What is pulmonary hypertension?
Pulmonary hypertension is a term to describe abnormally high blood pressure in your lungs.
It can be difficult to diagnose PH because the symptoms are common to many other respiratory and cardiac illnesses such as COPD, asthma or congestive heart failure.
There are five different groups or types of PH. The symptoms experienced and medications used to treat different types of PH are similar however, the causes of PH vary.
Group 1: Pulmonary arterial hypertension
Pulmonary arterial hypertension (PAH) is one type of PH. It is caused by physical changes or "remodelling" in the walls of the pulmonary arteries.
Your pulmonary arteries play a very important role in your body. They carry oxygen-poor blood from your heart to your lungs, where the blood gains oxygen and gets rid of carbon dioxide. The oxygen-rich blood then returns to your heart where it is pumped to the rest of your body.
When PAH causes the walls of the arteries become stiff and narrow, less blood can be carried to the lungs. The result is less oxygen in the blood.
This group includes PAH that has no known cause (idiopathic), that is genetically inherited (hereditary) and PAH associated with connective tissue or autoimmune disease, congenital heart disease, severe liver disease, or the use of certain drugs or medications.
Group 2: PH due to left-side heart disease
The left side of your heart pumps out blood to your entire body. Problems on the left side of the heart (for example, leaky valves or narrowing ventricles) can cause blood to back up in your heart. Over time, this raises the blood pressure in your pulmonary arteries.
Treatment of Group 2 PH (caused by left heart disease) focuses on treatment of the underlying problems with the left side of the heart.
Group 3: PH due to lung disease
Certain lung diseases such as COPD, interstitial lung disease or sleep apnea, can cause the pulmonary arteries to tighten, which means less blood flow and higher blood pressure in the lungs.
Group 4: PH due to blockages in the lungs
Blood clots or scars from blood clots prevent your blood from flowing normally through your lungs. This puts more stress on the right side of your heart and raises pulmonary blood pressure.
Chronic thromboembolic pulmonary hypertension (CTEPH) is an example of Group 4 PH. CTEPH is caused by recurring pulmonary embolisms (blood clots) forming scar-like tissue in the lung’s arteries, blocking or narrowing the arteries.
Conditions that increase the risk of blood clots in general (for example, obesity, smoking, estrogen-containing birth control and major surgery) can increase the risk of CTEPH. Certain cancers, removal of the spleen, thyroid disorders can also increase the risk of CTEPH. It can also happen in individuals with no known risk factors.
Group 5: PH due to other diseases or conditions
PH can occur as a result of other conditions like blood disorders (such as thrombocythemia), sarcoidosis, vasculitis, thyroid disease, kidney disease, sickle cell disease and more. This type of PH can also be caused by tumours putting pressure on the pulmonary arteries.
Symptoms of pulmonary hypertension
PH may not cause any noticeable symptoms until the condition progresses. It can be difficult to diagnose PH because the symptoms are common to many other respiratory and cardiac illnesses such as COPD, asthma or congestive heart failure. Many people wait several years for a diagnosis.
Common symptoms of PH include:
- Increased shortness of breath
- Fatigue
- Swelling of the feet and legs
- Dizziness and fainting spells
- Chest pain
- Racing or pounding heart
- Lips and fingers turning blue
- Cough
- Hoarseness
Diagnosing pulmonary hypertension
The process of diagnosing PH will likely involve both lung specialists (respirologists) and heart specialists (cardiologists), who will rule out other diseases and conditions with similar symptoms.
Your doctor will ask about your family history, do a physical exam and order one or more tests.
- You may have a chest x-ray to look for physical signs of PH.
- An echocardiogram (or “echo”) examines the structure and function of the heart using ultrasound. An echo can check the size and conditions of the chambers of the heart and can be used to estimate your pulmonary blood pressure.
- An electrocardiogram (or EEG) examines the electrical activity and rhythm of the heart.
- Right heart catheterization is typically done to confirm suspected PH as it is a more invasive test that requires local anesthetic. A catheter (small tube) is inserted into a large vein in the neck, arm or groin. The catheter is then threading through to the right side of the heart and into the pulmonary artery. The blood pressure in your lungs can be accurately measured.
