An irrigation system for use primarily with in situ bypass and valvulotomy procedures. The system includes access to both the proximal and distal ends of a length of vein and allows for irrigation flow to be provided from proximal to distal, distal to proximal or to both proximal and distal ends of the vein simultaneously. The use of the irrigation system provides for a clear field of view by angioscope during medical procedures. Introducers are also described which may be used with the irrigation system or with many other procedures which require access to an internal body conduit.
