Deep Vein Thrombosis Introduction Deep vein thrombosis (DVT) is a blood clot in a vein. This condition can affect men and women of any age and race. DVT is a potentially serious condition. If not treated, the blood clot can travel to the lung and cause pulmonary embolism, which could be life threatening. Advances in medical technology have made it relatively easy to diagnose and treat deep vein thrombosis. This reference summary explains deep vein thrombosis. It discusses the causes, symptoms, diagnosis, and treatment options. Tips for preventing deep vein thrombosis are also presented. Anatomy To understand deep vein thrombosis, it may help to review the anatomy of the circulatory system. This system is made up of the heart, blood, and the blood vessels of the body. The heart pumps blood rich in oxygen to the body through the arteries. The arteries become smaller tiny vessels, called capillaries, which carry the blood into the body tissues and cells. The cells use the oxygen in the blood and return it as carbon dioxide. Blood then flows into veins, which carry the blood back to the heart. Veins have valves that prevent the blood from flowing back. Veins deep in the body are known as deep veins. Veins near the surface of the skin are called superficial veins. 1
The blood from the veins enters the right side of the heart, from there it is pumped to the lungs. In the lungs, blood picks up oxygen and gives away carbon dioxide. Deep Vein Thrombosis A deep vein thrombosis is a blood clot that forms in a vein deep in the body. Deep vein thrombosis is also called DVT, venous thrombosis, or blood clot in the legs. Most deep vein clots occur in the leg veins. They also can occur in other parts of the body. Blood clots in the veins in the thigh or pelvis are usually more serious than blood clots that happen in veins in your lower leg. If a clot in a vein breaks off and travels through your bloodstream, it can lodge in your lung. This is called a pulmonary embolism, which is a very serious condition that can cause death. Blood clots can also form in veins that are close to the surface of the skin. These types of blood clots are called superficial venous thrombosis or phlebitis. Blood clots in superficial veins cannot travel to the lungs. Blood Clot Causes Deep vein thrombosis is caused by a combination of sluggish blood flow and factors that may increase the tendency of blood to clot. Sitting for a long period of time like on a long trip in a car or on an airplane can increase your risk of deep vein clots. Low blood flow in a deep vein, due to injury, surgery, or immobilization can increase the risk of deep vein clots. Having an inherited medical condition that causes increased risk for clotting is another factor that increases the risk for deep vein clots. Deep vein thrombosis is more likely to occur with people that have medical conditions such as varicose veins, heart attack, or heart failure. People with cancer are more likely to get deep vein thrombosis. Pregnancy, especially the first 6 months after giving birth, increases the chances of having deep vein clots. 2
Women taking birth control pills or hormone therapy are more likely to have deep vein thrombosis. Smokers are at a higher risk of having DVTs. Although deep vein thrombosis can occur in any age group, it is more likely in people over age 60 and in overweight people. Your risk for deep vein clots increases if you have several factors at the same time. For example, a woman who smokes and who also takes birth control pills has an even higher risk for having a blood clot. Signs and Symptoms Only about half of the people with deep vein thrombosis have symptoms. Symptoms of DVT may include: Swelling of the leg or swelling along the vein in the leg Pain or tenderness in the leg. The pain is usually only in one leg and may only be present when standing or walking Feeling of increased warmth in the area of the leg that is swollen or that hurts Red or discolored skin Some people only find out they have a deep vein thrombosis after the clot has moved from the leg and traveled to the lung. This condition is known as pulmonary embolism. Symptoms of pulmonary embolism may include: Chest pain Shortness of breath Can t catch your breath It is important to contact your doctor right away if you have symptoms of a pulmonary embolism or deep vein thrombosis. Diagnosis Your doctor will obtain a medical history and examine you to determine if you have deep vein thrombosis. 3
Doppler ultrasound is the most common test used to diagnose deep vein clots. It uses sound waves to evaluate the flow of blood in your veins. A gel is put on the skin of the leg. A handheld device, called a transducer, is placed on the leg and passed back and forth over the affected area. The Doppler ultrasound sends sound waves from the leg to an ultrasound machine. A computer then turns the sounds into a picture. The picture is displayed on a T.V. screen where your doctor can see the blood flow in your leg. Venography may be performed if the Doppler ultrasound does not provide a clear diagnosis. A venogram is an x-ray used to Doppler Ultrasound examine veins. A dye is injected into a vein and then an x-ray is taken of the leg. The dye makes the vein visible on the x-ray. If the blood flow in the vein is slowed, it will show on the x-ray. Other less frequently used tests include magnetic resonance imaging and computer tomography. If your doctor suspects that an inherited disorder could be causing the clots, the doctor may order tests to screen for these disorders. Additional tests are very important if: You have a blood clot that cannot be linked to any other cause Someone in your immediate family has had a blood clot in a vein You have a blood clot in a vein at an unusual location, such as in an arm Treatment Options The main goals in treating deep vein thrombosis are to: Stop the clot from getting bigger Prevent the clot from breaking off in your vein and moving to your lungs Reduce your chance of having another blood clot There are several medications used to treat and/or prevent deep vein thrombosis, such as anticoagulants, thrombolytics, and thrombin inhibitors. 4
