Artificial grafts are frequently placed in the arms and legs to provide access to the circulation for hemodialysis. These grafts frequently develop narrowing where they are sewn into the vein. When these graft clot, patients cannot have their usual dialysis. In most cases, the graft can be reopened without surgery using a device placed directly into the graft through a needle stick. After removing the clot, an angiogram can reveal areas of narrowing that can be dilated with a balloon. If clotting occurs frequently or a severe narrowing is found that does not respond well to angioplasty, open, surgical repair of the graft may be required.