Pulmonary Hypertension

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General Information About Pulmonary Hypertension


What is pulmonary hypertension?

Pulmonary hypertension (PH) is a general term that refers to high blood pressure in the lungs. In regular hypertension (commonly referred to as high blood pressure), the arteries of the “systemic circulation” that feed the rest of the body are affected, while in pulmonary arterial hypertension (PAH), only the arteries in the lungs and right side of the heart are affected. Pulmonary hypertension can occur for a number of reasons and there are a number of different types of PAH.

Pulmonary arterial hypertension is a chronic and currently incurable disease that causes the walls of the arteries in the lungs to tighten and stiffen. This forces the right side of the heart to work harder to push blood through narrowed arteries in the lung. This extra stress can cause the heart to enlarge and become less flexible, making it more difficult to push blood out of the heart, through the lungs and into the rest of the body.

Major types of PAH include:

  • Idiopathic pulmonary arterial hypertension refers to PAH cases where no specific cause can be determined
  • Associated pulmonary arterial hypertension refers to PAH that is secondary to another disease such as scleroderma, congenital heart disease, HIV or others;
  • Heritable PAH is a type of PAH that is inherited or genetic and can run in families.

What are the symptoms of PAH?

The frequent symptoms of pulmonary arterial hypertension are often common and non-specific:

- Breathlessness
- Fatigue
- Dizziness
- Chest pain
- Fainting
- Swelling of the arms, legs or abdomen

Because these symptoms are fairly common, PAH can remain undiagnosed or misdiagnosed for months or even years.

Who is at risk?

People of all ages, races and ethnic backgrounds can get pulmonary arterial hypertension. Although anyone can be diagnosed with PAH, there are factors that increase a person’s risk for the disease:

  • A family history of PAH may put someone at higher risk for the disease. Genetic testing is available to find out if someone carries the PAH gene.
  • While obesity by itself is not a risk factor, obesity combined with obstructive sleep apnea (a lack of adequate breathing during sleep) can sometimes cause PAH.
  • Other diseases – like connective tissue diseases, lung disease, liver disease, congenital heart disease and others – can also increase the risk for pulmonary arterial hypertension.
  • Certain types of PAH – such as idiopathic and heritable PAH – are more common in women than men. Pregnancy in women with pulmonary hypertension can be very dangerous and women with PAH who become pregnant have a higher risk of mortality.
  • Living at higher altitudes for many years can increase the risk of PAH.
  • Taking certain drugs, such as methamphetamines and the diet drug “fen phen” can also put someone at risk for PAH as these drugs are known to cause the disease.

How is PAH Diagnosed?

When your physician first suspects PAH, he or she may schedule a preliminary test such as an echocardiogram and pulmonary function test. If these tests point to PAH, yourdoctor will schedule a right heart catheterization – the “gold standard” for PAH diagnosis.

During this test, a catheter is placed into the veins and advanced in to the pulmonary arteries to measure the pressures in both the right side of the heart and the lungs as well as the amount of blood that the heart pumps (cardiac output). This is the only test that directly measures the pressure inside the pulmonary arteries and should be done in all patients at least once before initiating treatment.

How is PAH Treated?

There are a number of FDA-approved medications for the treatment of PAH. These medications can be administered in several ways: directly into the vein (intravenously), beneath the skin (subcutaneously), orally and by inhalation. PAH medications also work in three distinct ways and can be prescribed alone or in combinations.

  • Prostacyclins make the blood vessels relax. They mimic a substance called prostaglandin that is often deficient in PAH patients. Treatments in this category are often very effective, especially in patients with the most serious form of the disease. These treatments include epoprostenol, treprostinil and iloprost.
  • Endothelin receptor antagonists block endothelin, a substance that causes blood vessels to constrict, which PAH patients tend to have in excess. Treatments in this category include bosentan and ambrisentan.
  • PDE-5 Inhibitors help the lungs to produce more of their own vasodilators which tell blood vessels to relax and, in turn, improve blood flow. This category of treatment includes sildenafil and tadalafil. 

Source: Nicholas S. Hill, MD, President, American Thoracic Society
Source: Pulmonary Hypertension Association (www.phassociation.org)

Four Facts About PAH

  1. Women are four times more likely than men to be diagnosed with pulmonary hypertension.
  2. The average time between symptom onset and diagnosis is 2.8 years. This time has not changed in the past 20 years. 
  3. Many patients will see three or more different physicians over a three year period before they are properly diagnosed with PAH.
  4. Most patients are not diagnosed until they are in the late stages of the disease and are experiencing significant limitations of ordinary physical activity. 

(Source:  www.phassociation.org )