What Is Pulmonary Hypertension?

  • Manal Andijani MSc genes and proteins in disease - Sheffield Hallam University, UK
  • Khushleen Kaur MSci Chemistry with a Year in Industry, Imperial College London, UK

Pulmonary hypertension also known as pulmonary artery pressure, is a condition that can be diagnosed very late as its symptoms are usually general. Pulmonary hypertension is characterised by high pressure inside the pulmonary arteries that carry the blood from the right side of the heart to the lung, it is a medical condition that should be taken seriously as it causes damage to the right side of the heart muscle which makes the heart weak and less efficient at pumping blood and oxygen to the other organs in the body, consequently causes shortness of breath, fatigue and dizziness. Symptoms can seriously affect the quality of life and prevent the patients from doing their daily and regular activities.


Pulmonary hypertension (PH) is defined as resting mean pulmonary artery pressure of ≥ 25 mm Hg. Pulmonary hypertension (PH) is characterised and defined as an increase in the pulmonary artery pressure. Patients with PH most commonly encounter dyspnea, exercise intolerance and/or right heart failure who have elevated pulmonary artery systolic pressure (PASP). It is common in the general population and linked to a high mortality rate.

The diagnosis of pulmonary hypertension is not straightforward and high pulmonary artery systolic pressure is not a sign of PH and not sufficient for the diagnosis and secondary causes of PASP most commonly left heart disease. Treatment of these diseases is challenging and may lead to worsening symptoms. As a result, improving symptoms in patients with pulmonary hypertension requires the following: 

  • understanding the use of echocardiography for the diagnosis of pulmonary hypertension
  • understanding the hemodynamic testing before starting pulmonary vasodilator therapy
  • Recognising the PH from pulmonary venous hypertension is due to left heart disease
  • understanding the proper treatment plan for pulmonary hypertension

Types of pulmonary hypertension

According to the Pulmonary Hypertension Association, pulmonary hypertension is divided into five groups based on different causes. The five groups are categorised by the World Health Organisation (WHO), and they are called PH WHO groups.

Pulmonary arterial hypertension  

The first WHO group is pulmonary arterial hypertension (PAH), where the lung arteries become thick and narrow, due to this the right side of the heart will be under more stress and has to work harder to push the blood through those narrowed arteries, in the long run, if the right-side heart keeps working hard and stayed under this stress, this will eventually cause the heart to lose its ability to pump enough blood through the lungs to the rest of the body.

Several types of PAH have been reported by WHO:

  • Idiopathic PAH which appears with no clear cause
  • Heritable PAH that is associated with inherited genes in the family
  • PAH can also develop associated with other diseases or medical conditions such as congenital heart diseases, live disease, HUV and lupus

It was also reported that PAH can also occur associated with certain lung drugs such as methamphetamine.

Pulmonary hypertension due to left heart disease

This group of PH is most common and occurs because of the left heart disease. In this group, the left heart side has a problem in squeezing or relaxing the left side valve, as a result, the left heart will not be able to keep up the blood returning from the lungs, therefore, causing it to return to the lung and increase the pressure.

Pulmonary hypertension due to lung disease

This PH form occurs due to chronic lung disease such as COPD or emphysema, where the lung airways are narrow and make it harder to exhale and the lungs can have a tough time expanding once inhaled. This tightening causes an increase in lung blood pressure.  

Pulmonary hypertension due to chronic blood clots in the lungs

WHO Group 4 is called chronic thromboembolic pulmonary hypertension (CTEPH). This group of PH can appear when blood clots accumulate in the lungs and the body is not able to dissolve it.

Pulmonary hypertension due to unknown causes

The last form of PH is the one associated with other diseases and secondary to other conditions including sarcoidosis, sickle cell anaemia and certain metabolic disorders.

Causes of pulmonary hypertension

The most common causes of pulmonary hypertension is due to left heart disease and lung disease. 

