How Is Pulmonary Arterial Hypertension Diagnosed?

There is no one specific test that will show why you have pulmonary arterial hypertension (PAH). Even in its later stages, the signs of the disease are similar to those of other heart and lung conditions.

Your doctor will determine if you have PAH by conducting a series of tests to:

• Determine the pressure in your pulmonary artery
• Find out how well your heart and lungs are working
• Rule out any other conditions that may be causing the hypertension

These tests include:

• Chest x ray. A chest x ray takes a picture of your heart and lungs. It can show if the pulmonary arteries or the right side of the heart are enlarged. It will also help your doctor rule out a number of lung diseases, including chronic obstructive pulmonary disease (COPD), as the cause of your PAH.
• EKG (electrocardiogram). This test is used to measure the rate and regularity of your heartbeat, as well as the size and position of the right ventricle in your heart. It can help the doctor rule out a number of diseases of the heart.
• Echocardiogram. This test uses sound waves to create a moving picture of your heart. Echocardiogram provides information about the size and shape of your heart and how well your heart chambers and valves are functioning. The test also can identify areas of poor blood flow to the heart, areas of heart muscle that are not contracting normally, and previous injury to the heart muscle caused by poor blood flow.
• There are several different types of echocardiograms, including a stress echocardiogram. During this test, an echocardiogram is done both before and after your heart is stressed either by having you exercise or by injecting a medicine into your bloodstream that makes your heart beat faster and work harder. A stress echocardiogram is usually done to find out if you have decreased blood flow to your heart (coronary artery disease).
• Stress Test. Some heart problems are easier to diagnose when your heart is working harder and beating faster than when it’s at rest. During stress testing, you exercise (or are given medicine if you are unable to exercise) to make your heart work harder and beat faster while heart tests are performed.
• During exercise stress testing, your blood pressure and EKG readings are monitored while you walk or run on a treadmill or pedal a bicycle. Other heart tests, such as nuclear heart scanning or echocardiography, also can be done at the same time. These would be ordered if your doctor needs more information than the exercise stress test can provide about how well your heart is working.
• If you are unable to exercise, a medicine can be injected through an intravenous line (IV) into your bloodstream to make your heart work harder and beat faster, as if you are exercising on a treadmill or bicycle. Nuclear heart scanning or echocardiography is then usually done.
• During nuclear heart scanning, radioactive tracer is injected into your bloodstream, and a special camera shows the flow of blood through your heart and arteries. Echocardiography uses sound waves to show blood flow through the chambers and valves of your heart and to show the strength of your heart muscle.
• Your doctor also may order two newer tests along with stress testing if more information is needed about how well your heart works. These new tests are magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning of the heart. MRI shows detailed images of the structures and beating of your heart, which may help your doctor better assess if parts of your heart are weak or damaged. PET scanning shows the level of chemical activity in different areas of your heart. This can help your doctor determine if enough blood is flowing to the areas of your heart. A PET scan can show decreased blood flow caused by disease or damaged muscles that may not be detected by other scanning methods.
• Spirometry (spi-ROM-e-tre). This test measures how well your lungs inhale and exhale air. It is most useful for ruling out obstructive lung diseases like COPD.
• Cardiac catheterization. This test provides a precise measure of the blood pressure in the right side of your heart and the pulmonary artery. Cardiac catheterization is the only way to get this measure. It also shows the amount of blood the right ventricle pumps with each heartbeat. This helps your doctor evaluate the pumping ability of the right ventricle. This procedure must be performed in the hospital by a specialist.

Usually, these tests are sufficient to confirm that you have PAH. Sometimes these tests do not rule out all possible causes for the PAH. In that case, your doctor may call for these additional tests:

• Perfusion lung scan. This test shows how the blood is moving in your lungs and whether there are large blood clots that may be causing the PAH.
• Pulmonary arteriography. When the results of a perfusion lung scan do not rule out blood clots in the pulmonary arteries, your doctor may order a pulmonary arteriogram. This test also shows blood clots and other blockages in the blood vessels in the lung.
• Blood tests. Blood tests will rule out HIV, auto-immune diseases like scleroderma, and liver disease.
• Polysomnography (POL-e-som-NOG-ra-fe). This test will help your doctor rule out sleep-disordered breathing as a cause of your PAH.

If these tests do not show an underlying cause for the PAH, the diagnosis is primary pulmonary arterial hypertension.