What is Normal Pulmonary Artery Pressure?

What is Normal Pulmonary Artery Pressure?

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. According to the World Health Organisation (WHO), each year, nearly 17.9 million people succumb to CVDs. High blood pressure or hypertension is one of the main risk factors for CVDs.

Pulmonary hypertension is a specific condition in which the pressure in the vessels supplying blood from the heart to the lungs is higher than normal.

To understand pulmonary hypertension, let us first look at how the heart and lungs function. The heart is made up of 4 chambers – the two atria and the two ventricles. Venous circulation brings deoxygenated blood from the various organs to the right side of the heart. This blood goes through the right ventricle and is pumped into the lungs. Here carbon dioxide is released, and the blood absorbs oxygen. Now, this oxygenated blood travels back to the heart. It passes through the left atrium into the left ventricle and is sent to the various organs through the aorta.

The main blood vessels that connect the heart and lungs are the pulmonary artery and the pulmonary vein. The pulmonary artery carries blood from the heart to the lungs, and the pulmonary veins carry freshly oxygenated blood from the lungs back to the heart.

When the blood flow in the pulmonary artery or its branches is constricted and reduced, the pressure in these vessels starts to build up. When the condition causes higher than normal pulmonary artery pressure in the long term, it is referred to as pulmonary hypertension.

Types of Pulmonary Hypertension

Pulmonary hypertension may be caused by various health conditions and disorders. Depending on the underlying cause, pulmonary hypertension is classified into five different groups.

Group 1 – Pulmonary arterial hypertension (PAH)

PAH refers to increased pressure in the small arteries of the lungs. This could be caused by –

  • Unknown causes (idiopathic PAH)
  • Genetic factors
  • Use of recreational drugs and narcotics
  • Congenital heart disease
  • Autoimmune diseases such as scleroderma
  • Infections such as HIV

Group 2 – Pulmonary Hypertension caused by left-sided heart disease

This is usually the result of –

  • Left-sided heart diseases such as a mitral valve or aortic valve disease
  • Conditions affecting the left ventricle

Group 3 – Pulmonary Hypertension caused by underlying lung diseases 

Lung problems that can lead to pulmonary conditions include –

  • Chronic obstructive pulmonary disease (COPD)
  • Scarring of lung tissue (pulmonary fibrosis)
  • Emphysema
  • Obstructive sleep apnoea
  • Long-term exposure to high altitudes

Group 4 – CTEPH (chronic thromboembolic pulmonary hypertension)

  • Pulmonary hypertension can also be caused by the formation of pulmonary emboli or blood clots in the lungs. Chronic clots can form scar-like tissue, narrowing the arteries and restricting blood flow.
  • In some cases, CTEPH is completely reversed through pulmonary thromboendarterectomy (PTE) surgery.

Group 5 – Pulmonary Hypertension caused by other health conditions/disorders

This group includes pulmonary hypertension caused by a number of diseases, including –

  • Blood disorders such as polycythaemia vera and essential thrombocythemia
  • Inflammatory disorders such as sarcoidosis and vasculitis
  • Metabolic disorders such as thyroid dysfunction and glycogen storage disease
  • Kidney diseases
  • Tumours pressing against the pulmonary arteries

Eisenmenger syndrome

Eisenmenger syndrome is a complication of having a ventricular septal defect. This occurs when there is a hole between two ventricles. This condition also causes pulmonary hypertension.

Signs & Symptoms of Pulmonary Hypertension

Some of the common signs and symptoms of pulmonary hypertension include –

  • Shortness of breath during regular activity
  • Chest pain
  • Fatigue
  • Heart palpitations

As the disease progresses, it could cause increased distress and symptoms such as –

  • Oedema or swelling around ankles
  • Fainting or syncope
  • Bluish lips due to lack of oxygen

With Pulmonary Arterial Hypertension, the reduced blood flow to the lungs raises the blood pressure in the arteries. As a result, the heart pumps harder to meet the body’s need for oxygenated blood. In the long run, this leads to the weakening of heart muscle and heart failure.

Medical Evaluation

Normal pulmonary artery pressure ranges between 8 and 20 mm Hg at rest. If the pulmonary arterial pressure is greater than 25 mm Hg at rest or 30 mmHg during physical activity, the condition is referred to as Pulmonary Hypertension.

