Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The rare disease that we will be learning about today is:

Pulmonary Arterial Hypertension

Sometimes just called pulmonary hypertension or Ayerza syndrome; however, many experts make a distinction between pulmonary hypertension and pulmonary arterial hypertension.

What is Pulmonary Arterial Hypertension?

• Pulmonary arterial hypertension (PAH) is high blood pressure in the arteries of the lungs (called pulmonary arteries). Pulmonary arteries carry blood from the heart into the lungs, where it picks up oxygen for delivery to the rest of the body.
  • Blood travels from the heart to the lungs through arteries. When the blood reaches the lungs, it picks up oxygen and carries it to the rest of the body. When PAH causes those arteries to narrow, pressure increases greatly to help move the blood through the narrowed arteries. High blood pressure, or hypertension, in the pulmonary arteries causes the right side of the heart to work harder and eventually weaken.​
• PAH worsens over time and can lead to serious complications. The physical symptoms you experience may not always reflect whether PAH is progressing or how it is affecting your heart. If you believe you have PAH, it’s important to talk to your healthcare provider as early as possible so it can be determined if you have PAH and whether or not you need to begin treatment.​
• Pulmonary hypertension is hard to diagnose early because it’s not often detected in a routine physical exam. Even when the condition is more advanced, its signs and symptoms are similar to those of other heart and lung conditions.
• Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR), leading to right ventricular failure and death . PAH is a rare disease.​​

How Do You Get It?

• Annual incidence of 1-2 cases per million people in the US and Europe and is 2-4 times as common in females as in males. The mean age at diagnosis is around 45 years, although the onset of symptoms can occur at any age.​
• Up to 80 percent of patients are females, making sex a significant risk factor.
• Sickle cell disease is also associated with PAH; up to 3.75 percent of sickle cell patients have PAH as well.
• PAH usually occurs in isolation and is very rare. It is only effectively treated with specialized medicines and there currently is no cure.
• In many individual cases, a specific cause is never identified
• Certain genetic mutations have been associated with the disease in some cases.​

What Are The Symptoms?

• Symptoms of pulmonary arterial hypertension are nonspecific and can include:
  • Fatigue
  • ​Swollen ankles and legs
  • Dizziness
  • Fainting
  • Chest pain
  • Irregular or rapid heartbeat
  • Shortness of breath

How Is It Treated?

• The management of PAH is complex and involves the use of a range of treatment options, including supportive and general measures, the assessment of vasoreactivity, and the optimal use of different drugs and interventions.​
• Some drugs doctors commonly prescribe to treat PAH include sildenafil, prostanoids, and calcium channel blockers. One drug, digoxin, helps the heart beat more strongly. You may also need to take a diuretic, which helps lower blood pressure by reducing fluid levels in the body. ​
• Pulmonary hypertension can’t be cured, but doctors can help manage the condition. Treatment may help improve symptoms and slow the progress of pulmonary hypertension.​
• It often takes some time to find the most appropriate treatment for pulmonary hypertension. The treatments are often complex and require extensive follow-up care. The doctor might also need to change the treatment if it’s no longer effective.​ When pulmonary hypertension is caused by another condition, the doctor will treat the underlying cause whenever possible.
  • There are a number of FDA approved treatments for pulmonary arterial hypertension including:
    • Tracleer (bosentan)
    • Letairis (ambrisentan)
    • Opsumit (macitentan)
    • Adempas (riociguat)
    • Ventavis (iloprost)
    • Veletri (epoprostenol sodium)
• The doctor may also prescribe medications that are used to treat the effects of PAH on the rest of your body. These can include the following:​
  • Calcium channel blockers (CCBs) open the blood vessels​
  • Anticoagulants prevent the blood from clotting​
  • Diuretics help the body eliminate excess fluid and reduce swelling​
  • Antiproliferative agents are anticancer drugs that may reduce abnormal cell growth in the pulmonary arteries​
  • Oxygen therapy increases the amount of oxygen available to the blood​
  • A balloon atrial septostomy creates a right-to-left interatrial shunt, helping to ease the pressure in the right heart and improve heart function​
  • A heart or lung transplant is performed only in rare cases for select patients with the most severe cases of PAH and is limited by organ availability​
• Treatment for pulmonary arterial hypertension is an area of ongoing research, and new therapies are in the midst of development.

Where Can I Learn More???

• Learn more about this disease from the Pulmonary Hypertension Association.
• Check out our cornerstone on this disease here.