Pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a type of pulmonary hypertension in which the small arteries in the lungs become narrowed and stiff, raising the pressure in them and straining the right side of the heart. It is rare. It can be idiopathic (no known cause), inherited, or linked to connective tissue diseases such as systemic sclerosis, congenital heart disease, liver disease with portal hypertension, HIV, and some drugs and toxins, such as certain appetite suppressants and methamphetamine. It is most common in women. Symptoms include breathlessness on exertion, tiredness, chest pain, dizziness or fainting, and swollen ankles. Specific medicines can improve symptoms and outcomes.

Lab tests linked to pulmonary arterial hypertension:

• Doctors may order NT-proBNP to judge heart strain and risk, along with a CBC, liver and thyroid tests, HIV testing, autoimmune tests such as ANA and anti-centromere antibodies, and sometimes genetic testing. PAH is suspected on an echocardiogram and confirmed with right heart catheterization. Lung function tests, a lung (V/Q) scan and CT rule out other types of pulmonary hypertension.

How results are read:

• Right heart catheterization confirms PAH. Under current guidelines, it shows a raised mean pulmonary artery pressure with normal pressures on the left side of the heart and raised resistance in the lung vessels.
• NT-proBNP is used in risk scores and to track response to treatment.
• Positive autoimmune tests or a positive HIV test point to an associated cause.

When to see a doctor:

• See a doctor about breathlessness on exertion that is getting worse, unexplained tiredness, or swollen ankles.
• If you have systemic sclerosis, ask about regular screening for PAH.
• Get emergency care for fainting, chest pain, severe breathlessness, or coughing up blood.

Clinical takeaway: pulmonary arterial hypertension is confirmed with right heart catheterization, and blood tests such as NT-proBNP help judge risk and find associated causes.