Pulmonary Hypertension Diagnosis

  • Diagnosis

    Pulmonary hypertension is a disorder in which the blood pressure in the vessel that leads from the heart to the lungs (pulmonary artery) rises to higher-than-normal levels Figure 01. High blood pressure in the pulmonary artery puts added strain on the heart, which must then work much harder to pump blood throughout the body. Under the strain, the heart may eventually fail completely.

    Sometimes, the cause of pulmonary hypertension remains unknown. In these very rare cases, the disorder is referred to as primary pulmonary hypertension (PPH). In the U.S., only about 500 to 1,000 people are diagnosed each year with PPH. Although PPH can strike anyone at any age, it occurs most often in young adults—primarily women between the ages of 20 and 40.

    When a cause for pulmonary hypertension can be identified, such as emphysema or a birth defect in the heart, the disorder is known as secondary pulmonary hypertension (SPH). SPH is believed to be relatively common, but is underdiagnosed. Many cases are mild and cause little or no illness; however, when severe, SPH can be serious. For that reason, there are no reliable estimates of how many people develop the condition each year. It is known, however, that enlargement of the right ventricle of the heart (cor pulmonale)—the heart condition that develops when pulmonary hypertension goes untreated—is the third most common type of heart disorder in people over 50 years of age.

    Certain diet drugs have been linked to pulmonary hypertension. The link to diet drugs was first recognized in 1967 when there was an epidemic of pulmonary hypertension in Europe among people who had used the appetite suppressant aminorex fumarate (Menocil). In 1997, two diet drugs—fenfluramine hydrochloride (Pondimin) and dexfenfluramine hydrochloride (Redux)—were taken off the market after they, too, were associated with an increased risk for pulmonary hypertension.

    Pulmonary hypertension has no cure. Early diagnosis and effective treatment can, however, make it possible for some people to extend and improve their lives.

    Click to enlarge: The circulatory system

    Figure 01. The circulatory system

    Pulmonary hypertension appears to be triggered by changes to the cells lining the small blood vessels of the lungs. These changes cause the muscles around the blood vessels to constrict, narrowing the vessels. Because of the narrowed vessels, the heart must pump harder to get blood to the lungs, increasing pressure within the artery. This increased effort thickens and damages the artery, and enlarges one of the chambers of the heart muscle (the right ventricle). Eventually, the right side of the heart may become so weakened that it fails completely.

    In cases of primary pulmonary hypertension, doctors simply do not know what causes the damage to the lung’s small blood vessels. Research suggests, however, that family genetics, an immune system disease, or exposure to chemicals may be involved.

    With secondary pulmonary hypertension, the source of the damage to the lung’s small blood vessels can be traced to a known cause. Emphysema and chronic bronchitis--strongly linked to cigarette smoking and together known as chronic obstructive pulmonary disease (COPD)—are among the more common causes of SPH. Other causes of SPH include:

    • birth defects in the heart
    • liver disease
    • connective tissue disease (such as lupus or scleroderma)
    • sleep apnea (a serious condition in which breathing is repeatedly interrupted during sleep)
    • HIV infection
    • use of illicit drugs

    Certain diet drugs also have been linked to pulmonary hypertension. The problem was first recognized in 1967 when there was an epidemic of pulmonary hypertension in Europe among people who had used the appetite suppressant aminorex fumarate (Menocil). In 1997, two diet drugs—fenfluramine (Pondimin) and dexfenfluramine hydrochloride (Redux)—were taken off the market after they, too, were associated with an increased risk for pulmonary hypertension.

    The earliest symptoms of pulmonary hypertension are usually fatigue and shortness of breath, especially after physical exertion. Many people with pulmonary hypertension mistakenly blame these early symptoms on aging or being “out of shape.” Other symptoms of pulmonary hypertension include:

    • dizziness or fainting spells
    • ankle or leg swelling
    • bluish lips and skin
    • chest pain (angina)
    • heart palpitations
    • racing pulse
    • dry cough
    • hoarseness when speaking

    As the disorder progresses, the symptoms become more severe. People with pulmonary hypertension lack the energy to do everyday activities, and may experience symptoms even while resting. Eventually, patients with pulmonary hypertension may become completely bedridden.

    Certain conditions increase your risk for developing pulmonary hypertension.Table 01 These conditions include:

    • emphysema
    • chronic bronchitis
    • liver disease
    • connective tissue disease
    • sickle cell anemia ( a chronic disorder of the blood)
    • HIV infection
    • Raynaud’s disease (a condition in which blood vessels overreact to cold temperatures, turning the body’s extremities—mostly fingers and toes--blue when exposed to cold).
    • sleep apnea
    • congenital heart defects
    • use of illicit drugs

    Taking diet drugs, particularly for longer than three months, increases the risk for pulmonary hypertension. Research has shown that the incidence of pulmonary hypertension among users of appetite suppressants may be as high as 25 to 50 per million (compared to 1 to 2 per million for the general population).

