What is Pulmonary Arterial Hypertension?
Pulmonary arterial hypertension (PAH), formerly known as primary pulmonary hypertension, is a rare type of high blood pressure. It affects your pulmonary arteries and capillaries. These blood vessels carry blood from the lower right chamber of your heart (right ventricle) into your lungs. Which means high blood pressure in the lungs
As the pressure in your pulmonary arteries and smaller blood vessels builds up, your heart must work harder to pump blood to your lungs. Over time, this weakens your heart muscle. Eventually, it can lead to heart failure and death.
There is no known cure for PAH, but treatment options are available. If you have PAH, treatment may help relieve your symptoms, lower your chance of complications, and prolong your life.
Symptoms of Pulmonary Arterial Hypertension
In the early stages of PAH, you might not have any noticeable symptoms. As the condition gets worse, the 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 of your abdomen, particularly in the later stages of the condition
You might find it hard to breath during exercise or other types of physical activity. Eventually, breathing can become difficult during periods of rest, too.
Causes of Pulmonary Arterial Hypertension
PAH develops when the pulmonary arteries and capillaries that carry blood from your heart to your lungs become constricted or destroyed. This is thought to be triggered by a variety of related conditions, but the exact cause as to why PAH occurs is unknown.
In about 15 to 20 percent of cases, PAH is inherited, according to the National Organization for Rare Disorders (NORD). This involves genetic mutations that can occur in the BMPR2 gene or other genes. 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 infection or schistosomiasis
- certain toxins or drugs, including certain recreational drugs (methamphetamines) or currently off-the-market appetite suppressants
In some cases, PAH develops with no known related cause. This is known as idiopathic PAH.
Diagnosis of Pulmonary Arterial Hypertension
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 or MRI 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 will try to rule out other potential causes before diagnosing PAH.
Treatment of pulmonary arterial hypertension
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 condition, your doctor might prescribe one or more of the following medications:
- prostacyclin therapy to dilate your blood vessels
- soluble guanylate cyclase stimulators to dilate your blood vessels
- endothelin receptor antagonists to block the activity of endothelin, a substance that can cause narrowing of your blood vessels
- anticoagulants to prevent formation of blood clots
If PAH is related to another health condition in your case, 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 condition is, your doctor might recommend a surgical treatment. Atrial septostomy can be done to reduce the pressure on the right side of your heart, and a lung or heart and lung transplant can replace the damaged organ(s).
In an atrial septostomy, your doctor will likely guide a catheter through one of your central veins to the upper right chamber of your heart. In the upper chamber septum (the strip of tissue in between the right and left sides of the heart), going through from right to left upper chamber, they will create an opening. Next, they will inflate a small balloon at the tip of the catheter to dilate the opening and cause blood to be able flow between the upper chambers of your heart, relieving pressure on the right side of your heart.
If you have a serious case of PAH that’s related to severe lung disease, a lung transplant may be recommended. In this procedure, your doctor 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 lung transplantation.
Lifestyle changes to adjust your diet, exercise routine, or other daily habits can help reduce your risk of PAH complications. These include:
- eating a healthy diet
- exercising regularly
- losing weight or maintaining a healthy weight
- quitting tobacco smoking
Following your doctor’s recommended treatment plan may help relieve your symptoms, reduce your risk of complications, and prolong your life.
Life Expectancy with Pulmonary Arterial Hypertension
PAH is a progressive condition, which means it gets worse over time. Some people may see symptoms get worse faster than others.
A 2015 study published in CHEST Journal examined the five-year survival rates for people with different stages of PAH and found that as the condition progresses, the five-year survival rate decreases.
Here’s the five-year survival rate researchers found for each stage.
- 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 cure, recent advancements in treatment have helped improve the outlook for people with PAH.
Stages of Pulmonary Arterial Hypertension
PAH is divided into four stages based on the severity of symptoms.
According to criteria established by the World Health Organization (WHO), PAH is classified into four functional stages:
- 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 are 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.
Types of Pulmonary Hypertension
PAH is one of five types of pulmonary hypertension (PH). It’s also known as Group 1 PAH.
Other types of PH include:
- Group 2 PH, which is linked to certain conditions that involve the left side of your heart
- Group 3 PH, which is associated with certain breathing conditions in the lungs
- Group 4 PH, which can by caused by chronic blood clots in vessels to your lungs
- Group 5 PH, which can result from a variety of other health conditions
Some types of PH are more treatable than others.
Prognosis for Pulmonary Arterial Hypertension
In recent years, treatment options have improved for people with PAH. But there is still no cure for the condition.
Early diagnosis and treatment may help to better relieve your symptoms, reduce your risk of complications, and prolong your life with PAH.
Pulmonary Hypertension in Newborn Infants
In rare cases, PAH affects newborn infants. 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 is diagnosed with PPHN, 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 risk of developmental delays and functional disabilities, helping to improve the chance of survival.
Guidelines for Pulmonary Arterial Hypertension
In 2014, the American College of Chest Physicians released updated guidelines for the treatment of PAH. In addition to other recommendations, these guidelines advise that:
- 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 be 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.
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.