Blood clots can be deadly, but they are often preventable and treatable. (istockphoto)

Blood clots — jellylike masses of protein, blood cells and platelets — can be lifesaving when they stop bleeding caused by an injury. But they can be deadly if they form where they aren’t needed.

A clot in a vein close to the skin’s surface causes a burning or itching sensation yet typically doesn’t lead to serious problems. But a clot that develops in a vein deep in the lower abdomen or legs, called a deep-vein thrombosis, or DVT, can interfere with blood flow, often causing swelling and inflammation. It can also break up and form clots that travel through the bloodstream and lodge in the lungs, which can lead to severe organ damage and death.

Up to 100,000 people die each year in the United States from such pulmonary embolisms, according to the Centers for Disease Control and Prevention. But most blood clots are preventable and can usually be treated if discovered early.

The danger

Every year, as many as 600,000 Americans experience DVTs and clots in the lungs. (A DVT refers to a clot in the lower leg, thigh or pelvis. When clots occur in the arms or other areas, they’re usually referred to simply as venous thrombi.)

If traveling clots, or emboli, reach the lungs, they can block blood flow and cause a pulmonary infarction, a serious condition that can severely compromise lung function. Untreated pulmonary emboli lead to death in about 30 percent of cases, so it’s urgent to seek prompt medical care.

Who’s at risk?

Blood clots were very much in the news when it was announced in December that doctors had discovered a clot near the brain of Hillary Rodham Clinton, who was then the secretary of state. While Clinton’s clot might have been due to an earlier concussion, not all risk factors are injury-related.

A number of situations can increase your risk. They include:

●Sitting for longer than six to eight hours, such as during a trip in a car or plane.

●Having limited mobility due to a medical problem, surgery or paralysis.

●Having an injured vein from a bone fracture, severe muscle injury, trauma or major surgery (especially involving the abdomen, pelvis, hip or legs).

●Having a tube placed in a vein for medication or other treatment, such as a central venous catheter.

●Having heart failure or cancer in the abdomen.

●Having previously suffered a clot or having a family history of blood clots.

●Being pregnant, taking birth control pills or taking prescription hormones for menopause symptoms.

●Being older than 60, being overweight or obese, having high blood pressure or being a smoker.

●Having certain genetic or inherited blood-clotting disorders, such as Factor V Leiden.

Prevention measures

About half of the people with deep-vein thrombosis don’t have symptoms. So the best way to protect yourself is to reduce your risk by following a healthy lifestyle, including regular exercise, losing weight if needed and not smoking.

Avoid immobility. Sitting or lying down for long periods allows blood to pool and can induce clotting. If you’re on a long trip and are unable to get up, you can exercise your legs while in your seat. Wear loose-fitting clothing that doesn’t restrict blood flow.

Recognizing symptoms

Be alert for symptoms. See your doctor promptly if you have unexplained swelling, pain, tenderness or redness in an arm or leg, as they could be signs of a dangerous clot.

A clot in the lungs is more serious because it can quickly become deadly. Signs include difficulty breathing, a rapid or irregular heartbeat, chest pain or discomfort, coughing up blood and feeling faint. If you have any of those symptoms, go to an emergency room or call 911; prompt treatment is essential.


If you receive a diagnosis of a deep-vein thrombosis, your doctor will probably prescribe medication. The first anticoagulant treatment is usually given intravenously in the hospital, with heparin (preferably low-molecular-weight heparin) or fondaparinux (Arixtra and generics). This is often followed by warfarin (Coumadin, Jantoven and generics).

You probably won’t receive intravenous medication for more than a few days. After that, most people are switched to self-injections of heparin and to warfarin, which is usually taken in pill form. Warfarin takes two or three days to become effective, but once it does, heparin can be stopped and you can continue taking warfarin for several months or longer.

Copyright 2013. Consumers Union of the United States Inc.

For further guidance, go to, where more detailed information, including CR's ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.