Pulmonary Hypertension

Pulmonary hypertension (PH) is abnormally high blood pressure in the arteries of the lungs. It is a serious condition that may lead to failure of the right heart ventricle. It is sometimes difficult to diagnose because many symptoms of PH aren’t exclusive to the condition but can be caused by a variety of health conditions.

An accurate diagnosis of PH can lead to effective condition management through medication and other therapies. At the Pulmonary Hypertension Program at Boston Children’s, we aim to ensure your child can live as normal a life as possible.
 

Many initial symptoms of PH — breathing difficulties and fatigue — are also symptoms of other conditions, making it difficult to diagnose the disease early. For example, PH can often be confused for asthma. As the disease advances, symptoms such as chest pain and heart palpitations may surface, which can lead to the consideration of PH, but a delayed diagnosis can sometimes make it more difficult to effectively treat. It is critical to not overlook the possibility of pulmonary hypertension if your child is experiencing these symptoms:

• Shortness of breath while performing everyday activities such as walking or climbing stairs
• Excessive fatigue
• Fainting spells
• Dizziness
• Rapid heart beat
• Low blood pressure
• Swelling of legs and hands

The types of PH and their causes are separated into five categories by the World Symposium on Pulmonary Hypertension:

Group 1: Pulmonary arterial hypertension (PAH)

PAH causes the right side of the heart to work harder to pump blood because pulmonary arteries are narrowed or constricted and at high pressure. There are several types of PAH:

• Idiopathic PAH (IPAH) occurs without a clear cause
• Heritable PAH (HPAH) is linked to inherited genes
• PAH associated with congenital heart disease, liver disease, and connective tissue diseases such as scleroderma and lupus
• Persistent pulmonary hypertension of the newborn (PPHN)

Group 2: Pulmonary hypertension from left-heart disease

Heart and valve obstructions prevent the left side of the heart from keeping up with blood returning from the lungs. This overflow of blood raises pressure in the lungs. These conditions include:

• Left ventricular dysfunction
• Stenosis of the mitral or aortic valves
• Restrictive cardiomyopathy
• Pulmonary vein stenosis

Group 3: Pulmonary hypertension from lung disease and chronic hypoxia

Several lung diseases can cause PH. Conditions include:

• Obstructive lung diseases that narrow airways and make it difficult to exhale: cystic fibrosis, chronic obstructive pulmonary disease (COPD), and emphysema
• Interstitial lung disease — an umbrella of about 100 restrictive lung diseases, including hypoxia — that prevent the lungs from expanding because they are inflamed and usually scarred (a state that is known as pulmonary fibrosis)
• Sleep apnea
• Developmental lung diseases such as bronchopulmonary dysplasia (a developmental lung disease sometimes present in premature newborns), congenital diaphragmatic hernia, TBX4 gene variants, and alveolar capillary dysplasia

Group 4: Pulmonary hypertension from chronic lung blood clots

Chronic thromboembolic pulmonary hypertension (CTEPH) is when a blood clot in the lungs cannot be dissolved. This can create scar tissue in the blood vessels of the lungs, which blocks normal blood flow and makes the right side of the heart work harder. Other causes of pulmonary artery obstructions include malignant and non-malignant tumors, arteritis, and moyamoya disease.

Group 5: Pulmonary hypertension that has miscellaneous causes

This is when PH is associated with other diseases in ways that are not well understood. Associated conditions include the blood disorders sickle cell disease and hemolytic anemia, and the inflammatory disease sarcoidosis.

Because pulmonary hypertension can vary from child to child, and because its symptoms overlap with those of other conditions, it’s critical to pinpoint the causes of your child’s condition. To form a diagnosis, we collaborate with specialists across Boston Children’s — the Division of Pulmonary Medicine, Cardiac Catheterization Program, Division of Cardiac Imaging, Department of Cardiac Surgery, Neonatal Intensive Care Unit, and several genetics programs — who will best understand how to get to the bottom of the symptoms we’re seeing in your child. We approach a diagnosis in two ways:

Measuring pulmonary blood pressure

• A pediatric cardiologist or other physician will perform a physical examination, listening to your child's heart and lungs.
• An echocardiogram (a test which uses sound waves to determine the structure and function of the heart) may reveal elevated pulmonary artery pressure. This test is painless, takes about 30 minutes, and is easily performed in a doctor’s office. To get the clearest possible images, it’s important for your child to hold still. Children younger than 3 who are restless may be given a sedative to help them relax during the lengthy procedure.
• Cardiac catheterization is a procedure that gives us detailed information about the structures inside heart muscle. In some cases, we may need your child to stay overnight in the hospital for this test.

Finding underlying causes

• Blood tests may help identify the cause of the pulmonary hypertension, as well as related medical conditions that occur as a result of high blood pressure.
• CT scans of the chest show the lungs in more detail than a chest X-ray and better detect certain problems.
• A cardiac MRI is a non-invasive test that shows the structure and function of the heart without the radioactive radiation used in X-rays.
• Pulmonary function tests measure breathing and lung capacity.
• During ventilation and perfusion scans, oxygen and a special type of test medicine is inhaled or injected into a vein in your child’s arm to determine the path of air and blood flow within the lungs.
• Because genetic conditions can cause pulmonary hypertension, we collaborate with our Pulmonary Genetics and Cardiovascular Genetics programs to discover how your child’s genetic profile connects to their lung condition and could possibly cause PH.

Your child will benefit from the expertise of these and other specialists as we review and discuss their test results and determine the specifics of their condition. We’ll then meet with you and your family to review the results, answer any questions, and outline the best treatment options.

We will create an individualized treatment plan that will address the specifics of your child’s condition. Although there is no cure for pulmonary hypertension, we’re committed to the goal of improving your child’s health. We can treat your child with one or several therapies that are most suitable for their condition. We will explain all of the options to your family and consider your feedback as we collectively decide which treatment options to pursue.

The most common types of treatments for PH include:

• Medications will help relax pulmonary blood vessels and make it easier for your child's heart to pump blood. These include oral, inhaled, intravenous, and subcutaneous medications such as phosphodiesterase 5 inhibitors, inhaled nitric oxide, endothelin receptor antagonists, and prostacyclin therapies.
• Anticoagulants can prevent blood clots in your child's lungs, and diuretics can help your child’s kidneys eliminate water.
• Inhaled oxygen can help raise the levels of oxygen in the bloodstream. This might be recommended for when your child is sleeping and breathing less strongly than when awake, but it can also be used during the day.

Advanced treatments for pulmonary hypertension

If medication and oxygen fail to reduce pulmonary pressures and the ability of your child’s heart to pump blood, there are several advanced therapies that can be considered:

• Balloon atrial septosomy is a catheterization procedure where an opening is created or enlarged between the atria, allowing blood from the right side of the heart to mix with that from the left side.
• Stenting of the patent ductus arteriosus (PDA) is a procedure in which a stent is placed to keep the PDA open. The PDA is a blood vessel required for fetal blood circulation, but one which typically closes shortly after birth. When an infant has PH, in some cases this blood vessel is required to allow adequate flow of blood from the heart to the rest of the body.
• Surgical Potts shunt is a procedure in which a small shunt is placed between the pulmonary artery and the aorta to increase blood flow to the heart and decrease blood pressure in the right ventricle.
• Mechanical support such as ECMO or implanted oxygenator membranes may be considered as a bridge to lung transplant.
• Lung transplantation is a possibility if your child has or is approaching severe end-stage PH. We will review your child’s case with the Lung Transplant team to determine whether you child is an ideal candidate for transplantation.