• Pulmonary hypertension (PH) commonly occurs among the general public. Pulmonary arterial hypertension (PAH) is considered a rare disorder.
• PAH and PH are distinct but related conditions. PAH is a type of PH.
• Common symptoms of both PAH and PH can include shortness of breath, dizziness, fatigue, and heart palpitations.
• There is no cure for most types of PH, including PAH. There are treatments that can help manage the condition and its symptoms.

Hypertension is the medical term for high blood pressure. Pulmonary means “relating to the lungs.” Pulmonary hypertension (PH) is an umbrella term describing high blood pressure of the lung-to-heart system, which has a variety of causes. Pulmonary arterial hypertension (PAH) is high blood pressure of the lungs due to narrowing, injury, or other obstruction of the small pulmonary arteries.

Pulmonary hypertension and pulmonary arterial hypertension are distinct but related health conditions. It can be confusing, since some people — even health journals and doctors — use PH and PAH interchangeably. Pulmonary hypertension is the collective term; pulmonary arterial hypertension is a type of pulmonary hypertension. In other words, all PAH is PH, but not all PH is PAH.

Pulmonary hypertension affects approximately 10 percent to 20 percent of the general population. Pulmonary arterial hypertension is quite rare, with just 500 to 1,000 new cases diagnosed each year in the U.S. Both PAH and PH are more common among women than men. Certain types of heart failure due to PH and PAH are also more prevalent in women than in men. Both PH and PAH are serious health conditions with a high mortality rate.

What Causes PAH and PH?

In both PAH and PH, high blood pressure disrupts proper circulation of blood between the heart and lungs. The heart overcompensates for this reduced heart-lung functionality. The extra work causes the right side of the heart to thicken and grow progressively weaker.

PH can be caused by many other health conditions, including heart disease, blood clots in the lungs, and lung diseases like chronic obstructive pulmonary disorder (COPD). In PAH specifically, the tiny blood vessels in the lungs progressively narrow and directly create high pulmonary blood pressure.

Both PAH and PH can lead to severe cardiac problems, including heart failure. To understand these conditions, it can help to learn more about how the lungs and heart work.

Types of PH

Different types of PH have different causes. The World Health Organization’s (WHO) international classification of diseases separates PH into five groups based on what causes it:

• Group 1 — Pulmonary arterial hypertension
• Group 2 — Pulmonary hypertension due to left heart disease
• Group 3 — Pulmonary hypertension due to lung disease
• Group 4 — Pulmonary hypertension due to blood clots in the lungs
• Group 5 — Pulmonary hypertension due to unknown causes or miscellaneous disease

Types of PAH

There are different types of PAH. Pulmonary arterial hypertension can be influenced by genetics or environmental factors. Some cases of PAH have no identifiable cause.

Associated PAH

PAH can develop in relation to other health conditions. Almost half of people living with PAH have another associated systemic health condition. Conditions commonly associated with PAH include liver disease, HIV, congenital heart disorders, and connective tissue diseases such as lupus and rheumatoid arthritis.

Environmental PAH

PAH can develop as a result of exposure to toxins or past or present drug use, specifically methamphetamines or certain appetite suppressants.

Heritable PAH

Heritable or familial PAH is linked to a specific mutated gene that is passed along the family tree. Scientists have found a genetic link to mutations on the BMPR2 gene in most people with heritable PAH (HPAH). In fact, more than 350 BMPR2 gene mutations can cause HPAH. Between 15 percent to 20 percent of PAH cases are heritable.

Not all gene mutations are inherited. Some PAH-linked genetic mutations are spontaneous or have occurred in people without a family history of PAH or PH.

Idiopathic PAH

Idiopathic pulmonary arterial hypertension is hypertension of the lungs that has no clear cause. About 40 percent of PAH cases have no identifiable cause.

Symptoms of PAH and PH

Symptoms of pulmonary hypertension are different in each person. PAH symptoms also vary from person to person. The way a person experiences PAH or PH symptoms may depend on how advanced their condition is, and their age, sex, and lifestyle factors. Some people in earlier stages of PAH may not have any noticeable symptoms. Others with PH or PAH may experience some or all of these common symptoms.

Early symptoms of PH and PAH include:

• Shortness of breath with physical activity
• Fatigue
• Chest pain
• Swift heartbeat or heart palpitations

More advanced PAH and PH symptoms may include:

• Feeling light-headed, especially when you exert yourself
• Edema, or swelling, in the ankles or legs
• Shortness of breath at rest
• Bluish lips or skin (caused by low oxygen levels in the blood)
• Fainting

How Are PAH and PH Diagnosed?

Diagnosing pulmonary hypertension can be challenging. PH symptoms are common and resemble many other health conditions. Diagnosing PH is usually a process of elimination to identify the underlying cause.

