Facts
Deep Vein Thrombosis and Pulmonary Embolism (DVT/PE) are often underdiagnosed and serious, but preventable medical conditions.
Deep vein thrombosis (DVT) is a medical condition that occurs when a blood clot forms in a deep vein. These clots usually develop in the lower leg, thigh, or pelvis, but they can also occur in the arm.
It is important to know about DVT because it can happen to anybody and can cause serious illness, disability, and in some cases, death. The good news is that DVT is preventable and treatable if discovered early.
Complications of DVT
The most serious complication of DVT happens when a part of the clot breaks off and travels through the bloodstream to the lungs, causing a blockage called pulmonary embolism (PE). If the clot is small, and with appropriate treatment, people can recover from PE. However, there could be some damage to the lungs. If the clot is large, it can stop blood from reaching the lungs and is fatal.
In addition, nearly one-third of people who have a DVT will have long-term complications caused by the damage the clot does to the valves in the vein called post-thrombotic syndrome (PTS). People with PTS have symptoms such as swelling, pain, discoloration, and in severe cases, scaling or ulcers in the affected part of the body. In some cases, the symptoms can be so severe that a person becomes disabled.
For some people, DVT and PE can become a chronic illness; about 30% of people who have had a DVT or PE are at risk for another episode.
Risk Factors for DVT
Almost anyone can have a DVT. However, certain factors can increase the chance of having this condition. The chance increases even more for someone who has more than one of these factors at the same time.
Following is a list of factors that increase the risk of developing DVT:
Injury to a vein, often caused by:
Fractures,
Severe muscle injury, or
Major surgery (particularly involving the abdomen, pelvis, hip, or legs).
Slow blood flow, often caused by:
Confinement to bed
(e.g., due to a medical condition or after surgery);
Limited movement (e.g., a cast on a leg to help heal an injured bone);
Sitting for a long time, especially with crossed legs; or
Paralysis.
Increased estrogen, often caused by:
Birth control pills
Hormone replacement therapy, sometimes used after menopause
Pregnancy, for up to 6 weeks after giving birth
Certain chronic medical illnesses, such as:
Heart disease
Lung disease
Cancer and its treatment
Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
Other factors that increase the risk of DVT include:
Previous DVT or PE
Family history of DVT or PE
Age (risk increases as age increases)
Obesity
A catheter located in a central vein
Inherited clotting disorders
Preventing DVT
The following tips can help prevent DVT:
Move around as soon as possible after having been confined to bed, such as after surgery, illness, or injury.
If you’re at risk for DVT, talk to your doctor about:
Graduated compression stockings (sometimes called “medical compression stockings”)
Medication (anticoagulants) to prevent DVT.
When sitting for long periods of time, such as when traveling for more than four hours:
Get up and walk around every 2 to 3 hours.
Exercise your legs while you’re sitting by:
Raising and lowering your heels while keeping your toes on the floor
Raising and lowering your toes while keeping your heels on the floor
Tightening and releasing your leg muscles
Wear loose-fitting clothes.
You can reduce your risk by maintaining a healthy weight, avoiding a sedentary lifestyle, and following your doctor's recommendations based on your individual risk factors.
Symptoms
Know the Signs. Know your Risk. Seek Care.
Everybody should know the signs and symptoms of DVT/PE, their risk for DVT/PE, to talk to their health care provider about their risk, and to seek care immediately if they have any sign or symptom of DVT/PE
DVT
About half of people with DVT have no symptoms at all. The following are the most common symptoms of DVT that occur in the affected part of the body:
Swelling
Pain
Tenderness
Redness of the skin
If you have any of these symptoms, you should see your doctor as soon as possible.
PE
You can have a PE without any symptoms of a DVT.
Signs and symptoms of PE can include:
Difficulty breathing
Faster than normal or irregular heart beat
Chest pain or discomfort, which usually worsens with a deep breath or coughing
Anxiety
Coughing up blood
Very low blood pressure, lightheadedness, or fainting
If you have any of these symptoms, you should seek medical help immediately.
Diagnosis of DVT and PE
The diagnosis of DVT or PE requires special tests that can only be performed by a doctor. That is why it is important for you to seek medical care if you experience any of the symptoms of DVT or PE.
Treatments for DVT and PE
DVT
Medication is used to prevent and treat DVT. Compression stockings (also called graduated compression stockings) are sometimes recommended to prevent DVT and relieve pain and swelling. These might need to be worn for 2 years or more after having DVT. In severe cases, the clot might need to be removed surgically.
PE
Immediate medical attention is necessary to treat PE. In cases of severe, life-threatening PE, there are medicines called thrombolytics that can dissolve the clot. Other medicines, called anticoagulants, may be prescribed to prevent more clots from forming. Some people may need to be on medication long-term to prevent future blood clots.
