What Is Pulmonary Hypertension?

Pulmonary hypertension (PULL-mun-ary HI-per-TEN-shun), or PH, is increased pressure in the pulmonary arteries. These arteries carry blood from your heart to your lungs to pick up oxygen.

PH causes symptoms such as shortness of breath during routine activity (for example, climbing two flights of stairs), tiredness, chest pain, and a racing heartbeat. As the disease worsens, its symptoms may limit all physical activity.

Overview

The lower right chamber of your heart, the right ventricle (VEN-trih-kul), pumps blood to your pulmonary arteries. The blood then travels to your lungs, where it picks up oxygen. This oxygen-rich blood is pumped to the rest of your body. (For more information, see the Diseases and Conditions Index article on How the Heart Works.)

Three types of changes can affect the pulmonary arteries and cause PH:

• The walls of the arteries tighten.
• The walls of the arteries are stiff at birth or become stiff from an overgrowth of cells.
• Blood clots form in the arteries.

These changes make it hard for the heart to push blood through the arteries and into the lungs. Thus, the pressure in the arteries rises. Also, as a result of the heart working harder, the right ventricle becomes strained and weak.

The heart may become so weak that it can't pump enough blood to the lungs. This causes heart failure. Heart failure is the most common cause of death in people who have PH.

PH is divided into five groups based on its causes. In all groups, the average pressure in the pulmonary artery is higher than 25 mmHg at rest or 30 mmHg during physical activity. The pressure in a normal pulmonary artery is about 15 mmHg at rest. (The mmHg is millimeters of mercury—the units used to measure blood pressure.)

Usually, other diseases or conditions, such as heart and lung diseases or blood clots, cause PH. Some people inherit the condition. In some cases, the cause isn't known.

Outlook

PH has no cure. However, research for new treatments is ongoing. The earlier PH is treated, the easier it is to control.

Treatments include medicines, procedures, and other therapies. These treatments can relieve PH symptoms and slow the progress of the disease. Lifestyle changes also can help control symptoms.

Types of Pulmonary Hypertension

The World Health Organization divides pulmonary hypertension (PH) into five groups. These groups are organized based on the cause of the disease.

In all groups, the average pressure in the pulmonary artery is higher than 25 mmHg at rest or 30 mmHg during physical activity. The pressure in a normal pulmonary artery is about 15 mmHg at rest.

(Note that group 1 is called pulmonary arterial hypertension (PAH) and groups 2 through 5 are called pulmonary hypertension. However, together all groups are called pulmonary hypertension.)

Group 1 PAH includes:

• PAH that has no known cause.
• PAH that's inherited (passed from parents to children through the genes).
• PAH that's caused by conditions such as:
  • Congenital heart disease. This is heart disease that's present at birth.
  • HIV infection.
  • The use of certain diet medicines and street drugs (such as cocaine).
  • Thyroid diseases.

Group 2 includes PH with left heart disease. Conditions that affect the left side of the heart, such as mitral valve disease or long-standing high blood pressure, can cause left heart disease and PH.

Group 3 includes PH linked to lung conditions such as COPD (chronic obstructive pulmonary disease) and interstitial (IN-ter-STISH-al) lung disease. Interstitial lung disease refers to a group of lung diseases that cause scarring of the lung tissue. Group 3 also includes PH linked to sleep disorders that cause breathing problems, such as sleep apnea.

Group 4 includes PH due to blood clots in the lungs or blood clotting disorders. This group also includes PH due to sickle cell anemia.

Group 5 includes PH due to various other diseases or conditions. Examples include sarcoidosis, Langerhans cell histiocytosis, and lymphangioleiomyomatosis (LAM). This type of PH also may be due to an object, such as a tumor, pressing on the pulmonary blood vessels.

Sometimes other terms are used to describe the different types of PH. Group 1 PAH that has no known cause may be called primary or idiopathic (id-ee-o-PATH-ick) PAH. When PH occurs with or is caused by another disease or condition, it may be called secondary PH.

Other Names for Pulmonary Hypertension

Group 1 pulmonary arterial hypertension (PAH) that occurs without a known cause is often called primary PAH or idiopathic PAH (IPAH).

Group 1 PAH that occurs with a known underlying disease or condition is often called associated PAH. For example, PAH that occurs in a patient who has scleroderma might be called "PAH occurring in association with scleroderma," or simply "scleroderma-associated PAH."

