Pulmonary hypertension – Types, Causes and Treatment

Definition

Pulmonary Hypertension is a term to describe a rare disease in which the blood pressure in the lungs (pulmonary artery system) is higher than normal. The blood pressure that is measured on your arm by a cuff reflects systemic or your body’s blood pressure. Normal systemic blood pressure is 120/80 mmHg. Normal blood pressure within the lungs is much lower and much more difficult to evaluate. Normal blood pressure in the lungs is 15 -25 mmHg, or about 1/5th the bodies blood pressure.

Pulmonary Hypertension results when the blood vessels constrict (tightens). Over time this constriction causes fibrosis (scars) of the vessel and higher pulmonary blood pressure. The chambers on the right side of the heart (right atrium and right ventricle) have difficulty pumping blood out to the pulmonary artery and through the lungs. The strain on the heart to overcome this high pressure and constriction causes the heart to become enlarged and weak. Eventually the heart cannot keep up with the body’s demands. This is known as heart failure.

Types of Pulmonary Hypertension

Pulmonary hypertension is divided into 5 categories:

Pulmonary arterial hypertension involves destruction or narrowing of the pulmonary artery due to inherited or unknown causes, some drugs or toxins, and certain medical conditions, including connective tissue diseases, HIV, liver cirrhosis, congenital heart disease, and a parasitic infection called schistosomiasis.

Pulmonary hypertension due to heart disease involves increased pressure in the blood vessels of the lung from heart failure or problems with the heart valves.

Pulmonary hypertension due to lung disease is caused by low oxygen levels from lung illnesses (such as chronic obstructive pulmonary disease or progressive lung scarring due to interstitial lung disease) or from other medical conditions (such as sleep apnea).

Pulmonary hypertension due to blockage of blood vessels typically involves large blood clots in the lungs but may also be due to tumors within or externally compressing the pulmonary artery.

Pulmonary hypertension due to other causes includes other medical conditions, such as some blood disorders (such as sickle cell disease), certain systemic diseases (such as sarcoidosis), chronic kidney disease, and complex congenital heart disease.

Risk factors

Pulmonary hypertension is more often diagnosed in people ages 30 to 60. Growing older can increase the risk of developing pulmonary arterial hypertension (PAH). However, idiopathic PAH is more common in younger adults.

Other things that can raise the risk of pulmonary hypertension include:

• A family history of the condition
• Being overweight
• Blood-clotting disorders or a family history of blood clots in the lungs
• Exposure to asbestos
• Use of certain weight-loss drugs
• Congenital heart disease
• Use of illegal drugs such as cocaine
• Living at a high altitude
• Use of selective serotonin reuptake inhibitors (SSRIs), used to treat depression and anxiety

Causes of Pulmonary Hypertension

It’s not always easy to find out what causes pulmonary hypertension. There are several causes, but some of the most common causes are:

• Autoimmune diseases, such as scleroderma or systemic lupus erythematosus (SLE)
• Certain medications and drugs
• Heart defects from birth (also known as congenital heart disease)
• Genetics
• Lung disease, such as pulmonary fibrosis or chronic obstructive pulmonary disease (COPD)
• Liver disease
• Sleep apnoea (where your breathing stops when you’re asleep)
• Clots in the lungs (pulmonary embolism)
• HIV

Pulmonary Hypertension symptoms

The most common symptoms of pulmonary hypertension are related to breathing trouble. They include:

• Progressive shortness of breath (especially with activity)
• Hyperventilation (breathing harder and faster)
• Fatigue (tiring easily)
• Fainting spells
• Lightheadedness or dizziness
• Coughing up blood

These symptoms may occur all at once or progress over a period of time. A patient’s cardiologist or pulmonologist will check for these symptoms during routine office visits. If any new symptoms develop, patients should call their doctor right away.

A physical exam of patients with pulmonary hypertension may show:

• Bulging neck veins
• Swelling of the legs and hands due to fluid retention
• Enlarged liver

All of these signs are related to the right side of the heart working harder to pump blood into the high resistance of the blood vessels in the lungs.

Pulmonary Hypertension complications

Pulmonary Hypertension can cause multiple complications like-

Enlargement of the right-sided heart- The right ventricle of the heart is expanded to pump more blood through narrow arteries causing a heart failure called cor pulmonale. In this condition, the heart initially thickens its walls to release pressure from arteries but eventually, this leads to suppress the blood flow.

Arrhythmia- The heart starts to beat irregularly from the upper or lower chambers which leads to palpitations and dizziness. This, later on, leads to fatal heart failures.

Bleeding- At advanced stages, Pulmonary Hypertension causes internal bleeding in the lungs. This results in hemoptysis (coughing sessions with blood). This condition is fatal.

Diagnosis and test

Primary pulmonary hypertension (PPH) is rarely discovered in a routine medical exam. In its later stages, the signs of the disease can be confused with other conditions affecting the heart and lungs.

