Diagnosing pulmonary hypertension requires a careful, step-by-step approach because the symptoms can easily be mistaken for other heart and lung conditions. Early and accurate diagnosis is essential to begin appropriate treatment and improve quality of life.

Introduction: Who Should Seek Diagnostic Testing

Pulmonary hypertension often develops slowly, and its symptoms can be vague or similar to those of many other conditions. This makes it challenging to identify in its early stages. Anyone experiencing persistent shortness of breath during routine activities, unusual fatigue that doesn’t improve with rest, or dizziness and fainting spells should consider seeking medical evaluation.^[1]

People with existing heart or lung conditions face a higher risk of developing pulmonary hypertension and should remain vigilant about new or worsening symptoms. Those with left-sided heart disease (a problem affecting the left chambers of the heart), chronic lung diseases like COPD (chronic obstructive pulmonary disease), or a history of blood clots in the lungs should discuss screening with their healthcare provider.^[3]

Certain other groups also warrant closer attention. People living with conditions such as HIV, liver disease, connective tissue disorders like scleroderma (a disease causing skin and internal organ stiffening), or those who have used certain medications or illegal drugs may be at increased risk. Additionally, individuals with a family history of pulmonary hypertension should inform their doctor, as some forms of the disease can run in families.^[7]

It’s important not to dismiss symptoms like chest pain, a racing heartbeat, or swelling in the legs and ankles as simply part of aging or stress. These warning signs can indicate that blood pressure in the lung arteries is rising, forcing the heart to work harder than it should. The sooner these symptoms are evaluated, the better the chances of managing the condition effectively.^[5]

Classic Diagnostic Methods

Diagnosing pulmonary hypertension requires multiple steps because no single test can confirm the condition on its own. The process begins with a thorough medical history and physical examination. Your doctor will ask about your symptoms, how long you’ve had them, and whether you have any other medical conditions. They will also listen to your heart and lungs and check for signs of fluid buildup in your body, such as swelling in your legs or abdomen.^[9]

Blood Tests

Blood tests are often among the first diagnostic tools used. These tests help identify underlying causes of pulmonary hypertension and check for complications. Doctors may look for signs of anemia (low red blood cell count), problems with blood clotting, or stress on the heart. Blood work can also reveal whether organs like the liver or kidneys are functioning properly, which is important since pulmonary hypertension can affect multiple body systems.^[9]

Chest X-Ray

A chest X-ray provides a simple picture of the heart and lungs. While it cannot diagnose pulmonary hypertension directly, it can reveal enlarged heart chambers or changes in the lung blood vessels that suggest increased pressure. This imaging test also helps doctors rule out other lung conditions that might be causing similar symptoms.^[9]

Electrocardiogram (ECG or EKG)

An electrocardiogram, or ECG, records the electrical activity of your heart. This test shows how your heart beats and whether any chambers are enlarged or under strain. In pulmonary hypertension, the right side of the heart often works harder than normal, and an ECG can detect signs of this extra effort. The test is quick, painless, and performed by placing small sensors on your chest.^[9]

Echocardiogram

An echocardiogram is one of the most important tests for evaluating suspected pulmonary hypertension. This test uses sound waves to create moving pictures of the heart. It shows how blood flows through the heart chambers and valves, and it can estimate the pressure in the pulmonary arteries. Doctors often use this test as an initial screening tool because it is non-invasive and provides valuable information about heart function. Sometimes, an echocardiogram is performed while you exercise on a treadmill or stationary bike to see how your heart responds to physical activity.^[9]

However, an echocardiogram alone cannot provide a definitive diagnosis. It can suggest that pulmonary hypertension is present, but further testing is needed to confirm the diagnosis and determine its severity and cause.^[14]

Right Heart Catheterization

The gold standard for diagnosing pulmonary hypertension is right heart catheterization. This invasive procedure provides the most accurate measurement of blood pressure inside the pulmonary arteries. During the test, a doctor inserts a thin, flexible tube called a catheter into a blood vessel, usually in the neck or groin. The catheter is carefully guided into the right side of the heart and then into the pulmonary artery. The doctor can then directly measure the pressure and collect other important information about how well the heart and lungs are working together.^[9]