Groups 2–5 PH are sometimes called secondary PH.

What Causes Pulmonary Hypertension?

Pulmonary hypertension (PH) is the result of a process that begins with changes in the cells that line your lungs' arteries. This process includes three types of changes that affect the pulmonary arteries:

• The walls of the arteries tighten.
• The walls of the arteries are stiff at birth or become stiff from an overgrowth of cells.
• Blood clots form in the arteries.

These changes make it hard for the heart to push blood through the arteries and into the lungs. Thus, the pressure in the arteries rises, resulting in PH.

A number of different factors can contribute to the process that leads to the different types of PH.

Group 1 pulmonary arterial hypertension (PAH) may have no known cause, or it may be inherited (passed from parents to children through the genes). Certain diseases and conditions, such as congenital heart disease, HIV, and thyroid disease, also can cause this type of PH. Also, the use of certain diet medicines and street drugs (such as cocaine) can lead to this type of PH.

Many different diseases and conditions can lead to the development of groups 2 through 5 PH (often called secondary PH), including:

• Mitral valve disease
• Lung conditions, such as COPD (chronic obstructive pulmonary disease)
• Sleep apnea
• Sickle cell anemia
• Sarcoidosis

For more information about the types of PH and the diseases, conditions, and factors that can contribute to PH, see "Types of Pulmonary Hypertension."

Who Is At Risk for Pulmonary Hypertension?

The exact number of people who have pulmonary hypertension (PH) isn't known. Group 1 pulmonary arterial hypertension (PAH) without a known cause is rare. PH that occurs with another disease or condition is more common.

Anyone can develop PH. However, PAH that has no known cause affects about two to three times as many women as men. PH usually develops between the ages of 20 and 60, but it can occur at any age.

People who are at increased risk for PH include:

• Those who have a family history of the condition.
• Those who have certain diseases or conditions, such as heart and lung diseases, liver disease, HIV infection, or blood clots in the pulmonary arteries. (For more information on diseases, conditions, and factors that can lead to PH, see "Types of Pulmonary Hypertension.")
• Those who use certain diet medicines or street drugs (such as cocaine).

What Are the Signs and Symptoms of Pulmonary Hypertension?

Signs and symptoms of pulmonary hypertension (PH) may include:

• Shortness of breath during routine activity, such as climbing two flights of stairs
• Tiredness
• Chest pain
• A racing heartbeat

As PH worsens, you may find it hard to do any physical activities. At this point, other signs and symptoms may include:

• Feeling lightheaded, especially during physical activity
• Fainting at times
• Swelling in your legs and ankles
• A bluish color on your lips and skin

How Is Pulmonary Hypertension Diagnosed?

Your doctor will diagnose pulmonary hypertension (PH) based on your medical and family histories, a physical exam, and the results from tests and procedures.

PH can develop slowly. In fact, you may have it for years and not know it. This is because the disease has no early symptoms.

When symptoms do develop, they're often like those of other heart and lung conditions, such as asthma. This makes PH hard to diagnose.

Medical and Family Histories

To learn about your medical history, your doctor may ask about your signs and symptoms and how and when they began. He or she also may ask whether you have other medical conditions that can cause PH.

Your doctor also may ask whether you have any family members who have or have had PH. People who have a family history of PH are at increased risk for the condition.

Physical Exam

During the physical exam, your doctor will listen to your heart and lungs with a stethoscope. He or she also will check your ankles and legs for swelling and your lips and skin for a bluish tint. These are signs of PH.

Diagnostic Tests and Procedures

You may need tests and procedures to confirm a diagnosis of PH and to look for the underlying cause of the disease. Your doctor also will use test results to find out the severity of your PH.

Tests and Procedures To Confirm a Diagnosis

Echocardiography. This test uses sound waves to create a moving picture of your heart. Echocardiography (EK-o-kar-de-OG-ra-fee) can estimate the pressure in your pulmonary arteries. The test also can show the size and thickness of your right ventricle and how well it's working.

Chest x ray. A chest x ray takes pictures of your heart and lungs. This test can show whether your pulmonary arteries and right ventricle are enlarged. The pulmonary arteries and right ventricle may get larger if the right ventricle has to work hard to pump blood through the pulmonary arteries.

