What is pulmonary arterial hypertension (PAH)?

PAH is high blood pressure in the blood vessels in the lungs. In people who have PAH, the blood vessels in the lungs become too narrow. This makes it harder for blood that is being pumped to the lungs from the heart to pick up the important oxygen it needs and carry it to the rest of the body. It also puts extra stress on the heart.

Source: www.remodulin.com