Pulmonary arterial hypertension (PAH) is like having high blood pressure, but it affects the arteries in your lungs. This ongoing condition gets worse over time. To understand how severe your PAH is, how it’s progressing, and its impact on your heart and lungs, doctors conduct various tests during regular checkups. These tests are recommended about every three to six months.

Tests that measure PAH disease progression are a part of a risk assessment, an essential tool in the management of PAH. These tests help PAH specialists predict your mortality risk (risk of dying from PAH). Doctors also use test results to set a treatment plan and evaluate how well different PAH medications work for you.

From a risk assessment, your doctor will classify your PAH into one of three groups:

• Low-risk PAH
• Intermediate-risk PAH
• High-risk PAH

Test results also let you know which World Health Organization functional class your PAH is considered to be. This classification system includes four classes — ranging from having no symptoms with normal exercise capacity (class 1) to having symptoms at rest or during minimal physical activity (class 4). In people with PAH, doctors determine their functional class based on their medical history instead of using tests. This class helps predict how long they might live. Generally, people in lower classes are expected to live longer.

If you’re living with PAH, your doctor will regularly conduct one or more of the following tests to help assess your PAH risk.

1. Exercise Capacity Tests

Testing a person’s ability to exercise is a regular part of assessing the functional capacity of their heart and lungs. Your doctor may have you do an exercise test to establish your baseline and then see how that changes over time.

Two well-accepted, noninvasive types of cardiovascular exercise testing are routinely used to measure exercise capacity:

• The six-minute walk test — This simple test measures the distance walked during a six-minute time period.
• The cardiopulmonary exercise test — During this type of test, a person walks on a treadmill or rides a stationary bicycle for a set amount of time or until symptoms arise.

During these activities, doctors can easily measure both your systolic blood pressure, which indicates the pressure when your heart beats, and your diastolic blood pressure, which measures the pressure when your heart is at rest between beats. They can also monitor electrical heart signals, which are the heart’s electrical activities, and oxygen saturation levels, a measure of how much oxygen your blood is carrying, using a noninvasive method. Generally, a higher exercise capacity points to a lower risk of dying from PAH.

2. Cardiac Imaging Exams

Echocardiography and MRI are common tools doctors use to get a clear picture of how the heart looks and works. These imaging tools help doctors see how a disease is progressing and check for signs of heart failure.

Increased atrial pressure can cause pericardial effusion, which is when fluid builds up around the heart. An echocardiogram and MRI can help find complications like pericardial effusion so doctors can treat it.

An echocardiogram can also estimate cardiac output — the volume of blood the heart can pump in one minute. In PAH, if the heart can’t pump enough blood, it is often linked to heart failure. ​

3. Right Heart Catheterization

Right heart catheterization (RHC) is another risk assessment tool that can measure disease progression and right ventricular dysfunction (when the right side of the heart doesn’t pump blood as well as it should) in PAH. During an RHC, a small catheter is inserted into a vein in the neck, arm, or groin. The catheter is slowly guided through the right side of the heart, the right ventricle, and the pulmonary arteries. It measures pulmonary artery pressure and hemodynamics (blood flow) in the heart and lungs.

The procedure typically takes one hour. Doctors may perform RHC during follow-up exams.

4. Blood Tests To Measure Brain Natriuretic Peptide and N-Terminal-Prohormone BNP

Brain natriuretic peptide (BNP) and N-terminal-prohormone (NT-proBNP) are proteins released by the ventricles of the heart in response to high pressure. These proteins act to reduce the pressure load on the heart. Levels of BNP and NT-proBNP are measured from a blood sample. High levels can indicate heart failure. Levels also rise as heart failure gets worse and decrease as heart failure stabilizes. ​

Clinical trials, which are research studies that test new treatments to determine their safety and effectiveness, show that low levels of BNP and NT-proBNP are associated with better long-term PAH outlook.

5. High-Resolution Lung Scans

Two types of lung scans can be used to detect changes in lung disease and function. A ventilation/perfusion (V/Q) lung scan measures blood and airflow in the lungs. It may be used in the diagnosis phase to rule out conditions like chronic thromboembolic pulmonary hypertension. This imaging tool can also reveal small defects in lung tissue in people with PAH. A chest X-ray may be performed before or after a ventilation and perfusion scan.

High-resolution CT scans may be used to help determine the type of PAH you have. A CT scan is similar to a chest X-ray but provides more detailed images of the lungs.

Other Considerations for the Diagnosis and Outlook of PAH

Other factors like the type of PAH and demographic characteristics, which are details about people such as age, gender, and ethnicity, can influence PAH progression and outlook. Although doctors don’t test these factors regularly, they’ll record them when they make an initial PAH diagnosis to better understand your risks with PAH.

For example, when you’re first diagnosed with PAH, doctors may try to determine the type of PAH. It might be heritable PAH (passed down through families), idiopathic pulmonary arterial hypertension (from an unknown cause), primary pulmonary hypertension, or PAH associated with other medical conditions or drug use.

Demographics

During your initial medical visits, a health care provider will note risk factors like your age, sex, race, and ethnicity. According to NORD, PAH is more common in females between the ages of 30 to 60. Research studies have also found differences in the type of PAH by racial and ethnic groups.

Genetics

When you’re first diagnosed with PAH, your doctor may conduct genetic testing to check if you have a genetic mutation, or change, that’s causing your PAH. Genetic testing usually involves a blood or saliva sample to examine your DNA.

Mutation of a gene called bone morphogenetic protein receptor 2 (BMPR2) is the most common genetic cause of heritable PAH. Mutation in the BMPR2 gene is associated with a worse PAH outcome, partially because people with this mutation usually have higher blood pressure in the arteries of their lungs and more resistance in their lung blood vessels when they are first diagnosed.

Associated Conditions

PAH caused by another health condition is called associated PAH. They can include:

• Congenital heart disease — A condition people are born with that changes the way their heart works
• Chronic liver disease
• Human immunodeficiency virus (HIV)
• Connective tissue diseases — Including scleroderma, a disease that causes skin and other body parts to harden, and lupus, an autoimmune condition where the body’s immune system attacks its own tissues

Scleroderma or systemic sclerosis-associated PAH are also predictors of poorer PAH outcomes.

When trying to figure out the cause of your PAH, doctors may ask whether you have any health conditions that are associated with PAH. If you are unsure but have symptoms of other conditions, your doctor may run some medical tests to gather more information. Having other health conditions can change how doctors decide to treat and manage the disease.

Talk With Others Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 54,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.

Have you had risk assessment tests to measure your disease progression? What tests did you have at your last risk assessment? Share your experience in the comments below, or start a conversation by posting on your Activities page.

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