The dreaded deep venous thrombosis or DVT. We've all heard the letters in a commanding order that raise our curiosity asking, what is deep venous thrombosis? I'll try to break it down into simple concepts that will leave you with some basic understanding of what DVT is.
DVT has many causes, some of which are complex and may be cumulative and increase your chance of developing DVT. I'll review a few of these causes, put meaning to some other medical terms you may have heard and touch on some treatment options. This blog is for a basic understanding of some medical conditions, however always seek advice from a vein specialist if you have concerns about having or knowing someone who may have deep vein thrombosis.
Simply put, DVT or deep vein thrombosis, is a clot within a deep vein. Clots may develop within any vein but most commonly occur within the deep veins of our legs and pelvis. This is related to the fact that our legs and pelvis are below the level of our hearts. The blood within the veins of our legs needs to fight the added force of gravity which is constantly pulling the blood back down towards our feet. This used or deoxygenated blood within our veins needs to make it back to the heart, so it can be oxygenated by the lungs then pumped backed to the body by the heart. The blood within our veins is under no pressure, unlike our arteries, which are under constant pressure by the pumping of our hearts. The blood is most likely to become stagnant within the deep veins of our legs, making it the most common source of DVT.
Yes, we have superficial and deep veins. Together, they make up the superficial and deep venous systems of our bodies. Clots may possibly develop in either system. however once there is clot within a deep vein, you have developed deep vein thrombosis (DVT). A clot within a superficial vein is call superficial venous thrombosis or thrombophlebitis (SVT). If there is associated inflammation of the vein with a blood clot, you have superficial venous thrombophlebitis. This may present as an area of redness, swelling and pain, usually along the calf. If you have varicose veins, which can result in slow or stagnant blood, you are at an increased risk of developing SVT. The superficial and deep veins are connected by perforator veins, so a clot in a superficial vein may progress or move into a deep vein and lead to deep vein thrombosis (DVT).
Deep vein thrombosis is a complex subject with many different causes, that at times can be cumulative and lead to an increased chance of developing DVT. Our bodies have a fine balance between clotting and bleeding. When we bleed, like cutting a finger during cooking, we need the blood to clot, so the bleeding can stop. But, we don't want the blood to clot when its normally flowing through our arteries and veins. This fine equilibrium between clotting and bleeding can be affected by many factors including our genetics, hormones, medications, life style, and associated medical conditions including cancer.
Genetics plays a significant factor in the propensity to develop DVT and since the clotting cascade involves many different proteins and enzymes, there are a number of different genetic factors that may increase one's risk of developing deep vein thrombosis. If you have a parent or first generation relative that developed a blot clot at a young age for no apparent reason, they likely have a genetic predisposition. There are numerous different inherited clotting disorders, with the most common in the population being Factor V Liden variant. Other disorders, like antithrombin, Protein S or Protein C deficiencies, are less common in the population but when present, have a higher risk of developing DVT. Fortunately there are blood tests that can easily check for many different inherited clotting disorders. Some patient that have an inherited clotting disorder along with deep venous thrombosis may need to be treated with blood thinners for life.
Some risk factors for developing deep venous thrombosis include family history, pregnancy, prolonged immobilization, birth control or hormonal therapy, cancer, obesity, heavy smoking, venous catheter placement and major surgery. Many of these factors are reversible, so eating healthy, exercise and not smoking reduces ones chances of developing DVT. Patients on hormonal therapy or birth control may need to stop these medications if they develop DVT. On rare occasions, patients present with an unexplained painful swollen leg and found to have DVT but then soon after, found also to have a newly diagnosed cancer. Cancer, especially in its late stages, may cause hypercoagulable states and increase ones chances of suffering from DVT. Major surgeries especially to the extremities, like a total knee replacement leading to immobilization, will clearly increase ones risk of developing a DVT.
As I stated earlier, simply staying healthy by eating right, regular exercise and weight management will keep your risks low. If you are at an increased risk of developing DVT because of recent surgery, immobilization because of an injury, medications like birth control pills, hormone replacement or hormonal therapy for cancer, you would be advised to wear compression stockings. Compression stockings add pressure to our superficial veins, forcing blood to flow into our deep veins in an attempt to keep our blood flowing and avoid DVT. If you have a job that requires a lot of standing and sitting in place without moving, you would benefit from raising your legs once you have a chance to rest. Raising our legs uses gravity to our advantage. By raising your legs, you're using the force of gravity to help return the blood back to the heart. Compression stockings are helpful anytime we are limited in our mobility, including certain jobs, long plane rides and recent surgeries,
It's not always easy to tell if someone is developing DVT. Usually the affected limb will be painful and swollen. There may be areas of redness along the calf or thigh. Sometimes a palpable cord is present. This is the clotted vein, which is now firm and can be felt underneath the skin. The visible veins in the skin may become more prominent because of blockages of the deep veins. A DVT can be life threatening and should be taken very seriously. The danger of a clot forming in the deep veins arises from its ability to be dislodged and travel to our lungs. If this happens, one may feel chest pain and shortness of breath. A blood clot that has moved into our lungs is called a pulmonary embolism. Pulmonary embolism (PE) is a life threatening complication of deep venous thrombosis (DVT). Because of this life threatening potential, PE and DVT need to be monitored and treated by an appropriate vein specialist.
Most DVT's need to be treated with blood thinners. Fortunately, newer blood thinners, such as Xarelto or Eliquis, can be taken orally and don't have any dietary restrictions, unlike Warfarin, that has dietary restrictions and Enoxaparin, which must be injected. The blood thinner is needed to protect you from a life threatening pulmonary embolism. Only rarely does a blood thinner not work or more likely a patient is prohibited from taking the blood thinner because of higher bleeding risks. In these cases, a filter may be placed in the largest vein, the inferior vena cava. This procedure is called IVC filter placement. If the blood clot resorbs and disappears, depending on the cause, you may be fortunate and be able to stop the blood thinner. If you have multiple, unprovoked episodes of DVT, you may need to be on blood thinners for life. Uncommonly, blood clots are small and asymptomatic and may be observed with diagnostic ultrasound. Treatment usually requires use of graduated compression stockings and ambulation. Deep venous thrombosis (DVT) is an extremely dangerous condition and should never be taken lightly. If you are concerned about DVT or know someone who is suffering from DVT, call the Center for Varicose Veins at 203-529-5521 for more information.
