11/14/24, 10\:48 AM Pulmonary Hypertension

Pulmonary Hypertension

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Pulmonary hypertension (PH)\: mean pulmonary artery pressure >25mmHg at rest; umbrella term for diseases causing
increased pulmonary artery pressure.
Pulmonary arterial hypertension (PAH)\: subtype of PH, pre-capillary, absence of other causes; 97 cases per million in the
UK, most commonly due to left heart disease.
Aetiology\: narrowed, thickened, or damaged pulmonary arteries, or left heart disease reducing right heart
include PAH, left heart disease, lung disease, chronic thromboembolic disease, multifactorial mechanisms.
Risk factors\: pre-existing lung/heart disease, connective tissue disorders, obesity, sleep apnoea, high altitude exposure;
family history and female gender for PAH.
Symptoms\: shortness of breath, weakness, fatigue, chest pain, syncope, haemoptysis; initially exertional, can be at rest in
severe cases.
Examination
peripheral oedema, parasternal heave, elevated JVP, hepatomegaly.
Investigations\: echocardiogram (initial), right heart catheterisation (PAH), ECG (right ventricular strain), liver function tests,
autoimmune screen, chest X-ray, V/Q scan, CT chest, cardiac MRI, pulmonary function tests, genetic testing.
Management\: treat underlying cause, specialist referral for PAH; conservative measures (exercise, vaccinations,
contraception, support), medical management (diuretics, oxygen therapy, digoxin, anticoagulation, speci
cardiopulmonary transplantation in selected cases.
Complications\: right heart failure, peripheral oedema, severe exertional dyspnoea, pneumonia, sudden cardiac death.
Prognosis\: varies with underlying disorder; untreated idiopathic PAH at least 5 years, better prognosis than PAH with
systemic sclerosis.
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A comprehensive topic overview

Introduction

Pulmonary hypertension (PH) is a pathophysiological disorder occurring when mean pulmonary artery pressure is
>25mmHg at rest when assessed with right heart catheterisation.
Pulmonary hypertension is an umbrella term for many di
arteries.
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Pulmonary arterial hypertension (PAH) is a subtype of PH, characterised by pre-capillary pulmonary hypertension in the
absence of other causes (e.g. lung disease or other systemic diseases).
1
In the United Kingdom, the prevalence of PH has been reported as 97 cases per million. Left heart disease has been
reported as the most common cause.
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Aetiology

There are many causes of pulmonary hypertension and therefore pathophysiology depends on the underlying aetiology.
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In general, pulmonary hypertension occurs when the pulmonary arteries become narrowed (due to hypoxic pulmonary
vasoconstriction or thrombosis), thickened or damaged causing increased pressure in the vessels.
In addition, left heart disease can reduce
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pressure.
Table 1. An overview of the subtypes of pulmonary hypertension.
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Subtype Description
Pulmonary arterial hypertension (PAH)
Pulmonary hypertension due to left
heart disease
Pulmonary hypertension due to lung
disease
Chronic thromboembolic pulmonary
hypertension (CTEPH) and other
pulmonary artery obstructions
Pulmonary hypertension with
unclear/multifactorial mechanisms
Can be idiopathic (IPAH), inherited,
associated with other systemic diseases
(e.g. HIV or connective tissue
disordered) or medication-related (e.g.
selective serotonin reuptake inhibitors)
Left heart disease includes left
ventricular dysfunction (both systolic
and diastolic), valve disease,
in
congenital cardiomyopathies.
Causes include chronic obstructive
pulmonary disease,
interstitial lung disease
, obstructive sleep apnoea and chronic
high-altitude exposure.
Caused by obstruction of the vascular
bed (e.g. due to chronic pulmonary
embolism).
Rarer causes include intravascular
tumours and arteritis.
Can be associated with conditions
including\:
Myeloproliferative disorders
Sarcoidosis
Glycogen storage disease
Chronic renal failure

Risk factors

Risk factors are related to the subtype of PH (Table 1) and may include\:
Pre-existing diseases\: lung disease, left heart disease, congenital heart disease, connective tissue disorders
Obesity and sleep apnoea
Altitude\: prolonged exposure to high altitude
Risk factors for pulmonary arterial hypertension include family history and female gender.
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Clinical features

History

Symptoms of PH are related to gradually worsening right ventricular function. Initially, symptoms are worse on exertion
but can occur at rest in severe cases.
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Typical symptoms of PH include\:
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Shortness of breath
Weakness and fatigue
Chest pain
Syncope
Haemoptysis (uncommon but may be present in chronic thromboembolic disease or due to abnormal distribution of
blood
It is also important to ask about family history of PAH and medication history (including SSRIs and weight loss medication).

Clinical examination

In the context of PH, a thorough cardiovascular examination is required.
Typical clinical
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Loud pulmonary component of S2
Third heart sound
Pansystolic murmur (tricuspid regurgitation) and diastolic murmur (pulmonary regurgitation)
In later stages of PH, clinical
Ascites and peripheral oedema
Parasternal heave
Elevated jugular venous pressure
Hepatomegaly
There may be clinical features speci
disease or interstitial lung disease).

