Blood Clots - Blood Clots that form in the deep veins of the lower legs (known as deep vein thrombosis or DVT) can cause chronic swelling and leg pain when walking. There is a risk that the clots will move to the lung (pulmonary embolism) or heart -- a potentially life-threatening complication. Interventional radiologists treat DVT by dissolving the clot with thrombolytic therapy. Thrombolytic drugs that dissolve clots are injected through a catheter to eliminate the clot and restore blood flow. This treatment opens up blood flow and may prevent permanent damage to the blood vessels, a common side effect of DVT. Blood Clot Filters - Patients with certain chronic illnesses or other conditions that require prolonged periods of inactivity, are at risk of forming blood clots that can travel to the heart or lungs. The interventional radiologist can insert a small filter (called a vena cava filter) into a blood vessel to catch and break up blood clots.