WHAT IS PULMONARY ARTERIAL HYPERTENSION (PAH)? PAH is a chronic and currently incurable disease that causes the walls of the arteries of the lungs to tighten and stiffen. In someone with PAH, the right side of the heart has to work harder to push blood through narrowed arteries in the lungs. Eventually, the extra stress causes the heart to enlarge and become less flexible, compromising the heart's ability to push blood out of the heart, through the lungs, and into the rest of the body.

The term pulmonary hypertension refers to high blood pressure in the lungs. While in regular hypertension (also known as high blood pressure), the arteries throughout the body are constricted, PAH affects only the blood vessels in the lungs and the right side of the heart.

SYMPTOMS of Pulmonary Hypertension

The symptoms for all types of pulmonary hypertension (PH) may be similar, and symptoms are usually more severe as the disease progresses. Symptoms of PH may include:

  • Breathlessness
  • Chest pain (also called angina pectoris)
  • Dizziness
  • Fainting
  • Loss of energy
  • Swelling of the arms, legs, ankles, or abdomen (also called edema)
  • Dry cough
  • Raynaud's phenomenon (chalky white or dusky blue fingers that may be painful and can sometimes be provoked by the cold)

In advanced stages of pulmonary hypertension, minimal activity may produce some or all of these symptoms. Patients in advanced stages may experience irregular heartbeat, a racing pulse, passing out and difficulty breathing at rest.

Sometimes these symptoms mean you have another condition, but sometimes, these symptoms mean you have pulmonary hypertension.

  • Idiopathic PAH: Means the cause of PAH is unknown.
  • Familial or genetic PAH: This PAH can be inherited. Heritable PAH is relatively uncommon. Of the small percentage of people who carry the PH gene, only a small number of carriers will develop the disease.
  • Associated PAH: This PAH is associated with other diseases or conditions shown below.


Many pulmonary hypertension patients are diagnosed with PH in association with one or more related conditions. Research shows that up to 30% of scleroderma patients, 20-40% of sickle cell patients and one out every 200 HIV patients develop at least mild PH, to name a few.

Other conditions commonly associated with PH include mixed connective-tissue disease, congenital heart disease (CHD), chronic obstructive pulmonary disease (COPD), hereditary hemorrhagic telangiectasia (HHT), sleep apnea, liver disease and lupus. PH has also been linked to the use of certain drugs and toxins, including fenfluramine, dexfenfluramine and methamphetamines.

LIVER DISEASE: Liver disease can cause what is known as "portal hypertension," meaning increased blood pressure in the veins that enter the liver. This increased pressure causes blood to bypass the liver, as a result, the blood is not subject to the liver's work, which includes the removal or detoxification of chemicals and poisons in the body. As a result, the blood vessels of the lungs are exposed to possible toxic substances and this can damage the small arteries of the lungs, causing pulmonary arterial hypertension (PAH).

Portopulmonary hypertension, or POPH, is a type of PAH that occurs as a result of advanced liver disease. This disease has the same characteristic symptoms as those found in cases of PAH that are not associated with liver disease.

Those characteristic symptoms of POPH include blod clots and other changes in the blood vessels of the lung. Symptoms the patient may notice are similar to those associated with classic PH, and include shortness of breath and limited ability to tolerate excercise.

METHAMPHETAMINE USE: Information from a new study suggests that methamphetamine (speed) use is associated with the occurence of IPAH. In that study, individuals with IPAH were 10 times more likely to have used stimulants than individuals with PAH associated with other known risk factors.

In addition, we know that amphetamines are similar to diet pills like fenfluramine, which is most well known as one component of the once-popular anti-obesity drug known as Fen-Phen. Fen-Phen has since been withdrawn from the market because of a potential link between use of that drug and development of PH and heart valve problems.

SCLERODERMA: PAH is a common complication of scleroderma. Between 8 to 12 percent of all scelroderma patients develop PAH.

Scleroderma patients tend to have excercise limitations and it is important to report any changes in your current abilities. Unexplained shortness of breath or increasing fatigue, swelling of the ankles, legs, abdomen or arms, chest discomfort or pain, and light-headedness and fainting are all symptoms your doctor will want to know about, since these can also be signs of pulmonary arterial hypertension.

SICKLE CELL DISEASE: PH is an increasingly recognized complication of SCD. Studies show that approximately 30% of screened adult patients with SCD develop mild PH in adulthood. In 10% of patients , the PH is more severe. Recent autopsy studies also suggest that up to 75% of sickle cell patients show changes in the lung tissue at the time of deatrh, indicating the existance of pulmonary arterial hypertension (PAH).

One possible reason sickle cell patients seem to be at risk for developing PH is that increased breakdown of red blood cells within the blood vessels causes inflammation and a decrease of nitric oxide (a substance that causes relaxation of the blood vessels). This causes constriction of the small arteries of the lungs which may lead to PH.

SLEEP APNEA: What is the relationship between sleep apnea and pulmonary hypertension?

The 2004 American College of Chest Physicians (ACCP) consensus panel found that pulmonary hypertension occurred in 17 percent to 53 percent of individuals with OSA, whereas a review from John Hopkins found that 82 percent of patients with PAH had underlying sleep-disordered breathing. The nocturnal drop in oxygen impairs nitric oxide synthesis and causes vascular remodeling which can lead to the development of pulmonary vascular disease. However, whether OSA independently causes clinically significant pulmonary hypertension remains controversial. Thus, the current ACCP guidlines do not recommend evaluating patients with OSA for pulmonary hypertension unless it is clinically suspected. However, patients with pulmonary arterial hypertension should be evaluated for OSA.

HIV: PAH is still an uncommon complication of HIV infection. As research into HIV continues and as new and better therapies are developed to combat the disease, HIV patients are living longer lives. As a result, the chance that an HIV-positive individual may develop PAH may increase as time goes on.

We can still safely say that PH occurs more frequesntly in the HIV-infected population than it does in those who do not have HIV. Thus, IPAH (pulmonary hypertension that results from unknown causes, in this case an HIV-negative group of people), occurs less frequently than it does in those who are HIV infected. Those who are infected with HIV have roughly 6 to 12 times the occurrence of PAH than the uninfected general population.

HEREDITARY HEMORRHAGIC TELANGIECTAISIA (HHT): About 15 to 20 percent of people with HHT have at least mildly elevated pulmonary artery pressures, which means they either have or are developing PH. HHT patients can develop PH in two ways and the differences are significant.

In HHT-associated pulmonary arterial hypertension, abnormal blood flow through the blood vessels in the lungs causes elevated blood pressure. While it is not known exactly how many people have HHT-associated PAH, research has identified one affected member in 15 percent of families with a form of HHT known as HHT2. In another type of HHT, known as HHT1, HHT-associated PAH appears to be much less common.

More commonly, PH can develop in HHT patients as a result of increased blood flow from the heart, a condition called high cardiac output state. A high cardiac output state may be the result of several things, and a doctor may be able to determine the cause. Treatment will vary depending on what type of PH you have.

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