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Pulmonary Hypertension

Pulmonary Hypertension: What is it, Symptoms, Causes & Risk Factors, Treatments | NHCS

Pulmonary Hypertension - What is it for

lung illustration

Pulmonary hypertension refers to high blood pressure in the lungs. It is a complex health condition and a relatively rare disease that affects people of different ages and ethnic groups.

The rare lung disorder occurs when the blood pressure in the pulmonary arteries rises far above normal levels and the walls of the pulmonary arteries become thicker. There are many different types of pulmonary hypertension and sometimes, the cause is unknown.

The detailed pulmonary hypertension processes are:

  1. Vasoconstriction or narrowing of the blood vessels of the lungs slow down the blood flowing through the lungs where it picks up oxygen
  2. Proliferation or scarring of the blood vessel walls causes them to stiffen and become thicker, further restricting the blood flow
  3. These changes make it more difficult for blood to circulate back through the lungs, causing added stress to the heart as it pumps harder to overcome the resistance

Pulmonary Hypertension - Symptoms

The common symptoms may include:

  • Shortness of breath during activity
  • Fatigue and weakness
  • Dizziness and fainting spells
  • Swelling in the legs or ankles
  • Lightheadedness during activity
  • Chest pain, particularly during exercise
  • Abdominal swelling or discomfort

The symptoms of pulmonary hypertension are similar to those of other more common heart and lung problems. For this reason, diagnosis for pulmonary hypertension can be challenging and patients and doctors might overlook the condition until symptoms become severe. Further investigation is needed for an accurate diagnosis.

Pulmonary Hypertension - How to prevent?

Pulmonary Hypertension - Causes and Risk Factors

There are three causes for this abnormal narrowing:

  • The muscles within the walls of the arteries may contract or squeeze, making it harder for blood to flow through them
  • The walls of the arteries may thicken from too much cell growth in the lining of the vessels
  • Tiny blood clots may form within the smaller arteries, blocking blood flow

arteries illustration

Any of these changes in the body will make it difficult for blood to pass through the lungs. When that happens, the heart is forced to work very hard, resulting in the eventual weakening of the heart muscle and the loss of its ability to pump blood efficiently.

There are several subtypes of pulmonary hypertension and they are categorised according to various causes ranging from genetic mutations to unknown causes.

Pulmonary Hypertension - Diagnosis

In the early stages of the disease, a patient’s physical examination results may appear almost normal. To establish a diagnosis, doctors may order a series of tests to measure the lung pressure and the function of the patient’s heart and lungs. These tests are done at the same time to accurately narrow down the heart condition(s) causing the symptoms.

nhcs cardiac lab test echo

  • ​Chest X-Ray (of the heart and lungs)
  • Electrocardiogram
  • Echocardiogram (an ultrasound of the heart to help determine its structure and how well it functions)
  • Right-heart catheterisation (the cardiologist inserts a special tube through a vein into the heart and lung vessels to measure the lung pressure and test how well the heart is pumping)
  • Lung/pulmonary function tests (to measure lung function)
  • Perfusion lung scan (an imaging of blood flow through the lungs)
  • Six-minute walk test (a measurement of how far a patient can walk within six minutes)

How serious is pulmonary hypertension?


Even though there is no known cure for or prevention against pulmonary hypertension, the condition is still treatable.

According to the American Lung Association, approximately 50 per cent of people diagnosed with pulmonary hypertension die within five years. For those whose condition is left untreated, the average survival is shortened to about three years.

Even with treatment, the high blood pressure in the lung arteries will continue to worsen and make daily activities more difficult. Adopting lifestyle modifications, however, may help patients with pulmonary hypertension get through their daily routine.

Cardiologists refer to the World Health Organization (WHO) Functional Classification to identify the severity of pulmonary hypertension in patients and decide on suitable treatments.

Functional status is a person’s ability to perform daily activities and is ranked from Class I (no limitations) to Class IV (unable to perform any physical activity). Below are the brief descriptions of the four NYHA functional classes.

  • WHO Class I: No limitation of usual physical activity; ordinary physical activity does not cause increased breathing problems, fatigue, chest pain or lightheadedness.
  • WHO Class II: Mild limitation of physical activity; there is no discomfort when at rest, but normal physical activity causes increased breathing problems, fatigue, chest pain or lightheadedness.
  • WHO Class III: Marked limitation of physical activity; there is no discomfort when the person is at rest, but less than ordinary physical activity causes increased breathing problems, fatigue, chest pain or lightheadedness.
  • WHO Class IV: Unable to perform any physical activity and possible signs of heart failure in the right ventricle (the heart chamber that pumps blood to the lungs); at rest, patients have difficulty breathing and/or fatigue, and symptoms get worse with almost any physical activity. History of fainting will place patients in NYHA Class IV even if their limitations in activity is categorised under NYHA Classes II or III.

