pulmonary arterial hypertension
Pulmonary arterial hypertension (PAH) is continuous high
blood pressure in the pulmonary
artery. The average blood pressure
in a normal pulmonary artery is about 14 mmHg when the person is resting.
In PAH, the average is usually greater than 25 mmHg.
PAH is a serious condition for which there are treatments but no cure. Treatment
benefits many patients.
The pulmonary arteries are the blood vessels that carry oxygen-poor blood
from the right ventricle in the heart to the
small arteries in the lungs. In PAH, three
types of changes may occur in the pulmonary arteries:
There is less room for the blood to flow through these narrower arteries.
The arteries may also stiffen. Over time, some of the arteries may become
- The muscles within the walls of the arteries may tighten up. This
makes the inside of the arteries narrower.
- The walls of the pulmonary arteries may thicken as the amount of muscle
increases in some arteries. Scar tissue may form in the walls of arteries.
As the walls thicken and scar, the arteries become increasingly narrow.
- Tiny blood clots may form within the smaller arteries, causing blockages.
The narrowing of the pulmonary arteries causes the right side of heart to
work harder to pump blood through the lungs. Over time, the heart muscle
weakens and loses its ability to pump enough blood for the body's needs.
This is called right heart failure.
Heart failure is the most common cause of death in people with PAH.
There are two types of PAH:
About 300 new cases of PPAH are diagnosed in the United States each year.
SPAH is much more common.
- Primary pulmonary arterial hypertension (PPAH) is inherited or occurs
for no known reason.
- Secondary pulmonary arterial hypertension (SPAH) either is caused
by or occurs because of another condition. The conditions include chronic
heart or lung disease, blood clots in the lungs, or a disease like scleroderma.
Doctors have learned a lot about PAH in recent years. More treatments are
now available. Researchers are also studying several promising new treatments
that may prolong lives as well as improve the quality of life for people
living with PAH.
What causes pulmonary
Certain factors appear to increase your chances of developing pulmonary
arterial hypertension (PAH). They include:
Doctors do not know what causes primary pulmonary arterial hypertension
(PPAH), although it is inherited in some people. Recently, researchers discovered
a defect in a gene that can lead to changes in the pulmonary arteries like
those seen in PPAH. They think that other genes may be involved as well.
As we learn more about how different genes work in the development of PPAH,
better treatments and perhaps a preventive treatment or cure will be found.
- Use of appetite suppressants, especially fenfluramine and dexfenfluramine
- Chronic use of cocaine or amphetamines
- HIV infection
- Liver disease
- Connective tissue diseases, such as scleroderma or lupus erythematosus
Secondary pulmonary arterial hypertension (SPAH) is caused by a variety
of conditions. Chronic obstructive pulmonary disease is the most common
cause in adults.
Other conditions that can lead to SPAH
PPAH is most common in women in their thirties and men in their forties.
Twice as many cases are reported in women as in men.
- Obstructive sleep apnea
- Congenital heart defects
- Chronic blood clots in the pulmonary artery
- PAH affects men and women of all ages, from very young children to
seniors, and people of all racial and ethnic backgrounds.
What are the signs and symptoms of pulmonary arterial hypertension?
Difficulty breathing or shortness of breath (dyspnea) is the main symptom
of pulmonary arterial hypertension (PAH). If you have PAH, you may feel
that it is difficult to get enough air.
signs and symptoms
As the disease advances:
- Fainting spells (syncope)
- Swelling in the ankles or legs (edema)
- Bluish lips and skin (cyanosis)
- Chest pain
- Racing pulse
- Palpitations (a strong feeling of a fast heartbeat)
In the more advanced stages, you:
- The pumping action of your heart grows weaker.
- Your energy decreases.
- Are able to perform very little activity
- Have symptoms even when resting
- May become completely bedridden
Limitations on physical activity
Doctors may classify your symptoms based on how much activity you can comfortably
undertake. The classes are the same as those for heart failure. They are:
- Class 1: No limits – Ordinary physical activity does not cause
undue tiredness or shortness of breath.
- Class 2: Slight or mild limits – Person is comfortable at rest,
but ordinary physical activity results in tiredness or shortness of
- Class 3: Marked or noticeable limits – Person is comfortable
at rest, but less than ordinary physical activity causes tiredness or
shortness of breath.
