Geoffrey S Martin, Jonathan E Last: Pre-curved dual lumen catheter. Rogers & Scott, October 20, 1992: US05156592 (141 worldwide citation)

A dual lumen catheter especially for use in prolonged access haemodialysis, which meets the requirements of flexibility and softness for prolonged access in a vein, and which is shaped to include a curved portion to be placed between the tunnel and the subclavian vein.