A patient implantable vascular catheterization system incorporating an anchoring element for maintaining the tip of an implanted catheter at a desired position within a blood vessel. The anchoring element comprises a deformable element such as a coiled wire or one or more expandable legs. The anchoring element is caused to assume a streamlined or compressed condition through placing it within an introducer catheter to facilitate placement or removal of the implanted catheter. Once positioned, the introducer catheter is retracted allowing the anchoring element to expand into engagement with the blood vessel. A material to induce occlusion of the blood vessel through clotting can be incorporated into the anchoring element.