Major Types of Pulmonary Arterial Hypertension

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, PH primarily affects the blood vessels in the lungs, making the right side of the heart work harder.

In idiopathic pulmonary arterial hypertension, the cause of PAH is unknown.

Heritable PAH, formerly known as familial or genetic PAH, is a form of PAH that can be inherited. Heritable PAH is relatively uncommon. Of the small percentage of people who do carry the PH gene, only a small number of carriers will develop the disease. Learn more about heritable PAH.

Learn what genetics can teach us about PAH.

In associated pulmonary arterial hypertension, the PAH is associated with another disease or condition. PAH is commonly associated with connective tissue diseases (such as scleroderma, CREST syndrome and lupus), congenital heart disease, chronic liver disease, HIV, drugs and toxins, and more.

There are some other types of pulmonary arterial hypertension, but they aren’t quite as common.

What’s Your PH?
(Download poster)

PH vs. PAH: What’s the Difference?

Pulmonary hypertension (PH) is a general term used to describe high blood pressure in the lungs from any cause.

Pulmonary arterial hypertension (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.

Other Types of Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension caused by old blood clots in the lungs (pulmonary embolism). Learn more about CTEPH

Explore the classifications of PH below for more information about the other types of PH.

Classifications of Pulmonary Hypertension

The World Health Organization (WHO) first defined the classifications of pulmonary hypertension in 1973 and the classifications have been revised over the years. The classifications of PH were most recently updated in Nice, France, in 2013.

Learn more about the classifications in the Pathlight article, “What’s Your PH? Understanding the Five PH WHO Groups,” written by Dr. John Kingrey of the Oklahoma Heart Hospital.

Updated clinical classification of PH (Nice 2013)

1. Pulmonary arterial hypertension (PAH)
1.1. Idiopathic
1.2. Heritable
1.2.1. BMPR2
1.2.2. ALK1, ENG, SMAD9, CAV1, KCNK3
1.2.3. Unknown
1.3. Drug- and toxin-induced
1.4. Associated with:
1.4.1. Connective tissue diseases
1.4.2. HIV infection
1.4.3. Portal Hypertension
1.4.4. Congenital heart diseases
1.4.5. Schistosomiasis

1’. Pulmonary veno-occlusive disease (PVOD) and/or pulmonary capillary hemangiomatosis (PCH)

1’’. Persistent pulmonary hypertension of the newborn (PPHN)

2. Pulmonary hypertension due to left heart disease
2.1. Left ventricular systolic dysfunction
2.2. Left ventricular diastolic dysfunction
2.3. Valvular disease
2.4. Congenital/acquired left heart inflow/outflow tract obstruction and congenital cardiomyopathies

3. Pulmonary hypertension due to lung disease and/or hypoxia
3.1. Chronic obstructive pulmonary disease
3.2. Interstitial lung disease
3.3. Other pulmonary diseases with mixed restrictive and obstructive pattern
3.4. Sleep-disordered breathing
3.5. Alveolar hypoventilation disorders
3.6. Chronic exposure to high altitude
3.7. Developmental abnormalities

4. Chronic thromboembolic pulmonary hypertension (CTEPH)

5. Pulmonary hypertension with unclear multifactorial mechanisms
5.1. Hematologic disorders: chronic hemolytic anemia, myeloproliferative disorders, splenectomy
5.2. Systemic disorders: sarcoidosis, pulmonary histiocytosis, lymphangioleimoyomatosis
5.3. Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders
5.4. Others: tumoral obstruction, fibrosing mediastinitis, chronic renal failure on dialysis, segmental PH