    Among children, primary pulmonary hypertension affects both genders equally; but after puberty, it is almost twice as common in women as in men. Age is also a factor: most people diagnosed with PPH are between the ages of 20 and 40. In about 6% to 10% of cases, PPH appears to be inherited.

    Table 1.  Risk Factors for Pulmonary Hypertension

    For primary pulmonary hypertension (PPH)
    Being female
    Being between the ages of 20 and 40
    Having a family history of PPH
    For secondary pulmonary hypertension (SPH)
    Emphysema and/or chronic bronchitis
    Liver disease
    Connective tissue disease
    HIV infection
    Sickle cell anemia
    Raynaud?s disease
    Sleep apnea
    Congenital heart defect
    Use of illicit drugs
    Use of appetite suppressants

    Because its early symptoms are subtle and similar to those of other conditions, pulmonary hypertension often remains undiagnosed until it has reached its later stages. Even then, it can be confused with other conditions affecting the heart and lungs. Evaluation for pulmonary hypertension should be done at a medical center that has expertise in the condition.

    Several pulmonary hypertension clinics have been established around the country. These clinics include a variety of medical specialists—cardiologists, pulmonologists, general and transplant surgeons, and others—who are dedicated to the evaluation, treatment, and follow-up care of people with pulmonary hypertension. Ask your primary care physician for a referral to such a clinic.

    Your doctor will take a medical history and a complete physical exam, paying careful attention to the heart and lungs. Your doctor will check for unusual heart sounds that may indicate higher pressure in the lungs. He or she will also look for enlarged veins in your neck, which are associated with pulmonary hypertension. Samples of your blood also will be taken to check blood counts and to assess how well your liver and kidneys are functioning.

    A series of medical tests will be used to rule out other medical conditions, or, if it is determined that you have pulmonary hypertension, to identify the medical condition that may be causing it. Your doctor will first order noninvasive tests (ones that require no surgery) to determine how well your heart and lungs are performing. If these tests strongly suggest that you have pulmonary hypertension, you will probably need to undergo a catheterization procedure to confirm the diagnosis (see below).

    The following tests and procedures may be part of your evaluation.

    • Chest x-ray. Your doctor will be looking for a larger-than-normal right ventricle and pulmonary artery. These x-rays can also help your doctor determine a possible cause for the pulmonary hypertension, such as emphysema.
    • Electrocardiogram (ECG). This test, which records the electrical activity of the heart, can determine if your heart is undergoing any unusual stress. It looks for evidence of a thickened heart or abnormal heartbeats. You may be given two ECGs: one while you are resting, and one while you are doing some kind of exercise, such as walking on a treadmill.
    • Echocardiogram. This “ultrasound of the heart” uses sound waves to create both moving and still images of your heart. During the procedure, a microphone-like device is placed on your chest. The device sends sound waves into your heart; the waves are then bounced back to create a moving image of your heart on a TV screen. Your doctor uses the images to tell how well your heart is functioning. With still pictures taken from the videotape, your doctor can also measure the size and thickness of your heart and determine if the right ventricle is enlarged. In most cases, the diagnosis of pulmonary hypertension can be confirmed or excluded by the echocardiogram.
    • Pulmonary function tests. These tests measure how well the lungs can receive, hold, and use air. To take these tests, you exhale into a special mouthpiece attached to monitoring equipment. In people with pulmonary hypertension, these tests usually show that air movement in the lungs is being mildly restricted, probably due to increased stiffness of the lungs.
    • Perfusion lung scan. This test is usually given to distinguish people with pulmonary hypertension from those with blood clots in the lungs. During this procedure, a radioactive substance is injected into a vein. Your chest is then scanned for radioactivity. If blood clots are blocking the flow of blood in your lungs, they will show up as clear areas on the scanner.
    • Right heart cardiac catheterization. This is the most important test for diagnosing pulmonary hypertension and deciding which treatment option to follow. In this procedure, a thin, flexible tube (a catheter) is inserted through a vein in your arm, leg, or neck, and then threaded into the right ventricle of your heart and your pulmonary artery. This is the only way to get a precise measurement of blood pressure in the pulmonary artery. The procedure, which must be performed in a hospital with a specialist, can also evaluate how well the right heart is pumping.

    Depending on your health history and symptoms, you may also undergo additional tests Table 02.

