Heart Diseases

Pulmonary Hypertension

What is pulmonary hypertension?

Pulmonary hypertension is a clinical syndrome where the blood flow that leaves the right side of the heart faces an increased resistance (pressure).

Normally blood flows from the right ventricle into the pulmonary arteries and then flows into smaller and smaller blood vessels until it reaches the capillaries (thin walled blood vessels near the small air chambers of the lungs or alveoli). There gas exchange occurs where oxygen is picked up and carbon dioxide is released. The blood vessels have muscles in their walls that can regulate their diameter and thereby allow more or less blood flow to enter the capillaries.

In pulmonary hypertension, the blood vessels of the lungs have an increased amount of muscle in the walls. This causes a higher resistance in the lungs. The right ventricle then has to work harder to pump blood out to the lungs. The right ventricle will enlarge and thicken in response to this extra work. With time, the extra work placed on the right side of the heart can cause it to fail.

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Pulmonary hypertension causes

Pulmonary hypertension may be idiopathic when there is no obvious cause. However, secondary pulmonary hypertension may occur in many other types of diseases. Certain types of congenital heart disease, if left unrepaired, may cause pulmonary hypertension. Likewise, severe forms of lung disease can also damage blood vessels in the lungs and result in pulmonary hypertension. Rarely seen in young infants but more so in adolescents is pulmonary hypertension associated either with connective tissue diseases or sickle cell disease.

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Who gets pulmonary hypertension?

The incidence of idiopathic pulmonary hypertension is 8 out of 100,000 people. Women between the ages of 20 and 40 are most at risk. There is often a family history of pulmonary hypertension or sudden death. However, pulmonary hypertension can occur at any age, especially in teenagers.

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Pulmonary hypertension signs and symptoms

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

Progressive shortness of breath (especially with activity)
Hyperventilation (breathing harder and faster)
Fatigue (tiring easily)
Progressive weakness
Fainting spells
Lightheadedness or dizziness
Coughing up blood
Progressive cyanosis (blue tinge to lips hands and feet)

These symptoms may occur at presentation, or progress over a period of time. A patient with pulmonary hypertension must be monitored for these symptoms by routine visits to their cardiologist or pulmonologist. If any new symptoms develop, patients should notify their doctor immediately.

A physical examination of patients with pulmonary hypertension may show:

Distension of veins in the neck
Swelling of the legs and hands due to fluid retention
Enlarged liver

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

Diagnosing pulmonary hypertension

A good history and physical exam can give the physician clues to the diagnosis.

An electrocardiogram should be performed which will show enlargement of the right side of the heart.

A chest X-ray may show enlargement of the size of the heart, and is often a good way to follow the patient's heart size over time.

An echocardiogram, or ultrasound of the heart, will be performed initially and can also be used to follow the progression of the disease. An echo can show enlargement of the right ventricle and can sometimes estimate the pressures of the right ventricle and pulmonary arteries.

A six-minute walk test is used to evaluate the exercise capacity of an individual with pulmonary hypertension, and the subsequent response to therapy. During this test an oxygen saturation monitor (pulse ox) is placed on the side of the head (temple), and the patient walks along the measured course at their own pace for six minutes. The total distance walked is then calculated and compared with previous six-minute walk tests.

The gold standard for making the diagnosis of pulmonary hypertension is a cardiac catheterization. This will actually measure the pressures on the right side of the heart and the resistance of the blood vessels in the lungs. Various drugs may be used during a cardiac catheterization to determine if the blood vessels in the lungs will relax in response to them. This may lower the pressures in the lungs and can help guide therapy.

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Pulmonary hypertension treatment

Unfortunately there is no cure for pulmonary hypertension. There are now many treatments that have been found to relieve some of the symptoms and slow the progression of disease.

Oxygen is a drug that can be used at home and can often help relieve some of the symptoms of difficult breathing. It is also known to relax the muscles in the arteries of the lungs, which will lower the pressures in the pulmonary arteries.
Inhaled nitric oxide is a drug that has been shown to relax the blood vessels in the lungs without having any effect on the blood vessels of the rest of the body. It is used in the inpatient setting for pulmonary hypertension. In rare cases it can be used as a home regimen, though it needs to be on continuously and is very bulky and difficult to manage.
Diuretics such as Lasix are used to get rid of excess fluid in the body.
Calcium channel blockers such as nifedipine can relax the muscles in blood vessel walls and thereby help with the function of the right side of the heart.
Sildenafil is an oral drug that results in relaxation of blood vessels in the lungs. It is often used in combination with other medications to lower pulmonary artery pressures.
Bosentan is also an oral drug that results in relaxation of blood vessels in the lungs but functions differently to sildenafil. As a result it is often used in combination with sildenafil. Patients who are on Bosentan might have monthly blood tests.
Prostanoids, including prostacyclin, are drugs that have been shown to slow the progression of pulmonary hypertension. They are available in many forms but are most commonly used as chronic infusions through permanent intravenous lines. These drugs are also available as subcutaneous (under the skin) infusions, and frequent inhalations.

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Prognosis for pulmonary hypertension patients

The long-term prognosis for pulmonary hypertension depends on its course, the severity of the disease at the time of diagnosis and response to therapy. Recent advances in medical therapies have had a profound impact on the outcome of pulmonary hypertension. If the disease does progress to the point that symptoms are excessively severe, some patients may be suitable for lung transplantation.

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What should be done for patients who have been diagnosed with pulmonary hypertension?

It is important to see your doctor on a regular basis and report any changes in energy level, ability to exercise, or overall health. Patients should restrict themselves from competitive sports and only participate in light activity if they're able to rest when tired. If patients have been placed on therapy, it is important to use it regularly and not just when they feel bad.

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