In a through-the-cannula catheter placement system, a catheter is used which comprises a body portion and a tip portion at one end of the body portion. The body portion has a double-wall structure. The outer wall is a tube of pliable, nonthrombogenic material. The inner wall is a reinforcing tube of a material having sufficient resilience to avoid collapse during use. The tip portion is also made of a pliable nonthrombogenic material. The tip may be an extension of the outer wall.