18th February 2025

Diagnosis of pulmonary hypertension

Signs and symptoms of pulmonary hypertension

Symptoms are often non-specific and attributed to other conditions, which may themselves have caused the PH (e.g. chronic lung disease or left-sided heart disease). As a result, there is often a delay in diagnosis until the disease becomes severe.

The most common symptoms of PH are:

• Progressive exertional dyspnoea
• Fatigue and weakness
• Substernal chest pain
• Syncope or near syncope on exertion
• Symptoms of right-sided heart failure, e.g. peripheral oedema, abdominal swelling and bloating from ascites

Symptoms such as cough and palpitations can occur but are rarer. A hoarse voice may be a presenting feature of PH from compression of the left recurrent laryngeal nerve by a dilated main pulmonary artery; this is called Ortner’s syndrome.

Early-stage PH may manifest no physical signs. As the disease progresses, signs may develop, such as:

• Elevated JVP with prominent ‘a’ waves and prominent ‘v’ waves in significant tricuspid regurgitation
• Right ventricular heave
• Loud P2 on auscultation, which may be palpable
• Pansystolic murmur of tricuspid regurgitation
• Diastolic murmur of pulmonary regurgitation
• Signs suggestive of tricuspid regurgitation and right heart failure: pulsatile hepatomegaly, peripheral oedema, ascites
• Cyanosis 
• Signs of underlying causative disease, e.g. clubbing in ILD, sclerodactyly in systemic sclerosis

Investigations in pulmonary hypertension

The work up for PH is intended to confirm the diagnosis, assess severity and identify the underlying cause.

Echocardiography is recommended as the first-line non-invasive diagnostic investigation in suspected PH and right heart catheterisation (RHC) is the gold standard for diagnosis. However, there may be suggestive features on other investigations that raise suspicion of PH, and there are numerous other recommended investigations in the work up of PH to identify the cause.

Examples of these include:

• ECG – P pulmonale, right axis deviation, right ventricular hypertrophy, right bundle branch block
• Chest X-ray – right heart enlargement, pulmonary artery enlargement, pruning of peripheral vessels; there may also be signs of left heart disease or underlying lung disease
• Lung function testing – may be normal in early disease or show mild restrictive or obstructive disease in later disease stages; it may be abnormal if underlying lung disease is the cause of the PH
• Arterial blood gas – may show hypoxia and hypocapnia
• High-resolution CT chest – identify any underlying lung disease
• Overnight oximetry or polysomnography – to identify sleep-disordered breathing
• Ventilation-perfusion (VQ) scan – to exclude CTEPH as the cause of PH; a CT pulmonary angiogram may also be used, but VQ scanning is preferred as a normal VQ scan essentially excludes CTEPH with high sensitivity and specificity
• 6-minute walk test (6MWT) – helps establish a baseline and is useful for prognosis; those with a walk distance >440 m have a better prognosis
• Blood tests – there are no specific diagnostic blood tests; bloods may be done to screen for underlying disease such as liver function tests or a connective tissue disease screen; elevated NT-proBNP levels are associated with worse prognosis
• Abdominal/liver ultrasound – if liver cirrhosis/portal hypertension is suspected as the underlying cause

As mentioned, transthoracic echocardiography is the first-line investigation in suspected PH. It helps establish the probability of PH and can also help determine the subsequent required tests. Probability of PH is determined by the peak tricuspid regurgitation velocity (TRV) and presence of other features of PH on echocardiogram, e.g dilated right heart chambers. A peak TRV ≤2.8 m/s with no other features of PH suggests a low probability of PH, and a peak TRV of >3.4 m/s suggests a high probability of PH.

Right heart catheterisation (RHC) is the gold standard for diagnosing PH. RHC also allows for determining the contribution of left heart disease to PH and allows assessment of baseline severity and vasoreactivity testing, which is important for choosing treatment and monitoring the subsequent response. However, it is not always necessary to carry out RHC to confirm a diagnosis of PH: for example, in patients with severe left heart disease or severe lung disease with a high probability of PH on echocardiogram, a clinical diagnosis would suffice. However, RHC would be indicated if there is a discrepancy between echocardiogram and clinic suspicion of PH, where the contribution of left heart disease to PH is uncertain if the aetiology of PH remains undetermined after extensive non-invasive testing or where mixed aetiologies are suspected.