It can happen to anyone at any age. Clots form in the deep veins, usually in the legs. Patients with this deep vein thrombosis might experience leg pain, redness or swelling…or they might have no symptoms at all.
These clots can break free and travel to the lungs, blocking blood flow. This condition, a pulmonary embolism, can easily be fatal.
The risk is elevated in people who…
Are immobile for extended periods. The veins require muscle movements to push blood back to the heart. If you can’t move your legs freely—because of an injury, a hospitalization or a long car or plane trip—blood tends to pool in the veins and gets “sludgy.”
Have cancer or are receiving chemotherapy. Some cancers and cancer treatments increase levels of procoagulants, clot-promoting substances in the blood.
Have an inherited blood-clotting disorder that causes blood to clot more easily.
Have a personal history or family history of deep vein thrombosis or pulmonary embolism.
Patients with deep vein thrombosis always are treated with an anticlotting medication, such as heparin or warfarin. (Heparin is given as an injection and acts quickly. Warfarin is a pill that takes two to three days to start working.) The drugs prevent a clot from getting larger while the body’s anticlotting mechanisms slowly break it down.
Anticlotting medication also may be given as a preventive measure. Patients undergoing an orthopedic procedure, such as knee or hip replacement, are routinely given anticlotting medication prior to surgery. (In the past, before anticlotting drugs, between 50% and 70% of patients would develop clots after surgery.)
Patients taking anticlotting medications should limit their consumption of foods high in vitamin K, which can affect how drugs such as warfarin work. Foods high in vitamin K include leafy green vegetables and canola and soybean oils.
Other medications your doctor might prescribe…
Low-dose aspirin. Two recent studies in The New England Journal of Medicine found that patients with deep vein thrombosis who were treated for three to six months with anticlotting medication could be started on 100 milligrams of aspirin after these medications were stopped. This prevented recurrent clots.
Rivaroxaban (Xarelto). This is a new oral blood thinner approved by the Food and Drug Administration for the treatment of blood clots. It also reduces the recurrence of clots.
Your doctor may recommend compression stockings, which usually are worn from your foot to about knee level. These exert pressure on the legs and cause less pooling of blood. They are recommended for patients who have had a blood clot in the legs.
Different patients require different amounts of leg pressure. I usually recommend stockings with a pressure of 20 to 30 mmHg (millimeters of mercury). These are available at pharmacies for about $20 a pair—much less than prescription stockings.
Even if you have never had a blood clot, you still need to take measures to prevent one…
Flex and extend feet and knees. It’s among the best ways to prevent clots from forming in the leg veins. When you’re sitting or lying down for more than two hours—in the hospital, on an airplane—rotate your ankles and flex your toes at least three times an hour. If you’re able to stand, flex the calf muscles by rising up and down on your toes. It pushes blood out of the veins.
Drink more water. Dehydration is a common cause of clots because it decreases blood volume and makes blood “sticky.” It’s particularly important to drink more water during airplane flights because the dry air increases dehydration. Drink a large glass of water before getting on a plane, and have several glasses during your flight.
Lose weight. Patients with a body mass index (BMI) of 40 or higher have an elevated risk for clots when they are immobile or have surgery. Those who lose weight and lower their BMI can reduce their blood clot risk. In addition, quit smoking and control your blood pressure—these measures also can lower your risk.
Source: Geno J. Merli, MD, FACP, FHM, FSVM, an internist and a leading specialist in vascular medicine. He is a professor of medicine and codirector of Jefferson Vascular Center, part of Thomas Jefferson University Hospitals in Philadelphia. He specializes in the treatment and prevention of deep vein thrombosis and pulmonary embolism.