Diagnosing PAH

The symptoms of pulmonary arterial hypertension (PAH) are similar to symptoms of other diseases, conditions, and disorders, so specific tests need to be performed to be sure your symptoms are not caused by something else, such as other lung conditions, low blood pressure, or asthma. If you think you are experiencing symptoms of PAH, talk to your doctor.

To diagnose PAH, your doctor will need to obtain a thorough medical history, a physical exam, and assess results from certain tests and procedures.

Common Tests

There are several tests your doctor may run to diagnose PAH:

6-minute walk distance (6MWD): Track how far you can walk in 6 minutes
Pulmonary function test: Measure how well the lungs take in and release air
Echocardiogram: View the heart as it pumps
Chest X-ray
Blood tests
Ventilation/perfusion scan or V/Q lung scan: Measure breathing and circulation in all areas of the lungs

Test to Confirm Diagnosis: Right Heart Catheterization

Once PAH is suspected, a diagnosis can only be confirmed with a procedure known as right heart catheterization (RHC). RHC involves inserting a long, thin, flexible tube called a catheter through the blood vessels and into the heart. This procedure allows your doctor to test heart function and blood pressure in the heart and pulmonary artery. It also helps evaluate the severity of PAH.

Right Heart Catheterization (RHC) is the only definitive test to diagnose PAH.

Four Levels of PAH

The New York Heart Association (NYHA) came up with a scale called the NYHA Functional Classification System to describe the four levels of activities that cause symptoms in patients with heart disease.¹ The more severe the symptoms are in a patient with PAH, the higher the functional class. Doctors often use this scale to help determine the severity of PAH and the type of treatment for their patients.

NYHA Functional Classification

Indication

Tyvaso is a prescription medicine used in adults to treat pulmonary arterial hypertension (PAH) (WHO Group 1), which is high blood pressure in the arteries of your lungs. Tyvaso can improve exercise ability in people who also take bosentan (an endothelin receptor antagonist) or sildenafil (a phosphodiesterase-5 inhibitor). The effects decrease over 4 hours; treatment timing can be adjusted for planned activities.

Studies establishing effectiveness included predominately patients with NYHA Functional Class III symptoms and etiologies of idiopathic or heritable PAH (56%) or PAH associated with connective tissue diseases (33%).

Important Safety Information for Tyvaso

Tyvaso is breathed in (inhalable) through your mouth into your lungs. Tyvaso should only be used with the Tyvaso Inhalation System
The effects of Tyvaso are unknown in patients with lung disease (such as asthma or chronic obstructive pulmonary disease) and in patients under 18 years of age
If you have low blood pressure, Tyvaso may cause symptomatic hypotension (low blood pressure)
Because Tyvaso reduces the ability of your blood to clot (coagulate), it may increase your risk for bleeding if you are taking blood thinners (anticoagulants), such as warfarin or heparin
The use of Tyvaso with diuretics (water pills), antihypertensives (medications used to treat high blood pressure or heart disease), or other vasodilators (medications that lower blood pressure) may increase your risk for hypotension (low blood pressure)

Other medical conditions and medicines may affect your use of Tyvaso by increasing the risk of side effects or decreasing effectiveness. It is important to tell your doctor about your medical conditions and any medicines you may be taking, including:

If you are taking gemfibrozil (for high cholesterol) or rifampin (for infection), your Tyvaso dosage may need adjustment
If you have liver or kidney problems, your ability to tolerate Tyvaso may be affected
If you are pregnant, breast-feeding, or planning to become pregnant, talk with your healthcare provider about whether you should take Tyvaso

The most common side effects of Tyvaso are coughing, headache, throat irritation and pain, nausea, reddening of the face and neck (flushing), and fainting or loss of consciousness. These are not all the possible side effects of Tyvaso. Tell your doctor about any side effects that bother you or do not go away. Your doctor may be able to help you manage the side effects.

For more information about Tyvaso, please see the Full Prescribing Information, Patient Package Insert, and the Tyvaso Inhalation System Instructions for Use Manual. Questions? Call the Customer Service Line at 1-877-UNITHER (1-877-864-8437).

1.	Benedict N, Seybert A, Mathier MA. Evidence-based pharmacologic management of pulmonary arterial hypertension. Clin Ther. 2007;29(10):2134-53.