PPH may be diagnosed when other diseases are ruled out. Tests may include:

Chest X-ray: A test that takes pictures of internal tissues, including the heart.

Electrocardiogram (ECG): This test records the strength and timing of the electrical activity of the heart. It shows abnormal rhythms  and can sometimes detect heart muscle damage. Small sensors are taped to your skin to pick up the electrical activity.

Echocardiogram (echo): This test uses sound waves to check the heart’s chambers and valves. The echo sound waves create a picture on a screen as an ultrasound transducer is passed over the skin over the heart. Echo can show damage and enlargement of the heart.

Pulmonary function tests (PFTs): These are diagnostic tests that help to measure the lungs’ ability to move air into and out of the lungs. The tests are usually done with special machines you breathe into.

Perfusion lung scan: A type of nuclear radiology test in which a small amount of a radioactive substance is used to help find changes in the arteries leading to the lungs and blood flow within the lungs. This scan can also be used to assess the function of the lungs.

Cardiac catheterization of the right side of the heart: With this procedure, X-rays are taken after a dye (contrast agent) is injected into the pulmonary artery to look for any narrowing, blockages, or other changes. This is the only test that directly measures the pressure inside the pulmonary arteries.

Blood tests: These can be used to check the oxygen levels in the blood, evaluate liver and kidney function, and look for other diseases. Certain blood tests can also help to assess strain on the heart.

Treatment and medications

Treatment for PH can be divided into two main categories: supportive therapy and PH-specific therapy. Supportive therapy is used to treat the underlying factors which may worsen PH, and to prevent complications. PH-specific therapies are designed to reduce the blood pressure within the lungs.

Several PH-specific therapies have recently been approved by the U.S. Food and Drug Administration (FDA) for use in patients with other forms of PH – specifically pulmonary arterial hypertension. The efficacy of these therapies in patients with PH and ILD remains uncertain. Using PH-specific therapy in ILD patients remains controversial, so you should discuss the benefits and risks with your provider.

Supportive therapy

Oxygen – Supplemental oxygen helps increase oxygen supply to the blood and helps prevent narrowing of the pulmonary blood vessels, which can worsen PH.

Diuretics – Diuretics, or water pills, help prevent swelling and are sometimes useful in improving heart and lung function in PH patients.

Anticoagulants (blood thinners) – Anticoagulants are sometimes required if blood clots are detected in the lungs or if PH is severe.

Pulmonary Rehabilitation – Pulmonary rehabilitation has been shown to improve outcomes in patients with ILD, as well as patients with PH. Be sure to tell your pulmonary rehabilitation provider if you have been diagnosed with PH.

PH-specific therapy

Prostanoids (Flolan, Treprostinil, Iloprost): Prostanoid, or prostacyclin, therapy is available as a continuous intravenous infusion or as an inhaled medication. Prostanoids are rarely used for PH in patients with ILD.

Endothelin Receptor Antagonists (Bosentan, Ambrisentan): Endothelin receptor antagonists are taken by mouth. Patients who take them must have their liver function monitored regularly.

Phosphodiesterase Inhibitors (Sildenafil): Phosphodiesterase inhibitors are taken by mouth. They should not be used in patients taking nitrates (for example, nitroglycerin) for heart disease.

Surgeries and Procedures

The following procedures may be recommended in some cases of pulmonary hypertension:

Atrial septostomy– This procedure involves creating a small hole between the right and left atria of your heart to reduce pressure on the right side and increase oxygen in your blood.

Pulmonary Angioplasty- This procedure uses a balloon to help restore blood flow through your pulmonary arteries.

Pulmonary Endarterectomy- This surgery removes blood clots from the blood vessels of your lungs.

Heart or Lung Transplantation- A transplant may be an option for some younger people with pulmonary hypertension from unknown causes, but it carries significant risks and drawbacks.

These lifestyle changes can improve your symptoms

Quit smoking: Your doctor can recommend programs and products to help.

Follow a healthy diet: Eat a variety of fruits, vegetables, and whole grains, plus lean meat, poultry, fish and low-fat/fat-free milk. Your diet should be low in fat, cholesterol, sodium and sugar.

Watch your weight: A daily record of your weight can help you be aware of rapid weight gain, which may be a sign that your pulmonary hypertension is worsening.

Stay active: Incorporate physical activity such as walking into your lifestyle. Discuss the level of activity with your doctor. Avoid straining or lifting heavy weights. Rest when you need to.

Avoid sitting in a hot tub or sauna, or taking long baths, which will lower your blood pressure.

Be cautious about air travel or high-altitude locales: You may need to travel with extra oxygen.

Get support for the anxiety and stress of living with pulmonary hypertension. Talk with your healthcare team, or ask for a referral to a counselor. A support group for people living with pulmonary hypertension can be invaluable in learning how to cope with the illness.