A Guide to Pulmonary Arterial Hypertension
Although pulmonary arterial hypertension (PAH) is only one form of a broader range of pulmonary hypertension (PH), it nevertheless is quite common. In the United States alone, as many as 1,000 new cases are diagnosed annually.1 The disorder affects about twice as many females as it does males. PAH can be inherited, in which case it is referred to as familial pulmonary arterial hypertension. However, it often affects individuals who have no evidence of PAH in their family history.
While about 20 percent of non-familial cases can be traced to gene mutations associated with the disorder, there usually is no evidence of a causative mutation. As a result, such cases are referred to as idiopathic, meaning that the root cause has not yet been identified.
While pulmonary arterial hypertension is the most common name for the disorder, there are several other names that it goes by:
- Ayerza Syndrome
- Familial Primary Pulmonary Hypertension
- Idiopathic Pulmonary Hypertension
- Primary Pulmonary Hypertension
- Sporadic Primary Pulmonary Hypertension
What Is Pulmonary Arterial Hypertension?
PAH is a form of abnormally high blood pressure occurring in the pulmonary artery, which is the main blood vessel carrying blood to the lungs from the heart.2 It often results from a decrease in the diameter of arteries that traverse through the lungs which restricts the flow of blood. To overcome that resistance, blood pressure rises in the pulmonary artery and in the heart. Ultimately, this can lead to damage in the right ventricle of the heart.
When elevated blood pressure is inadequate to overcome the resistance created by the constricted blood vessels, there is insufficient blood flow to other parts of the body. Although this condition may produce a variety of signs and symptoms, the condition is progressive, and it sometimes takes years for the restrictions to become severe enough to be noticeable. As a result, PAH may not be properly diagnosed until it has progressed significantly.
Signs and Symptoms
There are multiple signs and symptoms that have been associated with PAH. Here is a brief list of the more common ones:
Shortness of breath
One of the first recognizable signs of pulmonary arterial hypertension is shortness of breath.3 This is because breathing is made possible by the arteries and blood vessels that carry blood to the lungs, and when the blood flow is reduced, it becomes more difficult to breathe. Some patients find themselves quickly inhaling and exhaling in order to secure enough oxygen. Any type of aerobic activity may become very difficult and leave a person short of breath. Even such mild things as climbing the stairs can be difficult.
Another sign of PAH is fatigue. When the lungs cannot get enough blood, they struggle to send an adequate supply of oxygen to the brain. Without enough oxygen, a person will find it difficult to carry on their normal routine. When this happens, a person tires more easily and has difficulty with thought processing. In some cases, a person may feel dizzy. Oftentimes, a patient will ignore these symptoms, thinking they simply are out of shape. However, this can ultimately make the condition worsen.
Swelling in limbs
PAH can produce swelling, otherwise known as edema, in a person’s limbs, including the feet, ankles, and legs. Unlike a healthy body where the kidneys flush away waste body material in an efficient manner, PAH often leads to fluid retention which results in swelling. The longer a person has PAH, the more likely it is that swelling will occur.
In addition to the lungs, brain, and limbs, PAH causes a reduction in the amount of oxygen delivered to other parts of the body. Normally, red blood cells are rich with oxygen. However, blood cells that are deprived of oxygen tend to take on a bluish color, a condition known as cyanosis.
When the heart is working harder to compensate for reduced blood flow, the heart muscles can become overworked and may become weak. This prevents a heart from beating with the same intensity or regularity as it once did. Consequently, this can lead to an irregular heartbeat, heart palpitations, or a racing pulse.
When the blood pressure in the arteries or heart becomes high enough, a person can begin to experience chest pain or pressure in the chest area. Also, a heart that is overworked while trying to compensate for decreased blood flow can lead to chest pain.
There is still much to be learned about the causes of pulmonary arterial hypertension. In some cases, a person inherits a predisposition to the disorder through a genetic mutation.4 In other cases, a disease may lead to its development, such as the following:
- Heart abnormalities
- HIV infection
- Cirrhosis of the liver
In some cases, PAH has been linked to drug use. This includes certain prescription drugs such as diet pills, plus illegal drugs like cocaine and methamphetamine. In other cases, the causes are simply not known.
PAH is often treated in a way that is designed to help a person manage their condition, improve their symptoms, and slow the disorder’s progress. It typically takes a significant amount of time to find the most appropriate treatment options for specific patients. When PAH results from an underlying condition, treatment revolves around treating the underlying condition.5 Typical treatments include medication and surgery, as described below.
- Blood vessel dilators, or vasodilators, work by opening constricted blood vessels and improving blood flow. Some are inhaled while others are injected intravenously. Common names include Flolan, Veletri, Ventavis, Tyvaso, Remodulin, and Orenitram.
- Endothelin receptor antagonists work by reversing the effects of endothelin, a substance that causes the blood vessel walls to narrow. Common names include Tracleer, Opsumit, and Letairis.
- High-dose calcium channel blockers work by helping to relax the muscles in the blood vessel walls. Common names include Norvasc, Cardizem, Tiazac, and Procardia.
- Soluble guanylate cyclase (SGC) stimulators work by interacting with nitric oxide to help the pulmonary arteries relax, which leads to lower blood pressure. One common name is Adempas.
- Anticoagulants help prevent blood clots from forming within the pulmonary arteries. Common names include Coumadin and Jantoven.
- Digoxin helps the heart to beat stronger and pump more blood. It also can help control the heart rate if a person is experiencing arrhythmias. One common name is Lanoxin.
- Diuretics work by eliminating excess body fluid which will help reduce swelling. This also reduces the amount of work that the heart has to do. These medications are commonly known as water pills.
- Breathing pure oxygen, a treatment known as oxygen therapy, is an effective treatment for pulmonary arterial hypertension, especially for patients who live at high altitudes or have sleep apnea. Some patients require continuous oxygen therapy in order to deal with the effects of PAH.
- Atrial septostomy is an open-heart type of surgery where an opening is created between the upper chambers of a patient’s heart to relieve pressure on the right side of the heart.
- Transplanting a heart is a serious option for treating PAH. In some cases, it may be more appropriate for younger patients who have idiopathic PAH.
The future holds much promise for advancing the treatment of pulmonary arterial hypertension. Research is presently underway that will help guide medical professionals in diagnosing and treating the ailment. It also is believed that research in other fields dealing with race and ethnicity will shine new light on targeted treatments that prove beneficial in the treatment of PAH, such as improved methods for controlling blood pressure in blacks. Additionally, it may be possible in the future to realize structural differences in abnormalities of the right ventricle that will allow technicians to formulate a treatment based on genetics.6