This procedure is crucial before starting certain treatments because it confirms whether pulmonary hypertension is present and helps classify which type a person has. Right heart catheterization is typically performed at specialized centers where doctors have extensive experience managing pulmonary hypertension.^[9]

Additional Imaging and Tests

Other tests may be ordered depending on what your doctor suspects might be causing the pulmonary hypertension. A CT scan (computed tomography) provides detailed cross-sectional images of the chest and can reveal blood clots, lung disease, or other structural problems. A ventilation-perfusion scan, also called a V-Q scan, checks how well air and blood flow through the lungs and is particularly useful for detecting chronic blood clots.^[8]

Lung function tests, which measure how much air your lungs can hold and how well they move oxygen into the blood, help determine whether lung disease is contributing to the condition. These tests involve breathing into a machine that measures various aspects of lung performance.^[9]

Diagnostics for Clinical Trial Qualification

When patients with pulmonary hypertension are considered for enrollment in clinical trials, they must undergo specific diagnostic evaluations to ensure they meet the study criteria. These assessments help researchers identify the right participants and ensure that the trial results are meaningful and accurate.

Confirmation of Diagnosis

Before entering a clinical trial, participants typically must have their diagnosis of pulmonary hypertension confirmed through right heart catheterization. This invasive test provides precise measurements of pulmonary artery pressure and is considered the definitive diagnostic standard. Trials may require specific pressure thresholds to be met, such as a mean pulmonary arterial pressure greater than a certain value at rest. These measurements help ensure that all participants truly have the condition being studied.^[8]

Classification of Disease Type

Clinical trials often focus on specific types or groups of pulmonary hypertension. The World Health Organization classifies pulmonary hypertension into five groups based on the underlying cause. Group 1, called pulmonary arterial hypertension (PAH), is the type most commonly studied in trials for new targeted therapies. To qualify for these studies, patients must undergo extensive testing to confirm they have PAH rather than pulmonary hypertension caused by heart disease, lung disease, blood clots, or other conditions.^[4]

This classification process may involve echocardiograms, CT scans, V-Q scans, lung function tests, and blood work to rule out other causes. Researchers need to be certain about the disease type because treatments that work for one group may not be appropriate or effective for another.^[14]

Assessment of Disease Severity

Many clinical trials enroll patients based on disease severity. A common tool used to assess functional capacity is the six-minute walk test. During this test, participants walk as far as they can in six minutes while being monitored. The distance covered provides information about exercise tolerance and overall physical ability. Researchers often use this test as an entry criterion and as a way to measure whether an investigational treatment is helping.^[16]

Other measurements of severity include blood tests that check for markers of heart stress, echocardiogram findings that show how well the right side of the heart is functioning, and hemodynamic data from right heart catheterization. These baseline assessments are critical for monitoring how participants respond to the experimental treatment over time.^[16]

Exclusion Criteria Testing

Clinical trials have strict rules about who can participate. Diagnostic tests are used to ensure that potential participants do not have conditions that would make the study unsafe or confuse the results. For example, trials may exclude people with severe liver or kidney disease, uncontrolled heart rhythm problems, or recent heart attacks. Blood tests, electrocardiograms, and imaging studies help identify these exclusion factors before enrollment begins.^[9]

Ongoing Monitoring

Once enrolled, participants in pulmonary hypertension clinical trials undergo regular diagnostic testing throughout the study period. This monitoring helps researchers track disease progression, measure treatment response, and identify any adverse effects. Repeated echocardiograms, blood tests, and functional assessments like the six-minute walk test are common. Some trials may also include periodic right heart catheterizations to obtain precise hemodynamic measurements over time.^[14]

These rigorous diagnostic standards ensure that clinical trials produce reliable, high-quality data that can advance understanding of pulmonary hypertension and lead to better treatments in the future.