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Pulmonary Arterial Hypertension

What is primary pulmonary hypertension?

Primary pulmonary hypertension is now known as pulmonary arterial hypertension (PAH). The name was changed in 1998 because it was determined to be more descriptive of the condition.

PAH is a disorder characterized by an abnormal increase in pulmonary artery pressure, normal pulmonary capillary wedge pressure, and increased pulmonary vascular resistance. A gradual increase of pulmonary artery pressure can lead to eventual right-heart failure and death. Increases in pulmonary arterial pressure are the most important indicators of PAH.

Imaging tests are used to look inside the body for a diagnosis. Enlarged arteries or damage to the heart are sure signs of PAH. Medications are used to slow heart damage and deal with symptoms.

Even with treatment, about one-third of people with PAH will die within three years of diagnosis. Thanks to new treatments, this number is an improvement from the 50 percent who used to die within 3 years. The medical community hopes to find a cure to stop the damage of PAH.

Causes of pulmonary arterial hypertension

The cause of PAH can be either idiopathic (IPAH) or familial (FPAH). Idiopathic diseases arise spontaneously, and their causes are unknown. Familial diseases are genetically passed down through families.

Environmental factors and medications are believed to be possible causes of IPAH.

Possible causes of IPAH:

  • appetite suppressants (aminorex, fenfluramine, dexfenfluramine, etc.)
  • hormone therapy (which may explain why more women than men have the disease)

Most cases of FPAH arise from a mutation in the BMPR2 gene. Severe cases are generally linked to the presence of the mutation. Although the mutation may be present at birth, the disease may take months or years to appear.

Symptoms of pulmonary arterial hypertension

The characteristic symptom of PAH is an increase in pulmonary vascular resistance. This causes an increase in pressure on the right ventricle of the heart. That problem leads to trouble in filling the left part of the heart. Eventually, the heart fails as a result.

Common symptoms of PAH are:

  • difficult or labored breathing on exertion
  • fatigue, caused by the heart having to pump harder and harder
  • nearly fainting
  • fainting

Risk factors of pulmonary arterial hypertension

PAH is still not well understood. Research has found certain diseases that may make a person more likely to develop PAH:

  • The exact link is unknown, but the rate for developing PAH among people with human immunodeficiency virus (HIV) is 0.5 percent, which is 6 times higher than in the general population.
  • In 70 percent of cases of FPAH, the person has a mutation in the 2(BNP2) gene.
  • PAH is noted in about six percent of people with portal hypertension (increased pressure in the veins that carry blood from the gastrointestinal tract and organs to the liver).
  • Certain unrepaired, congenital heart abnormalities also may make someone more likely to develop PAH.

Diagnosis of pulmonary arterial hypertension

Diagnosis isn’t easy, because damage inside the heart can’t be seen during a routine examination. Doctors try to rule out all other causes of pulmonary hypertension before a diagnosis is made. Your doctor may order some or all of the following tests:

  • electrocardiogram to look for proof of right ventricle damage or strain
  • chest X-ray to look for enlarged arteries from the overworking heart
  • computed tomography (CT) scan to see enlarged pulmonary arteries and the right ventricle
  • transthoracic echocardiography to look at the size and motion of the heart, function of the heart valves, etc. (essential for diagnosis)
  • 6-minute test to assess exercise endurance by having the person being tested be physically active for 6 minutes
  • lung biopsy, done only if PAH is not assumed to be your primary disease

Treatment of pulmonary arterial hypertension

Treatments for PAH are meant to reduce symptoms and prolong life. Doctors often begin treatments late in the disease, because it’s hard to detect.

The FDA has approved several medications for PAH. They can ease symptoms and improve physical function. None of the medications can completely relieve the symptoms of PAH and some are extremely expensive, costing upward of $175,000 a year.


  • prostacyclins, the first new treatment for pulmonary hypertension
  • endothelial receptor antagonists, which relax blood vessels
  • phosphodiesterase inhibitors, which relax the muscles of the arterial walls to widen blood vessels

Other treatment

  • heart-lung transplantation, although this is only done in certain cases
  • restriction of physical activity

Outlook for pulmonary arterial hypertension

Although modern treatment has come a long way, one-third of all people with PAH will die within three years of diagnosis.

Death is an expectation and a common occurrence with PAH, because no cure or effective treatment exists. The medications that are available to treat symptoms can extend life for a while, but they can’t stop eventual terminal heart failure.

Content licensed from:

Written by: Lydia Krause
Medically reviewed on: Mar 15, 2017: Graham Rogers, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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