What is Deep Venous Thrombosis?
Deep venous thrombosis is the formation of a blood clot in a deep vein, usually in a calf or thigh muscle. Deep venous thrombosis can partly or completely block blood flow, causing chronic pain and swelling.
A blood clot (thrombus) in the deep venous system of the leg is not dangerous in itself. The situation can become dangerous when a piece of the blood clot breaks off (embolus), travels downstream through the heart into the pulmonary circulation system, and becomes lodged in the lung. If a blood clot breaks free and travels to your lungs, it is called a pulmonary embolism and it can be fatal. Both deep venous thrombosis and pulmonary embolism can cause serious, possibly life-threatening problems if not treated.
Pulmonary emboli from lower extremity deep venous thrombosis have the potential to lead to a number of complications due to obstruction of the pulmonary arteries. These include increased respiratory rate and hyperventilation. Pulmonary embolism is the most common cause of hospital-related death and the most common preventable cause of hospital-related death. The mortality rate for pulmonary embolism without treatment is approximately 30%, while it is only 2% to 8% with adequate therapy.
What are the Symptoms of Deep Venous Thrombosis?
The symptoms of deep venous thrombosis may include pain, swelling, warmth and redness of a leg. However, not all of these symptoms may be present; one, all or none may be present with deep venous thrombosis. Leg swelling, redness and pain may be indicators of a blood clot and should not be ignored. The symptoms of deep venous thrombosis are related the obstruction of blood returning to the heart and causing a backup of blood in the leg.
A blood clot can form if one or a combination of the following is present: prolonged sitting, hospitalization, surgery, pregnancy including 6-8 weeks post-partum, obesity or trauma to the legs.
What are the Risk Factors for Deep Venous Thrombosis?
All surgical patients are at risk for deep venous thrombosis. Prolonged bedrest is common following surgery and can allow blood to pool in areas of the body. Individuals undergoing certain types of surgery are especially prone to blood clots, including those having pelvic (gynecological and urological surgery), orthopedic surgery (including hip replacement or fracture repair), and pelvis/hip socket surgery. Operations lasting more than three hours are associated with a high risk of deep venous thrombosis, compared to operations lasting one to two hours. Obesity raises the relative risk of deep venous thrombosis.
Risk factors for deep venous thrombosis include pregnancy and the post-natal period. Pregnancy causes blood to favor clotting and in the post-partum period, placental tearing releases substances that favor clotting. Due to high levels of estrogen in pregnancy, during and until 4 to 6 weeks after delivery, women have a higher risk of deep venous thrombosis.
How is Deep Venous Thrombosis Diagnosed?
The tests to diagnose deep venous thrombosis include duplex ultrasound and MRI. Ultrasound is now the standard method of diagnosing the presence of deep venous thrombosis. The ultrasound technician may be able to determine whether a clot exists, where it is located in the leg and how large it is.
D-dimer is a blood test that may be used as a screening test to determine if a blood clot exists. D-dimer is a chemical that is produced when a blood clot in the body gradually dissolves.
What is the Treatment for Deep Venous Thrombosis?
Deep venous thrombosis needs to be treated right away. The goal is to prevent the blood clot from getting bigger or becoming an embolism. Treatment also aims to keep you from getting more blood clots.
The treatment for deep venous thrombosis is intravenous anticoagulation (blood thinners). Anticoagulation prevents further growth of the blood clot and prevents it from forming an embolus that can travel to the lung. Anticoagulation is a two-step process. Warfarin (Coumadin) is the drug of choice for anticoagulation. Warfarin is begun immediately but it may take a week or more for the blood to be appropriately thinned. Hence, low molecular weight heparin (Lovenox) is administered at the same time. Lovenox is used as a bridge therapy until Warfarin has reached the therapeutic level.
For uncomplicated deep venous thrombosis, the recommended length of therapy with Warfarin is 3 to 6 months. An alternative may be to place a filter in the inferior vena cava (the major vein that collects blood from both legs) to prevent emboli from reaching the heart and lungs.
If you have questions about deep venous thrombosis or pulmonary embolism, you can call me at 845-802-0047. I look forward to speaking with you.