Pulmonary arterial hypertension (PAH), formerly known as primary pulmonary hypertension, is a rare type of high blood pressure.
PAH affects the pulmonary arteries and capillaries. These blood vessels carry blood from the lower right chamber of your heart (right ventricle) into your lungs.
As the pressure in the pulmonary blood vessels builds up, the heart must work harder to pump blood to the lungs. Over time, this weakens the heart muscle. Eventually, it can lead to heart failure and death.
There’s no cure yet for PAH, but treatment options are available. Treatment may help relieve your symptoms, lower your chance of complications, and prolong your life.
In the early stages of PAH, you might not have any noticeable symptoms. As the condition worsens, symptoms will become more noticeable. Common symptoms include:
- difficulty breathing
- chest pressure
- chest pain
- rapid pulse
- heart palpitations
- bluish tint to your lips or skin
- swelling of your ankles or legs
- swelling with fluid inside your abdomen, particularly in the later stages of PAH
You might find it hard to breathe during exercise or other types of physical activity. Eventually, breathing can become difficult during periods of rest, too.
PAH develops when the pulmonary arteries and capillaries that carry blood from your heart to your lungs become constricted or destroyed.
Various conditions may trigger it, but the exact cause is unknown.
The mutations can then be passed down through families, allowing the person with one of these mutations to have the potential to later develop PAH.
Other potential conditions that can be associated with developing PAH include:
- chronic liver disease
- congenital heart disease
- certain connective tissue disorders
- certain infections, such as HIV or schistosomiasis
- sickle cell anemia
- use of certain toxins or substances, including methamphetamine and banned or discontinued appetite suppressants
In some cases, PAH develops with no known related cause. This is known as idiopathic PAH. Discover how idiopathic PAH is diagnosed and treated.
If your doctor suspects you might have PAH, they will likely order one or more tests to assess your pulmonary arteries and heart.
Tests for diagnosing PAH may include:
- electrocardiogram to check for signs of strain or abnormal rhythms in your heart
- echocardiogram to examine the structure and function of your heart and measure pulmonary artery pressure
- chest X-ray to learn if your pulmonary arteries or the lower right chamber of your heart are enlarged
- CT scan to look for blood clots, narrowing, or damage in your pulmonary arteries
- right heart catheterization to measure the blood pressure in your pulmonary arteries and right ventricle of your heart
- pulmonary function test to assess the capacity and flow of air into and out of your lungs
- blood tests to check for substances associated with PAH or other health conditions
Your doctor can use these tests to check for signs of PAH as well as other potential causes of your symptoms. They’ll try to rule out other potential causes before diagnosing PAH. Get more information about this process.
Currently, there’s no known cure for PAH, but treatment can ease symptoms, reduce the risk of complications, and prolong life.
To help manage your PAH, your doctor might prescribe one or more of the following medications:
- prostacyclin therapy to dilate (widen) your blood vessels
- soluble guanylate cyclase stimulators to dilate your blood vessels
- anticoagulants to prevent blood clots from forming
- a class of drugs known as
endothelin receptor antagonists, such as ambrisentan (these drugs block the activity of endothelin, a substance that can narrow blood vessels)
If your PAH is related to another health condition, your doctor might prescribe other medications to help treat that condition. They might also adjust any medications that you currently take.
Depending on how severe your PAH is, your doctor might recommend surgical treatment.
Options include atrial septostomy or a lung or heart transplant. Atrial septostomy can reduce the pressure on the right side of your heart. A lung or heart transplant can replace the damaged organ(s).
In atrial septostomy, your doctor will guide a catheter through one of your central veins to the upper right chamber of your heart. They’ll create an opening in the upper chamber septum. This is the strip of tissue between the right and left sides of the heart.
Next, your doctor will inflate a small balloon at the tip of the catheter to dilate the opening, causing blood to be able to flow between the upper chambers of your heart. This will relieve pressure on the right side of your heart.
If you have a serious case of PAH that’s related to severe lung disease, your doctor may recommend a lung transplant. Your surgeon will remove one or both of your lungs and replace them with lungs from an organ donor.