Also, a chest x ray may show signs of an underlying lung disease that may be causing or contributing to PH.

EKG (electrocardiogram). An EKG is a simple test that shows how fast your heart is beating. It also shows whether your heart's rhythm is steady or irregular. An EKG may show whether your right ventricle is enlarged or strained.

Right heart catheterization. This procedure measures the pressure in your pulmonary arteries. It also shows how well your heart is pumping blood to the rest of your body. Right heart catheterization (KATH-e-ter-i-ZA-shun) can find any leaks between the left and right side of the heart.

During this procedure, a thin, flexible tube called a catheter is put into a blood vessel in your groin (upper thigh) or neck. The tube is then threaded into the right side of your heart and into the pulmonary arteries. Through the tube, your doctor can do diagnostic tests and test treatments on your heart.

Tests To Look for the Underlying Cause of Pulmonary Hypertension

Lung function tests. Lung function tests measure the size of your lungs, how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs deliver oxygen to your blood. These tests can help find an underlying lung disease that may be causing PH.

Overnight oximetry. This test measures the level of oxygen in your blood overnight. A low oxygen level during sleep is common in PH, and it can cause the condition to worsen.

For this test, a small light is attached to your fingertip, earlobe, or toe. A machine that's attached to the light measures the amount of oxygen in your blood throughout the night. In the morning, the light is removed and your oxygen levels are recorded. Overnight oximetry can be done at home or in a sleep lab.

Lung ventilation/perfusion (VQ) scan. This test measures air and blood flow in your lungs. A lung VQ scan can show whether there are blood clots in your lung's blood vessels.

Blood tests. Blood tests are used to rule out other diseases, such as HIV, liver disease, and autoimmune diseases like rheumatoid arthritis.

Exercise testing. Exercise testing consists of either a 6-minute walk test or a cardiopulmonary exercise test. These tests can help find out whether another disease or condition is causing your symptoms.

A 6-minute walk test measures the distance you can quickly walk in 6 minutes. A cardiopulmonary exercise test measures how well your lungs and heart work while you exercise on a treadmill or bicycle.

Finding Out the Severity of Pulmonary Hypertension

Exercise testing is used to find out how severe PH is. During this test, your doctor will rate your activity level. Your level is linked to how severe your PH is. The rating system ranges from class 1 to class 4.

• Class 1 has no limits. You can do regular physical activities, such as walking or climbing stairs. These activities don't cause PH symptoms, such as tiredness, shortness of breath, or chest pain.
• Class 2 has slight or mild limits. You're comfortable while resting, but regular physical activity causes PH symptoms.
• Class 3 has marked or noticeable limits. You're comfortable while resting. However, walking even one or two blocks or climbing one flight of stairs can cause PH symptoms.
• Class 4 has severe limits. You're not able to do any physical activity without discomfort. You also may have PH symptoms while at rest.

Over time, you may need more exercise tests to find out how well your treatments are working. Each time testing is done, your doctor will compare your activity level to the previous one.

How Is Pulmonary Hypertension Treated?

Pulmonary hypertension (PH) has no cure, but treatment may help relieve symptoms and slow the progress of the disease.

PH is treated with medicines, procedures, and other therapies. Treatment will depend on what type of PH you have and how severe it is. (For more information, see "Types of Pulmonary Hypertension.")

Group 1 Pulmonary Arterial Hypertension

This type of PH includes PH that's inherited, that has no known cause, or that's caused by certain conditions. Treatment for group 1 pulmonary arterial hypertension (PAH) includes medicines or medical procedures.

Medicines

If you have group 1 PAH, you may need medicines to relax the blood vessels in your lungs and reduce excess cell growth in the blood vessels. As the blood vessels relax, more blood can flow through them.

Examples of these medicines include phosphodiesterase-5 inhibitors, prostanoids, endothelin receptor antagonists, and calcium channel blockers.

To find out which of these medicines will work best, you'll likely have an acute vasoreactivity test. This test shows how the pressure in your pulmonary arteries reacts to certain medicines. This test is done during right heart catheterization.

Medical and Surgical Procedures

If you have group 1 PAH, you may need one or more of the following procedures.

Atrial septostomy. For this procedure, a thin, flexible tube called a catheter is put into a blood vessel in your leg and threaded to your heart. The tube is then put through the wall that separates your right and left atria (the two upper chambers of your heart). This wall is called the septum.

