Introduction: Who Should Undergo Diagnostics

Diagnosing heritable pulmonary arterial hypertension (HPAH) begins with recognizing who should be tested. If you have a family member diagnosed with pulmonary arterial hypertension, which means high blood pressure in the lung arteries, you should talk to your doctor about screening even if you feel healthy. This condition can run in families because of genes passed down from parent to child.^[1]

You should seek medical attention if you experience certain warning signs. The most common early symptom is shortness of breath that starts during physical activity and slowly gets worse over time. Other symptoms that should prompt you to see a doctor include unusual tiredness that doesn’t go away, chest pain or pressure, feeling dizzy or fainting, a racing or pounding heartbeat, or swelling in your feet and legs.^[2][3]

The challenge with HPAH is that symptoms often develop slowly and may not be noticeable for months or even years. Many people dismiss their early symptoms as simply being out of shape or getting older. By the time symptoms become obvious, the disease may have already progressed. This is why maintaining a high level of suspicion is so important, especially if you have risk factors like a family history of the disease.^[2]

Certain groups of people need to be especially vigilant. Women are twice as likely as men to develop HPAH and are typically diagnosed in their mid-thirties, though the condition can affect people of all ages, including children and the elderly. If you’re a woman with a family history of PAH, regular check-ups and awareness of symptoms becomes even more critical.^[2][4]

People who have been diagnosed with or have a history of certain conditions should also be evaluated for PAH. These include connective tissue diseases like lupus, congenital heart disease, liver disease, HIV, or a history of using certain drugs. Additionally, if your doctor hears unusual sounds when listening to your heart or notices signs of heart strain, they may recommend testing for pulmonary hypertension.^[2]

Diagnostic Methods

Diagnosing heritable pulmonary arterial hypertension requires multiple steps and different types of tests. The process begins with a detailed conversation with your doctor about your symptoms and medical history. Your doctor will ask when your symptoms started, what makes them better or worse, whether anyone in your family has heart or lung disease, and if you smoke or have other risk factors.^[9]

A thorough physical examination is an essential part of the diagnostic process. During this exam, your doctor will listen to your heart and lungs with a stethoscope. They’re checking for specific sounds that indicate problems, such as a loud second heart sound, a right ventricular heave (which means your heart is working harder than normal), or unusual murmurs. They’ll also look for visible signs like swelling in your legs or a bluish tint to your skin, which can indicate low oxygen levels.^[2][4]

Blood tests are typically ordered early in the evaluation. These tests serve multiple purposes: they can help identify complications of PAH, rule out other conditions that might be causing your symptoms, and look for underlying diseases associated with PAH. Your doctor might test for markers of autoimmune diseases, liver function, thyroid problems, or HIV, depending on your individual situation.^[9][14]

An electrocardiogram, or ECG (sometimes called EKG), is a simple, painless test that records your heart’s electrical activity. This test shows how your heart is beating and can reveal whether the right side of your heart is under strain, which is a warning sign of pulmonary hypertension. Small sticky patches are placed on your chest, arms, and legs, and the machine records your heart’s signals for a few minutes.^[9][14]

A chest X-ray provides a picture of your heart, lungs, and chest. While it cannot diagnose HPAH on its own, it can show if your pulmonary arteries are enlarged or if there are other lung conditions that might be causing your symptoms. This test is quick and uses a small amount of radiation to create the image.^[9][14]

The echocardiogram is one of the most important initial tests for suspected HPAH. This test uses sound waves to create moving pictures of your beating heart. It’s similar to the ultrasound used to view babies during pregnancy. An echocardiogram shows how blood flows through your heart and heart valves, and it can estimate the blood pressure in your pulmonary arteries. This test is painless and doesn’t involve any needles or radiation. Sometimes, you may be asked to exercise on a treadmill or stationary bike during the test to see how activity affects your heart.^[9][13][14]

If the echocardiogram suggests pulmonary hypertension, your doctor will order a right heart catheterization to confirm the diagnosis. This is the gold standard test for diagnosing HPAH. During this procedure, a doctor inserts a thin, flexible tube called a catheter into a blood vessel, usually in your neck. The tube is gently guided through the blood vessel into the right lower chamber of your heart and into the pulmonary artery. This test directly measures the blood pressure in your pulmonary arteries. A diagnosis of HPAH is established when the mean pulmonary artery pressure is greater than 20 mm Hg at rest during this test.^[2][9][14]

