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,
and treatment benefits many patients.
The pulmonary artery is the blood vessel that carries oxygen-poor blood
from the right ventricle in the heart to the small arteries in the lungs.
In PAH, 3 types of changes may occur in the pulmonary arteries:
- 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
- Tiny blood clots may form within the smaller arteries, causing blockages.
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 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
patients with PAH.
There are 2 types of PAH:
- Primary (PPAH) is inherited or
occurs for no known reason. Primary
- Secondary (SPAH) 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
About 300 new cases of PPAH are diagnosed in the United States each
year. SPAH is much more common.
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.
Other names for Pulmonary Arterial Hypertension
- Idiopathic pulmonary arterial hypertension
- Sporadic primary pulmonary hypertension
- Familial primary pulmonary hypertension
- Secondary pulmonary arterial hypertension
- Pulmonary hypertension
What causes Pulmonary Arterial Hypertension?
Certain conditions appear to increase your chances of developing PAH.
Doctors do not know what causes
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.
SPAH is caused by a variety of conditions.
Chronic obstructive pulmonary disease (COPD) is the most common cause
Other conditions that can lead to SPAH include:
PAH affects men and women in all age ranges, from very young children
to seniors, and people of all racial and ethnic backgrounds.
PPAH is most common in women in their 30's and men in their 40's. Twice
as many cases are reported in women as in men.
What are the signs and symptoms of Pulmonary Arterial Hypertension?
Difficulty in breathing or shortness of breath (dyspnea) is the main
symptom of PAH. You may feel that it is difficult to get enough air.
Other common symptoms are:
- 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)
As the disease advances:
- The pumping action of your heart grows weaker
- Your energy decreases
In the more advanced stages, you
- 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.
- Class 1: No limits--ordinary physical activity does not cause undue
tiredness or shortness of breath.
- Class 2: Slight or mild limits--comfortable at rest, but ordinary
physical activity results in tiredness or shortness of breath.
- Class 3: Marked or noticeable limits--comfortable at rest, but less
than ordinary physical activity causes tiredness or shortness of breath.
- Class 4: Severe limits--unable to carry on any physical activity
without discomfort. Symptoms may also present at rest. If any physical
activity is undertaken, discomfort increases.
How is Pulmonary Arterial Hypertension Diagnosed?
There is no one specific test that will show why you have 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
- 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
These tests include:
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 COPD, as the cause of your PAH.
EKG or ECG (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.
Doppler Echocardiogram . This test shows whether the right
side of your heart is enlarged and how well it is functioning. It is
the most reliable noninvasive test for obtaining an estimate of the
blood pressure in the pulmonary artery.
Stress Test . This test helps the doctor evaluate the effect
of exercise on your heart.
Spirometry (spi·rom·e·tre) 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. It 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.
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:
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 PAH.
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 to rule out HIV, auto-immune diseases like scleroderma,
and liver disease.
This test will help your doctor rule out sleep-disordered breathing
as a cause of your pulmonary hypertension.
How is Pulmonary Arterial Hypertension Treated?
The goals of treatment for patients with PAH are to:
- Treat the underlying cause. This is the first priority in patients
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
blood clots; and
- Increase the supply of blood and oxygen to the heart, while reducing
These treatments include:
- Lung Transplantation
The main medicines are:
- Anticoagulants (an-ty-ko-AG-u-lants), which reduce
the formation of blood clots.
Calcium channel blockers , which 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 minority
of patients. All patients who take them should be monitored carefully.
Epoprostenol (Prostacyclin präs-t&-'sI-kl&n)
is currently considered the most effective therapy for
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 PH. This medication can be inhaled through a nebulizer.
This makes it more convenient and less painful to take. Plus the medication
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 that 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 involving
- Nitric oxide inhalation , which causes the pulmonary
arteries to widen or open, is also being used by some doctors.
Sildenafil , (Viagra), another drug that causes the pulmonary
arteries to open, has recently been shown to improve the condition of
PH 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 pulmonary
You may need oxygen therapy if the level 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 medications 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 PH in the not too distant future.
Living with Pulmonary Arterial Hypertension.
Many people with 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 medical 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, not smoke, and get plenty
Situations that can make PAH symptoms worse are:
- Living at or travel to high altitudes, where the air is thin and
the amount of oxygen in the air is low
- Air travel