pulmonary arterial hypertension (PAH)

What Is Pulmonary Hypertension?

Pulmonary Hypertension

Pulmonary hypertension occurs when the pressure in the blood vessels that carry blood from your heart to your lungs is higher than normal. One type of pulmonary hypertension is pulmonary arterial hypertension (PAH).

Pulmonary hypertension can happen on its own or be caused by another disease or condition. In the United States, the most common cause of pulmonary hypertension is left heart disease, such as left heart failure. There are several other medical conditions and environmental factors that can increase the risk of developing pulmonary hypertension.

If you have pulmonary hypertension, your heart has to work harder to pump blood into the lungs. This increase in pressure can damage your heart. It can also cause other symptoms such as shortness of breath, chest pain, and lightheadedness. Your healthcare provider will consider your symptoms and health history before conducting tests to diagnose pulmonary hypertension.

Treatments for pulmonary hypertension will depend on the cause of the condition. Many times, there is not a cure for pulmonary hypertension, but your healthcare provider can work with you to manage the symptoms. This may include medicine or healthy lifestyle changes.

What causes pulmonary hypertension?

The cause of pulmonary hypertension is not always clear. Certain medical conditions can damage, change, or block the blood vessels of the pulmonary arteries, which can lead to pulmonary hypertension.

Some examples of medical conditions include:

  • Left heart diseases, such as left heart failure, which may be caused by high blood pressure throughout your body or coronary heart disease
  • Other heart and blood vessel diseases such as congenital (inherited) heart defects
  • Lung diseases such as chronic obstructive pulmonary disease (COPD), interstitial lung disease, emphysema, or sleep apnea
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  • Other medical conditions such as liver disease, sickle cell disease, blood clots in the lungs, or connective tissue disorders like scleroderma

How does pulmonary hypertension affect the heart and lungs?

To understand pulmonary hypertension, it is helpful to understand the job of the heart and lungs, and the flow of blood.

As your heart beats, it sends blood throughout the body. The tissues of the body need oxygen from the blood to function properly. After the tissues use oxygen from the blood, they send oxygen-poor blood to the right side of the heart. Then, the heart pumps oxygen-poor blood through the pulmonary arteries to the lungs so the lungs can add oxygen to the blood. The force (pressure) of the blood against the walls of the pulmonary arteries is called the pulmonary pressure.

When this pressure gets too high, the pulmonary arteries become narrow or blocked. This makes the blood not flow as well, so the heart has to work harder to maintain blood flow into the lungs. Over time, this can cause damage to the heart and lungs.

What raises the risk of pulmonary hypertension?

Several factors can increase your risk of developing pulmonary hypertension.

  • Age: Pulmonary hypertension can occur at any age, but your risk increases as you get older. The condition is usually diagnosed between ages 30 and 60.
  • Environment: You may be at an increased risk of pulmonary hypertension if you have or are exposed to Asbestos or certain infections caused by parasites.
  • Family history and genetics: Certain genetic disorders, such as Down syndrome, congenital heart disease, and Gaucher disease, can increase your risk of pulmonary hypertension. A family history of blood clots also increases your risk.
  • Lifestyle habits: Unhealthy lifestyle habits such as smoking and illegal drug use can raise your risk of developing pulmonary hypertension.
  • Medicine: Some prescribed medicines used to treat cancer and depression may increase your risk of pulmonary hypertension.
  • Sex: Pulmonary hypertension is more common in women than in men. Pulmonary hypertension with certain types of heart failure is also more common in women.


Symptoms of pulmonary hypertension are sometimes hard to recognize. People may have symptoms for years before being diagnosed. This is because many symptoms of pulmonary hypertension are also symptoms of other medical conditions.

Some symptoms of pulmonary hypertension include:

  • Chest pain
  • Coughing that is dry or produces blood
  • Shortness of breath
  • Dizziness that may lead to fainting
  • Nausea and vomiting
  • Hoarseness
  • Fatigue
  • Swelling of the abdomen, legs, or feet
  • Weakness
  • Wheezing, which is a whistling sound when you breathe out

Symptoms can get worse over time. For example, in the early stages of pulmonary hypertension, you may only have shortness of breath with exercise. As the disease progresses, shortness of breath will occur more often.

Diagnostic tests

There are many tests that doctors can use to tell if you have pulmonary hypertension.

The most common tests to measure the pressure in your pulmonary arteries are cardiac catheterization and echocardiography. Normal pressure in the pulmonary arteries is between 11 and 20 millimeters of mercury (mm Hg). If the pressure is too high, you may have pulmonary hypertension. A pressure of 25 mm Hg or greater measured by cardiac catheterization or 35 to 40 mm Hg or greater on echocardiography suggests pulmonary hypertension.

Other tests may include:

  • Blood tests look for blood clots, stress on the heart, or anemia.
  • Heart imaging tests, such as cardiac MRI, take detailed pictures of the structure and functioning of the heart and surrounding blood vessels.
  • Lung imaging tests, such as chest X-ray, looks at the size and shape of the heart and surrounding blood vessels, including the pulmonary arteries.
  • Electrocardiogram (ECG or EKG) looks for changes in the electrical activity of your heart. This can help detect if certain parts of the heart are damaged or working too hard. In pulmonary hypertension, the heart can become overworked due to damage or changes in the pulmonary arteries.

Medicines to treat pulmonary hypertension may include:

  • Anticoagulation or blood thinners to prevent blood clots in people whose pulmonary hypertension is caused by chronic blood clots in the lungs. These thinners also can help some people who have pulmonary arterial hypertension, heart failure, or other risk factors for blood clots.
  • Digitalis or digoxin to control the rate blood is pumped throughout the body.
  • Vasodilator therapy to relax blood vessels and lower blood pressure in the pulmonary artery most affected in people who have pulmonary arterial hypertension. This includes calcium channel blockers such as nifedipine and diltiazem, as well as newer groups of medicines called endothelin receptor antagonists and phosphodiesterase type 5 inhibitors.

Procedures and therapies

Your doctor may recommend a procedure, surgery, or therapy to treat pulmonary hypertension.

  • Oxygen therapy if oxygen levels in the blood are too low.
  • Balloon atrial septostomy to decrease pressure in the right heart chambers and improve the output of the left heart and oxygenation of the blood. In this procedure, a small hole is made in the wall between the right and left atria to allow blood to flow from the right to the left atrium.
  • Balloon pulmonary angioplasty to lower the blood pressure in your pulmonary artery and improve heart function in people who cannot have a pulmonary endarterectomy.
  • Pulmonary endarterectomy surgery to remove blood clots from the inside of the blood vessels of the lungs.

Treatments for other conditions

Your doctor may recommend medicines or procedures to treat the condition that is causing your pulmonary hypertension.

  • Blood pressure medicines such as angiotensin-converting enzymes inhibitors, beta blockers, or calcium channel blockers when left heart disease is the cause
  • Blood transfusions or hydroxyurea to treat sickle cell disease
  • Heart valve repair
  • Iron supplements to increase blood iron levels and improve anemia

Information courtesy: https://www.nhlbi.nih.gov/health/pulmonary-hypertension


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