Classifying Your Condition

Once you've been diagnosed with PAH, your doctor will describe the type and severity of your condition using two common classification systems. The World Health Organization (WHO) Group is used to classify the type of PAH and the New York Heart Association (NYHA) Classification is used to describe the severity (or stage).³

WHO Group

The WHO divides pulmonary hypertension (PH) into five groups. Pulmonary arterial hypertension (PAH) makes up the first group, referred to as
WHO Group 1, and includes:⁷

• PAH that has no known cause—often referred to as primary PAH or idiopathic PAH (iPAH)
• PAH that is inherited (passed from parents to children through the genes) or caused by a gene mutation—often referred to as heritable PAH
• PAH that is associated with risk factors, such as the use of various drugs and chemicals (such as certain diet drugs)
• PAH that is associated with a known underlying disease or condition—often referred to as associated PAH (APAH)—and underlying diseases or conditions, such as:
  • Connective tissue diseases (including scleroderma, CREST syndrome and lupus)
  • HIV infection
  • Portopulmonary hypertension (a type of PAH caused by complications from liver disease)
  • Congenital heart disease (heart disease that's present at birth)
  • Schistosomiasis (a disease caused by a parasitic worm)
  • Chronic hemolytic anemia (a condition in which there are not enough red blood cells in the blood)
• A form of PAH called persistent pulmonary hypertension of the newborn (failure of the normal circulatory transition that occurs after birth)

NYHA Classification is Used to Determine Severity of PAH by Symptoms

A second classification system, created by the NYHA, is used to describe disease severity in patients with PAH. Referred to as functional classifications, this system is one of the tools physicians use to monitor disease progression and response to treatment.³ It includes the following functional classes and related symptoms:

The World Health Organization (WHO) developed a similar functional classification system, used to describe disease severity.³

Here are Some Additional Symptoms that Illustrate the Functional Classes:

Shortness of breath experienced with these activities:

• Class II: Two flights of stairs, walking uphill, walking fast, gardening
• Class III: One flight of stairs, light cleaning, golf, power push lawn mower
• Class IV: Rest, dressing, showering, walking at home

These are intended to be useful guidelines only. Every patient's disease is different, individualized and multifaceted.

Next: Learn About Types of Treatment