Pulmonary Hypertension

Pulmonary hypertension is a serious condition where there is abnormally high pressure in the blood vessels between the lungs and the heart.

Key Facts

• When the blood pressure in the pulmonary arteries gets too high, the arteries in the lungs narrow (or constrict), reducing blood flow through the lungs and causing low levels of oxygen in the blood.
• There are numerous causes of pulmonary hypertension, which can be inherited or acquired as a result of other medical conditions such as heart disease, lung disease, or connective tissue disease.
• In most cases, pulmonary hypertension cannot be cured, but with proper treatment, you can improve symptoms and slow the disease’s progression. The exception is CTEPH which can be cured through surgery.

How Pulmonary Hypertension Affects Your Body

Oxygen-poor blood returning to the heart from all body organs and tissues travels from the right side of the heart through the pulmonary arteries into the lungs. Within the lungs, these arteries divide into smaller vessels in order to take in oxygen and get rid of carbon dioxide. The oxygen-rich blood then returns to the left side of the heart from where it is pumped back to all body organs and tissues.

Normally, the blood flows relatively easily through these vessels in your lungs but in PH, the walls of the arteries become stiff, damaged and narrow. This makes blood flow much more difficult and causes the blood pressure in the lungs to rise and the right side of your heart to work harder. Over time, this added stress to the right side of your heart can lead to other medical problems, specifically heart failure.  

Pulmonary hypertension is classified by the World Health Organization according to its causes or associated underlying conditions:

• Group 1: Pulmonary arterial hypertension (PAH) refers to increased pressure in the vessels caused by obstruction in the small arteries in the lung, for a variety of reasons. These include "idiopathic" (no known cause or underlying condition); drug-related, HIV infection; connective tissue/autoimmune disorders (such as scleroderma) and others. 
• Group 2: Pulmonary hypertension due to left-side heart disease. This is when long-term heart disease results in damage to the pulmonary arteries eventually causing PH.
• Group 3: Pulmonary hypertension caused by underlying lung diseases or hypoxemia. The common diseases that cause hypoxia are COPD, emphysema, pulmonary fibrosis, obstructive sleep apnea, lung development abnormalities and chronic high-altitude exposure.
• Group 4: CTEPH (chronic thromboembolic pulmonary hypertension)—In some patients, pulmonary embolism, or blood clots, in the lung’s arteries can form scar-like tissue, blocking or narrowing the arteries and leading to CTEPH. Some CTEPH patients can be cured with pulmonary thromboendarterectomy (PTE) surgery.
• Group 5: Pulmonary hypertension from numerous other disorders. This group includes any other cause that doesn’t fit under another heading. Examples are blood disorders, systemic disorders like sarcoidosis, metabolic disorders like thyroid diseases and chronic kidney failure or tumors obstructing pulmonary arteries.

Symptoms of Pulmonary Hypertension

Diagnosing PH can be difficult because many of the signs and symptoms are similar to other lung diseases, like asthma and COPD. However, if you suspect a problem you should see your doctor immediately as early diagnosis is the key to preventing fatalities. Some of the most common symptoms include shortness of breath, fatigue, chest pain, dizziness and fainting, heart palpitations, and edema (or swelling in your ankles and legs). If your doctor suspects that you have PH, they will need a detailed medical and family history, and will initially perform a physical exam and one or more diagnostic tests.