Key learning points:
- Understanding pulmonary hypertension
- Recognising patients that might have pulmonary hypertension
- Investigations to carry out when this is suspected
Pulmonary hypertension (PH) is a chronic condition affecting more than 6,000 people in the UK, although many more are thought to live with it undiagnosed. PH is an intricate condition and little known outside of a specialised setting. It is defined as the elevation of blood pressure in the pulmonary circulation, and should be suspected in patients who have elevated pulmonary pressures on a routine echocardiogram.
Unfortunately, PH can be masked and a delay in diagnosis is common as the signs and symptoms are similar to more common conditions such as asthma, COPD or heart conditions such as angina. It is reported that the mean time to diagnosis of PH is 2.5 years. The National Institute for Health and Care Excellence (NICE) states that untreated PH leads to a progressive increase in pulmonary vasculature resistance, right heart failure and death.1
It is important to raise awareness about PH so that if it is suspected, further investigations can be organised and a referral made to a specialist centre. This enables consideration for specific treatments for PH, which can help patients who are symptomatic.
The British Journal of Cardiology categorises the types of PH according to their manifestations.2 These are:2
1. Pulmonary arterial hypertension, this includes two subtypes: a) pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis and b) persistent PH of the newborn.
2. PH resulting from left heart disease.
3. PH due to lung diseases and/or hyoxia.
4. Chronica thrombeombolic PH and other pulmonary artery onstructions.
5. PH with unclear and/or multifactorial mechanisms.
In some forms of PH (groups 1 and 4) specific therapies are available that work on the pulmonary arteries. However, in other forms of PH the rise in the mean pulmonary artery pressure (mPAP) is secondary to other conditions such as left heart disease and lung disease (groups 2 and 3).
In primary care, it is unusual to see a patient with group 1 or 5 PH. The common types of PH seen in the community are groups 2, 3 and 4. In patients with group 2 and 3 it is important that treatment is focused on the underlying condition that is causing PH.
Diagnosis
Early diagnosis is important as advanced disease is linked to a poorer prognosis. The main symptom is dyspnoea. Other common symptoms include dizziness, syncope or pre-syncope on exertion, chest pain, palpitations, peripheral oedema, ascites and fatigue. These symptoms occur because of the right ventricle’s inability to pump enough blood through the lungs. As PH progresses, the right ventricle begins to fail and cannot meet the needs of the body, resulting in breathlessness at rest or on minimal exertion.
There are a number of physical signs associated with PH that primary care nurses should look out for: peripheral oedema, hepatomegaly, cool extremities, cyanosis and jugular vein distension.
If a primary care practitioner has a patient who presents with PH signs and symptoms and their history and family history makes it likely, this warrants further investigations, which can be done in the community.
Blood tests
Routine screening of biochemistry, haematology and thyroid function should be performed. Also, specific tests or investigations for underlying causes of PH such as immunology screening for connective tissue disease or HIV. A brain natriuretic peptide (BNP) is a marker that can be used to assess the disease severity and prognosis.3
Standard 12-lead ECG
This may provide evidence of PH by illustrating right ventricular hypertrophy and right atrial dilatation. However, patients with mild PH may have an entirely normal ECG.
Chest X-ray
This shows an image of the heart and lungs. A patient with signs of pulmonary hypertension on a chest X-ray will most likely have a large right ventricle which will be clear to see on X-ray. This may also show enlarged pulmonary arteries depending on the severity of PH.
A chest X-ray can also show conditions that may be causing PH, for example chronic obstructive pulmonary disease (COPD).
2D echocardiogram
An echocardiogram will examine the size and functioning of the right ventricle and the thickness of its wall. It also gives an estimation of the mPAP and helps determine if a referral to a PH centre is appropriate.
If the echocardiogram shows an estimated mPAP greater than 25mmHg and there is no other cause for the rise in pulmonary pressures, it would be reasonable to refer to your local PH specialist or centre.
Following this referral it is most likely that the team will do other non-invasive investigations prior to performing a right heart catheter (RHC).
CT scan
This is useful to assess the lungs, and is often completed in the form of a CT pulmonary angiogram, to rule out thromboembolic disease as the cause of PH. Any evidence of airways disease or interstitial lung disease as a possible cause for PH can be reviewed.
Right heart catheter
This is the gold standard for PH diagnosis and is defined by an mPAP of more than 25mmHg. The procedure can be done as a day case under local anaesthetic. There are minimal potential risks.
Causes of PH
Examples of group 1 disorders include idiopathic PH, PH associated with genetic factors, connective tissue disorders (eg systemic lupus erythematosus), congenital heart diseases, portal hypertension, HIV.4 Advanced pulmonary vasodilator therapy is given to these patients.
Group 2 disorders consist of left heart disease, eg valvular disease and atrial or ventricular dysfunction.
Group 3 diseases cause pulmonary hypertension in association with lung disease or hypoxaemia, eg COPD, interstitial lung disease or sleep disordered breathing.
Groups 4 and 5 include other rare causes such as histiocytosis, post splenectomy and glycogen storage disease.4
Treatment
Treatment depends on various factors, including the mPAP and whether the PH is due to left heart disease. In general, if PH is secondary to other conditions, the primary ailment should be treated with the focus medical optimisation. If the RHC reveals that the PH is either group 1 or 4, oral treatment can be considered in the form of advanced pulmonary vasodilation therapies.
There is, unfortunately, no cure for PH, but the targeted therapies aim to improve quality of life and slow down progression of the disease.
Conclusion
PH is a progressive and life-changing disease but not well known outside of a specialised setting. Once a diagnosis is made, patients should be managed in a dedicated centre with experienced nurses and clinicians.
There are new therapies on the horizon, and understanding and recognising the disease will aid this development to help future patients.
References
1. National Institute for Health & Clinical Excellence. Pulmonary Hypertension Association UK, Appraisal of the drug treatments used in Pulmonary Arterial Hypertension (PH), 2007. nice.org.uk/guidance/gid-tag382/documents/pulmonary-arterial-hypertension-association-uk4 (accessed 15 August 2016).
2. The British Journal of Cardiology. Focus on Pulmonary Hypertension. https://bjcardio.co.uk/2015/10/focus-on-pulmonary-hypertension/ (accessed 16 August 2016).
3. Pulmonary Hypertension Association UK. Living with PH. phauk.org/(accessed 16 August 2016).
4. Madden BP. Pulmonary arterial hypertension (adults) – drugs [ID12]. European Cardiology Review, 2015.