A tiny balloon on the tip of the tube is inflated to create an opening between the atria. This procedure relieves the pressure in the right atria and increases blood flow. Atrial septostomy is rarely done in the United States.

Lung transplant. A lung transplant is surgery to replace a person's diseased lung with a healthy lung from a deceased donor. This procedure may be used for people who have severe lung disease that's causing PAH.

Heart–lung transplant. A heart–lung transplant is surgery in which both the heart and lung are replaced with healthy organs from a deceased donor.

Group 2 Pulmonary Hypertension

Group 2 PH is caused by conditions that affect the left side of the heart, such as mitral valve disease. Treating these conditions also will help treat PH. Treatments may include lifestyle changes, medicines, and surgery.

Group 3 Pulmonary Hypertension

Group 3 PH is linked to lung conditions, such as COPD (chronic obstructive pulmonary disease) and interstitial lung disease. Group 3 PH also may be linked to certain sleep disorders, such as sleep apnea.

If you have this type of PH, you may need oxygen therapy. This treatment raises the level of oxygen in your blood. You'll likely get the oxygen through soft, plastic prongs that fit into your nose. You can get oxygen therapy at home or in a hospital.

Your doctor also may recommend other treatments if you have an underlying lung disease.

Group 4 Pulmonary Hypertension

This type of PH is due to blood clots in the lungs, blood clotting disorders, or sickle cell anemia. If you have this type of PH, your doctor will likely prescribe anticoagulants, or "blood thinners." These medicines prevent clots from forming or from getting larger.

In some cases, surgery is used to remove scarring in the pulmonary arteries due to old blood clots.

Group 5 Pulmonary Hypertension

Various diseases and conditions cause group 5 PH. Examples include sarcoidosis, Langerhans cell histiocytosis, and lymphangioleiomyomatosis (LAM). This type of PH also may be due to an object, such as a tumor, pressing on the pulmonary blood vessels.

This type of PH is treated by treating its cause.

All Types of Pulmonary Hypertension

Several treatments may be used for all types of PH. These treatments include:

• Diuretics, or "water pills." These medicines help reduce fluid buildup in your body, including swelling in your ankles and feet.
• Blood-thinning medicines. These medicines help prevent blood clots from forming or getting larger.
• Digoxin. This medicine helps the heart beat stronger and pump more blood. Digoxin is sometimes used to control the heart rate when certain abnormal heart rhythms occur, such as atrial fibrillation or atrial flutter.
• Oxygen therapy. This treatment raises the level of oxygen in your blood.
• Physical activity. Regular activity may help improve your ability to be active. Your doctor can help you create an exercise plan that's safe for you.

Research on new treatments for PH is ongoing. These treatments offer hope for the future. Talk to your doctor about whether you should consider participating in research studies.

Living With Pulmonary Hypertension

Pulmonary hypertension (PH) has no cure. However, you can work with your doctor to manage your symptoms and slow the progress of the disease.

Ongoing Care

Follow your treatment plan and call your doctor if your PH symptoms worsen or change. The earlier symptoms are addressed, the easier it is to treat them. Some symptoms, such as chest pain, may require emergency treatment. Talk to your doctor about when you should call him or her and when to seek emergency care.

Also, talk to your doctor before taking any over-the-counter medicines. Certain medicines can make your PH worse or interfere with the medicines you're taking for PH. Ask your doctor whether you should get a pneumonia vaccine and a yearly flu shot.

Know the names of your medicines and how they work. Keep a list of your medicines with you. Don't stop or change your medicines unless you talk with your doctor.

Pay careful attention to your weight. You may want to keep a daily record of your weight. You should weigh yourself at the same time each day. If you notice a rapid weight gain (2 or more pounds in 1 day or 5 or more pounds in 1 week), call your doctor. This may be a sign that your condition is worsening.

Pregnancy is risky for women who have PH. Consider using birth control if there's a chance you may become pregnant. Talk to your doctor about which birth control methods are right for you.

Lifestyle Changes

Making lifestyle changes can help you manage your symptoms. These changes will depend on the type of PH you have. Talk to your doctor about which steps can help you.

Quit Smoking

If you smoke, quit. Smoking makes PH symptoms worse. Ask your doctor about programs and products that can help you quit. Also, avoid exposure to secondhand smoke.

