What is PAH?

Pulmonary arterial hypertension (PAH) is an uncommon disorder of the lungs or, more specifically, of the arteries of the lungs. In PAH, the arteries of the lungs (called the pulmonary arteries) become narrower than usual. Greater pressure is needed to push blood through these narrowed pulmonary arteries, and the heart must pump harder as a result. Over time, this extra work weakens the heart, and it can lose its ability to pump as much blood as the body needs.

PAH begins with abnormal changes in the walls of the pulmonary arteries. It is not clear what triggers the changes that lead to PAH; but once the process begins, it tends to progress over time.

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What causes PAH?

There are many causes of PAH. Some of these are known and some have yet to be identified. If no specific cause for a person’s PAH can be identified, then it is referred to as idiopathic PAH (IPAH).

PAH that runs in families and can be inherited is called familial PAH (FPAH). PAH associated with another disease or condition is called associated PAH (APAH). Diseases and conditions associated with APAH include:

• Collagen vascular disease (also known as connective tissue disease), which occurs when the body’s immune system mistakenly attacks its own tissues and cells (scleroderma is an example)
• Congenital heart disease (a birth defect in the heart)
• Chronic liver disease, such as cirrhosis (scarring of the liver)
• Human immunodeficiency virus (HIV)
• Drugs and toxins, such as amphetamines (for example, “speed” or methamphetamine) and cocaine

This list shows only some common associations. PAH can also be associated with other, more rare conditions.

FLOLAN is indicated for the long-term intravenous treatment of primary pulmonary hypertension and pulmonary hypertension associated with the scleroderma spectrum of disease in NYHA Class III and Class IV patients who do not respond adequately to conventional therapy. Pulmonary hypertension is high blood pressure in the arteries of the lungs.

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How are the pulmonary arteries affected?

The pulmonary arteries carry blood from the heart to the lungs. There, the blood picks up oxygen needed for physical activity. In PAH, the walls of the pulmonary arteries grow abnormally thick—narrowing the insides of the vessels. This reduces the amount of blood that can flow through the lungs and limits the body’s oxygen supply.

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What are the symptoms of PAH?

The symptoms of PAH may not be recognized at first because they can be similar to those of other, more common conditions. PAH can develop for some time before symptoms appear. Symptoms of PAH may include:

• Shortness of breath, especially with physical activity
• Feeling tired
• Chest discomfort or pain
• Dizziness
• Light-headedness or fainting
• Swelling of the arms and legs

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Diagnosing PAH

To learn whether you have PAH or another illness that has similar symptoms, your doctor may schedule a series of tests:

• Chest x-ray (can reveal clues about the health of your heart and lungs)
• Echocardiogram (evaluates heart function)
• Right heart catheterization (measures blood pressure in the pulmonary arteries and how much blood the heart is able to pump)

Your doctor may also ask you to have one or more of the following tests:

• Electrocardiogram
• Pulmonary function test
• Ventilation/perfusion scan
• Chest CT or MRI
• Oximetry/sleep study

These tests help your doctor determine if your symptoms are the result of PAH or another illness.

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PAH classification

Treatment depends on each individual’s needs and the severity of their PAH. The World Health Organization (WHO) categorizes PAH severity by the symptoms people experience. This is called the WHO functional class. This classification was adapted from one originally published by the New York Heart Association (NYHA). Doctors use WHO (or NYHA) class as one guide to determine the most appropriate treatment for their patients with PAH.

WHO Class

Class	Definition
I	Physical activity is not limited. Ordinary physical activity does not cause shortness of breath, fatigue, chest pain, or feeling faint.
II	Comfortable at rest, but ordinary physical activity causes shortness of breath, fatigue, chest pain, or feeling faint.
III	Comfortable at rest, but less than ordinary physical activity causes shortness of breath, fatigue, chest pain, or feeling faint.
IV	Unable to perform any physical activity. Shortness of breath and/or fatigue may be present at rest, and symptoms increase with almost any physical activity.

FLOLAN is indicated for patients with Class III or Class IV symptoms.

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Treating PAH

The goals of treatment for PAH are to relieve symptoms and slow the progression of the disease. The type of treatment a doctor may choose is based partly on how far the disease has progressed.

Treatment approaches for PAH include:

• Oral therapy—medications that are taken by mouth
• Inhaled therapy—medications that are inhaled
• Continuous intravenous (into a vein) or subcutaneous (into the skin) infusion—medications that are delivered continuously to the bloodstream through a vein or a needle placed under the skin
• Surgery—including lung or heart-lung transplantation; considered for the most severe disease in people for whom medication is not successful

Treatment may also include:

• Calcium channel blockers to help reduce blood pressure in the pulmonary arteries in some patients
• Blood thinners to help prevent blood clots
• Diuretics to help reduce swelling
• Digoxin to help the heart beat more forcefully
• Supplemental oxygen to make sure the body has enough oxygen

Talk to your doctor to learn about the treatment options that are best for you.

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Additional resources

Learning everything you can about PAH and understanding your options are key to playing an active role in your health. The organizations listed below provide additional information along with support and guidance for people living with PAH.

National Institutes of Health
www.nih.gov
An online library to research health topics, including PAH—produced by the US Department of Health and Human Services

PH Central
www.phcentral.org
PAH information and support for patients and healthcare professionals

Pulmonary Hypertension Association
www.phassociation.org
Providing support, education, advocacy, and awareness to the PAH community

Scleroderma Foundation
www.scleroderma.org
The national organization for people with scleroderma that provides support and education to patients and funds research into the disease

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