Changes to the pulmonary vasculature lead to the typical symptoms of PAH.

The symptoms are caused by the high resistance to blood flow through the lungs, which results in increased stress on the heart and a compromised blood circulation through the whole body as a result of decreased cardiac output. This progressive right ventricular (RV) dysfunction can severely impact a patient’s ability to exercise or carry out normal daily activities. Common early symptoms are typically induced by exertion and include:1


Dizziness & fatigue



Chest pain


Palpitations may occur during physical exercise and may reveal underlying cardiac arrhythmias.2 With progressive strain on the heart, further symptoms of right heart failure may become apparent including peripheral oedema and abdominal distension.1

The symptoms may not be obvious at first and are often attributed to more common conditions such as asthma, COPD, chronic heart failure or lack of physical fitness.3 Over time, however, they can become more severe and begin to limit normal activities. As the disease progresses, some patients may experience constant dyspnoea and fatigue so that even simple tasks, such as getting dressed and walking short distances, become difficult.1,4

Although there is no cure for PAH, both supportive therapy and PAH-specific treatments can significantly improve clinical symptoms.1,2 Read more about the treatment and prognosis of PAH.

Pulmonary Hypertension Association UK (PHA UK), provides information, support and advice to people with PH. Further information about how PH impacts on patients and their families can be found on the PHA UK website.

This video, developed by PHA UK, offers an insight into how breathlessness can affect a patient’s life.


Clinical examination can detect signs of right heart dysfunction and may also suggest an underlying cause of PH.

Listening to the chest may reveal a loud pulmonary component of the second heart sound (P2), an RV third heart sound (S3), a pansystolic murmur caused by tricuspid regurgitation and/or a diastolic murmur due to pulmonary regurgitation.1

Physical signs include:1

  • Left parasternal heave
  • Elevated jugular venous pressure (JVP)
  • Hepatomegaly
  • Ascites
  • Peripheral oedema
  • Cool extremities

Examination may also point towards a cause of PH, for example, fine inspiratory crackles in interstitial lung disease or telangiectasia in scleroderma.1 Learn more about the different types of PH.



Assessing patients with PAH involves evaluating the severity of their disease using a range of clinical assessments, exercise tests, echocardiographic and haemodynamic assessments.

The clinical severity of PAH is classified according to the World Health Organization (WHO) Functional Classes (FCs) for patients with PH.1

This system grades PAH severity according to the functional status of the patient and links symptoms with activity limitations. The grades range from FC I, where the patient’s disease does not affect their day-to-day activities, to FC IV, where patients are severely functionally impaired, even at rest.5 FC remains a powerful predictor of outcomes in patients with PAH.1

FC Symptoms
I Patients with PH but without resulting limitation of physical activity. Ordinary physical activity does not cause dyspnoea or fatigue, chest pain or near syncope
II Patients with PH resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity causes undue dyspnoea or fatigue, chest pain or near syncope
III Patients with PH resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary activity causes undue dyspnoea or fatigue, chest pain or near syncope
IV Patients with PH with inability to carry out any physical activity without symptoms. These patients manifest signs of right heart failure. Dyspnoea and/or fatigue may even be present at rest. Discomfort is increased by any physical activity

Table 1. Severity of PH according to the WHO FC.5 Adapted from McGoon, Chest 2004


Patients are also stratified according to risk (low, medium or high) based on multiple variables, as recommended in the 2015 Joint European Society of Cardiology and European Respiratory Society guidelines, since no single variable provides definitive prognostic information.1

Regular assessment of a patient’s risk status via this multi-variable approach allows clinicians to monitor disease progression, prognosis and response to therapy.6


Clinical signs of heart failure
Progression of symptoms
Cardiopulmonary exercise testing (CPET)
N-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels
Imaging (echo, cardiovascular magnetic resonance [CMR])

Table 2. Parameters used in the assessment of risk in PH1



The severity of PAH can also be graded by the patient's exercise capacity. The 6-minute walk test (6MWT) is an important test in PAH management because it is a measure of the patient's functional limitation and correlates with peak aerobic capacity.7 It is also a simple test to perform, and is inexpensive and convenient. In addition to distance walked, dyspnoea on exertion and oxygen saturation can also be recorded, which can provide further information regarding the patient's condition.1


This video, developed by PHA UK, explains how a patient undertakes the 6MWT.




Cardiopulmonary exercise testing (CPET) assesses lung gas exchange and gives a more sensitive and comprehensive measure of exercise capacity than the 6MWT.8 It is a maximal stress test1 – the patient exercises to a level that progressively increases their symptoms to the maximum workload they can tolerate. It is therefore difficult to perform in patients with advanced disease. CPET may not be suitable for more severe patients who may not tolerate the exercise and may be exposed to risk of syncope and discomfort.

One important measure assessed using CPET is peak oxygen consumption (VO2 max),1 which is a measure of the ability of the cardiovascular system to transport oxygen to the tissues and the ability of the cells to use oxygen. It is important for assessing a patient's exercise capacity and maximal cardiovascular response. PAH patients show reduced VO2 max, and this measurement correlates with a patient's prognosis.8 CPET can add to the diagnostic and prognostic information provided by the 6MWT,1 but these tests are more difficult to perform and require specialist equipment.


  1. Galiè N, et al. Eur Heart J 2016;37:67–119
  2. Montani D, et al. Orphanet J Rare Disease 2013,8:97
  3. Humbert M, et al. Eur Respir Rev 2012;21(126):306–12
  4. Pulmonary Hypertension Association UK (2012). The impact of pulmonary arterial hypertension (PAH) on the lives of patients and carers: results from an international survey
  5. McGoon M, et al. Chest 2004;126(1 Suppl):14S–34S
  6. Raina A and Humbert M. Eur Resp Rev 2016;25:390–8
  7. Ross RM, et al. BMC Pulm Med 2010;10:31
  8. Wensel R, et al. Circulation 2002;106:319–24

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