What is PH-ILD?

Pulmonary Hypertension Associated with Interstitial Lung Disease (PH-ILD)

WHAT IS PH-ILD?

Pulmonary hypertension associated with interstitial lung disease (PH-ILD) is a type of Group 3 pulmonary hypertension that develops in people who have interstitial lung disease (ILD).

ILD is a group of more than 200 lung conditions that can cause inflammation, scarring, or damage to the tissue around the air sacs in the lungs. Over time, ILD can make it harder for oxygen to move into the blood and can damage or narrow the blood vessels in the lungs.

When pulmonary hypertension develops along with ILD, the heart has to work harder to pump blood through the lungs. This can make breathing problems and exercise limitations worse.

PH-ILD is different from pulmonary arterial hypertension (PAH). PAH is Group 1 pulmonary hypertension, while PH caused by ILD is Group 3. Because the underlying causes are different, the approach to treatment is also different.

PH-ILD can be difficult to recognize because its symptoms can overlap with those of ILD itself. Healthcare providers may suspect PH-ILD when a person's shortness of breath or reduced ability to exercise seems greater than would be expected from the severity of their underlying lung disease.

Symptoms of PH-ILD

The symptoms of PH-ILD can be similar to symptoms caused by ILD, which can make the condition difficult to recognize.

Symptoms may include:

  • Shortness of breath: Especially during walking, exercise, climbing stairs, or other physical activity.

  • Fatigue: Feeling unusually tired or having less energy than usual.

  • Reduced ability to exercise: Becoming tired or short of breath more quickly than you used to.

  • Chest pain or pressure: Discomfort or pressure in the chest.

  • Dizziness or fainting: Especially during physical activity.

  • Heart palpitations: Feeling like your heart is racing, pounding, fluttering, or skipping beats.

  • Swelling: Fluid buildup can cause swelling in the feet, ankles, or legs.

  • Low oxygen levels: Some people may need supplemental oxygen, particularly during activity or sleep.

If symptoms are becoming worse or seem out of proportion to your underlying ILD, talk with your healthcare provider. PH-ILD may need to be considered and evaluated.

Who Gets PH-ILD?

PH-ILD can develop in people with many different types of interstitial lung disease. The likelihood of developing pulmonary hypertension generally increases as lung disease becomes more advanced, although PH can occur in people with less severe ILD as well.

PH-ILD may occur in people with:

  • Idiopathic pulmonary fibrosis (IPF)

  • Connective tissue disease-associated ILD (CTD-ILD), including ILD related to conditions such as systemic sclerosis or rheumatoid arthritis

  • Combined pulmonary fibrosis and emphysema (CPFE)

  • Chronic hypersensitivity pneumonitis

  • Other idiopathic interstitial pneumonias

  • Other forms of interstitial lung disease

PH-ILD may be more likely when there is significant lung scarring, low oxygen levels, reduced exercise capacity, or evidence that the pulmonary blood vessels are also being affected.

Having ILD does not mean that you will develop pulmonary hypertension. Your healthcare team can determine whether you should be evaluated based on your symptoms, lung function, imaging, oxygen levels, and other findings.

Types of PH-ILD

PH-ILD is not divided into separate “types” in the same way that PAH is. Instead, PH-ILD is pulmonary hypertension associated with different types of interstitial lung disease.

Some of the ILDs that may be associated with PH include:

Idiopathic Pulmonary Fibrosis (IPF)

IPF causes progressive scarring of the lungs for reasons that are not fully understood. Pulmonary hypertension can develop as IPF progresses.

Connective Tissue Disease-Associated ILD

Conditions such as systemic sclerosis, rheumatoid arthritis, and other autoimmune diseases can affect the lungs and cause ILD. Pulmonary hypertension may develop as a complication.

Combined Pulmonary Fibrosis and Emphysema (CPFE)

CPFE involves both areas of lung scarring and emphysema. Pulmonary hypertension is a recognized complication of this condition.