Investigations

The most useful initial investigation in suspected cases of pulmonary hypertension is an echocardiogram to estimate
pulmonary pressure. In cases of suspected pulmonary arterial hypertension, right heart catheterisation is usually
performed.

Bedside investigations

Relevant bedside investigations include\:
ECG\: to look for evidence of right ventricular strain including right ventricular hypertrophy, right axis deviation, right
bundle branch block, and arrhythmias (atrial
not exclude PH.
1

Laboratory investigations

Relevant laboratory investigations include\:
Liver function tests\: to assess for liver disease
Serology\: to look for HIV and hepatitis
Autoimmune screen\: to look for evidence of connective tissue disease (e.g. anti-centromere antibodies and U3-RNP in
scleroderma)
Arterial blood gas\: to look for evidence of respiratory disease

Imaging

Relevant imaging investigations include\:
Chest X-ray\: to assess for signs of underlying lung disease or left ventricular dysfunction (pulmonary venous congestion).
PAH may present with central pulmonary arterial dilatation,
‘pruning’ of peripheral vessels, right atrial and ventricular
enlargement (later stages). A normal chest X-ray does not exclude PH.
1
Echocardiography\: to assess right ventricular function and estimate pulmonary arterial pressure.
Ventilation/perfusion (V/Q) scan and/or CT chest\: to look for chronic thromboembolic disease or other underlying lung
diseases. A CT may also be helpful for prognostication.
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Cardiac MRI\: to help assess cardiac structure and function, and assist with prognostication.
Figure 1. Chest X-ray showing enlarged pulmonary arteries, pruning of peripheral
pulmonary vessels and cardiomegaly in pulmonary arterial hypertension.
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Other investigations

Other relevant investigations include\:
Pulmonary function tests and overnight oximetry\: to look for signs of underlying lung disease as an aetiology. PAH can
lead to mild/moderate reduction in lung volumes.
Right heart catheterisation\: used to diagnose PAH, assess severity and guide treatment.
Genetic testing\: in speci

Management

Management varies depending on the underlying cause of PH.
It is important to treat the underlying cause and refer to specialist services for PAH or severe PH.
1

Conservative management

All patients should be advised on the following conservative measures\:
1
Exercise (within symptom limits) and rehabilitation
In
Contraceptive advice (pregnancy is associated with 30-50% mortality in PAH patients)
Psychosocial support

Medical management

Medical management di
For patients with PAH, medical management has uncertain long-term outcomes. Options that may be considered under
specialist guidance include\:
1
Diuretics\: for symptomatic bene
Long term oxygen therapy including ambulatory oxygen.
Digoxin\: improves cardiac output acutely but has unknown e
Oral anticoagulation\: there is thought to be increased risk of thrombosis intrinsically as part of the disease process and
through comorbid factors including immobility and heart failure.
Speci
inhibitors (e.g. sildena

Cardiopulmonary transplantation

Cardiopulmonary transplant is used in selected cases. There is a good prognosis with long term immunosuppressive
therapy.
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Complications

Complications relate to worsening right heart failure and include\:
Peripheral oedema
Severe exertional dyspnoea
Pneumonia and sudden cardiac death (including during childbirth) can also occur.
3

Prognosis

Prognosis in untreated idiopathic PAH has been reported recently as at least 5 years and has a better prognosis than PAH
associated with systemic sclerosis.
PH has a varying prognosis depending on the underlying disorder.
3

References

European Society of Cardiology/European Respiratory Society. 2 0 1 5 E S C / E R S G u i d e l i n e s f o r t h e d i a g n o s i s a n d t r e a t m e n t
o f p u l m o n a r y h y p e r t e n s i o n . Published in 2015. Available from\: [LINK].
British Lung Foundation. W h a t c a u s e s p u l m o n a r y h y p e r t e n s i o n ? Published in 2019. Available from\: [LINK].
Tidy C. P u l m o n a r y H y p e r t e n s i o n . Patient.info. Published in 2015. Available from\: [LINK].
Galiè N et al. P u l m o n a r y a r t e r i a l h y p e r t e n s i o n a s s o c i a t e d t o c o n n e c t i v e t i s s u e d i s e a s e s . Published in 2005. Available from\:
[LINK].
Pulmonary Hypertension Association. R i s k f a c t o r s . Published in 2017. Available from\: [LINK].
Dr Bernardo Jose Meza / Radiopaedia.org. ‘ P u l m o n a r y h y p e r t e n s i o n’
. License\: [CC-BY-NC-SA]. Available from\: [LINK].
Toyoda Y et al. L o n g-t e r m o u t c o m e o f l u n g a n d h e a r t-l u n g t r a n s p l a n t a t i o n f o r i d i o p a t h i c p u l m o n a r y a r t e r i a l h y p e r t e n s i o n .
The Annals of Thoracic Surgery. Published in 2008. Available from\: [LINK].

Reviewer

Dr Alison Moody
Respiratory Consultant
North Devon District Hospital

Related notes

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Bronchiectasis
Chronic Obstructive Pulmonary Disease (COPD)
Croup
Cystic Fibrosis

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Contents

Introduction
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Aetiology
Risk factors
Clinical features
Investigations
Management
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