|
Aortic Stenosis
Congenital aortic stenosis occurs in 3-6% of CHDs. It is 4 times more likely to occur in boys than in girls. 
Aortic
stenosis is a heart valve disorder that narrows or obstructs the aortic
valve opening. Narrowing of the aortic valve prevents the valve from
opening properly and obstructs the flow of blood from the left
ventricle to the aorta.
Subaortic stenosis refers to a narrowing of
the left ventricle just below the aortic valve, which blood passes
through to go into the aorta. This stenosis limits the flow of blood
out of the left ventricle. This can reduce the amount of blood that
flows to the body.
Supravalvular aortic stenosis (SVAS) is a
congenital narrowing of the ascending aorta which can occur as a
congenital defect itself or as one component of Williams syndrome.
All
increase the work the heart has to do to pump blood forward, causing
pressure inside the left ventricle to increase which results in the
walls of the ventricle to thicken. Unlike other muscles, thick heart
muscles are not desirable. Over a long period of time, a thick
ventricle can enlarge and fail. The thick muscle, increased pressure
and decreased flow of oxygen rich blood to the heart muscle make the
heart prone to rhythm disturbances (arrhythmia) and may cause sudden
cardiac death.
Few children are symptomatic in infancy, but the
incidence of problems increases dramatically in adulthood. Because the
coronary arteries that feed the heart muscle with oxygen rich blood are
not getting enough blood, fatigue, chest pain (angina), shortness of
breath (dyspnea), decreased tolerance to exercise, and
fainting(syncope) can occur. Symptoms become noticeable generally only
after the stenosis has significantly progressed in severity, and the
heart can no longer adapt to the abnormal pressure caused by the
obstruction. Once damage becomes severe, it is irreversible. It is
therefore very important to have this problem identified early and have
regular follow-up and evaluation,even if symptoms are not present. A
family history of a congenital heart defect and or an unidentified
heart murmur are indications for evaluation by a cardiologist at which
time he may perform one or more of the following tests: catherization,
echocardiogram, doppler ultrasonography, chest x-ray, chest MRI, aortic
angiography.
Once diagnosed, if there are no symptoms or
symptoms are mild, a child may only need to be monitored by a health
care provider. If symptoms become moderate to severe, a child may need
to stay in the hospital and should have a physical exam every 6-12
months and an echo every 1-3 years. Medications can include diurectics,
digoxin, and others medications to control heart failure. Often, these
children are advised to avoid strenuous physical activities.
There are a variety of surgical procedures that can help a person with congenital aortic stenosis:
Valvuloplasty
- For those high-risk patients who are poor candidates for open heart
surgery, this is a less invasive procedure where a balloon is placed
into an artery in the groin, advanced to the heart, placed across the
valve, and inflated in hope it will relieve the obstrucation caused by
the narrowed valve.
Valvotomy
- This is surgery, usually done in childhood, to "free up" the native
valve cusps without replacing the valve. The fused valve cusps are
surgically separated and are thus able to open more easily. Valvotomy
is done only when the aortic valve is still thin and pliable and has
not yet become stiff and calcified. It is very effective initially, but
usually reparative surgery will be required later.
Aortic Valve Replacement -
There are two types of artificial valve: mechanical and tissue. While
the mechanical valve is very durable, it requires lifelong
anticogulation. If a blood clot would from and break off, it could
result in a stroke. Often, coumadin is prescribed for those who have a
mechanical valve and requires regular monitoring. A tissue valve, made
of biological tissue (often pig valve), does not require longterm
anticoagulation. However, it may wear out over time and will likely
need replaced.
Resection of subaortic and suprs-aortic
obstruction - This is the surgical removel of the obstruction. In some
cases, the obstruction may grow back over time and require further
surgery.
*The materials used to make valves, patches, and grafts
does not grow and therefore when repairs are made during childhood,
often reoperation is required in adulthood. Recent research has led
scientists to grow human heart tissue. This is a very promising medical
advancement for growing human valves. To read complete article, please
see related links below.
| |