If you also have severe heart disease or heart failure, your doctor may recommend a heart transplant in addition to a lung transplant.
Adjusting your diet, exercise routine, or other daily habits can help reduce your risk of PAH complications. These include:
- eating a healthy diet
- exercising regularly
- maintaining a moderate weight
- quitting smoking
Following your doctor’s recommended treatment plan may help relieve your symptoms, reduce your risk of complications, and prolong your life. Learn more about the treatment options for PAH.
PAH is a progressive condition. This means it gets worse over time. Some people may see symptoms get worse faster than others.
A 2015 study examined the 5-year survival rates for people with different stages of PAH. Researchers found that as the condition progresses, the 5-year survival rate decreases.
Here are the 5-year survival rates researchers found for each stage, or class, of PAH:
- Class 1: 72 to 88 percent
- Class 2: 72 to 76 percent
- Class 3: 57 to 60 percent
- Class 4: 27 to 44 percent
While there isn’t a current cure, recent advancements in treatment have helped improve the outlook for people with PAH. Learn more about the survival rates for people with PAH.
PAH is divided into four stages based on the severity of symptoms.
These stages are based on criteria established by the
- Class 1. The condition doesn’t limit your physical activity. You don’t experience any noticeable symptoms during periods of ordinary physical activity or rest.
- Class 2. The condition slightly limits your physical activity. You experience noticeable symptoms during periods of ordinary physical activity, but not during periods of rest.
- Class 3. The condition significantly limits your physical activity. You experience symptoms during periods of slight physical exertion and ordinary physical activity, but not during periods of rest.
- Class 4. You’re unable to carry out any type of physical activity without symptoms. You experience noticeable symptoms, even during periods of rest. Signs of right-sided heart failure tend to occur in this stage.
If you have PAH, the stage of your condition will affect your doctor’s recommended treatment approach. Get the information you need to understand how this condition progresses.
PAH is one of five types of pulmonary hypertension (PH). It’s also known as group 1 PAH.
Below are the other types of PH:
- Group 2 PH is linked to certain conditions that involve the left side of your heart.
- Group 3 PH is associated with certain breathing conditions in the lungs.
- Group 4 PH can develop from chronic blood clots in blood vessels to your lungs.
- Group 5 PH can result from a variety of other health conditions.
Some types of PH are more treatable than others.
In recent years, treatment options have improved the outlook for people with PAH.
Early diagnosis and treatment may help better relieve your symptoms, reduce your risk of complications, and prolong your life with PAH.
In rare cases, PAH affects newborns. This is known as persistent pulmonary hypertension of the newborn (PPHN). It happens when the blood vessels going to a baby’s lungs don’t dilate properly after birth.
Risk factors for PPHN include:
- fetal infections
- severe distress during delivery
- lung problems, such as underdeveloped lungs or respiratory distress syndrome
If your baby receives a PPHN diagnosis, their doctor will try to dilate the blood vessels in their lungs with supplemental oxygen. The doctor may also need to use a mechanical ventilator to support your baby’s breathing.
Proper and timely treatment may help lower your baby’s chance of developmental delays and functional disabilities, helping improve the chance of survival.
- People who are at risk of developing PAH and those with class 1 PAH should be monitored for the development of symptoms that may require treatment.
- When possible, people with PAH should be evaluated at a medical center that has expertise in diagnosing PAH, optimally before beginning treatment.
- People with PAH should be treated for any health conditions that can contribute to the disease.
- People with PAH should get vaccinated against influenza and pneumococcal pneumonia.
- People with PAH should avoid becoming pregnant. If they do become pregnant, they should receive care from a multidisciplinary health team that includes specialists with expertise in pulmonary hypertension.
- People with PAH should avoid unnecessary surgery. If they have to undergo surgery, they should receive care from a multidisciplinary health team that includes specialists with expertise in pulmonary hypertension.
- People with PAH should avoid exposure to high altitudes, including air travel. If they must be exposed to high altitudes, they should use supplemental oxygen as needed.
- People with all types of pulmonary hypertension should take part in a supervised exercise program.
These guidelines provide a general outline for how to care for people with PAH. Your individual treatment will depend on your medical history and the symptoms you’re experiencing.