Accurately diagnosing the type of PH is crucial to treating and managing the condition. If you or your doctor suspect PH, diagnosis will likely start with a doctor giving you a thorough physical exam and capturing a detailed medical history.

Diagnostic Tests

A doctor or health team may conduct a variety of tests to diagnose PH and determine its underlying cause. These may include:

• Blood tests to look for an increased risk of blood clots, stress on the heart, or anemia
• Cardiac MRI to get images of the heart's structure, functioning, and surrounding blood vessels
• A chest X-ray to capture images of the size and shape of the heart, pulmonary arteries, and other blood vessels
• Echocardiograms to estimate the pressure of pulmonary arteries

Confirming Pulmonary Arterial Hypertension

There is only one test to definitively diagnose PAH. Right heart catheterization measures the blood pressure inside the pulmonary arteries. During a right heart catheterization, a thin, flexible tube called a catheter is threaded through a blood vessel in the neck or groin to the heart. This procedure can give doctors a great deal of information on a person's heart, PH progression, and how well or not their treatment is working.

Differences in Treating PH and PAH

The treatment a person receives for any type of pulmonary hypertension will depend on the type of PH they have, the underlying cause, and the person’s unique health characteristics. It is very important to have an accurate diagnosis of PH type to receive the best treatment. Some treatments for PAH may not have a beneficial effect on people with PH and could even harm people with certain kinds of PH.

Traditional treatments like diuretics and oxygen therapy are used to treat both PH and PAH. Depending on the severity or progression of a person's condition, a heart-lung transplant may also be an option.

Treating PH

The treatment for PH focuses on managing symptoms and addressing the underlying cause of the hypertension. For instance, people living with WHO Group 2 and Group 3 types of PH may be helped with treatments aimed at left heart and lung diseases.

Only one type of PH, caused by chronic blood clots that develop in the lungs, is curable. Known as chronic thromboembolic pulmonary hypertension (CTEPH), it is the WHO Group 4 PH type. Surgery called pulmonary thromboendarterectomy can be used to remove blood clots from the interior of the affected blood vessels. Surgery, sometimes in combination with PH-targeted drugs, is often the therapy of choice to treat CTEPH.

Treating PAH

There are treatments approved by the U.S. Food and Drug Administration (FDA) to treat pulmonary hypertension, including PAH. There are several treatments in the pipeline that show promise of even more improved options for people with PAH.

Treatments for PAH include conventional medical therapies like calcium channel blockers (CCBs), diuretics, and blood thinners such as Coumadin (warfarin). There are also oral, inhaled, intravenous, and subcutaneous options for treating PAH.

Infusions and Intravenous Drugs

These treatments help open the blood vessels and can improve symptoms, such as chest pain and shortness of breath. This type of PAH treatment is given by injection or infused beneath the skin. Remodulin (treprostinil), Flolan (epoprostenol), and Veletri (room temperature stable epoprostenol) are intravenous drugs used to treat PAH.

Inhalants

Inhaled treatment options help relieve shortness of breath. Some inhalants used to treat PH include Ventavis (iloprost) and Tyvaso (inhaled treprostinil). Both drugs belong to a class of drugs called prostacyclins.

Oral Treatments

There are several types of PAH-specific oral therapies, including endothelin receptor antagonists, phosphodiesterase-5 (PDE5) inhibitors, prostacyclin analogues, selective IP receptor antagonists, and soluble guanylate cyclase stimulators. Each works in different ways to improve blood flow in the vessels of the lungs.

• Letairis (ambrisentan) and Tracleer (bosentan) are two endothelin receptor agonists used to treat PAH. They help keep pulmonary blood vessels from narrowing.
• PDE5 inhibitors, such as Revatio (sildenafil) and Adcirca (tadalafil), are a class of drugs that help the lungs produce more vasodilators.
• Orenitram (treprostinil) is a prostacyclin analogue drug which helps the pulmonary blood vessels to dilate.
• Selective IP receptor agonists, such as Uptravi (selexipag), activate a prostacyclin receptor which helps pulmonary blood vessels in the lungs relax.
• Adempas (riociguat) is a soluble guanylate cyclase stimulator. These drugs increase a certain chemical reaction to help the blood vessels in the lungs to dilate.

Prognosis for PH and PAH

Life expectancy for PAH has substantially increased over the past two decades. A person’s prognosis may be greatly improved if PAH or PH is accurately diagnosed and treated early, with regular follow-up care. Unfortunately, there’s not yet a cure for all types of pulmonary hypertension. Fortunately, PH and PAH are treatable and manageable.

If you think you have PH symptoms, speak to your doctor as soon as possible. A doctor can help you explore different health care options to get the best care for you. Most health care providers now offer telemedicine appointments, so you can talk to a doctor without leaving home. Learn more about Telemedicine and PAH: How To Make Online Health Care Work for You.

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