Pulmonary hypertension is a type of high blood pressure that affects the arteries in your lungs and the right side of your heart.
In one form of pulmonary hypertension, tiny arteries in your lungs, called pulmonary arterioles, and capillaries become narrowed, blocked or destroyed. This makes it harder for blood to flow through your lungs, and raises pressure within your lungs' arteries. As the pressure builds, your heart's lower right chamber (right ventricle) must work harder to pump blood through your lungs, eventually causing your heart muscle to weaken and fail.
Some forms of pulmonary hypertension are serious conditions that become progressively worse and are sometimes fatal. Although some forms of pulmonary hypertension aren't curable, treatment can help lessen symptoms and improve your quality of life.
Pulmonary hypertension care at Mayo Clinic