Pulmonary Hypertension and Interstitial Lung Disease
Pulmonary hypertension, or PH, occurs when blood pressure within the lungs becomes abnormally elevated. It can be caused by a thickening of the pulmonary artery walls, heart failure, lung disease (such as interstitial lung disease), and clots within the lungs' blood vessels. It's common for ILD patients to also develop pulmonary hypertension.
PH should not be confused with ordinary hypertension – sometimes called systemic hypertension or high blood pressure. PH can occur in patients with or without ordinary hypertension.
PH in ILD is also a different disease than primary pulmonary hypertension – also called idiopathic pulmonary arterial hypertension – a rare condition in which PH develops in the absence of lung disease or any other known cause.
Symptoms of PH are similar to those of ILD. Patients with PH often complain of shortness of breath with physical activity that gradually worsens over time.
Patients may also experience the following symptoms:
- Chest pain
- Fainting episodes
- Difficulty breathing when lying flat
- Swelling of the ankles
In ILD patients, pulmonary hypertension is usually suspected when these symptoms are out of proportion to the severity of the patient's ILD.
In diagnosing PH, your doctor will start by conducting a thorough medical history and physical examination. This will include discussing your other medical problems, which may be associated with PH. A review of your medications and exposures is important, since certain diet pills and recreational drugs can increase the likelihood of having PH. The physical exam, which includes listening to your heart sounds and observing your neck veins, may also reveal findings suggestive of PH.
Your doctor may also conduct the following tests to make an accurate diagnosis:
- Echocardiogram. This is an ultrasound study that provides your doctor with video images of your heart and how it is functioning. We can estimate the blood pressure within your lungs based on the speed at which blood flows through your heart.
- Blood Tests. Certain blood tests, specifically for a polypeptide called B-type natriuretic peptide (BNP), can help support the diagnosis of PH. BNP is released into the blood when the heart is under strain, which often occurs as a result of PH.
- Right Heart Catheterization. This procedure is required to definitively diagnose PH. A short catheter (a thin, flexible tube) is placed into your neck or groin, and then a smaller, longer catheter is guided through it. This technique is used to directly measure the blood pressure in your lungs.
- Computed Tomography (CT) Angiogram. In patients with documented PH, CT angiography may be performed to look for potential causes. This is a special type of CT scan used to study the blood vessels in your lungs. For the blood vessels to appear on the scan, contrast dye will need to be injected into a vein in your arm at the time of the CT.
- Ventilation-Perfusion Scan (V/Q scan). In patients with documented PH, V/Q scanning may be performed to look for potential causes. A very small amount of radioactive tracer is injected and inhaled to determine whether blood is flowing appropriately to those areas of the lung that are receiving oxygen.
Treatment for PH can be divided into two main categories: supportive therapy and PH-specific therapy. Supportive therapy is used to treat the underlying factors which may worsen PH, and to prevent complications. PH-specific therapies are designed to reduce the blood pressure within the lungs.
Several PH-specific therapies have recently been approved by the U.S. Food and Drug Administration (FDA) for use in patients with other forms of PH – specifically pulmonary arterial hypertension. The efficacy of these therapies in patients with PH and ILD remains uncertain. Using PH-specific therapy in ILD patients remains controversial, so you should discuss the benefits and risks with your provider.
- Oxygen – Supplemental oxygen helps increase oxygen supply to the blood and helps prevent narrowing of the pulmonary blood vessels, which can worsen PH.
- Diuretics – Diuretics, or water pills, help prevent swelling and are sometimes useful in improving heart and lung function in PH patients.
- Anticoagulants (blood thinners) – Anticoagulants are sometimes required if blood clots are detected in the lungs or if PH is severe.
- Pulmonary Rehabilitation – Pulmonary rehabilitation has been shown to improve outcomes in patients with ILD, as well as patients with PH. Be sure to tell your pulmonary rehabilitation provider if you have been diagnosed with PH.
- Prostanoids (Flolan, Treprostinil, Iloprost). Prostanoid, or prostacyclin, therapy is available as a continuous intravenous infusion or as an inhaled medication. Prostanoids are rarely used for PH in patients with ILD.
- Endothelin Receptor Antagonists (Bosentan, Ambrisentan). Endothelin receptor antagonists are taken by mouth. Patients who take them must have their liver function monitored regularly.
- Phosphodiesterase Inhibitors (Sildenafil). Phosphodiesterase inhibitors are taken by mouth. They should not be used in patients taking nitrates (for example, nitroglycerin) for heart disease.
Survival in patients with ILD and PH is worse than in ILD patients without PH. Several research studies are now looking at the role of PH treatment in improving the prognosis for these patients. If you are a good candidate for a lung transplant and have progressively worsening ILD and PH, your doctor may refer you to a specialist for a lung transplant evaluation.
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.