Important information about prevalence, risks and treatment
March is Deep Vein Thrombosis (DVT) Awareness Month, also known as Blood Clot Awareness Month. Dr. K. Francis Lee, medical director at Advanced Vein Care Center, one of the premier treatment centers in New England for venous diseases, discussed the importance of deep vein blood clots, noting that increased awareness is needed for the public.
“Deep vein thrombosis is a potentially life-threatening condition that can happen suddenly, and it is much more common than people are aware,” said Dr. Lee. “Its incidence is not exactly known, but it is estimated to affect nearly 1 million people in the U.S. every year. Most commonly, the blood clot occurs in the leg and then may travel to the lungs and be fatal.”
In the U.S., up to 100,000 people each year die of DVT and/or blood clots to the lungs. “In other words,” said Dr. Lee, “every six minutes, someone may die of these conditions.”
Nearly half of the people who develop lower leg DVT further develop a long-term, disabling condition called post-thrombotic syndrome in which they may suffer from swollen, discolored, uncomfortable and thickened lower legs, sometimes with painful, open wounds. One in three people who develops DVT will have recurrence within the following 10 years. Studies show that people with DVT have an 80 percent higher risk of work-related disability than those without DVT.
“Anyone who has sudden pain and/or swelling in the leg must contact their primary care provider or go to the emergency department,” said Dr. Lee. “There are many medical conditions that can cause leg pain and swelling, but a potentially life-threatening blood clot or DVT must be ruled out with an ultrasound examination.”
Dr. Lee explained that not all blood clots are the same, and their degrees of danger vary based on their location and the extent of their involvement and size.
“Those diagnosed with DVT must receive care from a qualified health care provider, including anticoagulation therapy to help thin the blood,” said Dr. Lee. “If the blood clot is serious, they must be evaluated for possibly dissolving or removing the clot emergently.”
Dr. Lee noted that treatment for DVT has evolved significantly in the past decade. “For serious DVT, we no longer just treat with anticoagulation therapy and a ‘wait-and-see’ approach,” he said. “The best time to treat DVT is as soon as it is diagnosed, fully and thoroughly, depending on the nature of the clot. The less clot that remains inside the deep veins after the treatment course, the better the clinical outcome, and the less the chance of long-term risk of disability or death.”
Provoked and Unprovoked DVT
Sometimes, DVT is “provoked,” which means caused by major physical and physiologic disturbances in the body. For example, Dr. Lee said that blood clots are anticipated to occur in greater frequency after major surgery, traumas involving bone fracture or muscle injury, administration of estrogen (birth control pills, hormone replacement therapy or even pregnancy), or slow blood flow through the veins caused by immobilization (bed confinement, hospitalization, spinal cord paralysis, or prolonged fixed or sitting position such as when driving or flying for long periods).
“When faced with these conditions, patients should discuss appropriate preventative measures with their health care providers,” said Dr. Lee.
DVT can also occur without such conditions, thus considered “unprovoked.” In those cases, Dr. Lee said, “We must consider the possibility of underlying medical conditions previously unknown to the patient.”
One possible, but rare, cause of unprovoked DVT is cancer, including cancer that has not yet been diagnosed. DVT may be the first sign of the disease. Far more common though is a group of conditions known as thrombophilia or hypercoagulability: an increased liklihood to form blood clots, either due to genetic inheritance or an imbalance in the body’s blood clotting system.
The Centers for Disease Control estimates that between 5 to 8 percent of the U.S. population has one of several genetically inherited thrombophilia. “That’s one person out of every 12 to 20 people,” stated Dr. Lee. “That’s a lot of people who are walking around with a higher risk of blood clots and potential risk to their life than they may realize.”
He continued, “I’ve had patients who had lost a parent or siblings at a very young age, like in their 30s or 40s, after a massive heart attack, stroke or blood clot that traveled to their lungs. When we perform blood tests, we find they have a genetic mutation. It is likely that their relative had the same mutation, and had they known about their risk for DVT, might not have died so young.”
To be sure, there will always be unpreventable cases of DVT. Dr. Lee stressed that while the understanding of and treatment for DVT has come a long way, there is still a long way to go. “We know that thrombophilia is a common occurrence. Now we know how to better recognize and reduce the risk of DVT, but that alone is not enough. Greater awareness and understanding is required on the part of the public so they can take steps to prevent its occurrence.”