A catheter comprising a tube part, a tip part and at least one through-going opening, where the through-going opening is positioned distally to the proximal end of the tube part, wherein the outer surface of the tube part has at its proximal end a first outer diameter that is smaller than a second outer diameter at the tube parts distal end, and the diameter of the outer surface of the tube part increases constantly along the entire length of the tube part from its proximal first outer diameter end to its distal second outer diameter.