Anticoagulants, sometimes called blood thinners, decrease your blood s ability to clot. They are used to stop clots from getting bigger and to prevent a blood clot from forming. Anticoagulants do not break up blood clots that have already formed. Your body s natural system will dissolve the clot. Anticoagulants can either come as a pill, such as warfarin, or as an injection or shot, such as heparin or Lovenox. Heparin and warfarin may be given at the same time. Heparin and Lovenox will act quickly, while the warfarin takes 2 to 3 days before it starts to work. Once the warfarin is working, the heparin or the Lovenox will be stopped. Treatment for deep vein thrombosis with anticoagulants usually lasts for 3 to 6 months. However, if you are being treated for the prevention of a DVT in a short-term risk situation like surgery, your treatment may be shorter. If you have had clots before or if you have another illness, such as cancer, you will take anticoagulants for as long as those risk factors are present. If you have an inherited blood-clotting tendency, then you may need treatment indefinitely. The most common side effect of anticoagulants is bleeding. Blood tests will monitor how well the medicine is working. You should call your doctor right away if you are taking warfarin, Lovenox or heparin and have easy bruising or bleeding. Pregnant women should talk to their doctors before taking any blood thinner. Thrombolytics are medications given to quickly dissolve the blood clot. They are used to treat large clots causing severe symptoms. Because they can cause sudden bleeding, they are only used in life-threatening situations. Thrombin inhibitors are new medications that interfere with the clotting process. They are used in treating some types of clots and for patients who cannot take heparin. 5
Vena cava filters are used when you cannot take medications to thin your blood, or if you are taking blood thinners and continue to develop clots. The filter can prevent blood clots from moving from the vein in your legs to the lung (pulmonary embolism). The vena cava filter is inserted inside a large vein called the vena cava. It can catch the clots as they try to move through the body to the lungs. This treatment will prevent a pulmonary embolism, but will not stop you from developing more clots. At times, your doctor may recommend the use of graduated compression stockings. Graduated Compression stockings are worn on the legs from the arch of the foot to just above or below the knee. These stockings are tight at the feet and become looser as they go up the leg. This causes a gentle compression (or pressure) up your leg. The stockings provide support and reduce the chronic swelling that can occur in the leg after a blood clot has occurred. Compression stockings have some side effects: They can be uncomfortable when worn all day They can be hot They may be difficult to put on, especially for older adults and overweight people Much of the treatment for deep vein thrombosis takes place at home. It is important to: Take medications correctly Have blood work drawn as directed by your doctor Avoid activities that may cause a serious injury Ask your doctor about your diet, certain foods affect how well your anticoagulant works. 6
Talk to your doctor before taking any other medications, especially over-the-counter medications. You should discuss your activities with your doctor. In general, your activities do not need to be restricted. Prevention Preventing deep vein thrombosis depends on whether you have had a clot before or if you are at risk for developing a deep vein clot but never had one. If you have had a deep vein clot, then you will need to prevent further clots from developing by: Taking your medications to prevent or treat blood clots as prescribed by your doctor Following up with your doctor for medication changes and blood work If you have never had a deep vein clot, but are in a situation that may increase your risk, be sure to: Exercise your lower leg muscles if you will be sitting still for long periods of time. Get out of bed and move around as soon as you are able after having surgery or being ill. The sooner you move around the less chance you have to develop a clot. If you have never had a deep vein clot, you can also: Take medications to prevent clots after some types of surgery as directed by your doctor. Follow up with your doctor. Use special compression stockings if directed to do so by your doctor to prevent or reduce chronic swelling that can occur in the leg. Summary Deep vein thrombosis is a blood clot that forms in a vein deep in the body. Deep vein clots in the thigh and pelvis are more serious than those that happen in your lower leg. These clots are more likely to travel to the lung. Many things may increase your risk for deep vein clots. Some of these things alone can increase your risk; when several are combined, your risk increases further. 7
Only about half the people with deep vein clots have symptoms. Your doctor will obtain a medical history and examine you to determine if you have a deep vein clot. The main goals in treating deep vein thrombosis are to stop the clot from getting bigger, to stop the clot from breaking off your vein and moving to your lungs, and to decrease your chance of having another deep vein thrombosis. Medications are used to treat and/or prevent deep vein thrombosis. 8