Infusion medications for advanced PAH

Pulmonary arterial hypertension (PAH) is a rare disorder that creates high blood pressure in the lungs.

When a person has PAH, changes occur in the cells and tissues that make up the inner walls of the blood vessels inside the lungs. These changes cause “vascular remodeling,” where blood vessels become narrow and stiff, making it more difficult for the heart to pump blood through the lungs.

Early in the course of the disease, PAH can cause mild and nonspecific symptoms, most commonly shortness of breath during exertion or exercise. Over time, PAH can put significant strain on the heart (specifically, the lower right chamber), leading to right-sided heart failure and other life-threatening complications.

There is no cure for PAH, but there are therapies that can help reduce symptoms, slow the progression of the disease, support a better quality of life, and reduce the risk of serious medical events like hospitalizations and heart failure.

As PAH progresses, a treatment plan will also need to progress to keep up with treatment goals.

When is PAH considered advanced?

The severity of PAH is typically measured in two ways, the impact that it has on daily functioning and its risk of causing a serious medical event.

World Health Organization (WHO) functional class

WHO categorizes pulmonary hypertension (including PAH) with four functional classes based on how the condition affects a person’s ability to function:

• In the earlier functional classes (I to II), a person may experience mild to moderate shortness of breath during physical activity.
• In the advanced functional classes (III to IV), symptoms have a more significant impact on functioning, and a person may experience breathlessness, fatigue, and discomfort even at rest.

Risk stratification

Risk stratification takes into account the WHO functional class as well as other factors, including blood work, exercise capacity, imaging tests, direct measurements of blood pressure in the lungs and right side of the heart, age, and medical history.

A score is assigned based on factors and test results. This score determines the risk of dying or experiencing a serious medical event over the next year. More advanced and severe PAH is associated with a higher risk of hospitalization, right-sided heart failure, and death. Lowering risk and maintaining a lower risk are important treatment goals. Regular assessments are a critical part of treatment.

Treatment for PAH

Medications are the main treatment for PAH. In the early stages of the disease, PAH is typically treated with one or two oral medications. In many cases, a medication given by infusion will be added.

Therapies given as infusions fall into two broad categories:

Biologic therapy

Biologic therapies are a new and emerging treatment that can potentially reduce remodeling in the blood vessels. The first biologic drug was approved in 2024 and is given as a subcutaneous infusion. For adults, infusions can be self-administered every three weeks. This therapy can be used in the treatment of early or advanced PAH and is used in combination with other medications.

Prostacyclin analogues

Prostacyclin analogues are synthetic versions of a hormone called prostacyclin, which is one of the body’s natural vasodilators.

Continuous infusions (24 hours a day) of prostacyclin analogues are a mainstay of treatment for advanced PAH. This type of infusion is delivered with a medical device called an infusion pump. An infusion pump delivers medication continuously into the body. This ensures that a steady level of the drug is always in the bloodstream.

A healthcare team will review what medications and infusion pumps are available. They will also provide training, guidance, and support to help you learn how to use this device. While starting a PAH medication that requires an infusion pump can be intimidating, know that many people use these devices with success.

Also know that needing to switch to a more advanced treatment is not a sign of personal failing. PAH is a progressive condition, and treatment will need to change over time. The best thing you can do is continue to follow your treatment plan and work with your healthcare team.