Deep vein thrombosis (DVT) is the development of a blood clot (thrombus) in the deep veins of the legs, pelvis, or arms. Clots can form in superficial veins (called superficial thrombophlebitis or simply “phlebitis”) and in deep veins. While blood clots in superficial veins rarely cause serious problems, clots in deep veins require immediate medical evaluation.
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. One-way valves prevent the backflow 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. Blood clots in deep veins can grow in size, break loose, and then travel through the bloodstream to the lungs, resulting in a life-threatening pulmonary embolism.
Deep vein thrombosis can cause other long-term complications. In about 25% of cases, deep vein thrombosis damages the affected vein and leads to long-lasting post-thrombotic syndrome. This condition can cause pain, swelling, discoloration, and leg sores.
Blood clots can form in veins when you are inactive; for example, if you are paralyzed or bedridden or must sit while on a long flight or car trip. DVT has also been referred to as “Economy Class Syndrome” due to the occurrence after sitting on long flights.
RISK FACTORS FOR DEEP VEIN THROMBOSIS
- 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
SYMPTOMS OF DEEP VEIN THROMBOSIS
- DVT is characterized by generalized swelling of the affected leg. When measured, the affected leg may be larger than the other leg.
- Also, your affected leg may feel warm and be redder than the other leg.
- You may have pain or tenderness in the calf or thigh when it is touched or squeezed or with movement or standing. Calf or thigh pain may become constant and increase with squeezing or movement.
TREATMENT FOR DEEP VEIN THROMBOSIS
Clot-busting medications that dissolve clots in only an hour, instead of days, are now available for patients who have DVT. A vascular surgeon injects the medication then implants a mechanical vacuum called an Expedior® catheter to suck out any residual clots. A tiny retrievable vena cava filter is implanted to catch any potential traveling clots before they threaten the heart and lungs. This procedure has proven to be extremely effective.
Post-thrombotic syndrome is an under-recognized but relatively common aftereffect of having DVT if treated with blood thinners (anticoagulation) alone, because the clot remains in the leg.
Contrary to popular belief, anticoagulants do not actively dissolve a clot; they just prevent new clots from forming. The body will eventually dissolve a clot, but often the vein becomes damaged in the meantime. A significant proportion of these patients develop permanent irreversible damage in the affected leg veins and their valves, resulting in abnormal pooling of blood in the leg, chronic leg pain, fatigue, swelling, and, in extreme cases, severe skin ulcers.
While this used to be considered an unusual, long-term aftereffect, it actually occurs frequently, in as many as 60-70 percent of people, and can develop within two months of developing DVT. There is increasing evidence that clot removal via interventional catheter-directed thrombolysis in selected cases of DVT can improve quality of life and prevent the debilitating condition of post-thrombotic syndrome.
Left untreated, part of a deep vein thrombosis (DVT) can break off and travel in the blood stream, get trapped in the lung where it blocks the oxygen supply, and cause 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 (PE) 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 embolisms are caused by DVT
If a pulmonary embolism can be diagnosed and appropriate therapy started, the mortality can be reduced from approximately 30 percent to less than 10 percent.
Symptoms of Pulmonary Embolism
The symptoms are frequently nonspecific and can mimic many other cardiopulmonary events:
- Shortness of breath
- Rapid pulse
- Sharp chest pain
- Bloody sputum (coughing up blood)
If your doctor suspects that you have deep vein thrombosis after a medical history and physical examination, you will usually have ultrasound testing to verify the presence of a blood clot. Other tests, such as a venogram, are sometimes used if ultrasound results are unclear.