- Class 4: Severe limits – Person is unable to carry on any physical
activity without discomfort. Symptoms may also be present at rest. If
any physical activity is undertaken, discomfort increases.
How is pulmonary arterial hypertension
There is no one specific test that will show why you have pulmonary arterial
hypertension (PAH). Even in its later stages, the signs of the disease are
similar to those of other heart and lung conditions.
Your doctor will determine if you have PAH by conducting a series of tests
These tests include:
- Determine the pressure in your pulmonary artery
- Find out how well your heart and lungs are working
- Rule out any other conditions that may be causing the hypertension
Usually, these tests are sufficient to confirm that you have PAH. Sometimes
these tests do not rule out all possible causes for the PAH. In that case,
your doctor may call for these additional tests:
- Chest X-ray. A chest X-ray takes
a picture of your heart and lungs. It can show if the pulmonary arteries
or the right side of the heart are enlarged. It will also help your
doctor rule out a number of lung diseases, including chronic obstructive
pulmonary disease (COPD), as the cause of your PAH.
- EKG (electrocardiogram).
This test is used to measure the rate and regularity of your heartbeat,
as well as the size and position of the right ventricle in your heart.
It can help the doctor rule out a number of diseases of the heart.
- Echocardiogram. This test uses
sound waves to create a moving picture of your heart. Echocardiogram
provides information about the size and shape of your heart and how
well your heart chambers and valves are functioning. The test also can
identify areas of poor blood flow to the heart, areas of heart muscle
that are not contracting normally, and previous injury to the heart
muscle caused by poor blood flow.
There are several different types of echocardiograms, including a stress
echocardiogram. During this test, an echocardiogram is done both before
and after your heart is stressed either by having you exercise or by
injecting a medicine into your bloodstream that makes your heart beat
faster and work harder. A stress echocardiogram is usually done to find
out if you have decreased blood flow to your heart (coronary artery
- Stress test. Some heart problems
are easier to diagnose when your heart is working harder and beating
faster than when it's at rest. During stress testing, you exercise (or
are given medicine if you are unable to exercise) to make your heart
work harder and beat faster while heart tests are performed.
During exercise stress testing, your blood pressure and EKG readings
are monitored while you walk or run on a treadmill or pedal a bicycle.
Other heart tests, such as nuclear heart scanning or echocardiography,
also can be done at the same time. These would be ordered if your doctor
needs more information than the exercise stress test can provide about
how well your heart is working. If you are unable to exercise, a medicine
can be injected through an intravenous line (IV) into your bloodstream
to make your heart work harder and beat faster, as if you are exercising
on a treadmill or bicycle. Nuclear heart scanning or echocardiography
is then usually done. During nuclear heart scanning, radioactive tracer
is injected into your bloodstream, and a special camera shows the flow
of blood through your heart and arteries. Echocardiography uses sound
waves to show blood flow through the chambers and valves of your heart
and to show the strength of your heart muscle.
Your doctor also may order two newer tests along with stress testing
if more information is needed about how well your heart works. These
new tests are magnetic
resonance imaging (MRI) and positron
emission tomography (PET) scanning of the heart. MRI shows detailed
images of the structures and beating of your heart, which may help your
doctor better assess if parts of your heart are weak or damaged. PET
scanning shows the level of chemical activity in different areas of
your heart. This can help your doctor determine if enough blood is flowing
to the areas of your heart. A PET scan can show decreased blood flow
caused by disease or damaged muscles that may not be detected by other
- Spirometry. This test measures
how well your lungs inhale and exhale air. It is most useful for ruling
out obstructive lung diseases like COPD.
- Cardiac catheterization.
This test provides a precise measure of the blood pressure in the right
side of your heart and the pulmonary artery. Cardiac catheterization
is the only way to get this measure. It also shows the amount of blood
the right ventricle pumps with each heartbeat. This helps your doctor
evaluate the pumping ability of the right ventricle. This procedure
must be performed in the hospital by a specialist.
If these tests do not show an underlying cause for the PAH, the diagnosis
is primary pulmonary arterial hypertension.
- Perfusion lung scan. This test shows how the blood is moving in your
lungs and whether there are large blood clots that may be causing the
- Pulmonary arteriography. When
the results of a perfusion lung scan do not rule out blood clots in
the pulmonary arteries, your doctor may order a pulmonary arteriogram.