Other Interstitial Lung Diseases

PH can also occur with other ILDs, including idiopathic interstitial pneumonias and chronic hypersensitivity pneumonitis.

The type of ILD you have is important because treatment may need to address both the underlying lung disease and the pulmonary hypertension.

How is PH-ILD Diagnosed?

Diagnosing PH-ILD can be challenging because shortness of breath and reduced exercise ability may already be present because of ILD.

Your healthcare team may use several tests to look for signs of pulmonary hypertension, including:

  • Pulmonary function tests (PFTs) to measure how well your lungs are working

  • Chest CT scans to evaluate your ILD and look for changes that may suggest PH

  • Echocardiogram to evaluate heart structure and function and look for signs of pulmonary hypertension

  • Six-minute walk test or other exercise testing to assess exercise ability and oxygen levels

  • Blood tests, including biomarkers such as BNP or NT-proBNP when appropriate

  • Right-heart catheterization (RHC) when a definitive measurement of pulmonary pressures is needed or when the results will affect treatment decisions

The ESC/ERS guidelines recommend interpreting echocardiography together with lung function, oxygenation, and CT findings. Right-heart catheterization may be recommended when confirming PH would change management, such as when considering specific PH treatment, lung transplantation, or another diagnosis.

Treatments for PH-ILD

Treatment for PH-ILD is individualized. The goal is to treat the underlying lung disease, improve oxygen levels and physical function, manage symptoms, and address pulmonary hypertension when appropriate.

Treating the Underlying ILD

Your healthcare team will treat your specific type of ILD according to current treatment recommendations. Depending on the type of ILD, treatment may include antifibrotic medicines, immunosuppressive or other disease-specific therapies, or other approaches.

Supplemental Oxygen

If your blood oxygen level is too low, supplemental oxygen may be recommended. Oxygen can be particularly important during activity or sleep for people who experience low oxygen levels.

Inhaled Treprostinil

Inhaled treprostinil is an FDA-approved treatment for adults with PH-ILD to improve exercise ability. It is a prostacyclin therapy that is inhaled directly into the lungs.

The approval was supported by the INCREASE clinical trial, which found that inhaled treprostinil improved exercise capacity and reduced the occurrence of certain clinical worsening events compared with placebo.

Inhaled treprostinil is available in different inhaled formulations, including nebulized and dry-powder forms. Your healthcare provider can determine whether this treatment is appropriate for you.

Other Treatments

Depending on your condition, your healthcare team may also recommend:

  • Pulmonary rehabilitation to improve strength, endurance, and ability to perform daily activities

  • Diuretics to help manage fluid buildup and swelling when needed

  • Treatment for sleep-disordered breathing or other conditions that may worsen pulmonary hypertension

  • Evaluation for lung transplantation in eligible people with advanced disease

Other medications approved specifically for PAH are not routinely recommended for people with non-severe PH-ILD. Some treatments may be considered in carefully selected people with severe PH-ILD, but these decisions should generally be made by a pulmonary hypertension specialist or experienced PH center.

Do not assume that a medication used to treat PAH is appropriate for PH-ILD. Treatments for PH depend on the underlying cause and should be prescribed by a healthcare professional familiar with your condition.

Prognosis of PH-ILD

PH-ILD is a serious complication of interstitial lung disease and is associated with greater symptoms, lower exercise capacity, increased oxygen needs, and a higher risk of hospitalization and other complications compared with ILD alone.

However, prognosis is different for every person. It depends on several factors, including:

  • The type and severity of the underlying ILD

  • The severity of pulmonary hypertension

  • How well the right side of the heart is functioning

  • Exercise capacity and oxygen levels

  • Response to treatment

  • Other health conditions

Advances in the treatment of ILD and pulmonary hypertension are providing more options for some patients, and ongoing research continues to look for better treatments.

If you have PH-ILD, working with an experienced ILD and pulmonary hypertension team can help ensure that both conditions are evaluated and treated as appropriately as possible.