What is Pulmonary Arterial Hypertension?

Pulmonary arterial hypertension (PAH) is a rare, chronic (long-lasting) disease that affects both the heart and lungs. PAH occurs when the arteries that bring blood from the heart to the lungs become blocked by the tightening of the arterial wall, the growth and thickening of cells in the arterial wall, or the formation of blood clots (known as thrombosis).

As the arteries begin to narrow, it becomes harder for blood to reach the lungs and for oxygen to be circulated throughout the body. As a result, people living with PAH tire and become fatigued more quickly, and can even have trouble breathing after walking for only a few minutes. PAH also puts extra stress on the heart because it is forced to pump harder to circulate blood.

People with PAH develop high blood pressure in the lungs and the disease can ultimately lead to heart failure if the heart is unable to keep up with its extra load as PAH worsens over time. The exact cause of PAH is unknown and there is no cure. However, treatments are available to help ease symptoms.