Pulmonary arterial hypertension (PAH)

Pulmonary arterial hypertension (PAH) means that the blood is travelling through the lungs at a higher pressure than normal. The blood vessels that supply the lungs narrow and thicken, so that the heart has to work a lot harder to pump the blood through the vessels. The vessels cannot pick up as much oxygen as they should, so the body does not get as much oxygen as it needs.