Understanding PAH

PAH: A rare and progressive disease

WHO Group 1 PAH is a rare subset of PH.1 PAH is a serious, progressive disease of the lungs, primarily affecting small pulmonary arterioles.2 Over time, the pathophysiology of PAH causes progressive blood flow restriction and RV dysfunction, eventually leading to heart failure and death.3

WHO PH Classification1

The WHO categorizes PH into 5 groups based on pathophysiology, clinical features, and therapeutic approaches:
  • 1 PAH
  • 2 PH due to left heart disease
  • 3 PH due to lung diseases and/or hypoxia
  • 4 CTEPH
  • 5 PH with unclear and/or multifactorial mechanisms
Heart and lung image showing how WHO categorizes PH into 5 groups, along with the effects and location of PAH Group 1, a rare subset

The cause of PAH is often unknown4

PAH falls into 4 general clinical classifications:


Cause is unknown


BMPR2 is the most commonly mutated gene

Drug- and toxin-induced6

May include:

  • Aminorex
  • Fenfluramine
  • Dasatinib
  • Methamphetamines


  • Connective tissue disease (CTD)
  • Congenital heart disease (CHD)
  • HIV infection
  • Portal hypertension
  • Schistosomiasis
Other clinical classifications include6:
  • PAH long-term responders to CCBs
  • PVOD/PCH involvement
  • Persistent PH of the newborn syndrome

WHO Group 1 PAH etiologies by prevalence7

All etiologiesWho Group 1 PAH etiologies by prevalence pie chart
Image Description

The breakdown of PAH by etiology is:

  • Associated PAH: 51%
  • Idiopathic PAH: 44%
  • Heritable: 4%
  • Other: 1%
Associated conditions compositionPAH associated conditions composition pie chart
Image Description

The prevalence of associated conditions is:

  • CTD: 67%
  • Portal hypertension: 9%
  • Drugs/Toxins: 9%
  • HIV: 4%
  • CHD: 12%
  • Other: 1%
Adapted from: Badlam JB, et al. Chest. 2021;159(1):311-327.

How do you confirm a diagnosis of PAH?

Diagnosing PAH

PAH prognosis is similar to that of colorectal cancer8,9

As a progressive disease, the 5-year survival of patients with PAH falls near that of patients with colorectal cancer or stroke.8-10 An estimated 61% of patients with PAH survive 5 years post-diagnosis, giving PAH a higher 5-year survival rate than ovarian cancer but lower than breast cancer.8,9

Find out more about the prognosis of patients with PAH.

Estimated 5-year survival across disease statesEstimated 5-year survival across disease states graph
Image Description

The estimated 5-year survival across disease states is:

  • Breast cancer: 90%9
  • Colorectal cancer: 65%9
  • PAH: 61%8
  • Stroke: 60%10
  • Heart failure: 52%11
  • Ovarian cancer: 47%9
  • Lung cancer: 18%9
  • Pancreatic cancer: 8%9

PAH prevalence and characteristics

PAH prevalence and statistics
Image Description
  • PAH affects 15 to ~60 people per 1 million inhabitants in countries where studies have been conducted1,12
  • ~1000 new cases are diagnosed in the United States every year13
  • PAH is more commonly diagnosed in women (70%-80% of cases)4
  • ~2 years from symptom onset to diagnostic catheterization7
  • Older patients 50 to 65 years of age1*
  • The 5 year survival average is 61%8
*In the first US National Institutes of Health registry (started 1981), the mean age of patients was 36 years.1

PAH guidelines:

Target low risk as the goal to improve patient survival14

Review Treatment Guidelines

Help patients delay disease progression:

Perform formal risk assessments and escalate therapy appropriately14

Integrating Risk Assessment
CCB=calcium channel blocker; CHD=congenital heart disease; CTD=connective tissue disease; CTEPH=chronic thromboembolic pulmonary hypertension; HIV=human immunodeficiency virus; PH=pulmonary hypertension; PVOD/PCH=PAH with overt features of venous/capillaries; RV=right ventricle; WHO=World Health Organization.References: 1. Galiè N, et al. Eur Heart J. 2016;37(1):67-119. 2. Lai YC, et al. Circ Res. 2014;115(1):115-130. 3. Gaine S, et al. Eur Respir Rev. 2017;26(146):170095. 4. Hoeper MM, et al. Eur Respir Rev. 2014;23(134):450-457. 5. Girerd B, et al. Eur Respir Rev. 2017;26(145):170037. 6. Simonneau G, et al. Eur Respir J. 2019;53(1):1801913. 7. Badlam JB, et al. Chest. 2021;159(1):311-327. 8. Farber HW, et al. Chest. 2015;148(4):1043-1054. 9. Siegel RL, et al. CA Cancer J Clin. 2018;68(1):7-30. 10. Koton S, et al. JAMA. 2014;312(3):259-268. 11. Roger VL, et al. JAMA. 2004;292(3):344-350. 12. Humbert M, et al. Am J Respir Crit Care Med. 2006;173(9):1023-1030. 13. National Institutes of Health, US National Library of Medicine. Accessed March 19, 2021. https://medlineplus.gov/genetics/condition/pulmonary-arterial-hypertension/ 14. Galiè N, et al. Eur Respir J. 2019;53(1):1801889.