- You may undergo a CT scan of your heart to get a more clear picture of the size of your heart and any potential blockages in your pulmonary arteries.
- You may also be tested for lung conditions like asthma or COPD that may be causing your PH. This testing may include lung function testing and/or the Six-Minute Walk Test.
- Blood tests cannot be used to diagnose PH but can help determine common underlying conditions that are causing suspected PH.
Diagnosing CTEPH: V/Q scanning
Ventilation/perfusion scans (V/Q scans) are commonly used to identify blood clots in the lungs to determine if you have CTEPH.
A V/Q scan measures two different things. These scans can be done separately or together.
A ventilation scan measures how well air moves in and out of your lungs. You will be asked to inhale a radioactive mist. This helps to show areas of the lungs that aren't getting enough air or that hold too much air.
A perfusion scan measures how well the blood flows in the lungs. You will be injected with a radioactive tracer in your arm. The tracer travels through your blood and into the lungs. This scan can show areas of the lungs that aren't getting enough blood. Comparing the results of the two scans can help identify potential blood clots in your lungs.
Treatments for pulmonary hypertension
There is no cure for PH but there are prescription medications and surgical options available to help ease symptoms, extend survival and improve quality of life.
Prescription medications
Prescription medications to treat PH work by either blocking naturally occurring vasoconstrictors (substances that tighten blood vessels) or maximizing naturally occurring vasodilators (substances that enlarge blood vessels.)
Endothelin receptor antagonists (ERAs) are medications that help widen the pulmonary arteries by blocking endothelin, a protein that your body produces that constricts blood vessels. People with PH can have an excess of endothelin in their blood.
Phosphodiesterase inhibitors (PDE-5 inhibitors) and soluble guanylate cyclase stimulators (sGC stimulators) both work by leveraging nitric oxide, which is a vasodilator that naturally occurs in the body. PDE-5 inhibitors were originally used to treat erectile dysfunction, but they proved beneficial in the treatment of PH.
IP receptor agonists stimulates the IP prostacyclin receptors to cause the blood vessels to widen. Prostacyclin is a vasodilator that occurs naturally in the body.
Prostacyclin analogues are medications that mimic the body’s natural prostacyclin.
Surgical treatment for CTEPH
A pulmonary thromboendarterectomy (PEA) is a treatment option for, and may cure, CTEPH. PEA is a major surgery and not appropriate for everyone with CTEPH. The location of the blockage(s) within your lungs (if they’re accessible through surgery) and your overall health will be considered when your team determines if PEA is right for you.
Living with CTEPH: Tina's story
As a 21-year-old woman attending college in Toronto, it was very difficult for me to imagine that an illness could possibly hit me at this stage in my life, but it did.
I slowly started to notice that my daily walk to school was getting more difficult to do and not easier, which struck me as odd. So, I brought up my concerns with my family doctor. A misdiagnosis of a mild case of asthma along with a variety of puffers led me to believe that all was good, but I wasn’t getting any better.
After several emergency visits, tests and a few specialist appointments, it was discovered that I had Chronic Thromboembolic Pulmonary Hypertension (CTEPH), a disease caused by old micro blood clots that had been gradually adding up in my lungs since birth.
Over the years, I’ve always tried to keep a positive attitude when dealing with my lung disease and feel extremely grateful for the many good years that I have had. I have had tremendous support from all my family and friends, as well as my specialists here in Ottawa. Now at the age of 31, I am currently on a new brand of meds and am being evaluated for a double lung transplant. No matter what the outcome may be and whichever one of these options works for me, I am so looking forward to being able to breathe again!
Tina :0)
World Pulmonary Hypertension Day, May 5
Held annually on May 5th, World Pulmonary Hypertension Day raises awareness of PH and celebrates the strength and resilience of the PH community worldwide. It is also an opportunity to highlight new developments in PH research and treatment.
More information
For more information on pulmonary hypertension, visit:
- Pulmonary Hypertension Association of Canada (PHA Canada)
- PHA Canada's Find a PH Center tool
- Canadian Thoracic Society / Canadian Cardiovascular Society Position Statement on Pulmonary Hypertension (2020)