One in four deaths worldwide are the result of blood clots (thrombosis), according to the International Society on Thrombosis and Haemostasis (ISTH), which founded World Thrombosis Day (October 13). The Centers for Disease Control and Prevention (CDC) estimates that blood clots affect as many as 900,000 Americans each year. Now the CDC and the National Blood Clot Alliance (NBCA) are raising awareness about the life-threatening but preventable condition through the “Stop the Clot, Spread the Word” public education campaign. “This is probably one of the biggest health problems that the public doesn’t know about,” says Elliott R. Haut, MD, associate professor of surgery, anesthesiology, and critical care medicine at Johns Hopkins School of Medicine in Baltimore. “The number of people who die from clots is more than breast cancer, AIDS, and motor vehicle collisions combined. But when you ask people on the street what they know about it, they just don’t know that much,” says Dr. Haut. “So I think a big national campaign is absolutely the right thing to do.” The awareness campaign focuses on deep vein thrombosis (DVT), in which blood clots occur in one of the large veins, usually in a leg or arm. These clots can break loose and travel to the lungs, blocking off blood flow to the lungs, known as a pulmonary embolism (PE). Blood clots can also lead to stroke and heart attack.
What Are the Risk Factors for a Blood Clot?
There are several factors that can raise your risk for blood clots. One of the most common is hospitalization, especially when associated with physical trauma, major surgery, and extended immobility. About one-half of all blood clots occur during hospitalization or within three months of a hospital stay or surgery, according to the CDC. Other possible risk factors include:
A family history of blood clots or inherited clotting disorderSitting too long, such as traveling for more than four hoursBeing overweightSmokingBirth control or hormone replacement therapy involving estrogenSerious medical conditions, such as heart and lung disease, diabetes, and cancer
Cancer Patients at Especially High Risk
Cancer patients are especially susceptible to thrombosis. About 20 percent of clots occur in individuals who have cancer. Clots are the second leading cause of death among cancer patients, according to the North American Thrombosis Forum. “Among people with cancer, survival rates are lower for people who also have blood clots,” says Karon Abe, PhD, a health scientist in the CDC’s division of blood disorders in the National Center on Birth Defects and Developmental Disabilities. “The risk of a dangerous blood clot is greatest in the first few months after a cancer diagnosis, the time when treatment generally occurs.” “It’s tragic when a patient is mounting a successful fight against cancer and then loses life due to a blood clot,” says Alok Khorana, MD, professor of medicine at Cleveland Clinic Lerner College of Medicine and Case Western Reserve University in Ohio. Dr. Khorana suggests that clots may even fuel the cancer and make it worse. “Cancer cells may use the properties of blood clots to grow or metastasize faster,” he says. “Research is ongoing to better understand this association.”
Why Are Cancer Patients Susceptible to Clots?
Cancer is often associated with the production of substances that increase the risk for blood clots. “Certain types of cancer secrete proteins which make patients more susceptible to clots,” says Khorana. Some types of cancers pose a greater danger for clots than others, including cancers of the pancreas, stomach, brain, lungs, uterus, ovaries, and kidneys, and certain blood cancers, such as lymphoma and myeloma. In some cases, tumors can compress blood vessels, making it easier for clots to form. “In addition, certain anti-cancer treatments, including chemotherapy, targeted therapy, and surgery, can increase the risk further,” says Khorana. Dr. Abe with the CDC adds that hospitalization, treatment with hormones, and catheters (thin tubes placed in the veins for administering various treatments) are also risk raisers.
How to Prevent Trouble From a Blood Clot?
Khorana urges people to be alert to the symptoms of a blood clot, especially leg swelling, calf pain, sudden shortness of breath, and chest pain. “Go to the ER or call 911 immediately if you’re having new onset chest pain or shortness of breath,” he says. Patients want to try to catch a clot before it travels and may become life-threatening.
How Are Blood Clots Treated
If doctors detect a blood clot, they may prescribe anticoagulants (blood thinners such as heparin) that help prevent clots from forming, or thrombolytics that dissolve clots that have already formed. Compression stockings can reduce leg swelling and the risk of clot formation. In some cases, surgery may be performed. Stents are sometimes used to treat clots, but they can also raise the risk for further clotting. There are also vascular filters called vena cavas filters, which are placed in the body’s largest vein to catch clots before they can travel to the lungs. “Work with your healthcare providers to get the right medication to help avoid the problem,” Haut says. “We can’t stop every blood clot in the world, but they are preventable.”
