Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a condition where a clot (thrombosis) develops in the deep veins of the leg. Patients who are at risk for this condition are those who:

have been sitting or lying down for prolonged periods of time without moving, like those who have been on a long airplane or car ride, for example, or someone who is bedridden.
have a condition where there blood is prone to clots, like a blood disorder, cancer, or extreme dehydration.
have had recent surgery, especially orthopedic surgery to the hip or knee.
have had trauma, like a pelvic injury, or a broken leg.
have a spinal injury and paralysis.

A deep vein thrombosis is dangerous because once these clots develop in the legs, they can break off from their location in the leg, and float to other parts of the body. Blood from the veins travels into the right side of the heart, and out to the lungs. There, it picks up oxygen from the lungs, returns to the heart (the left side), and is pumped out into the body, where the oxygen is delivered. Therefore, deep vein clots, will occasionally float into the lungs, where they become stuck. This is called a "pulmonary embolism" or PE, and can be very dangerous, even fatal.

Deep vein thromboses most often present as leg swelling that involves only one leg. It usually develops over a day or two, and can also involve pain in the leg. If questioned, the patient can usually think of something that put him/her at risk, like a long plane ride, or recent surgery, etc.

If your doctor suspects a DVT, he or she will immediately obtain an ultrasound. It is imperative that this is obtained as soon as possible in the case of new unilateral leg swelling. If the ultrasound shows a clot in the leg, blood thinners are started immediately. Your doctor will explain these medications carefully to you, since these medicines must be taken and monitored very carefully. The blood thinners are very important because they allow the body to break down the clot slowly over time, and they are effective at preventing the clot from floating into the lungs (pulmonary embolism).

Deep Venous thrombosis, however, can also damage the veins in the leg, especially if the clot involved is extensive. In this case, the damage to the veins can be serious, because the deep venous system is large, and is responsible for the lion's share of the work of bringing blood back up to the heart, against gravity. If these veins are blocked with clot, the clot can injure the valves over time, leading to an ineffective venous system. Patients then may have debilitating swelling, and severe changes of venous insufficiency in their leg, which lead to skin changes and ulcers. They can also have severe pain in this leg. This is called post phlebitic syndrome, and it is a dreaded complication of extensive DVT that can occur even with adequate anticoagulation.

Once a deep vein thrombosis has been diagnosed, treatment with blood thinners is initiated immediately. But if the clot is extensive, or if blood thinner treatment is not possible, patients can be referred to a vascular surgeon for further evaluation and treatment.