Pulmonary Hypertension

What is pulmonary hypertension?

Pulmonary hypertension (pronounced PULL-mun-airy hi-per-TEN-shun) is high blood pressure in the lungs. It happens when blood vessels in the lungs cannot expand enough to receive blood coming from the heart.

Normally, the right ventricle of the heart pumps oxygen-poor (blue) blood to the lungs to pick up oxygen. The blood leaves the heart through the pulmonary artery. The pulmonary artery branches out and becomes smaller blood vessels in the lungs. The smallest blood vessels in the lungs are called the capillaries.

The capillaries have thin walls and run near the small air chambers of the lungs. The blood absorbs oxygen in the capillaries. The oxygen-rich (red) blood then flows into larger vessels to return to the heart. The oxygen-rich (red) blood flows into the heart’s left side, where the left ventricle pumps it to the rest of the body.

The pulmonary arteries and the smaller blood vessels in the lungs (capillaries) have muscle in their walls. Normally, this muscle relaxes to allow in more blood or squeezes to allow in less blood based on the body’s needs.

In children with pulmonary hypertension, this muscle is thickened. Their blood vessels cannot expand as easily. When their right ventricle pumps blood toward their lungs, the vessel walls resist more than normal.

  • The main effect of pulmonary hypertension is that it causes the right ventricle to work harder to pump blood to the lungs. Because the right ventricle is working harder, it gets bigger and thicker, and it could fail.

    Pulmonary hypertension can have many causes or associated diseases.

    In children, one of the most common causes is congenital heart disease. Some heart defects can cause pulmonary hypertension because they direct more blood than normal to the pulmonary artery. This is one reason it can be important to repair heart defects, when possible, before the heart or blood vessels are damaged permanently. Often, but not always, pulmonary hypertension will improve after the congenital heart defect is repaired.

    Another common cause of pulmonary hypertension in children is lung disease. Lung disease may occur because a baby was born early (prematurely) or they have a congenital lung problem. Children can also get lung disease after being on a machine to help them breathe (mechanical ventilator) for a long time. Sometimes, children with obstructive sleep apneacan develop pulmonary hypertension.

    Rarely, the cause of pulmonary hypertension is not known, and then we call it idiopathic. In some cases, there is a family history of the condition.

Pulmonary Hypertension at Seattle Children’s


  • Our Heart Center is the top-ranked cardiology and cardiac surgery program in the Northwest and among the best in the nation, according to U.S. News & World Report. With more than 40 pediatric cardiologists, we have experience diagnosing and treating every kind of heart problem.

    Our heart team has treated many children with pulmonary hypertension. We have a special team and clinic to care just for children with pulmonary hypertension. We have years of experience with the treatment these patients may need, including oxygen therapy, medicine or surgery to correct an existing heart defect. We also have a pediatric cardiac anesthesia team and a Cardiac Intensive Care Unit ready to care for children who have heart surgery.

    The Adult Congenital Heart Disease Program shared by Seattle Children’s and the University of Washington can help with care throughout your child’s life.

    Seattle Children’s has been treating children since 1907. Our team members are specially trained in their fields and in meeting the unique needs of children. For example, the doctors who give your child anesthesia are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age.

  • When an infant, child or young adult arrives at Seattle Children’s, a team of people will take care of them. Along with your child’s heart doctor (cardiologist), you are connected with newborn intensive care physicians (neonatologists), lung doctors (pulmonologists), nurses, child life specialists, social workers and others, if their expertise is needed.

    We’re committed to your child’s overall health and well-being. We’ll discuss treatments in ways you can understand and involve you in every decision.

    Read more about the supportive care we offer.

Symptoms of Pulmonary Hypertension

The most common symptoms in children with pulmonary hypertension are breathing problems. If your child has symptoms, these may get worse with exercise or activity.

Other symptoms may include:

  • Feeling short of breath when active
  • Fainting or feeling weak or dizzy when active
  • Being more tired than normal
  • Chest pain
  • Bluish color to the lips, hands and feet (cyanosis)
  • Swelling in the ankles

Diagnosing Pulmonary Hypertension

To diagnose this condition, your doctor will examine your child and use a stethoscope to listen to their heart.

The doctor will ask for details about your child’s symptoms, their health history and your family health history.

Your child will also need echocardiography and an electrocardiogram. To get more information about how their heart and lungs look and work, they may need other tests, including chest X-rays, chest CT (computed tomography) scan, angiography, pulmonary function tests (to see how well they can breathe in and out), exercise testing and cardiac catheterization.

Your child may also be asked to do a 6-minute walk test. For this test, they’re asked to walk as far as they can in 6 minutes and then report on how tired they feel and how well they can breathe. We will also check the level of oxygen in their blood. This walk test can be used to monitor your child’s condition over time to see whether it is getting worse.

Treating Pulmonary Hypertension

There is no cure for pulmonary hypertension. However, many treatments can help with some of the symptoms and slow the progress of the disease. Children tend to do better if they get treatment as soon as possible.

  • Your child may need oxygen therapy to treat their pulmonary hypertension. This means breathing air that has more oxygen than normal through tubes that go into their nose or through a mask that goes over their nose and mouth. This treatment helps open up the blood vessels in their lungs.

    Some children need to take medicines to relax the muscles in the walls of the blood vessels in their lungs or medicines that help the heart pump better. This treatment depends on how serious their condition is. Some children need to take medicine by mouth. Some need to take inhaled medicines. Some children need constant medicine through a tube inserted into their vein. This is called infusion therapy, and it uses a pump to give the medicine.

    Children who have pulmonary hypertension due to a congenital heart defect may need surgery to repair the defect.

    Read more about the care we provide at Seattle Children’s Pulmonary Hypertension Clinic.

  • Many new treatments are being developed to help treat pulmonary hypertension, including new oral (by mouth) and inhaled therapies. These developments are exciting, but they also need to be used carefully. Our Pulmonary Hypertension Clinic works to improve care for children with this condition and to research new treatments.

  • To meet your child’s long-term healthcare needs, we have a special Adult Congenital Heart Disease Program to transition your child to adult care when they’re ready.

Contact Us 

Contact the Heart Center at 206-987-2515 to request an appointment, a second opinion or more information.

Providers, see how to refer a patient.