Pulmonary arterial hypertension (PAH) is a specific type of pulmonary hypertension that affects the small arteries in the lungs. These blood vessels become narrowed or changed, making it harder for blood to flow through them. The right side of the heart must work harder to pump blood to the lungs, and over time this strain can damage the heart. PAH is a serious condition that requires medical assessment and specialist care.
What Causes Pulmonary Arterial Hypertension?
PAH is one specific type of pulmonary hypertension; not all pulmonary hypertension is PAH. In some people, the cause is unknown. In others, it may be inherited or associated with conditions such as connective tissue diseases, congenital heart disease, or HIV infection, or with certain medicines and substances. A specialist evaluates a person’s history and test results to determine the likely type and cause.
PAH involves changes in the walls of the pulmonary arteries, which can become narrowed and less able to carry blood normally. This differs from other forms of pulmonary hypertension that may be related to left-sided heart disease, lung disease, low oxygen levels, or chronic blood clots in the lungs.
Common Symptoms
Symptoms may develop gradually and can resemble those of other heart or lung conditions. They may include:
- Shortness of breath, often first noticed during physical activity
- Fatigue or reduced ability to exercise
- Dizziness or fainting
- Chest discomfort or pain
- A racing or pounding heartbeat
- Swelling in the ankles, legs, or abdomen as the condition progresses
These symptoms do not confirm PAH, but ongoing or worsening breathlessness, unexplained fainting, chest discomfort, or swelling should be assessed by a healthcare professional. Sudden or severe chest pain, fainting, or difficulty breathing requires emergency medical care.
How Is PAH Diagnosed?
Assessment may include a medical history, physical examination, and tests to assess the heart and lungs and investigate other possible causes. Tests may include an echocardiogram, electrocardiogram, blood tests, chest imaging, lung-function testing, or scans to look for blood clots. Right-heart catheterization directly measures pressures in the heart and pulmonary arteries and is used to confirm pulmonary hypertension when indicated. A specialist interprets the findings together; an echocardiogram alone does not definitively confirm PAH.
Treatment and Ongoing Care
Treatment depends on the type and severity of pulmonary hypertension and the person’s overall health. For PAH, specialist-prescribed medicines may target pathways involved in the pulmonary blood vessels. Care may also include monitoring, oxygen when needed, supervised activity or pulmonary rehabilitation, and treatment of related conditions. Other forms of pulmonary hypertension can require different approaches, such as treating heart or lung disease or addressing chronic blood clots.
Treatment can help manage symptoms and may slow progression, but the right plan is individual. Do not start, stop, or change medicines or exercise intensity without advice from the treating team. People diagnosed with or suspected of having PAH should be assessed by clinicians experienced in pulmonary hypertension.
Pregnancy and PAH
Pregnancy can carry substantial risks for people with PAH. Anyone with known or suspected PAH who is pregnant or considering pregnancy should seek prompt, individualized advice from a specialist team. Do not rely on general online information to make decisions about pregnancy or treatment.
Reliable Further Reading
- U.S. National Heart, Lung, and Blood Institute: Pulmonary hypertension
- American Heart Association: Pulmonary hypertension
Pulmonary arterial hypertension is a complex condition, and outcomes vary according to its cause, severity, and response to treatment. Early specialist evaluation is important when symptoms raise concern. This article is for general information and does not replace medical advice.