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What is Chronic Thromboembolic Pulmonary Hypertension (CTEPH)?

CTEPH is a type of pulmonary hypertension (PH). It is caused by repeated blood clots or blood clots that don’t dissolve in the arteries of your lungs. These blood clots are called pulmonary emboli or PE.
Half of the patients with CTEPH don’t have symptoms or have never been diagnosed with pulmonary emboli. It is not well understood why some people are able to dissolve the pulmonary emboli inside their pulmonary arteries and others go on to develop chronic clot and scar tissue, even while taking blood thinners. 
Here is a breakdown of the name:
Chronic - a condition that last a long time (months to years)
Thromboembolic - blood clots (thrombi) travel from your arms and or legs through the veins into the blood vessels of the lungs and block the pulmonary arteries
Pulmonary - related to the lungs
Hypertension - high blood pressure inside blood vessels

What is CTEPH? | Dr. Marc de Perrot

Normal Blood Flow Through Your Lungs

Knowing what happens when blood flows through lungs normally can help you understand what happens when you have CTEPH.
Normal Blood Flow Through Your Lungs
Your heart and lungs work together to move blood easily through your lungs:
  1. The blood that flows from the veins in your arms, legs, and other body parts to your heart is low in oxygen and high in carbon dioxide. It flows into the right side of your heart.
  2. The blood flows through your right atrium into your right ventricle.
  3. Your right ventricle fills with blood and pumps the blood through your pulmonary arteries and through the millions of blood vessels in your lungs.
  4. As the blood moves through your pulmonary arteries, it picks up oxygen and gets rid of the carbon dioxide.
  5. When the blood is full of oxygen, it flows into the left atrium of your heart and into your left ventricle.
  6. Your left ventricle pumps this blood to the rest of your body.
  7. These steps happen every time your heart beats.

What Happens When You Have CTEPH?

Diagram of heart and lungs pointing to each part; right and left lungs, Right Atrium, Left Atrium, Right Ventricle, and Left Ventricle

Diagram of heart and lungs pointing to each part; right and left lungs, Right Atrium, Left Atrium, Right Ventricle, and Left Ventricle
  • The blood that flows through your lungs contains blood clots that travel from veins in legs or arms. These blood clots get stuck in the pulmonary arteries, causing them to become blocked or narrowed.
  • Over time, these clots become scar tissue (also called webs) inside your pulmonary arteries.
  • This scar tissue restricts the blood flow through your pulmonary arteries. This causes the pressure inside your lung vessels to increase (pulmonary hypertension).
  • The right side of your heart has to work harder to move blood through your narrowed pulmonary arteries.
  • Over time, blood from your pulmonary arteries backs up in the right side of your heart.
  • As the blood backs up, your right ventricle becomes larger, and its muscle becomes thicker (right-sided heart failure). This leads to swelling in your abdomen and ankles from water retention (fluid build-up).
  • Without treatment, average life expectancy for CTEPH patients is five years.

What Are the Symptoms of CTEPH?

At first, people with CTEPH do not have any symptoms. As the disease gets worse, most people will feel:
  • short of breath, especially when they are active;
  • very tired;
  • a tightness or pain in their chest or abdomen;
  • and light headed.
CTEPH can also lead to right-heart failure, which can cause:
  • swelling
  • bloating
  • nausea

Who Should Be Referred to a CTEPH Clinic?

Anybody with shortness of breath and an abnormal ventilation-perfusion scan (V/Q scan) should be referred to a CTEPH clinic.

A V/Q scan is a medical test that looks at how air and blood move through your lungs. This test can be done in any hospital. The result of this test is often the first step to finding out if you have CTEPH. 

What Can Increase the Chances of Having CTEPH?

  • Large blood clots (pulmonary emboli) or repeated pulmonary emboli in your pulmonary arteries;
  • Presence of pulmonary emboli with no other risk factors (also called idiopathic pulmonary emboli);
  • Surgery to remove your spleen;
  • and health problems that cause inflammation, such as osteomyelitis (bone inflammation) or inflammatory bowel disease.

Additional Questions About CTEPH?

For help and support with any questions related to CTEPH, you can search for the nearest CTEPH speciality clinic near you by visiting our national directory of PH Centres.

How is CTEPH Treated?

CTEPH is the only type of pulmonary hypertension that may be curable. Pulmonary thromboendarterectomy (PEA) is the treatment of choice for CTEPH. The PEA surgery leads to major clinical improvements due to improved hemodynamic parameters and oxygenation, and reduction in dead space ventilation. The surgery can be also curative in the large number of patients with resolution of the pulmonary hypertension. Majority of the patients experience significant functional recovery and are able to return to their baseline physical activity level without supplemental oxygen use.

CTEPH patients are evaluated for PEA surgery at a CTEPH clinic. During your clinic visit, the thoracic surgeon and their team will check your health and look at all of your test results. This will help them decide if you are a candidate for PEA surgery.
The goals of PEA surgery are to:
  • improve your breathing and reduce or remove your need for extra oxygen (if you are using it);
  • bring the blood flow inside your lung vessels back to normal;
  • decrease how hard the right side of your heart has to work and prevent heart failure;
  • and make it possible for you to return to your normal activities or exercises.
If PEA surgery is not the best option for you, the CTEPH team will assess you to find other treatment options that may include:
  • Pulmonary hypertension medication Riociguat®
  • Balloon Pulmonary Angioplasty (BPA) – an investigational procedure that is done by an interventional radiologist to dilate pulmonary arteries that are obstructed by the chronic scar tissue.
  • Click here to learn more about BPA

Dianne - CTEPH Patient


Adapted from a patient education brochure produced by University Health Newtork's Patient and Family Education Program.

© University Health Network, Patient and Family Education


PHA Canada thanks Bayer for its support developing this educational website. 

Bayer Inc. is required by Health Canada to collect and report any details of adverse events and product technical complaints related to its own products that are raised and/or monitored in relation to or through this website. 
Photo of Dianne Curle, a CTEPH patient

Dianne's Story

CTEPH has slowed me down a lot... [but] I do have hope.

Read Dianne's Story