Pulmonary Hypertension: Causes, Symptoms,
Diagnosis, Treatment
What is pulmonary hypertension?
Pulmonary hypertension is a rare lung disorder in which the arteries that
carry blood from the heart to the lungs become narrowed, making it difficult for
blood to flow through the vessels. As a result, the blood pressure in these
arteries -- called pulmonary arteries -- rises far above normal levels. This
abnormally high pressure strains the right ventricle of the heart, causing it to
expand in size. Overworked and enlarged, the right ventricle gradually becomes
weaker and loses its ability to pump enough blood to the lungs. This could lead
to the development of right heart failure.
Pulmonary hypertension occurs 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 as in men.
Why do the pulmonary arteries narrow?
Scientists believe that the process starts with injury to the layer of cells
that line the small blood vessels of the lungs. This injury, which occurs for
unknown reasons, may cause changes in the way these cells interact with the
smooth muscle cells in the vessel wall. As a result, the smooth muscle contracts
more than normal and narrows the vessel.
What are the symptoms of pulmonary hypertension?
Symptoms of pulmonary hypertension do not usually occur until the condition
has progressed. The first symptom of pulmonary hypertension is usually shortness
of breath with everyday activities, such as climbing stairs. Fatigue, dizziness,
and fainting spells also can be symptoms. Swelling in the ankles, abdomen or
legs; bluish lips and skin, and chest pain may occur as strain on the heart
increases. Symptoms range in severity and a given patient may not have all of
the symptoms.
In more advanced stages of the disease, even minimal activity will produce
some of the symptoms. Additional symptoms include irregular heart beat
(palpitations or strong, throbbing sensation), racing pulse, passing out or
dizziness, progressive shortness of breath during exercise or activity, and
difficulty breathing at rest. Eventually, it may become difficult to carry out
any activities as the disease worsens.
What causes pulmonary hypertension?
The following are some known causes of pulmonary hypertension:
- The diet drug "fen-phen." Although the
appetite suppressant "fen-phen" (dexfenfluramine and phentermine)
has been taken off the market, former fen-phen users have a 23-fold increase
risk of developing pulmonary hypertension, possibly years later.
- Liver diseases, rheumatic disorders, lung conditions.
Pulmonary hypertension also can occur as a result of other medical
conditions, 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. Heart diseases including aortic
valve disease, left heart failure, mitral valve disease, and congenital
heart disease can also cause pulmonary hypertension.
- Thromboembolic disease. A blood clot in a large
pulmonary artery can result in the development of pulmonary hypertension.
- Low-oxygen conditions. High altitude living, obesity,
and sleep apnea can also lead to the development of pulmonary hypertension.
- Genetic predisposition. Pulmonary hypertension is
inherited in a small number of cases. Knowing that someone in the family had
or has pulmonary hypertension should prompt you to seek early evaluation
should symptoms occur.
Pulmonary hypertension may also be caused by other conditions, and in some
cases, the cause is unknown.
How is pulmonary hypertension diagnosed?
Because pulmonary hypertension may be caused by many medical conditions, a
complete medical history, physical exam, and description of your symptoms are
necessary to rule out other diseases and make the correct diagnosis. During the
physical exam, your health care provider will:
- listen for abnormal heart sounds such as a loud pulmonic valve
sound, a systolic murmur of tricuspid regurgitation, or a gallop due to
ventricular failure.
- examine the jugular vein in the neck for engorgement.
- examine the abdomen, legs, and ankles for fluid retention.
- examine nail beds for bluish tint.
- look for signs of other underlying diseases that might be
causing pulmonary hypertension.
Other tests that might be ordered include:
Blood tests:
- Complete metabolic panel (CMP): Examines liver and kidney
function
- Autoantibody blood tests, such as ANA, ESR, and others: Screens
for collagen vascular diseases
- Thyroid stimulating hormone (TSH): A screen for thyroid
problems
- HIV: A screen for human immunodeficiency virus
- Arterial blood gases (ABG): Determines the level of oxygen in
arterial blood.
