Abstract: The invention includes a composite tube for forming an arteriovenous fistula with at least two conjoined segments or sections. The first section includes an elongated tubing formed from PTFE or another catheter material that is similarly amenable for convenient arterioveneous access. The second section includes an elongated tubing formed from silicone or another suitable long term catheter material. An intermediate connection couples the first section to the second section. The diameter of the first segment is between 2 mm. to 10 mm. while the second segment is between 4 to 8 millimeters at the coupling site and tapers to approximately 3 to 4 mm. distally. The second segment includes outlet ports proximate a beveled tip permitting outward blood flow. Several intermediate connections may be employed including single composite tubing, flanged segments and male and female tabbed collars, as long as the connection allows uninterrupted laminar flow across the entire length of the arteriovenous fistula.