Signs and symptoms of pulmonary hypertension

The primary and major symptoms of every form of PH are progressive exercise dyspnea, fatigue and exhaustion. In most cases, there is a delay of months or even years between the appearance of symptoms and diagnosis. By the time the disease progresses, the symptoms become worse like dyspnea when bending and some new symptoms might occur. Patients with PH mostly experience frequent syncope or fainting, which is a clear life-threatening sign associated with high mortality.

Management and treatment for pulmonary hypertension

There are several different types of medicines that can be used to treat PH and other forms of pulmonary hypertension. Drugs can be used alone or in combination. Combination therapy can be introduced in sequence in order to improve long-term patients result. Two types of therapy can be stated:

Background therapy includes:

Anticoagulant medicines: patients with PH can experience venous thromboembolism, which is characterised by a blood clot forming in a vein. If this blocks one of the lungs veins, it will block the blood supply called a pulmonary embolism. Anticoagulant medicines such as warfarin may reduce the risk of thromboembolism.

Diuretic medicines are used to remove excess fluid by increasing urination.

Oxygen treatment can be administered if the oxygen level in the blood is low.

Digoxin is used to strengthen the heart muscle contractions and slow down heart rate, this can be used if or when pulmonary hypertension leads to heart failure.

Targeted therapy includes:

Bosentan tablets can be taken to improve symptoms and the ability to exercise and perform daily activities.

Iloprost can be taken through a nebuliser which turns a medicine into a mist to inhale, it may be prescribed to be taken six to nine times a day. A patient needs to stay in the hospital for up to three days to be trained on how to use a nebuliser and watch for symptoms or side effects.

Epoprostenol might be prescribed if the patient did not respond to any other medicinesand it is administered through an intravenous infusion.

Diagnosis of pulmonary hypertension

The diagnosis of pulmonary hypertension is usually difficult due to the similarity of the symptoms with other conditions. That means early detection of the condition might be delayed. Early detection and clear classification of the disease is the primary goal and tests include:

  • Echocardiogram
  • Electrocardiogram (ECG)
  • Chest X-ray
  • Lung function tests
  • Exercise test
  • Ventilation test
  • Blood test

When any of the above is done, the diagnosis can be confirmed after measuring blood pressure by a procedure called right-heart catheterisation. 

Prevention of pulmonary hypertension

While not all pulmonary hypertension can be prevented, steps can be taken to prevent it by making healthy lifestyle changes and self-care to prevent high blood pressure, coronary heart disease and lung diseases.


What are the stages of pulmonary hypertension?
Stages are stated based on the severity of the symptoms

  • The condition does not affect physical activities
  • The condition slightly limits physical activities
  • The condition significantly affects and limits physical activities
  • The patient is unable to do any physical activities 

Who is at risk of pulmonary hypertension?

People with a family history of the condition, overweight and obese, congenital heart disease patients, blood clotting patients and people who live at high altitudes.

How common is pulmonary hypertension?

Pulmonary hypertension is a rare disorder found in 15 to 50 persons per million.

When should I see a doctor?

When you are short of breath and experience an irregular heartbeat, you should see your GP even though symptoms can be similar to other conditions but sometimes can be life-threatening.  


Pulmonary hypertension has become treatable in the past 30 years with improved survival rates. The exact classification of PH is important in order to be treated. If left untreated it can lead to right heart failure and death but because of the advancement in technology and diagnosis approach, patients can be treated and the condition can be managed when diagnosed correctly and early.


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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Manal Andijani

MSc genes and proteins in disease, Sheffield Hallam University, UK

Experienced Research Specialist with a demonstrated history of working in the higher education institution, highly skilled in DNA sequencing, specifically Next generation sequencing and single-cell RNAseq. I have ten years of experience as a Research Specialist in Genomics laboratories and Stem cell and regenerative medicine. In addition, I am a qualified fitness personal trainer with an ambition to help women over 40 and with chronic conditions reach their health goals and maintain a healthy lifestyle.

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