PYLORIC ANCHOR AND GASTRO-INTESTINAL TUBE

A bypass tube (14) has a distal end for placement into the small intestine of a patient and a proximal end for placement near or at the pylorus. The tube comprising a pyloric anchor (16) including a gastric anchor (22) for anchoring the proximal end of the tube with respect to the pylorus to prevent distal migration. The gastric anchor comprises a tubular balloon (24) and a self-expanding structure (22a, 22b) for biasing a radially inner wall and/or a radially outer wall of the tubular balloon outwardly towards its enlarged form. The self-expanding structure comprises a first zone comprising an annular hub or collar (22a) with a first resistance to inward collapsing, and a second zone comprising a plurality of independently deflectable beams or limbs (22b) extending from the first zone, and having a smaller second resistance to inward collapsing. Also described are a pyloric anchor that twists around its axis when expanding, and a non-helical reinforcement of the flexible tube in the small intestine.