Catheter-directed thrombolysis is performed under imaging guidance. This procedure is designed to rapidly break up the clot, restore blood flow within the vein, and potentially preserve valve function to minimize the risk of post-thrombotic syndrome. Any narrowing in the vein that might lead to future clot formation can be identified by venography, an imaging study of the veins, and treated by the interventional radiologist with a balloon angioplasty or stent placement.