Deep vein thrombosis (dvt) – blood clot in leg clotcare

A deep vein thrombosis (DVT) is a potentially deadly condition caused by a blood clot that forms in a vein – most commonly the deep veins in the legs. This clot formation can happen if the vein is damaged or if the blood flow in the vein is slow or stops. DVT can cause pain and swelling in the leg, but many times it produces no symptoms. If the clot breaks off and travels in the bloodstream, it can cause damage to the lungs. When a blood clot travels to the lungs, it is called a pulmonary embolism (PE). A PE often causes shortness of breath and chest pain. If the lung damage is severe, it can kill people very quickly, even before treatment can be given. For this reason, every effort should be made to prevent a DVT before it happens.


Although there are several effective methods to prevent blood clots, a recent study found that more than one-half of patients who developed a DVT in the hospital did not receive any of these preventive methods. For more information on this study, go to the DVT Prophylaxis page of our site.

Although you may have never heard about it before, DVT is a common medical problem. It is estimated that 2 million people in the United States develop a DVT every year — many of them don’t even know it. Of those who develop a pulmonary embolism, up to 200,000 die each year, which is more than die annually in the US from breast cancer and AIDS combined.

Some people are more prone to getting blood clots in the leg. The chances of getting a DVT increase as we age and doubles with each decade of life over the age of 40. For example, someone who is 80 years old is twice as likely to get a DVT as someone who is 70 years old and 16 times more likely than someone who is 40 years old. People who have had a DVT in the past are at a much higher risk of getting another DVT. Additionally, some people inherit conditions from their parents that make them more prone to forming blood clots.

A small blood clot below the knee is unlikely to cause symptoms or complications. However, if a clot extends or forms above the knee, it may break away, travel in the blood, and block a blood vessel in the lung. A clot that blocks a blood vessel in the lung is called a pulmonary embolism (PE). People who get a PE may develop sudden shortness of breath, coughing, or chest pain. Depending on the size of the clot, a PE can be life-threatening.

DVTs frequently damage the valves in the leg veins. Valves in the leg veins help blood to flow upward toward the heart and prevent blood from flowing backward toward the feet. When these valves become damaged by DVT, the blood pools in the leg instead of flowing upwards toward the heart. This pooling of blood can cause chronic leg swelling and pain, as well as skin changes and leg sores. This condition is called the post-thrombotic syndrome. The pain from post-thrombotic syndrome often remains even after you have stopped taking warfarin and/or after a clot has dissolved. Click here to learn more about post-thrombotic syndrome.

a venogram – This test is the "gold standard" for confirming a clot inside a vein, but it involves injecting a dye into the veins in the foot and then taking an x-ray of the veins in the leg to see if there is a clot present. The dye may cause some discomfort when injected and, in some cases, may even stimulate the blood to clot. Consequently, venograms are usually reserved for clinical studies and/or when the ultrasound result is uncertain.

People who are hospitalized are at higher risk for developing a DVT. Surgery, especially surgery that involves a leg joint or hip, dramatically increases the risk of having a DVT. Therefore, at the time of admission to a hospital, a health care practitioner should do a careful DVT risk assessment. Various methods can be used to keep the risk of DVT as low as possible. This may include anticoagulant medicines that inhibit the blood’s tendency to clot. Anticoagulant medicines are often referred to as "blood thinners," but they do not actually thin the blood. Rather, they reduce the body’s ability to form a blood clot. In some cases, an intermittent compression device that automatically squeezes the feet and lower legs is used to increase the blood flow in the legs.

Although the risk of developing a DVT during long-distance travel is quite low, it is a good idea to exercise the legs at least once every hour during the trip. Regular exercise at least once every hour means taking regular breaks if driving or walking the aisle if traveling by train, bus, or airplane. Travelers who are at risk of developing a DVT may wish to wear graduated compression stockings. These compression stockings can be purchased in different lengths and are designed to provide different levels of compression pressure. A patient should consult his/her healthcare provider for advice on which design and pressure gradient would be best for him or her. Click here to learn more about graduated compression stockings, including information on where to get them.

The most common treatment for a DVT is anticoagulant medicines. Anticoagulants such as heparin or low molecular weight heparin (LMWH) are initially given in an arm vein or injected just under the skin for several days. Common brand names of these drugs include Lovenox, Innohep, Fragmin, and Arixtra. The purpose of these anticoagulant medicines is to turn off the clotting system in the body.

After a few days, most patients begin taking warfarin (brand name Coumadin) tablets by mouth. The heparin or low molecular weight heparin is continued with the warfarin for at least 5 days. The heparin or low molecular weight heparin should not be stopped until the patient’s INR is in range and stable. The INR is the test used to measure the effectiveness of warfarin. Anticoagulation drugs require regular blood tests (the PT-INR test) to check if too little or too much of the drug is being taken. Click here to learn more about the INR.

Warfarin works differently than heparin and low molecular weight heparin. Whereas heparin/LMWH work to turn off the clotting system, warfarin works to keep the clotting system from becoming activated once it has been turned off. The length of time that a patient will need to take warfarin depends on what caused the blood clot and if the patient has had blood clots in the past. If it’s the patient’s first blood clot and it was provoked by a temporary cause, such as trauma or surgery, then 3 months of anticoagulation may be enough. If the clot was unprovoked or caused by a chronic condition, the usual recommendation is to treat with anticoagulation for at least 6 to 12 months. If the patient has had two or more unprovoked recurrent clots or if there is a biochemical condition that increases the risk of clot formation, then warfarin may be continued life-long. There are some clinicians who favor life-long anticoagulation after a single unprovoked DVT or PE.

To reduce the swelling caused by DVTs and to prevent post-thrombotic syndrome, some doctors recommend wearing graduated compression stockings. These stockings should be worn throughout the day, can be purchased in different lengths, and are designed to provide different levels of compression pressure. A patient should consult his/her healthcare provider for advice on which design and pressure gradient would be best for him or her. Click here to learn more about graduated compression stockings.

The Coalition to Prevent DVT serves "to reduce the immediate and long-term dangers of deep-vein thrombosis (DVT) and pulmonary embolism (PE), which together comprise one of the nation’s leading causes of death. The Coalition will educate the public, healthcare professionals and policy-makers about risk factors, symptoms and signs associated with DVT, as well as identify evidence-based measures to prevent morbidity and mortality from DVT and PE." (Mission statement as it appears on www.preventdvt.org)