) may be effective. This procedure requires the surgeon to place a restrictive band around the artery, thus reducing the blood flow into the lungs, and preventing the need for the body to form its own restriction. If successful, the normal development of pulmonary hypertension may be slowed or stopped, and surgical repair of the hole(s) may be possible at a later date.

Successful surgery will usually prevent the continuance of pulmonary hypertension, and the development of Pulmonary Vascular Disease.

In cases where banding is not successful or inappropriate, treatment includes the use of oxygen and certain nitrogen based drugs which relax the pulmonary vessels and increase the blood flow into the lungs. Drugs such as Digoxin may be used to increase the contraction of the heart muscle, and diuretics to limit fluid retention, in order to ensure the heart works as efficiently as possible.

Follow Up Advice
All patients with a cardiac defect, whether repaired or not, will require antibiotic cover during any dental treatment to p1-event any bacteria entering the blood stream from where they can reach the heart causing bacterial endocarditis (infection of the heart lining), which can he very serious. It is best, therefore, to encourage good dental care and avoid too many sweet drinks etc. while your child is young.

"The doctor explained that my baby had pulmonary hypertension and that if the pressure is very high, like my daughter's, it is too dangerous to operate. I'd met a couple of other mothers whose babies had had surgery and were doing well, and one whose son was older and hadn't had an operation. He wasn't too well, and I'd already decided to go ahead with surgery to give my baby a chance - now I was being told she couldn't have it done. Then the doctor told me about an operation to put a band around the lung artery which would protect her lungs from damage and hopefully give her a chance for surgery later on. She had the banding done at twelve weeks, and it worked. When she was ten months, her pulmonary pressure had reduced and she had a complete repair and she's doing well now. I still don't understand why her pressures were so high so soon, but at least they were able to do something about it."