Understanding a pulmonary arterial hypertension diagnosis

Pulmonary hypertension is a group of conditions characterized by chronic higher-than-normal blood pressure in the lungs.

When a person has pulmonary hypertension, blood vessels in the lungs become damaged, narrowed, or blocked. This forces the heart (specifically, the right side of the heart) to work harder than normal. This can lead to serious complications, including heart failure, arrythmias, blood clots in the lungs, bleeding in the lungs, and pregnancy complications.

Pulmonary arterial hypertension (PAH)

Pulmonary arterial hypertension (PAH) is a rare type of pulmonary hypertension. It has unique characteristics that make it different from other types.

Other types of pulmonary hypertension typically begin with some form of underlying heart or lung disease, where a problem with the functioning of the heart and/or lungs results in higher-than-normal blood pressure.

PAH originates inside the blood vessels of the lungs. It occurs as a result of changes to the cells that make up the blood vessel walls. These changes cause the blood vessel walls to become damaged, thickened, and inflexible. This prevents blood from moving through the blood vessels normally, increasing blood pressure and putting unnatural strain on the heart.

In most cases, the causes of PAH are unknown or cannot be identified. This is referred to as idiopathic PAH (IPAH). Roughly 15 to 20 percent of cases are linked to specific genetic mutations, which are referred to as heritable PAH (HPAH).

How is PAH diagnosed?

Early symptoms of PAH are typically mild. Common early symptoms include being out of breath during activity, fatigue, and abnormal heart sounds. These symptoms overlap with other conditions, including pulmonary hypertension that results from other causes. PAH can be challenging to diagnose.

The process for diagnosing PAH involves ruling out other possible causes for symptoms. This is referred to as a “diagnosis of exclusion.”

A healthcare provider will often use a combination of tests to rule out other conditions and diagnose PAH. These can include:

• Imaging tests, such as echocardiography (heart ultrasound), chest X-rays, CT scans, and heart MRI
• Blood tests to look for signs of other diseases, such as liver disease, autoimmune disease, and metabolic disorders
• Tests to measure lung function and how well blood moves through the lungs
• Electrocardiography (ECG), which measures electrical activity in the heart
• A 6-minute walk test to assess exercise tolerance and oxygen levels during activity

How is a diagnosis confirmed?

A test called a right heart catheterization will typically be used to confirm a diagnosis. This test directly measures blood pressure and oxygen in the lungs and heart.

To perform this test, a healthcare provider will insert a thin, flexible tube (called a pulmonary artery catheter) into a vein in the neck, groin, or arm. The tube is guided through the vein to the right side of the heart and the pulmonary artery. This tool measures blood pressure, oxygen, and the amount of blood the heart pumps per minute.

Sometimes, a vasodilating medication will be administered during the test. This is a medication that relaxes blood vessels. It will help show your healthcare providers how the blood vessels respond to this type of medication.

A healthcare team will also ask about family medical history and may advise speaking to a genetic counselor to determine if PAH is inherited.