- Complete blood count (CBC): Tests for infection, elevated
hemoglobin, and anemia
- B-type natriuretic peptide (BNP): A marker for heart failure
Doppler echocardiogram: Uses sound waves to show the function of the
right ventricle, to measure blood flow through the heart valves, and then
calculate the systolic pulmonary artery pressure.
Chest X-ray: Shows an enlarged right ventricle and enlarged pulmonary
arteries.
6 minute walk test: Determines exercise tolerance level and blood oxygen
saturation level during exercise.
Pulmonary function tests: Evaluates for other lung conditions such as
chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis among
others.
Polysomnogram or overnight oximetry: Screens for sleep apnea (results in
low oxygen levels at night).
Right heart catheterization: Measures various heart pressures (ie, inside
the pulmonary arteries, coming from the left side of the heart), the rate at
which the heart is able to pump blood, and finds any leaks between the right and
left sides of the heart.
Ventilation perfusion scan (V/Q scan): Looks for evidence of blood clots
along the pathway to the lungs.
Pulmonary angiogram: Looks for blood clot blockages in the pulmonary
arteries.
Chest CT scan: Looks for blood clots and other lung conditions that may
be contributing to or worsening pulmonary hypertension.
How is pulmonary hypertension treated?
Appropriate diagnosis and analysis of the problem is necessary before
starting any treatment. Treatment varies per individual based on the different
underlying causes but generally includes taking medications; making lifestyle
and dietary changes; having surgery, if necessary; and seeing your doctor
regularly. Listed below are the medication and surgical treatment approaches.
Medications
Many different types of medications are available to treat pulmonary
hypertension. Treatment choices, such as those listed below, depend on the
severity of pulmonary hypertension, the likelihood of progression, and
individual drug tolerance.
- Oxygen — replaces the low oxygen in your blood.
- Anticoagulants or "blood thinners" such as warfarin
sodium (Coumadin) — decreases blood clot formation so blood flows more
freely through blood vessels. Note: when taking anticoagulant
medications, it is important for you to monitor bleeding complications and
have regular lab work to monitor the level of medication in your
bloodstream.
- Diuretics or "water pills" [such as furosemide (Lasix)]
— removes extra fluid from the tissues and bloodstream, which reduces
swelling and makes breathing easier.
- Potassium (such as K-dur) — replaces potassium (an essential
nutrient) that may be lost with increased urination when taking diuretics.
- Inotropic agents (such as digoxin) — improves the heart’s
pumping ability.
- Vasodilators [such as nifedipine (Procardia) or diltiazem (Cardizem)]
— lowers pulmonary blood pressure and may improve the pumping ability of
the right side of the heart.
- Bosentan (Tracleer) — helps block the action of endothelin, a
substance that causes narrowing of lung blood vessels.
- Epoprostenol (Flolan), treprostinil sodium (Remodulin),
iloprost (Ventavis) — dilates pulmonary arteries and helps prevent blood
clots from forming.
- Sildenafil (Revatio) — relaxes pulmonary smooth muscle cells,
which leads to dilation of the pulmonary arteries.
Surgical therapies
- Pulmonary thromboendarterectomy. If present, a large
clot in the pulmonary artery may be surgically removed to improve blood flow
and lung function.
- Lung transplantation. Currently, this is the only cure
for primary pulmonary hypertension. Transplantation is reserved for advanced
pulmonary hypertension that is not responsive to medical therapy. The right
side of the heart will generally return to normal after the lung/lungs have
been transplanted. About 1,000 lung transplants are performed annually in
the United States. Many people are on the waiting list, yet a shortage of
donors is the major limiting factor. Your health care provider will discuss
transplantation if it is an appropriate treatment option for your condition.
- Heart/lung transplantation. This type of double organ
transplant is very rare but is necessary for all patients who have combined
lung and left heart failure.
©
Copyright 1995-2008 The Cleveland Clinic Foundation. All rights reserved
index#6530
|