    Table 2.  Additional Tests Commonly Used to Diagnose Pulmonary Hypertension

    Test Comments
    Office and laboratory tests
    Liver function tests These tests take blood samples, which are then examined for signs of liver disease.
    HIV serology Blood samples are examined for signs of HIV infection.
    Autoantibody tests: ANA, ANCA, RF Blood serum is tested for autoantibodies, substances produced by the body' s immune system in response to illness. The ANA, ANCA, and RF tests look for signs of certain autoantibodies often present in people with connective tissue disease, such as lupus or scleroderma.
    Blood gas testing This test takes a blood sample from an artery (usually one in the wrist), which is then immediately examined for below-normal levels of oxygen?a sign of possible heart problems.
    Polysomnography (sleep study) For this test, which helps detect sleep apnea, you will be monitored by special equipment while you sleep.
    Hemoglobin electrophoresis This blood test looks for evidence of sickle cell anemia.
    Serum or urinary beta subunit of chorionic gonadotropin This blood and/or urine test checks for choriocarcinoma, a rapidly growing cancerous tumor that develops from fetal tissue.
    Rectal biopsy, complement fixation, skin tests, blood smears These tests are conducted to identify parasitic disease.
    Radiologic/imaging tests
    Ultrafast CT scanning with contrast This test is used to look for blood clots.
    Transesophageal echocardiography (TEE) This test helps assess heart defects by transmitting sound waves to the heart from inside the body.
    Invasive tests
    Pulmonary angiography This surgical procedure helps determine if blood clots in the lungs are the cause of the pulmonary hypertension.

    The New York Heart Association classification for symptom severity can be applied to people diagnosed with pulmonary hypertension Table 03.

    This system, which is based on how much activity a patient reports he or she can comfortably undertake, helps doctors determine how to treat the condition.

    Table 3.  Classification System for Pulmonary Hypertension

    Class Description
    Class I Patients have no symptoms of any kind. Ordinary physical activity does not cause fatigue, heart palpitations, breathing problems (dyspnea), or chest pain (angina).
    Class II Patients are comfortable when resting, but have symptoms (fatigue, heart palpitations, breathing problems, or chest pain) when engaged in ordinary physical activity.
    Class III Patients are comfortable when resting, but have symptoms (fatigue, heart palpitations, breathing problems, or chest pain) when engaged in less-than-ordinary physical activity.
    Class IV Patients cannot perform any physical activity without symptoms (fatigue, heart palpitations, breathing problems, or chest pain); in addition, the symptoms may occur while at rest.

    Because the cause of primary pulmonary hypertension is unknown, methods of preventing the condition also remain a mystery. Treating the underlying cause of the condition can sometimes prevent secondary pulmonary hypertension (SPH). For example, since emphysema and chronic bronchitis are major risk factors for SPH, any actions you take to reduce your chances of getting those diseases—primarily, not smoking—may also help prevent SPH.

    The World Health Organization (WHO) recommends that certain groups of people be screened for pulmonary hypertension.

    • People with scleroderma. If you have any type of scleroderma, you should have an echocardiogram annually, whether or not you have symptoms of pulmonary hypertension.
    • People with a family history of pulmonary hypertension. If you have parents or siblings with pulmonary hypertension, you should be screened for the disorder every three to five years, whether or not you have symptoms. Should you develop symptoms of pulmonary hypertension, you should be screened immediately.
    • People undergoing liver transplantation. You should have an echocardiogram to screen for pulmonary hypertension at the time you are being evaluated for liver transplantation. People with pulmonary hypertension who need a liver transplant are sometimes given medication therapy first to help them become healthy enough to receive their new liver.

  • Prevention and Screening

    Because the cause of primary pulmonary hypertension is unknown, methods of preventing the condition also remain a mystery. Treating the underlying cause of the condition can sometimes prevent secondary pulmonary hypertension (SPH). For example, since emphysema and chronic bronchitis are major risk factors for SPH, any actions you take to reduce your chances of getting those diseases—primarily, not smoking—may also help prevent SPH.

    The World Health Organization (WHO) recommends that certain groups of people be screened for pulmonary hypertension.

    • People with scleroderma. If you have any type of scleroderma, you should have an echocardiogram annually, whether or not you have symptoms of pulmonary hypertension.
    • People with a family history of pulmonary hypertension. If you have parents or siblings with pulmonary hypertension, you should be screened for the disorder every three to five years, whether or not you have symptoms. Should you develop symptoms of pulmonary hypertension, you should be screened immediately.
    • People undergoing liver transplantation. You should have an echocardiogram to screen for pulmonary hypertension at the time you are being evaluated for liver transplantation. People with pulmonary hypertension who need a liver transplant are sometimes given medication therapy first to help them become healthy enough to receive their new liver.

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