Did you know?
DVT does not cause heart attack or stroke. There are two main types of blood clots.
How a clot affects the body depends on the type and location of the clot:
A blood clot in a deep vein of the leg, pelvis, and sometimes arm, is called deep vein thrombosis (DVT). This type of blood clot does not cause heart attack or stroke.
A blood clot in an artery, usually in the heart or brain, is called arterial thrombosis. This type of blood clot can cause heart attack or stroke.
Both types of clots can cause serious health problems, but the causes and steps you can take to protect yourself are different. To learn more about arterial thrombosis, visit CDC’s information about heart disease and stroke prevention.
Diagnosis of DVT and PE
The diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE) requires special tests that can only be performed by a doctor. That is why it is important for you to seek medical care if you experience any of the symptoms of DVT or PE. Some of the tests that may be performed are listed below.
DVT
DVT is often diagnosed using:
Duplex ultrasound—It uses sound waves to evaluate the flow of blood in the veins.
Venography—If the duplex ultrasound does not provide a clear diagnosis, a venogram, a type of X ray, is used to look at the veins to see if clots are present.
D-dimer—A blood test that can be used to rule out a clot.
DVT also can be diagnosed using the following, less frequently used, tests:
In many cases, magnetic resonance imaging (MRI) can provide information that would not show up on an x-ray. This test is being used more frequently to diagnose DVT.
A computed tomography scan is a special type of x-ray that can provide pictures of structures inside the body. However, this test is rarely used to diagnose DVT.
PE
Tests to find the location of and damage to the lungs caused by a PE include:
Computerized tomography (CT scan) of the lung, a special type of x-ray that can provide pictures of structures inside the body.
Pulmonary ventilation or perfusion scan, a special test looks at how the lung is working and if it is getting enough blood.
Pulmonary angiogram, the injection of a dye into the heart and then an x-ray, to look for clots in the lung.
Diagnosis Can Be Difficult
Unfortunately, there are other conditions whose symptoms are similar to those of DVT and PE. For example, muscle strains and swelling of veins close to the skin can mimic the symptoms of DVT. Heart attack and pneumonia have symptoms similar to those of PE. Therefore, it is difficult to diagnose either condition without tests.
Treatments of DVT and PE
DVT
Medication is used to prevent and treat DVT. Anticoagulants (blood thinners) are the medicines most commonly used. Although called blood thinners, these medications do not actually thin the blood. They work by stopping the clotting process and preventing the clot from becoming larger. The most frequently used medications are heparin, low molecular weight heparin (LMWH), and warfarin. All of these medications can cause bleeding, so people taking them have to be monitored to prevent unusual bleeding.
Heparin
Initial treatment of a clot is usually with heparin. Heparin is a powerful anticoagulant that is given IV (through a needle placed in the vein) or by an injection that works very quickly to stop clotting. Heparin is usually given while a person is in the hospital. Because heparin can cause bleeding, a person has to be monitored closely to prevent bleeding.
LMWH
LMWH is similar to heparin, but is given by an injection under the skin. People who take LMWH do not require frequent blood tests to monitor for bleeding, so this drug can be given at home.
Warfarin
Warfarin (Coumadin™) is a medicine that is taken by mouth. Warfarin works to stop clotting but because it takes some time to become effective it is usually started while a person is taking heparin or LMWH. Once it is effective the heparin is stopped and a person continues treatment with warfarin at home. People who take warfarin have to be monitored with frequent blood tests to see how the drug is working and to make sure that they are not at risk of bleeding. While taking warfarin it is important to eat a consistent diet and let your health care provider know if you change medications, because many foods and other medications affect the way that warfarin works.
Compression stockings
Compression stockings (also called graduated compression stockings) are sometimes recommended to prevent DVT and relieve pain and swelling. These might need to be worn for 2 years or more after having DVT.
Surgery
In severe cases, the clot might need to be removed surgically.
PE
Emergency treatment at a hospital is necessary to treat PE. In cases of severe, life-threatening PE, there are medicines that can dissolve the clot (thrombolytics) and medicines that prevent more clots from forming (anticoagulants).
Surgery is sometimes needed for patients at great risk for another PE.
Research and Treatment Centers
CDC supports the Thrombosis and Hemostasis Centers Research and Treatment Centers to foster collaborative epidemiologic research designed to identify risks for DVT/PE among the U.S. population and ultimately to improve diagnosis and treatment of these conditions. The centers collect data from patients of all ages and races while providing services to patients with DVT/PE and other thrombotic conditions. Currently, CDC funds five centers. These centers have multidisciplinary teams of health care specialists and state-of-the art clinical research programs that provide outreach and education programs for patients. Below is the contact information for these centers.