A CT scan, or computed tomography scan, uses X-rays and a computer to create detailed three-dimensional images of your chest. This test can show enlarged pulmonary arteries and help identify other problems in the lungs that might be causing your symptoms. The machine moves around you as you lie still on a table, and the process takes only a few minutes.^[9][14]

A ventilation-perfusion scan, also called a V-Q scan, is another imaging test that may be ordered. This test helps find blood clots in the lungs that could be causing high blood pressure in your pulmonary arteries. It involves breathing in a small amount of radioactive gas and receiving an injection of a radioactive substance to see how air and blood are flowing through your lungs.^[9][14]

Lung function tests, also called pulmonary function tests, measure how well your lungs work. During these tests, you breathe into a machine that measures how much air your lungs can hold and how quickly you can move air in and out. These tests help rule out lung diseases that could be causing symptoms similar to HPAH.^[9]

Genetic testing plays a special role in diagnosing HPAH. If you have PAH, whether you have a family history or not, your doctor may recommend genetic testing. The most common genetic cause is a mutation in a gene called BMPR2. Mutations in several other genes, including ACVRL1, KCNK3, CAV1, TBX4, and SMAD9, have also been found to cause HPAH, though these are less common. Identifying a genetic mutation helps confirm the diagnosis of heritable PAH and has important implications for your family members, who may also benefit from genetic counseling and testing.^[2][4][7]

Diagnostics for Clinical Trial Qualification

When patients with HPAH are being considered for clinical trials, additional standardized testing is typically required. Clinical trials have specific criteria that participants must meet, and these criteria often involve particular test results that demonstrate the severity and type of their condition.

Right heart catheterization is essential for clinical trial enrollment. Trials need precise measurements of pulmonary artery pressures to determine if a patient’s disease severity matches the study’s inclusion criteria. The procedure confirms that the mean pulmonary artery pressure exceeds specific thresholds, typically greater than 20 mm Hg at rest, as defined by updated guidelines.^[2][10]

Genetic testing becomes particularly important for clinical trials focused on heritable forms of PAH. Researchers need to confirm whether participants have mutations in specific genes like BMPR2 or other PAH-associated genes. Having documented genetic mutations helps trials study how these specific genetic forms of the disease respond to experimental treatments. Genetic counseling is often provided as part of the trial participation process, since this information has implications not just for the patient but for their family members as well.^[2][4]

Clinical trials typically require a thorough assessment of functional capacity. This often includes a six-minute walk test, where patients walk for six minutes and the distance covered is measured. This simple test provides valuable information about how HPAH affects daily functioning and serves as a baseline to measure whether experimental treatments improve physical ability. Patients may also be classified according to the New York Heart Association functional classification (NYHA FC), which ranges from Class I (no limitation of physical activity) to Class IV (symptoms at rest). Most HPAH patients entering clinical trials are in Class III or IV.^[4]

Blood tests for clinical trials are more comprehensive than routine diagnostic testing. These may include measurements of specific biomarkers that indicate disease severity or heart stress, such as brain natriuretic peptide (BNP) or N-terminal pro-BNP. These substances are released by the heart when it’s under strain, and their levels can help predict disease progression and treatment response.

Echocardiograms are repeated as part of clinical trial screening to provide detailed baseline information about heart function. Researchers need to document the size and function of the right ventricle (the heart chamber that pumps blood to the lungs), the degree of tricuspid regurgitation (leakage of a heart valve), and estimated pulmonary artery pressures before treatment begins.^[9][13]

Risk stratification is an important component of clinical trial qualification. Doctors use a combination of test results to categorize patients as low, intermediate, or high risk. This assessment considers factors like symptoms, exercise capacity, blood test results, and heart function measurements. Clinical trials may specifically target patients in certain risk categories to study whether new treatments can improve outcomes for those groups.^[2]

Additional imaging studies, such as cardiac MRI, may be required for some clinical trials. This advanced imaging provides detailed pictures of heart structure and function without using radiation. It can measure the volumes of the heart chambers, assess how well the heart is pumping, and evaluate blood flow patterns in ways that other tests cannot.

Lung function testing is standardized for clinical trial entry to ensure that participants don’t have significant lung disease that could interfere with interpreting study results. These tests help distinguish pure pulmonary arterial hypertension from cases complicated by chronic lung conditions.

Patients considering clinical trial participation should understand that these additional tests serve important purposes. They ensure that only appropriate candidates are enrolled, establish baseline measurements to track treatment effects, and maintain scientific rigor. While the testing process can feel overwhelming, it ultimately helps researchers develop better treatments for future patients with HPAH.