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 completely blocked.
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.
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 arterial hypertension?
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.
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.
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.
Other common signs and symptoms
As the disease advances:
In the more advanced stages, you:
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:
How is pulmonary arterial hypertension diagnosed?
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 to:
These tests include:
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 disease).
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 scanning methods.
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:
If these tests do not show an underlying cause for the PAH, the diagnosis is primary pulmonary arterial hypertension.
How is pulmonary arterial hypertension treated?
The goals of treatment for patients with pulmonary arterial hypertension (PAH) are to:
These treatments include:
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 hypertension
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 med 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: