Pulmonary arterial hypertension (PAH) is a rare disease; in the U.S. there about a thousand new cases diagnosed each year. It is treatable, but not curable.
Dr. Diego Maldonado, a pulmonary disease specialist in Vero Beach, says, “Pulmonary arterial hypertension (PAH) is kind of a new disease. Treatments have only been available since the mid 1990s.”
Dr. Maldonado says PAH’s rarity – only about 1,000 cases are diagnosed each year in the U.S. has actually led to it being under-diagnosed. Now, that is changing, as PAH becomes more recognized.
The word pulmonary means “of, related to, affecting, or occurring in the lungs.” PAH is most simply described as high blood pressure in the arteries of the lungs.
The function of pulmonary arteries is to carry blood from the heart to the lungs. While in the lungs, the blood picks up oxygen to be delivered to other parts of the body. In PAH, the pulmonary arteries constrict abnormally; this causes the heart’s lower right chamber (ventricle) to work harder to pump blood through the lungs. This results in a rise in blood pressure within the lungs. Eventually, the right side of the heart enlarges and weakens, leading to heart failure.
Dr. Maldonado says, “PAH is only one form of pulmonary hypertension, so when a patient is referred to me, the first thing I do is determine, through testing, what form of PH they have.” Once the other forms of pulmonary hypertension are ruled out, Dr. Maldonado confirms the diagnosis of PAH through a right heart catheterization, a minimally invasive procedure used to determine how well the heart is pumping, and to measure the pressure of the heart.
“The diagnosis has to be right so the patient can get the right treatment. The lifespan for a patient with untreated PAH is only about three years,” says Dr. Maldonado.
Even though there is no cure for PAH, there are treatments that slow its progress, reduce symptoms, and improve quality of life. Medications include:
- Blood vessel dilators that work to open the lung’s constricted blood vessels. These medications are typically administered through an IV worn a belt for administration as needed, or inhaled through a device called a nebulizer.
- Endothelin receptor antagonists. Endothelin is a naturally-occurring peptide (a molecule consisting of two or more amino acids); too much endothelin in the blood can slowly build up on vessel walls, causing the blood vessels to narrow. The receptor antagonists work to reverse this effect.
- Blood thinning medications. Blood clots can block pulmonary arteries; blood thinners prevent the formation of clots.
Each of these medications has side effects, so a consultation with a pulmonary specialist is essential. The treatment is chosen, at least in part, by which “functional class” the patient belongs to; four functional classes have been defined by the World Health Organization (WHO) based on how far the PAH has progressed.
There are also surgical options, but they are generally used only if medication is not having its intended effect.
Dr. Maldonado says that one of the reasons PAH has been under-diagnosed is that the symptoms are somewhat vague and mimic those of more common heart and lung problems. As outlined by the American Lung Association, symptoms of PAH may include:
- Chest pain, usually on the front of the chest.
- Dizziness
- Fainting
- Fatigue
- Leg swelling
- Light-headedness during exercise
- Shortness of breath during activity
- Weakness
Dr. Maldonado explained that some cases of PAH are “idiopathic,” meaning there is no known cause. This type of PAH is seen in women almost three times as often as in men. More common is secondary PAH, which is caused by another medical condition. “Risk factors include congenital right-heart defects, chronic liver disease, autoimmune conditions such as lupus or rheumatoid arthritis, connective tissue disorders such as scleroderma, and HIV,” says Dr. Maldonado. “Appetite suppressants have also been linked to PAH.”
A family history of PAH has also been identified as a risk factor. Age itself is a factor; Dr. Maldonado says the typical patient is in their 50s or 60s at the time of diagnosis.
In addition to right heart catheterization, PAH diagnostic tools include blood tests, chest X-rays, and echocardiograms. A Doppler echocardiogram is a non-invasive procedure that uses sound waves to see the heart; if it’s difficult to get a clear picture, a minimally invasive procedure called a transesophageal echocardiogram may be used. In this procedure, a flexible tube is guided into the esophagus from the throat. The tube contains a device (called a transducer) that sends out high-frequency sound waves. The sound waves reflect off the heart and allow for detailed images to be produced.
Along with treatment, lifestyle adjustments can help improve the condition of those diagnosed with PAH. As described by the Mayo Clinic, these include:
- Do not smoke, and avoid secondhand smoke.
- Get plenty of rest.
- Stay as active as possible; first be sure to consult with a pulmonary specialist on the recommended level of activity.
- Avoid high altitudes – any elevation over 8000 feet can worsen the symptoms of PAH.
- Eat a healthy diet and stay at a healthy weight. To minimize swelling, limit salt to no more than 2400 milligrams per day. Check labels on processed food; many are high in salt.
- Find ways to reduce stress – at least 30 minutes each day on a relaxing activity.
- Avoid situations that can excessively lower blood pressure, including sitting in a hot tub or sauna, taking long hot baths or showers, and activities that cause straining, such as lifting weights or heavy objects. A sudden drop in blood pressure can lead to fainting.
Since the introduction of the first PAH drug in 1995, 12 therapies have been approved for use in the U.S. “We are learning more and more about PAH,” says Dr. Maldonado. “We are doing a much better job of treating it and studies have shown that patients are living longer. Different treatment options, such as using two drugs in combination, are being researched.”
Dr. Maldonado says it’s very important for people who think they have signs of PAH to see their doctor and get referred to an expert, as early diagnosis is essential to increasing longevity and improving quality of life.