This test also shows blood clots and other blockages in the blood vessels
in the lung.
- Blood tests. Blood tests will rule out HIV, auto-immune diseases like
scleroderma, and liver disease.
- Polysomnography. This test will help your doctor rule out sleep-disordered
breathing as a cause of your PAH.
How is pulmonary arterial hypertension treated?
The goals of treatment for patients with pulmonary arterial hypertension
(PAH) are to:
These treatments include:
- Treat the underlying cause. This is the first priority in patients
with secondary pulmonary arterial hypertension (SPAH). Sometimes this
treatment can correct the PAH.
- Reduce symptoms and improve quality of life.
- Slow the growth of the smooth muscle cells and the development of
- Increase the supply of blood and oxygen to the heart, while reducing
- Lung transplantation
- Anticoagulants reduce
the formation of blood clots.
- Calcium channel blockers
relax blood vessels and increase the supply of blood and oxygen to the
heart, while reducing its workload. These drugs can be very helpful,
but only for a small amount of patients. All patients that take them
should be monitored carefully.
- Epoprostenol is a type of medicine called a prostacyclin. It
is currently considered the most effective therapy for primary pulmonary
arterial hypertension (PPAH). It may also be helpful in treating some
forms of severe SPAH. This medication widens the lung arteries and prevents
blood clot formation. Until recently, it was given intravenously through
a permanent tube, or catheter, placed in a vein in the neck and connected
to a battery-powered pump. But in December 2004, a new form of the drug,
iloprost, was approved for the treatment of PAH. This medicine can be
inhaled through a nebulizer. This makes it more convenient and less
painful to take. Plus the medicine goes directly to the lungs, where
it is needed.
- Treprostinil, another prostacyclin, also relaxes blood vessels
and increases the supply of blood to the lungs, reducing the workload
of the heart. It can be given under the skin.
- Bosentan, a relatively new treatment, widens the lung arteries
and reduces blood pressure. It also is available in pill form. Until
doctors learn more about the long-term effects, all patients taking
this drug should be monitored for complications, especially those involving
- Nitric oxide inhalation, which causes the pulmonary arteries
to widen or open, is also being used by some doctors.
- Sildenafil (ViagraŽ), another drug that causes the pulmonary
arteries to open, has recently been shown to improve the condition of
PAH patients and is expected to be approved soon. This drug is available
in pill form.
- diuretics (water or fluid
pills) may help ease symptoms and improve the heart's performance in
some patients with PAH.
You may need oxygen therapy if the level of oxygen in your blood is low.
Oxygen is usually given through nasal prongs or a mask. Over time, you may
need oxygen around the clock.
Surgery to replace one or both diseased lungs with healthy lungs from a
human donor may help some patients. This procedure is usually recommended
for patients for whom medical therapy is no longer effective. Complications
include rejection by the body of the transplanted lung and infection. Transplant
patients must take medicines for life to reduce the chances that their body
will reject the transplanted lung.
Other possible treatments
Researchers also are studying whether stem cell transplantation combined
with gene therapy may provide a cure for PAH in the not too distant future.
Living with pulmonary arterial
Many people with pulmonary arterial hypertension (PAH) do not look sick.
Many feel perfectly well most of the time, as long as they do not strain
themselves physically. In the early stages of the disease, many are able
to go to school or work on a full- or part-time basis.
Relaxation exercises and stress reduction activities may help many people
with PAH keep up with their regular activities for a while. Having a positive
attitude is also helpful.
Walking is good exercise for many people with PAH. Advanced patients who
find walking too exhausting may use a wheelchair or motorized scooter. Others
stay busy with activities that are not of a physical nature.
Some people with advanced PAH carry portable oxygen when they go out. Ongoing
ical care is important. Treatment by a cardiologist or pulmonologist who
specializes in pulmonary vascular medicine is usually recommended. These
specialists are usually located at major medical centers.
PAH patients should also eat a healthy diet and get plenty of rest, and
they should not smoke.
Situations that can make PAH symptoms worse are:
- Living at high altitudes or traveling to high-altitude areas where
the air is thin and the amount of oxygen in the air is low
- Air travel
Source: U.S. National Heart, Lung and Blood Institute