Factors that can increase the risk of developing pulmonary hypertension include –

  • A personal or family history of blood clotting disorders
  • Chronic exposure to asbestos
  • Chronic exposure to high altitude
  • Congenital heart disease
  • Excess weight/obesity
  • Family history
  • Prolonged use of selective serotonin reuptake inhibitors (SSRIs)
  • Use of narcotics or recreational drugs

Diagnosis and Testing for Pulmonary Hypertension

The diagnosis of pulmonary hypertension may often present several challenges. This is because the condition develops slowly over time and is not immediately recognisable. Apart from this, the signs and symptoms of pulmonary hypertension overlap with several conditions such as asthma, COPD or other heart and lung conditions.

Your internal medicine specialist, pulmonologist, or cardiologist may diagnose pulmonary hypertension based on your symptoms, risk factors, and personal or family medical history.

If you present with the symptoms of pulmonary hypertension, your doctor may recommend one or more of the following tests to confirm the diagnosis –

  • Echocardiograph
  • Chest x-ray
  • Electrocardiogram (EKG)
  • Right heart catheterisation

The series of tests recommended by the doctor may also involve ascertaining the underlying cause of the condition. This can be done through –

  • Blood tests
  • Chest CT scan
  • Chest MRI
  • Lung function tests
  • Lung perfusion scan
  • Polysomnogram (PSG)

Once the doctor reaches the diagnosis of pulmonary hypertension, it is important to understand the severity or extent of the condition. Exercise testing is the standard for determining this. A treadmill test may be administered to check pulmonary and cardiac functions during physical activity.

Treatment Options and Therapies

There is no cure for pulmonary hypertension. Some cases of CTEPH can be reversed through surgery. Treatment protocols involve easing the symptoms and improving pulmonary and cardiac functions in all other cases. If An underlying disorder or condition causes pulmonary hypertension, treatment may involve resolving the cause.

Currently, the medical treatment of pulmonary hypertension involves the administration of –

  • Vasodilators that lower pulmonary blood pressure
  • Blood thinners or anticoagulants that improve blood flow and prevent clotting
  • Diuretics that remove excess fluid
  • Potassium replacement to replenish electrolyte loss
  • Inotropic agents improve cardiac function
  • Oxygen therapy helps improve symptoms

Surgical treatment options –

  • In some cases, surgical removal of blood clots through pulmonary thromboendarterectomy can restore the blood flow to the lungs, thus reversing the condition.
  • Lung transplants and heart/lung transplants are often recommended as the surgical treatment option for those suffering from severe pulmonary hypertension. However, the acute shortage of donor organs makes this a limiting option.

Lifestyle Changes

Living a healthy, disciplined, and active life can be just as important as medication when it comes to managing pulmonary hypertension.

  • Dietary changes include adding foods that are high in micronutrients such as potassium, magnesium, and vitamins.
  • Losing excess weight can help ease some of the symptoms of pulmonary hypertension.
  • Eliminating foods high in sugar, salt, and cholesterol content helps maintain health and keep symptoms in check.
  • Eliminating tobacco use and restricting the intake of alcohol are highly recommended.
  • It is best to avoid OTC medicines to prevent drug interaction. Keep a record of your medication. Consult the doctor in case of any adverse reaction or increase in severity of symptoms.
  • Having a robust support system in place is essential for those suffering from pulmonary hypertension.
  • Staying active is important, but it is best to avoid heavy lifting and strenuous exercise. These may cause more harm than good.

Factors that can affect pulmonary artery pressure

While most cases of pulmonary hypertension cannot be cured, following a healthy lifestyle and punctiliously following the treatment protocol offered by your doctor at Max Hospital can enable you to lead a long and active life.  

Several factors can exacerbate pulmonary hypertension. Therefore, it is necessary to discuss any possible triggers with your doctor. For example, the use of over the counter (OTC) medication can elevate normal pulmonary artery pressure. This makes it important to discuss any medication or supplements you take with your doctor.

Similarly, several vaccines can also worsen pulmonary hypertension. If you are pregnant or intend to conceive, it is best to discuss the risks and management of your condition with your doctor.

It is important to remember that while it may not be possible to cure pulmonary hypertension, leading a long and fulfilling life is possible. Therefore, it is essential to regularly monitor health parameters and stay in touch with your doctors.

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