Clinical classification of pulmonary hypertension

1.Pulmonary arterial hypertension

1. Idiopathic
2. Heritable
  • BPMR2 mutation
  • Other mutations
  • Drugs and toxins induced
3. Drugs and toxins induced
4. Associated with:
  • Connective tissue disease
  • Human immunodeficiency virus (HIV) infection
  • Portal Hypertension
  • Congenital heart disease
  • Schistosomiasis
1’ Pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis

1. Idiopathic
2. Heritable
  • EIF2AK4 mutation
  • Other mutations
3. Drugs, toxins and radiation induced
4. Associated with:
  • Connective tissue disease
  • (HIV) infection

1” Persistent pulmonary hypertension of the newborn

2. Pulmonary hypertension due to left heart disease

1. Left ventricular systolic dysfunction
2. Left ventricular diastolic dysfunction
3. Valvular disease
4. Congenital/acquired left heart inflow/outflow tract obstruction and congenital cardiomyopathies
5. Congenital/acquired pulmonary veins stenosis

3.Pulmonary hypertension due to lung diseases and/or hypoxia

1. Chronic obstruction pulmonary disease
2. Interstitial lung disease
3. Other pulmonary diseases with mixed restrictive and obstructive pattern
4. Sleep-disordered breathing
5. Alveolar hypoventilation disorders
6. Chronic exposure to high altitude
7. Developmental lung diseases

4. Chronic thromboembolic pulmonary hypertension and other pulmonary artery obstructions

1. Chronic thromboembolic pulmonary hypertension
2. Other pulmonary artery obstructions
  • Angiosarcoma
  • Other intravascular tumours
  • Arteritis
  • Congenital pulmonary arteries stenosis
  • Parasites (hydatidosis)

5. Pulmonary hypertension with unclear and/or multifactorial mechanisms
1. Haematological disorders: chronic haemolytic anaemia, myeloproliferative disorders, splenectomy
2. Systemic disorders: sarcoidosis, pulmonary histiocytosis, lymphangioleiomyomatosis neurofibromatosis
3. Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders
4. Others: pulmonary tumoral thrombothic microangiopathy, fibrosing mediastinitis, chronic renal failure (with/without dialysis), segmental pulmonary hypertension

Extracted from the ESC/ERS Guidelines published on 15 September 2015

Pulmonary Hypertension - Treatments

​Treatments for pulmonary hypertension, such as medications and surgery, are aimed at relieving symptoms, improving quality of life, and slowing down the disease progression. Doctors will also treat the underlying disease for patients whose pulmonary hypertension is caused by another medical condition. In addition, patients will need to change their lifestyle when their symptoms become worsen or when their daily activities are limited


medication pharmacy

There are several types of medications available for the treatment of pulmonary hypertension. They are mainly formulated to reduce the workload of the heart and improve blood flow through the lung vessels.

Doctors may prescribe the medications based on the patients’ severity of the condition and how well they respond to treatment.

The medications typically prescribed for pulmonary hypertension include:

  • Anticoagulants to prevent blood clots from forming in the lung vessels
  • Calcium channel blockers to reduce constriction in the pulmonary vessels
  • Diuretics to reduce the volume of blood the heart needs to pump
  • Digoxin to help the heart pump blood more effectively
  • Inhaled oxygen to reduce shortness of breath
  • Endothelin receptor antagonists (ERAs) such as bosentan and macitentan to suppress the harmful effects of endothelin, a hormone that helps to control blood flow and cell growth in blood vessels
  • Phosphodiesterase-5 inhibitors (PDEI), such as sildenafil and tadalafil, to relax and reduce abnormal cell growth in blood vessels
  • Prostacyclins, including inhaled iloprost and epoprostenol, to relax the blood vessels, lower abnormal cell growth and help prevent blood clots

Cardiovascular procedures and surgeries

Doctors may recommend procedural or surgical treatment for pulmonary hypertension patients based on many factors.

nhcs cath lab

These procedures and surgeries include:

  • Pulmonary endarterectomy: This may be considered as treatment for chronic thromboembolic pulmonary hypertension (CTEPH). It involves removing blood clots from the pulmonary arteries, to restore blood flow to the lungs.
  • Balloon pulmonary angioplasty: This is a non-surgical option for patients with CTEPH who are not suitable for pulmonary endarterectomy.
  • Atrial septostomy: This procedure involves creating a hole between the top chambers of the heart to reduce the effects of high lung pressure in overworking the right side of the heart.
  • Lung or heart and lung transplantation: Patients who do not respond to standard treatments may be considered for heart and/or lung transplantation. While this major surgery can be life-saving, the availability of donor organs is extremely limited.

Lifestyle modifications

Pulmonary hypertension is a lifelong condition, thus patients with the condition may need to modify their living space and daily activities when symptoms worsen. They may also need assistance around the house due to their limitations.

Lifestyle modifications for pulmonary hypertension patients include:

  • Finding resources to ease daily and weekly house chores
  • Limiting climbing of stairs
  • Modifying showers and baths with easily reachable faucets and shower racks (for soap, shampoo, etc.)
  • Making laundry areas more accessible
  • Rearranging kitchen tools for easy access
  • Managing the daily needs of children, from transportation to school and preparation of meals
  • Arranging for regular and emergency child care
  • Securing handicapped parking
  • Managing family outings and home activities

family cycling

Pulmonary Hypertension - Preparing for surgery

Pulmonary Hypertension - Post-surgery care

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