Lysis therapy is an approach in which vascular specialists deliver clot-dissolving drugs directly to the site of the clot through a catheter. During this procedure doctors insert the catheter, a very thin tube sometimes tipped with surgical equipment, through an artery in the groin to the site of the clot. When the catheter reaches the blockage the clot dissolving drugs are released. The catheter may also be equipped with a miniature tool that mechanically breaks up the clot. Patients who undergo lysis therapy may be able to avoid systemic treatment with blood-thinning drugs such as heparin and warfarin, which can lead to vein damage called chronic venous insufficiency.