Pulmonary hypertension can be difficult to diagnose. Early on, signs of PH are unlikely to be detected during a regular physical exam. Symptoms of PH are often missed or misinterpreted as another pulmonary condition or heart disease. People with pulmonary hypertension are often misdiagnosed before later receiving a correct diagnosis.
Pulmonary hypertension may take years to diagnose correctly. In a small study of people diagnosed with one type of PH – idiopathic pulmonary arterial hypertension (IPAH) – it took almost four years on average from the first symptoms to diagnosis.
Pulmonary hypertension is usually diagnosed and treated by a PH specialist. Many types of doctors, including pulmonologists, cardiologists, and rheumatologists, have special training and experience that enables them to specialize in managing pulmonary hypertension.
How is pulmonary hypertension diagnosed?
Doctors use many tests to diagnose pulmonary hypertension. Some tests may be repeated to get an accurate idea of what is causing high blood pressure in the pulmonary arteries. During the process of diagnosis, the doctor will categorize the type and functional class of your PH.
The doctor will take a thorough history, asking for specific details about symptoms over time. They will likely ask whether anyone in your family has pulmonary hypertension, since a family history of PH is a risk factor for developing the condition. They will ask about any prescribed medications or illicit drugs you have used. A clear picture may emerge from the medical history that will help a doctor assess risk factors that may strengthen the suspicion of PH or rule out other conditions.
The doctor will carefully examine you, listening to your heart and lungs and checking for swelling, changes in skin color, or any other symptoms of PH. The results of the physical exam may suggest pulmonary hypertension or another condition.
Electrocardiogram (EKG or ECG)
An EKG is often one of the first tests performed when pulmonary hypertension is suspected. EKGs are painless, quick, and inexpensive to perform. An EKG monitors the heartbeat using patches that attach to the skin. A standard EKG uses 12 different patches with electrodes attached to leads. The leads go to a machine that senses electrical impulses in the heart and records the pattern of heartbeats. The results of an EKG test can be used to estimate blood pressure in the right side of the heart and evaluate overall heart function. If the EKG strengthens the suspicion of pulmonary hypertension, more tests will be performed.
Cardiac catheterization is considered a gold standard for diagnosing PH, since it can be used to estimate the blood pressure within the heart and pulmonary arteries and detect leaks between the right and left sides of the heart. You will be sedated before cardiac catheterization. The doctor will use a needle to make a hole in a blood vessel in your arm, groin, or neck. They will then introduce a thin tube into the blood vessel and guide it into the heart. Once the catheter reaches the heart, the doctor will inject dye that can be seen on X-rays. (This imaging procedure is referred to as a coronary angiogram.) The doctor may also use ultrasound technology to image the heart from inside it – known as intracoronary ultrasound. These imaging techniques provide a detailed picture of how the heart is functioning.
Cardiopulmonary exercise testing (Six-minute walk test)
You may be asked to walk on a treadmill for several minutes while your oxygen levels are measured. The exercise test is useful for determining the functional class of PH symptoms.
Spirometry measures lung function. During a spirometry test, you breathe into a tube that evaluates lung function by monitoring how much air you are able to blow in one second. The doctor uses this measurement to calculate forced expiratory volume, or FEV1. FEV1 scores can be used to check for lung problems and find out how effective your lungs are at exchanging oxygen.
Imaging tests help doctors visualize and diagnose problems with the structure of the heart and lungs. Imaging tests are painless and noninvasive. Imaging tests used to diagnose pulmonary hypertension include chest X-rays, computerized tomography (CT), magnetic resonance imaging (MRI), and echocardiogram (or echo), which uses ultrasound.
Blood samples tested in the lab can reveal many important clues about pulmonary hypertension. Blood tests for PH often include:
Also called a V/Q or nuclear scan, a ventilation/perfusion scan involves an injection of radioisotope followed by chest X-rays. A V/Q scan can help identify blood clots in the pulmonary arteries.
The doctor may ask you to undergo polysomnography – also called a sleep study or overnight oximetry – if obstructive sleep apnea is suspected. A sleep study can determine whether you have low levels of oxygen at night while you are sleeping.
Ruling out other conditions
The process of ruling out similar conditions is referred to as differential diagnosis. Pulmonary hypertension has symptoms in common with cardiovascular disease and lung disease such as asthma. PH can be caused by medications or illicit drugs. Pulmonary hypertension can also be caused by another disease; this is known as associated PH. Conditions that can cause associated PH include heart disease (such as coronary artery disease), lung disease such as chronic obstructive pulmonary disease (COPD), liver or kidney failure, infections such as HIV, and autoimmune conditions including lupus and scleroderma.
Your doctor may be able to quickly rule many of these conditions based on your medical and family history or simple blood tests. Other disorders may require time and repeated tests before they can be confirmed or ruled out. The presence of other diseases in addition to pulmonary hypertension may complicate the differential diagnosis and eventually result in multiple diagnoses.