We call such clots deep vein thrombosis or "DVT", and if one of these clots breaks away and settles in the lungs it can kill.
A DVT can be diagnosed with a simple sonogram and usually treated with a common blood thinner. But according to the Centers for Disease Control and Prevention (CDC), as many as 100,000 people in the United States die each year from pulmonary embolisms - blood clots in the lung - brought on by DVT.
I'm a vascular surgeon at Wake Forest Baptist's Heart and Vascular Center, where I treat dozens of patients a year for clots in the legs, so I know it's time for the public to understand common risk factors and the signs of this potentially fatal condition.
Risks and Signs of Deep Vein Thrombosis
The trouble is the signs are often subtle. Patients feel pain in their legs, either in their calves or thighs. But often they mistake the pain for a pulled muscle or a simple ache.
With DVT, the pain is almost always accompanied by swelling, usually in the calf and around the ankle. These symptoms, however, usually are cause for alarm only in people already at risk for blood clots.
Those at risk include:
- Patients recovering from surgery
- Women taking birth control pills or hormone replacement therapy, especially smokers
- Some cancer patients
Obesity also increases the risk of clots by putting pressure on the veins. And some people are born with an imbalance in the clotting compounds in their blood that when combined with other risk factors greatly add to the chance of developing a clot.
DVT can occur at any age. As a vascular surgeon, I've treated teenagers and men and women well into their 80s. According to the CDC, between 300,000 and 600,000 Americans a year develop a blood clot in a leg or, in rare cases, in an arm.
So, if you have a risk factor for DVT and your leg hurts and swells, see your doctor immediately or go to the nearest emergency facility. A clot will show up on a sonogram and doctors can give you blood thinners that will prevent the clot from breaking up and lodging in the lungs.
Traveling and Deep Vein Thrombosis
Long car trips and flights can put people - especially those predisposed to clots - at even greater risk of DVT.
A simple anatomy lesson may help you understand. Blood flows through the arteries with the force of the beating heart. But the return trip to the heart requires a more complicated system. A series of valves in the veins prevents blood from flowing backward and pooling, but the force needed to pump the blood comes from the muscles in the legs and arms. Any time the legs are immobilized for long periods of time, the risk of DVT increases.
There's no proof that travel causes DVT. But anyone at risk for clots should be cautious when traveling for long periods of time. Drink plenty of fluids to stay hydrated. Take a break and walk around every hour or so. Also, flexing and pointing your feet works the calf muscles, which can help keep the blood flowing.
Deep Vein Thrombosis Treatment
DVT always requires immediate vascular treatment to prevent a piece of the clot from breaking loose and lodging in the lungs. Generally, treatment includes a series of injections of blood thinners, which stabilize the clot, followed by long-term use of a blood thinner taken orally to prevent further clots.
Many patients are under the false impression that the blood thinner dissolves the clot. It does not. In most cases the clot slowly dissolves and reabsorbs and the patient recovers without complication. But in about a third of patients, the clot causes permanent damage to the vein and the patient develops a condition known as venous insufficiency.
When a vein is damaged, blood and other fluids may pool in the legs. Symptoms include swollen ankles, discolored skin, pain and in the most extreme cases skin ulcers about the ankles. Until recently, doctors prescribed elastic stockings to prevent venous insufficiency. The stockings help keep blood from pooling in the veins by keeping the veins collapsed. But patients dislike them. They are hard to put on, and, to put it bluntly, many patients find them so ugly they won't wear them.
Recently, vascular surgeons have started more aggressive vascular treatment for blood clots. Wake Forest Baptist has been part of a national study funded by the National Institutes of Health that focuses on using clot-busting drugs to treat new DVT. A catheter is used to inject the drug directly into the clot, a procedure similar to the treatment for certain kinds of stroke. The study was designed to show whether vascular treatment with clot-busting drugs will prevent permanent damage to the veins.In the meantime, know the risk factors and signs of DVT. Pain in a leg with swelling in the ankle in someone at risk requires immediate medical attention. And if you're planning a long trip by car or plane, remember to get up and move around and drink plenty of fluids.