What is Deep Vein Thrombosis (DVT)?
Deep vein thrombosis (DVT) is the formation of a blood clot, also known as a thrombus, in the deep leg vein of the thigh. It is a very serious condition that can cause permanent damage to the leg, known as post-thrombotic syndrome, or even life-threatening pulmonary embolism. In the United States alone, 600,000 new cases of DVT are diagnosed each year. One in every 100 people who develops DVT dies. It has sometimes been referred to as "Economy Class Syndrome" because it can occur after sitting on long flights.
The deep veins that lie near the center of the leg are surrounded by powerful muscles that contract and force deoxygenated blood back to the lungs and heart. Valves in the vein prevent the back-flow of blood between the contractions. (Blood is squeezed up the leg against gravity and the valves prevent it from flowing back to our feet.) When the circulation of the blood slows down due to illness, injury or inactivity, blood can accumulate or "pool," which provides an ideal setting for clot formation.
The deep veins that lie near the center of the leg are surrounded by powerful muscles that contract and force deoxygenated blood back to the lungs and heart. Valves in the vein prevent the back-flow of blood between the contractions. (Blood is squeezed up the leg against gravity and the valves prevent it from flowing back to our feet.) When the circulation of the blood slows down due to illness, injury or inactivity, blood can accumulate or "pool," which provides an ideal setting for clot formation.
What are risk factors for DVT?
- Previous DVT or family history of DVT
- Immobility, such as bed rest or sitting for long periods of time
- Recent surgery
- Above the age of 40
- Hormone therapy or oral contraceptives
- Pregnancy or post-partum
- Previous or current cancer
- Limb trauma and/or orthopedic procedures
- Coagulation abnormalities
- Obesity
What are symptoms of DVT?
- Discoloration of the legs
- Calf or leg pain or tenderness
- Swelling of the leg or lower limb
- Warm skin
- Surface veins become more visible
- Leg fatigue
How is DVT diagnosed?
Your blood may be tested to check the level of D-dimer. This small protein fragment can be found in blood when there has been a recent development of clot. However, this blood test isn't perfect and doesn't tell us where, or how much, clot there is.
Duplex ultrasound is used to evaluate DVT in the legs. Ultrasound is painless and noninvasive. It uses high-frequency sound waves to produce images of blood vessels. The test is performed by an ultrasound technologist, after which a radiologist -- a doctor specially trained to analyze medical images -- carefully reviews the study to look for any signs of DVT.
Duplex ultrasound is used to evaluate DVT in the legs. Ultrasound is painless and noninvasive. It uses high-frequency sound waves to produce images of blood vessels. The test is performed by an ultrasound technologist, after which a radiologist -- a doctor specially trained to analyze medical images -- carefully reviews the study to look for any signs of DVT.
What is Pulmonary Embolism (PE)?

Left untreated, a deep vein thrombosis (DVT) can break off and travel in the circulation, getting trapped in the lung, where it blocks the oxygen supply, causing heart failure. This is known as a pulmonary embolism, which can be fatal. With early treatment, people with DVT can reduce their chances of developing a life threatening pulmonary embolism to less than one percent. Blood thinners like heparin and coumadin are effective in preventing further clotting and can prevent a pulmonary embolism from occurring.
- It is estimated that each year more than 600,000 patients suffer a pulmonary embolism
- PE causes or contributes to up to 200,000 deaths annually in the United States
- One in every 100 patients who develop DVT die due to pulmonary embolism
- A majority of pulmonary embolism are caused by DVT
- If pulmonary embolism can be diagnosed and appropriate therapy started, the mortality can be reduced from approximately 30 percent to less than ten percent
What are symptoms of PE?
The symptoms are frequently nonspecific and can mimic many other cardiopulmonary events:
- Shortness of breath
- Rapid pulse
- Sweating
- Sharp chest pain
- Bloody sputum (coughing up blood)
- Fainting
What is an IVC filter?
Inferior vena cava (IVC) filters trap large clot fragments and prevent them from traveling through the vena cava vein to the heart and lungs, where they could cause severe complications or even death.
Who needs an IVC filter?
Inferior vena cava (IVC) filters are placed in patients who have a history of or are at risk of developing blood clots in the legs, including patients:
IVC filters are used when patients cannot be successfully treated by other methods, including blood thinning agents.
- diagnosed with deep vein thrombosis (DVT)
- with pulmonary embolus
- who are trauma victims
- who are immobile
- who have recently had surgery or delivered a baby
IVC filters are used when patients cannot be successfully treated by other methods, including blood thinning agents.
What are the risks and benefits of IVC filters?
Benefits
- No surgical incision is needed -- only a small nick in the skin that does not have to be stitched closed.
- The filter has a high rate of success in protecting lungs from serious pulmonary emboli (PE) in patients who have failed conventional medical therapy or cannot be given conventional medical therapy.
- Any procedure where the skin is penetrated carries a risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in 1,000.
- There is a very slight risk of an allergic reaction if contrast material is injected.
- Any procedure that involves placement of a catheter inside a blood vessel carries certain risks. These risks include damage to the blood vessel, bruising or bleeding at the puncture site, and infection.
- There is a chance that the IVC filter can lodge in the wrong place, change position or penetrate through the vein (which can rarely lead to injury of a nearby organ).
- The IVC filter or a piece of the IVC filter may break loose and travel to the heart or lungs causing injury or death.
- Rarely, IVC filters become so filled with clots that they block all flow in the blood vessel, causing swelling in the legs.
- In some cases, retrievable filters become scarred to the vein and cannot be removed, in which case they are left in permanently (as they are also designed to do).
Disclaimer
The information presented here is for the general knowledge of our patients and is not intended to be comprehensive or definitive. We strongly recommend that you see a doctor if you have any questions or concerns.
The information presented here is for the general knowledge of our patients and is not intended to be comprehensive or definitive. We strongly recommend that you see a doctor if you have any questions or concerns.