Definition

Pulmonary hypertension is a high blood pressure condition that affects the blood vessels in the lungs and on the right side of the heart. In pulmonary hypertension, blood vessels in the lungs may narrow, block, or be damaged. The damage will reduce the flow of blood to the lungs and raise blood pressure in the lungs' blood vessels (pulmonary arteries), forcing the heart to work harder to pump blood to the lungs. This additional effort will eventually cause the heart muscle to weaken and cease to pump.

Pulmonary hypertension is considered a rare disorder. It can occur in individuals of all ages, races, and ethnic backgrounds, although it is much more common in young adults and is approximately twice as common in women than in men. The disorder is also more common in people who have other underlying heart or lung conditions.

Causes

Under normal circumstances, blood will release carbon dioxide and bind oxygen in the lungs. Blood can normally flow easily through the blood vessels in the lungs (pulmonary veins, capillaries, and arteries) to the heart.

The development of pulmonary hypertension begins with an injury to the cells that line the small blood vessels in the lungs. This injury can cause changes in the way these cells interact with the smooth muscle cells in the blood vessel wall. As a result, the smooth muscle contracts and expands more than usual, narrowing the blood vessels.

Changes in the cells that line the blood vessels in the lungs can cause the walls to stiffen, swell, and thicken. These changes can slow or block blood flow to the lungs, causing pulmonary hypertension.

Some of the causes that can lead to pulmonary hypertension include:

• Liver disease, rheumatic disorders, and lung disease. Impairment of the liver, such as chronic liver disease and liver cirrhosis; rheumatic disorders such as scleroderma or systemic lupus erythematosus (lupus); and lung conditions, including tumors, emphysema, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis
• Certain heart diseases, including aortic valve disease, left heart failure, mitral valve disease, and congenital heart disease
• Thromboembolic diseases (blood clotting disorders). Blood clots in the large blood vessels of the lungs
• Low oxygen levels. Living in high altitudes, obesity, and suffering from sleep apnea (periods of breathlessness during sleep)
• Genetics. Pulmonary hypertension can be inherited in a small number of cases
• Unknown causes. Pulmonary hypertension can also be caused by other conditions, and in some cases, the cause is unknown

Risk Factor

Factors that may increase your risk of developing pulmonary hypertension include:

• Pulmonary hypertension can occur at any age, including children, and the incidence increases with age (30 to 60 years)
• Women are more likely to develop it than men
• Having a family history of pulmonary hypertension
• Having an excess body weight
• Suffer from blood clotting disorders or have a family history of blood clotting disorders in the lungs
• Have certain disease conditions, such as heart disease, lung disease, liver disease, HIV infection, or blood clots in the blood vessels in the lungs
• Have been exposed to asbestos
• Have congenital heart disease
• Living at high altitudes
• Using certain weight loss medications
• Using illegal drugs such as cocaine
• Using Selective Serotonin Reuptake Inhibitor (SSRI) drugs, which are used to treat depression and anxiety

Symptoms

Symptoms of pulmonary hypertension typically appear slowly. You might not notice them for months or even years. These symptoms will become more severe as the disease progresses. Symptoms may vary between individuals and depend on the severity of the disease.

Symptoms of pulmonary hypertension include:

• Shortness of breath, initially felt during exercise and later can occur even when at rest
• Fatigue
• Dizziness or fainting
• Pressure or pain in the chest
• Swelling (edema) in the ankles, feet, and eventually the abdomen (ascites)
• Bluish coloration of the lips and skin (cyanosis)
• Rapid pulse or pounding heartbeat (palpitations)

Diagnosis

When diagnosing pulmonary hypertension, the doctor will first conduct an interview. This will include questions about your symptoms, any illnesses you or your family have had, your previous medical history, and any other factors that may have contributed to the development of pulmonary hypertension.

The doctor will then perform a physical examination, including listening to your heart and lung sounds. The doctor may also perform additional supporting tests to help make a diagnosis, as often the symptoms of pulmonary hypertension resemble other heart or lung diseases.

Additional tests that may be performed include:

• Blood tests, which consist of:
• A complete metabolic panel to check liver and kidney function
• Blood autoantibody tests, such as ANA and ESR
• Thyroid hormone (TSH), to check for thyroid problems
• HIV screening
• Vascular blood gas, to determine the oxygen level in the vascular blood
• Complete blood count to check for infections, elevated hemoglobin, and anemia
• B-type Natriuretic Peptide (BNP), a marker for heart failure
• Doppler echocardiogram, which uses sound waves to show the function of the right chamber of the heart, measures blood flow through the heart valves and then calculates the pressure in the pulmonary arteries
• Chest X-ray, which can show an enlarged right chamber of the heart and enlarged pulmonary arteries
• A 6-minute walk test to determine the level of exercise tolerance and blood oxygen saturation level during exercise
• Pulmonary function tests to evaluate other lung conditions, such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis
• Polysomnogram, a screening to check for sleep apnea (periods of stopped breathing during sleep), which can result in low oxygen levels at night
• Right heart catheterization, to measure various heart pressures (within the pulmonary artery, which is the blood vessel originating from the right chamber of the heart), the speed at which the heart pumps blood, and to find leaks between the right and left sides of the heart
• Ventilation-perfusion scan (V/Q scan) to look for evidence of blood clots along the pathway to the lungs
• Pulmonary angiogram, to look for blockages of blood clots in the blood vessels of the pulmonary arteries
• CT scan of the chest to look for blood clots and other lung conditions that may be contributing to or worsening pulmonary hypertension

Management

There is no cure for pulmonary hypertension. However, treatment can alleviate symptoms and slow the progression of the disease. The type of treatment for your pulmonary hypertension is usually determined by the cause. If the cause of your pulmonary hypertension is known, treating it may help your condition. For example, if your condition is caused by lung disease, you may require oxygen therapy to increase your blood oxygen levels. If it is caused by a blood clot in the lungs, you will most likely need blood thinners to keep the clot from growing larger.

Some management options for pulmonary hypertension include:

• Medications, such as:
  • Diuretics, to reduce fluid build-up in your body
  • Blood thinners, to help prevent blood clots from forming or getting bigger
  • Oxygen therapy, to increase oxygen level in your blood and help your heart beat stronger and pump more blood
  • Other medications, such as drugs that work to relax the blood vessels to allow more blood to flow
• Lifestyle changes can also help you feel better, such as:
  • Stop smoking
  • Maintain an ideal body weight
  • Eat nutritious food
  • Reduce stress in your life
  • Regular exercise and physical activity
• Surgery. In some severe cases, people with pulmonary hypertension require surgery such as a lung transplant or a heart-lung transplant

Complications

Complications that may occur as a result of pulmonary hypertension include:

• Right-sided heart enlargement and heart failure (cor pulmonale)
• Formation of blood clots in small blood vessels in the lungs
• Arrhythmia, which is an irregular heartbeat rhythm
• Bleeding inside the lungs

Prevention

Although pulmonary hypertension cannot be completely avoided, you can reduce your risk by adopting a healthy lifestyle and managing any underlying conditions such as high blood pressure, coronary heart disease, chronic liver disease, and chronic lung disease.

When to See a Doctor?

Consult a doctor if you have symptoms of pulmonary hypertension. Diagnosing pulmonary hypertension sometimes takes time and various additional examinations as the symptoms often resemble other heart and lung conditions.

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