A blockage outside the heart can be just as dangerous as a heart attack.
A blood clot in the coronary arteries can cause a heart attack. But a blood clot in a large vein somewhere else in the body, called venous thromboembolism (VTE), can also end in a medical emergency. Fortunately, the risk factors for heart attacks and “vein attacks” are similar, and therefore VTE is preventable. And if you do develop a clot, treatment with anticoagulant medications can protect you from developing another.
Venous thromboembolism (VTE) means “blood clot in the veins.” If a clot breaks off and travels up the aorta  and through the heart  into the lungs, the resulting pulmonary embolism  can be fatal.
Where VTE strikes
VTE includes two kinds of problems. When a clot forms in the large veins of the arms, legs, or pelvis, it’s called deep vein thrombosis (DVT). Pulmonary embolism (PE) refers to a blockage in the lungs. PE can be fatal, or in some cases can damage the right side of the heart.
A report by the Surgeon General estimated that at least 600,000 Americans develop a deep-vein clot each year, and 100,000 to 180,000 die as a result. More than half of all VTEs occur after age 60. Fortunately, a heart-healthy lifestyle reduces risk for the condition, says Dr. Samuel Z. Goldhaber, a senior cardiologist and expert on VTE at Harvard-affiliated Brigham and Women’s Hospital.
“Many of the same risk factors for cardiovascular disease are also risk factors for VTE, such as cigarette smoking, poorly controlled blood pressure, high cholesterol, obesity, and diabetes,” Dr. Goldhaber says.
Why we clot
The body has a special system for clotting after injury. That’s a good thing, because otherwise you could lose too much blood when injured. “But with VTE, it’s a good thing that has gone too far,” Dr. Goldhaber says.
When a blood clot forms in a large vein, it can cause swelling in the affected limb, pain and tenderness, redness, and skin that feels warm to the touch. If a clot breaks off and travels to the lungs, causing a PE, the person commonly has difficulty breathing, breathes rapidly and gasps for air, or feels a stabbing chest pain when taking a breath. This is a medical emergency. “The death rate is double that of heart attack,”
Dr. Goldhaber says.
Most people recover from a PE. However, there can be damage to the heart or lungs, so it’s best to do everything you can to prevent it.
To help prevent painful or dangerous vein clotting, take the following steps:
Be active: “Stay physically active and do everything possible to avoid immobility,” Dr. Goldhaber says. “That means being on a heart-healthy exercise program, with some sort of exercise, such as walking, for at least 30 minutes a day, six days a week.”
Eat right: Eat a heart-healthy diet and maintain a lean body weight. Being overweight is a major risk factor for PE.
Know your family history: Clotting problems can be hereditary, so if the condition runs in your family, make sure your doctor knows about it.
Talk to your surgeon: In the aftermath of surgery or an accident, the clotting system is on high alert; it’s trying to protect you. Find out ways you can reduce your risk of developing a blood clot. “Ask the surgeon, ‘What are you going to do to prevent me from having a DVT?'” Dr. Goldhaber says.
Treatment for clots
If you do develop a DVT or PE, the immediate priority will be to clear the clot from the blocked area. Then you need to prevent another from happening. This is a complex issue, and your doctor’s approach will depend on your individual health status and risk factors.
You may initially receive an injection of clot-dissolving medication, followed by a prescription for an anticoagulant to suppress the body’s clotting system. Since the 1950s, the premier oral anticoagulant drug has been warfarin (Coumadin).
Warfarin saves countless lives every day, but it comes with a price. On warfarin, the risk of unwanted major bleeding is 1% to 2% per year. While taking warfarin, you must have regular lab tests and regulate your consumption of certain foods that could interact with the drug and increase the risk of bleeding.
How long on anticoagulation?
How long you are likely to be on warfarin depends on your situation. If the clot followed a major operation or a broken bone, you may need to continue taking warfarin for three to six months. However, if the clot came out of the blue, the situation changes. “If it’s truly unprovoked, your chance of another clot in the ensuing 10 years is about 50%,”
Dr. Goldhaber says.
Current expert guidelines call for indefinite anticoagulation after an unprovoked deep-vein clot. Your doctor may try to get you off warfarin sooner if you are at very high risk of bleeding.
Even with proper treatment, survivors can suffer long-term problems. Within two years of a DVT, 30% of people experience post-thrombotic syndrome, which causes chronic leg pain, swelling, and, on rare occasions, a painful, nonhealing leg ulcer. About 2% to 4% of PE survivors develop chronic thrombotic pulmonary hypertension, which causes breathlessness and fainting with exertion.
Wearing vascular compression stockings to aid blood flow through the legs can help prevent post-thrombotic syndrome. Doctors generally prescribe below-knee stockings, which should be worn during the day but not at night while in bed. The stockings should be replaced every three months after they lose elasticity. And they should be worn for about two years.
Leg veins contain small valves  that help to keep blood moving toward the heart. In deep vein thrombosis, a clot forms near one of the valves . If a piece of the clot , called an embolus, breaks off and enters the circulation, it can travel to the lungs and block an artery. This is a potentially fatal event known as a pulmonary embolism.
If you have been living with a clotting problem, you may have already heard of a new generation of anticoagulants coming into use. One, rivaroxaban (Xarelto), is already FDA-approved for preventing DVT and PE after total hip or knee replacement and to prevent stroke in people with the heart condition atrial fibrillation.
Steps to prevent DVT
Recent clinical trial results suggest that the new anticoagulants may eventually gain approval for use in treating DVT or PE, thus becoming the “new” warfarin. In the most recent major trial of PE, rivaroxaban prevented new clots just as well as standard warfarin-based therapy, with half the risk of major bleeding due to the anticoagulation medication itself.
These so-called novel anticoagulants have pluses and minuses, and the
FDA is weighing them. Compared with warfarin, rivaroxaban is potentially much easier for doctors to administer and for people to take. Another advantage is that laboratory tests are not required for people on rivaroxaban, unlike
those taking warfarin. On the other hand, the lab tests can alert your
doctor if the anticoagulation medication is not working as expected.
“I’m very excited about this new tool in our armamentarium,” Dr. Goldhaber said on his weekly video Clot Blog (blogs.theheart.org/clot-blog) after the rivaroxaban PE trial results were announced in March 2012. “The next step will be to see if real-world experience follows the clinical trial results.”