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, called pulmonary arterial hypertension (PAH), blood vessels in your lungs are narrowed, blocked or destroyed. The damage slows blood flow through your lungs, and blood pressure in the lung arteries rises. Your heart must work harder to pump blood through your lungs. The extra effort eventually causes your heart muscle to become weak and fail.
In some people, pulmonary hypertension slowly gets worse and can be life-threatening. Although there's no cure for some types of pulmonary hypertension, treatment can help reduce symptoms and improve your quality of life.