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What is pulmonary artery stenosis?
Pulmonary artery stenosis is a narrowing (stenosis) that occurs in the
pulmonary artery, a large artery that sends oxygen-poor blood into the lungs to
be enriched with oxygen. The narrowing may occur in the main pulmonary artery
and/or in the left or right pulmonary artery branches. This narrowing makes it
difficult for blood to reach the lungs to pick up oxygen. Without enough oxygen,
the heart and body cannot function as they should. In an effort to overcome the
narrowing, the pressure in the right ventricle (the chamber that pumps blood
into the pulmonary arteries) rises to levels that can be damaging to the heart
muscle.
What are the symptoms of pulmonary artery stenosis?
If the narrowing in the artery is less than 50 percent, your child may not
experience any symptoms. However, if the narrowing of the artery is more than 50
percent, your child may experience any of the following symptoms:
- shortness of breath
- fatigue
- heavy or rapid breathing
- rapid heart rate
- swelling in the feet, ankles, face, eyelids, and/or abdomen
What causes pulmonary artery stenosis?
Pulmonary artery stenosis is a congenital heart defect, meaning it is a
defect that is inborn or exists at birth. Stated another way, the defect is an
abnormality, not a disease. Pulmonary artery stenosis is often present in
combination with other congenital heart defects, such as:
- Tetralogy of Fallot - a four-pronged defect consisting
of: 1) a ventricular septal defect, 2) a narrowing at or just beneath the
pulmonary valve, 3) a right ventricle that is more muscular than normal, 4)
an aorta that lies directly over the ventricular septal defect
- Pulmonary atresia - absence of a pulmonary valve,
preventing blood from flowing from the right ventricle into the pulmonary
artery and onward to the lungs
- Truncus arteriosus - the formation of only one combined
artery instead of the normal two outlets from the heart, the aorta and
pulmonary artery
- Pulmonary valve stenosis - problems with the pulmonary
valve (for example, development of less than three leaflets, leaflets that
may be partially fused together, thick leaflets that do not open all the
way) that make it more difficult for the valve leaflets to open and permit
blood to flow from the right ventricle to the lungs
- Patent ductus arteriosus - an open passageway between
the pulmonary artery and the aorta. Normally, this passageway closes on its
own within a few hours of birth, but when it does not, surgery or an
outpatient catheter-based procedure is needed to close the opening
Other causes of pulmonary artery stenosis can include: other syndromes that
affect the heart (such as rubella syndrome [a group of heart and other health
problems in an infant caused by rubella infection in the mother during
pregnancy] and Williams syndrome [a group of abnormalities affecting the heart
and other organs]) and surgical procedures used to correct other heart defects
(for example, pulmonary artery banding - a purposeful narrowing of the artery to
reduce blood flow to the lungs).
How is pulmonary artery stenosis diagnosed?
During a routine examination, your child’s doctor may hear abnormal heart
sounds when listening to the heart. If abnormal sounds are identified, your
doctor will order other tests that can include:
- electrocardiogram (ECG or EKG) - a test that records
the electrical changes that occur during a heartbeat; reveals abnormal heart
rhythms (arrhythmias) and detects heart muscle stress
- chest X-ray - a test to show the size and shape of the
heart and lungs and pulmonary arteries
- echocardiogram - a test that uses sound waves to
create a moving picture of the heart’s internal structures
- doppler ultrasound - a test that uses sound waves to
measure blood flow; usually combined with echocardiogram to evaluate both
the internal structure of the heart and blood flow across the heart’s
valves and vessels
- cardiac magnetic resonance imaging (MRI) - a test that
uses three-dimensional imaging to reveal how blood flows through the heart
and vessels and how the heart is working
- CT scan - an x-ray procedure that combines many x-ray
images with the aid of a computer to generate cross-sectional views of the
heart. Cardiac CT uses the advanced CT technology with intravenous (IV)
contrast (dye) to visualize cardiac anatomy, coronary circulation, and great
vessels
- cardiac catheterization - a procedure that involves
inserting a thin tube (a catheter) into a vein or artery and passing it into
the heart to sample the level of oxygen, measure pressure changes, and make
x-ray movies of the heart and its internal structures
- pulmonary angiography - a dye-enhanced x-ray of the
pulmonary arteries and veins of the heart
- perfusion scan - a test in which the patient is injected
with a small amount of a radioactive material. A special machine shows how well blood is flowing through each
of the two lungs.
- Additional tests may be ordered as necessary
How is pulmonary artery stenosis treated?
If your child is diagnosed with pulmonary artery stenosis, your pediatrician
or primary care doctor will recommend that you meet with a congenital heart
specialist (a doctor who has the training and equipment to determine your child’s
heart problem and order the necessary special tests, medical care, heart
surgery, and follow-up checkups). The best treatment approach will depend on
your child’s symptoms as well as other characteristics of the stenosis. Mild
to moderate narrowing in one or more pulmonary atery branches usually does not
require treatment, but severe cases do require some form of therapy. Available
treatments include:
balloon dilation - this treatment method consists of
moving a balloon dilation catheter into the narrowed area of the artery. The
balloon is carefully inflated -- first under low pressure and then under
higher pressure -- until the narrowed area is widened. The balloon is then
deflated and removed. Although the narrowing is improved in a majority of
patients following balloon dilation, overtime the artery can again become
narrow in as many as 15% to 20% of cases, requiring further ballooning.
Different types of balloons are currently being developed that will likely
lead to better and longer-lasting results.
balloon dilation and stent placement - in an effort to
improve on the results of balloon dilation, a search for a more effective
treatment was begun and led to the development of the stainless steel
balloon-expandable stent. Stent placement is accomplished by positioning the
stent across the narrowed segment of the artery. The stent is mounted on a
balloon angioplasty catheter and covered with a sheath as it is moved into
position. The sheath then is withdrawn off the stent-balloon angioplasty
assembly and the balloon is inflated to its recommended pressure, expanding
the stent and anchoring it in place.
Cutting Balloon™ -- this procedure is similar to
standard balloon dilation but the balloon has been specially designed with
small blades running up and down its length. When the balloon is inflated,
the blades are activated and they cut through the narrowed area, making the
vessel easier to dilate and resulting in a larger opening. Cutting balloons
are available in different sizes. At the present time, the larger sizes are
available only by participation in a clinical trial. Cutting balloons can be
used on any patient with pulmonary artery stenosis. However, only patients
with native pulmonary artery stenosis are eligible to participate in the
ongoing trial of larger cutting balloons. For more information on
participating in the trial, see the document, "Cutting Balloon for
Pulmonary Artery Stenosis: A Clinical Trial."
surgery - various methods of surgical repair of
pulmonary artery stenosis are used, the choice of which depends on the
characteristics of the stenosis and the surrounding vessels and other
structures.
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