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What is PAH?

Early identification and intervention

Early diagnosis and therapeutic intervention may offer an improved outlook for patients. Prognosis and response to treatment have both been shown to be better for patients with less severe disease (i.e. WHO Functional Class I/II) compared with those who do not begin targeted therapy until their PAH has reached a more severe stage (i.e. WHO FC III/IV)(see section, Assessing the severity of PAH).1 Disease progression may be delayed by recognising and treating patients as early as possible.2

Early diagnosis poses a challenge to healthcare professionals because many of the initial symptoms of PAH, such as breathlessness, chest tightness, and fatigue, are mild and non-specific and so many patients are not diagnosed until their disease is already quite severe.3 However, around a quarter of patients are diagnosed earlier3 and, if left untreated, their disease will progress to a more symptomatic state.2 The rate at which this progression occurs will vary depending on a number of factors, such as the underlying aetiology of the patient's disease (see section: Classification of PH).4 Regular screening can improve early detection (see section: Screening for PAH) in those patients with conditions known to be associated with PAH (e.g. systemic sclerosis [see section: What is PAH in SSc?], or congenital heart disease).

Given the diagnostic challenges, referral to expert centres is recommended to assist in the early identification of PAH.5,6 Management of patients in such centres also helps to ensure that suitable treatment is provided, patients are appropriately monitored and treatment adjusted when required, and the complex comorbidities often associated with PAH are managed optimally.


  1. Sitbon O, Humbert M, Nunes H, et al. Long-term intravenous epoprostenol infusion in primary pulmonary hypertension: prognostic factors and survival. J Am Coll Cardiol 2002;40:780–8.
  2. Galiè N, Rubin LJ, Hoeper MM, et al. Treatment of patients with mildly symptomatic pulmonary arterial hypertension with bosentan (EARLY study): a double-blind, randomised controlled trial. Lancet 2008;371:2093–100.
  3. Humbert M, Sitbon O, Chaouat A, et al. Pulmonary arterial hypertension in France: results from a national registry. Am J Respir Crit Care Med 2006;173:1023–30.
  4. McLaughlin VV, Archer SL, Badesch DB, et al; ACCF/AHA. ACCF/AHA 2009 expert consensus document on pulmonary hypertension: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents and the American Heart Association: developed in collaboration with the American Collegeof Chest Physicians, American Thoracic Society, Inc., and the Pulmonary Hypertension Association. Circulation2009;119:2250–94.
  5. Galiè N, Hoeper MM, Humbert M, et al. Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Heart J 2009;30:2493–537.
  6. Badesch DB, Abman SH, Simonneau G, et al. Medical therapy for pulmonary arterial hypertension: updated ACCP evidence-based clinical practice guidelines. Chest 2007;131:1917–28.