Follow a Healthy Diet

Follow a healthy diet and maintain a healthy weight. A healthy diet includes a variety of fruits, vegetables, and whole grains. It also includes lean meats, poultry, fish, and fat-free or low-fat milk or milk products. A healthy diet also is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar.

Talk to your doctor about whether you need to limit the amount of salt and fluids in your diet. Ask him or her whether you also need to regulate foods that contain vitamin K. These foods can affect how well blood-thinning medicines work. Vitamin K is found in green leafy vegetables and some oils, such as canola and soybean oil.

For more information on following a healthy diet, see the National Heart, Lung, and Blood Institute's Aim for a Healthy Weight Web site, "Your Guide to a Healthy Heart," and "Your Guide to Lowering Your Blood Pressure With DASH."

All of these resources include general advice about healthy eating. The DASH eating plan focuses on foods that are lower in salt, which may be helpful if your doctor advises you to reduce the salt in your diet.

Do Physical Activity

Do regular physical activity, such as walking. This will keep your muscles strong and help you stay active. Talk to your doctor about how much activity is safe for you. Your doctor may tell you to limit or avoid certain activities, such as:

• Those that cause straining, such as lifting heavy objects or weights.
• Being in a hot tub or sauna or taking long baths. These activities can lower your blood pressure too much.
• Flying in an airplane or traveling to high-altitude areas. Your doctor may ask you to use oxygen during air travel.

Avoid activities that cause breathing problems, dizziness, or chest pain. If you have any of these symptoms, seek care right away.

Key Points

• Pulmonary hypertension (PH) is increased pressure in the pulmonary arteries. These arteries carry blood from your heart to your lungs to pick up oxygen.
• Three types of changes can affect the pulmonary arteries and can cause PH: the walls of the arteries tighten, the walls of the arteries are stiff at birth or become stiff from an overgrowth of cells, or blood clots form in the arteries.
• These changes make it hard for the heart to push blood through the arteries and into the lungs. Thus, the pressure in the arteries rises. Also, as a result of the heart working harder, the right ventricle becomes strained and weak.
• The heart may become so weak that it can't pump enough blood to the lungs. This causes heart failure. Heart failure is the most common cause of death in people who have PH.
• PH is divided into five groups based on its causes. In all groups, the average pressure in the pulmonary artery is higher than 25 mmHg at rest or 30 mmHg during physical activity. The pressure in a normal pulmonary artery is about 15 mmHg at rest.
• Usually, other diseases or conditions, such as heart and lung diseases or blood clots, cause PH. Some people inherit the condition. In some cases, the cause isn't known.
• The exact number of people who have PH isn't known. Group 1 pulmonary arterial hypertension (PAH) without a known cause is rare. PH that occurs with another disease or condition is more common.
• PH causes symptoms such as shortness of breath during routine activity (for example, climbing two flights of stairs), tiredness, chest pain, and a racing heartbeat. As the disease worsens, its symptoms may limit all physical activity.
• Your doctor will diagnose PH based on your medical and family histories, a physical exam, and the results from tests and procedures. PH can develop slowly. In fact, you may have it for years and not know it. This is because the disease has no early symptoms. When symptoms do develop, they're often like those of other heart and lung conditions, such as asthma. This makes PH hard to diagnose.
• PH has no cure, but treatments may help relieve symptoms and slow the progress of the disease. PH is treated with medicines, procedures, and other therapies. Treatment will depend on what type of PH you have and how severe it is. The earlier PH is treated, the easier it is to control.
• You can work with your doctor to manage your symptoms and slow the progress of PH. Get ongoing care. Follow your treatment plan and call your doctor if your symptoms worsen or change. Make lifestyle changes, such as eating healthy, quitting smoking, and doing regular physical activity.
• Research on new treatments for PH is ongoing. These treatments offer hope for the future. Talk to your doctor about whether you should consider participating in research studies.

Links to Other Information About Pulmonary Hypertension

NHLBI Resources

• NHLBI-Related Public Interest Organizations

Non-NHLBI Resources

• Pulmonary Hypertension (MedlinePlus)

Clinical Trials

• Current Research (ClinicalTrials.gov)
• Patient Recruitment for Studies Conducted by NHLBI, NIH