What is Pulmonary Arterial Hypertension?

Pulmonary Arterial Hypertension, pahA rare form of a broader disorder known as pulmonary hypertension, pulmonary arterial hypertension (PAH) refers to having high blood pressure in the arteries that stretch from your heart to your lungs. In PAH, scar tissue develops in the tiny blood vessels of the lung. This scar tissue narrows the vessels, blocking normal blood flow through the lungs and causing the pressure inside those blood vessels to increase.[1] As a result of this process, the heart has to work harder to pump blood through those arteries, which, over time, weakens the heart muscle leading to heart failure.[2]

I Don’t Have High Blood Pressure? How Can I Have PAH?

PAH may be present even if you have normal “general” (systemic) blood pressure because the blood vessels in your lungs differ greatly from the blood vessels in the rest of your body.1

Is PAH Serious?

PAH should not be confused with more common forms of pulmonary hypertension caused by underlying diseases of the heart, lungs or other organs. It is a very serious, uncommon disease affecting only 15-50 people per million in the US. Because symptoms of PAH mimic those of other conditions, it is often not diagnosed until the disease is in its later stages when symptoms are severe and patients only have a few years left to live, unless they receive life-saving treatment. Luckily, recent advances in medicine have led to more favorable outcomes for people with PAH.1

Causes of PAH

The characteristic scarring of the lung’s blood vessels that occurs in PAH can be caused by a number of diseases and conditions including:1

  • Connective tissue disorders such as scleroderma and lupus
  • Exposure to certain toxins and drugs including methamphetamine and cocaine
  • Infections such as HIV and schistosomiasis
  • Cirrhosis of the liver
  • Congenital heart abnormalities (anomalies present at birth)

When the cause of PAH cannot be determined, it is referred to as idiopathic pulmonary arterial hypertension.1

Symptoms of PAH

Because symptoms of PAH are similar to other conditions such as asthma, emphysema and chronic obstructive pulmonary disease (COPD), the disease is not readily diagnosed. Common symptoms include:1

  • Shortness of breath – initially with exertion and, as the disease progresses, even at rest
  • Swelling of the feet, legs, abdomen and neck
  • Fatigue

Less common symptoms that may occur in the advanced stages of the disease include:1

  • Chest pain
  • Pounding of the heart
  • Fainting
  • Changes in the voice
  • Hemoptysis (coughing up blood)

Treatment of Pulmonary Arterial Hypertension

Overall, advances in medications, physical therapies, other supportive therapies and surgical interventions have improved the prognosis for many PAH patients, but the disease remains a very serious, progressive illness in which survival is poor for those with very severe disease.[3] That said, treatment options for PAH vary, depending upon your underlying condition and the severity of your PAH. There are many medications that can help relieve your symptoms and make daily living easier.2

The first step in treating PAH is addressing the underlying condition that caused your PAH in the first place. For example, if your PAH was caused by lupus, treating the lupus will help improve your PAH.

If you need additional treatment to improve your breathing and lower the blood pressure in your lungs, there are medications that increase blood flow in the arteries in your lungs and medications that help your heart and lungs operate more efficiently. These medications can be inhaled, taken in pill form, or given through an IV catheter that goes directly into your vein. These medications include the following:2

  • Calcium channel blockers – lower blood pressure by relaxing muscles that control the arteries.
  • Digoxin – increases contractility of the heart, helping it to pump more strongly. Usually given if the cause of PAH is heart failure or irregular heart rhythm.
  • Blood thinners – thin the blood to help prevent blood clots from forming, which can worsen PAH. Examples: warfarin (Coumadin).
  • Diuretics – remove excess fluid from the body which can help the heart and lungs work better and alleviate the symptoms of PAH. Examples: furosemide (Lasix).
  • Endothelin receptor antagonists – help dilate the blood vessels lowering blood pressure in the arteries of the lungs. Examples: ambrisentan (Letairis), bosentan (Tracleer), macitentan (Opsumit).
  • Phosphodiesterase 5 (PDE5) inhibiters – help control blood flow to the pulmonary arteries by causing the blood vessels to relax. Examples: sildenafil (Viagra), tadalafil (Cialis).
  • IV Vasodilators relax and widen the blood vessels in the lungs, improving blood flow through the pulmonary arteries. Examples: IV epoprostenol (Flovan, Veletril).
  • Inhaled vasodilators – get directly into the lungs to relax and widen the blood vessels, improving blood flow through the pulmonary arteries. Examples: iloprost (Ventavis), treprostinil (Tyvaso).

Oxygen Therapy

If you have low levels of oxygen in your blood, you may need oxygen therapy to improve your oxygenation and help you breathe better. There are many benefits to oxygen therapy, including increasing survival when used for more than 15 hours per day for some patients. Oxygen therapy is administered through a face mask or nasal cannula. Some people with PAH will eventually need to breathe supplemental oxygen continuously.2

Surgical Options

If you have a severe form of pulmonary arterial hypertension, or the medications you’ve been taking don’t relieve your symptoms, your doctor may recommend one of the following surgeries:2

  • Atrial septostomy – a surgical opening is made between the right and left sides of your heart, which lowers the pressure on one side. This procedure may cause very serious side effects and is not often recommended.
  • Lung and heart transplants – if your condition is getting worse and medications don’t help your symptoms, you doctor may recommend these, especially if you have a serious, underlying lung disease that’s causing your PAH. Transplants are very serious surgeries and don’t come without serious risks. You’ll also need to take anti-rejection drugs for the rest of your life. For these surgeries to make sense, the benefits must outweigh the risks.

For more information about pulmonary arterial hypertension and its treatment, contact your primary healthcare provider or pulmonologist.   

[1] American Lung Association. Pulmonary Arterial Hypertension. Accessed May 26, 2018.

[2] WebMD. Pulmonary Arterial Hypertension. Last reviewed February 20, 2017.

[3] Corris, Paul. Degano, Bruno. Severe pulmonary arterial hypertension: treatment options and the bridge to transplantation. European Respiratory Review 2014 23: 488-497; DOI: 10.1183/09059180.00007214.


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