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Primary Hypertension
What Is 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, 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 narrow.
- 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 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 patients with PAH.
There are 2 types of PAH:
- Primary (PPAH) is inherited or occurs for no known reason. Primary Hypertension
- 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 scleroderma (skler-o-'d&r-m&).
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. They include:
- Use of appetite suppressants, especially fenfluramine (fen-'flur-&-"mEn) and dexfenfluramine (deks-'fen-flur-&-"mEn)
- Chronic use of cocaine or amphetamines
- HIV infection
- Liver disease
- Connective tissue diseases such as scleroderma or lupus erythematosus
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 in adults.
Other conditions that can lead to SPAH include:
- Obstructive sleep apnea
- Congenital heart disease
- Chronic blood clots in the pulmonary artery
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:
- Fatigue
- Dizziness
- 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. They are:
- 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 tests to:
- 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.
- Polysomnography (poly·som·nog·ra·phy): 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 with 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 its workload.
These treatments include:
- Medications
- Oxygen
- Lung Transplantation
Medications
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 the liver.
- 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 hypertension.
Oxygen
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.
Lung Transplantation
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 of rest.
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
- Pregnancy
