How is Pulmonary Arterial Hypertension (PAH) diagnosed?

The early symptoms of Pulmonary Arterial Hypertension (PAH) - such as Dyspnoea, dizziness and fatigue - are often mild and are common to many other conditions. At rest there are often no symptoms of Pulmonary Arterial Hypertension (PAH) and no apparent signs of illness. As a result, diagnosis can be delayed for months or even years meaning that Pulmonary Arterial Hypertension (PAH) is frequently not recognised until the disease is relatively advanced. Pulmonary Arterial Hypertension (PAH) is often diagnosed only once other conditions have been investigated and ruled out.

The non-specific nature of symptoms associated with Pulmonary Arterial Hypertension (PAH) means that the diagnosis cannot be made on symptoms alone. A series of investigations is required to make an initial diagnosis of Pulmonary Arterial Hypertension (PAH), to refine that diagnosis in terms of clinical class of pulmonary hypertension (please click here for a classification of Pulmonary Hypertension) and to evaluate the degree of functional and haemodynamic impairment. Consequently, it can be useful to adopt a four stage approach to diagnosis of Pulmonary Arterial Hypertension (PAH):

1.	Clinical suspicion of Pulmonary Hypertension
	Breathlessness (dyspnoea) without overt signs of specific heart or lung disease Screening of patients with associated conditions (Connective Tissue Disease, Congenital heart disease, HIV, Sickle Cell Disease) Incidental findings on examination for other clinical reasons
2.	Detection of Pulmonary Hypertension
	ECG Chest radiograph, may show evidence of cardiomegaly and enlarged pulmonary arteries (Figure 3) Doppler echocardiogram (Figure 2)
3.	Identify other causes of Pulmonary Hypertension
	pulmonary function tests (PFTs) and arterial blood gas samples ventilation and perfusion lung scan high resolution computed tomography (HRCT) pulmonary angiography
4.	Pulmonary Arterial Hypertension (PAH) evaluation and classification (type, functional capacity, haemodynamics)
	blood tests and immunology, HIV test, abdominal ultrasound scan 6 minute walk test (6-MWT) and peak VO2 Right heart catheterisation and vasoreactivity testing.