Diagnosis
Pulmonary Arterial Hypertension

PAH symptoms are so similar to those of other lung disease that it takes a specialized battery of tests to diagnose it. No one test can accurately diagnose PAH. The most important diagnostic tests for PAH are:

Electrocardiography (EKG, ECG) - The most important test for early identification of PAH is an EKG but it cannot identify the disease with certainty. However it can identify heart enlargement or malformation sometimes caused by PAH.

Doppler echocardiography - A useful, noninvasive tool for initial PAH diagnosis, a Doppler ultrasound test gives more detailed information about the size and shape of the heart. But it can also be used to estimate the pressure in the pulmonary artery as the blood leaves the heart.

Cardiac catheterization - The most important ultimate test for PAH, a "right-side cardiac cath" is the only direct method for measuring blood pressure in the pulmonary artery and the right side of the heart. It also gives the most detailed information about the heart's pumping ability.  Vasodilator testing may be completed during a catheterization. The aim of this test is to identify the small number of patients who can be effectively treated with calcium channel blockers.  The agents used to perform this test are intravenous adenosine or epoprostenol, and inhaled nitric oxide.

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Other tests that help in PAH diagnosis, mainly by identifying other diseases that are causing PAH, include:

Chest x-ray - An x-ray can identify enlargement of the right ventricle of the heart and enlarged pulmonary arteries. The x-ray can also give clues about COPD or other underlying lung disease.

Stress test - Doctors use exercise or medications to make the heart beat harder and more rapidly. This stress often reveals hidden heart disease. Blood pressure and EKG readings are standard in stress tests. Doctors may also use nuclear scans, echocardiography, magnetic resonance imaging, or PET scans as part of a stress test.

Six-minute-walk test – During this test, the patient walks as far as possible in 6 minutes.  The patient’s oxygen saturation, heart rate, and distance walked are measured.  The initial evaluation is used to assess exercise performance, and serial follow-up evaluations are used to measure patient progress and response to treatment. 

Spirometry - A method for measuring the volume of air breathed in and out, spirometry helps evaluate dyspnea and rule out restrictive (pulmonary fibrosis) and obstructive (COPD) disease. There are no pulmonary function test findings that are specific to PAH.

Perfusion lung scan - Identifies blood clots in the lungs.

Blood tests - Identify HIV infection, autoimmune disease, or liver disease.

Polysomnography - Diagnoses sleep breathing disorders.


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