Transpyloric anchoring

1. A gastrointestinal implant device comprising:

a planar proximal element configured to reside in a stomach to resist distal migration;

a distal element configured to reside in an intestine to resist proximal migration; and

one or more tethers coupling the planar proximal element to the distal element;

wherein the planar proximal element is between 40 mm and 100 mm in size in a first dimension, and is between 0.5 mm and 15 mm in size in a second dimension, orthogonal to the first dimension;

and wherein, in normal use of the implant device, a central longitudinal axis of the planar proximal element, perpendicular to a plane in which the planar proximal element lies, is substantially perpendicular to a central longitudinal axis of a lumen of a pyloric sphincter of the stomach.

2. The gastrointestinal device of claim 1 , wherein only a single tether couples the planar proximal element to the distal element.

3. The gastrointestinal implant device of claim 1 , wherein the distal element is configured to seal to tissue of the intestine, thereby channeling chyme from the stomach into the intestine.

4. The gastrointestinal implant device of claim 1 , wherein the planar proximal element comprises a hoop.

5. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a wave anchor.

6. The gastrointestinal implant device of claim 1 , wherein the planar proximal element is between 50 mm and 100 mm in size in the first dimension.

7. The gastrointestinal implant device of claim 1 , wherein the planar proximal element is between 0.5 mm and 5 mm in size in the second dimension.

8. The gastrointestinal implant device of claim 1 , wherein the planar proximal element comprises a hoop of between about 40 mm and about 60 mm diameter and of between about 0.5 mm and about 5 mm in thickness.

9. The gastrointestinal implant device of claim 1 , wherein the tether comprises a flexible tether.

10. The gastrointestinal implant device of claim 1 , wherein the tether comprises a rigid tether.

11. The gastrointestinal implant device of claim 1 , wherein the planar proximal element comprises a polygon or an ellipsoid shape.

12. The gastrointestinal implant device of claim 1 , wherein the distal element is planar.

13. The gastrointestinal implant device of claim 12 , wherein the distal element comprises at least one member of the group consisting of: a hoop, a polygon and an ellipsoid shape.

14. The gastrointestinal implant device of claim 1 , wherein the device comprises no tissue penetrating features.

15. The gastrointestinal implant device of claim 1 , further comprising an unsupported, thin-walled sleeve coupled to the distal element.

16. The gastrointestinal implant device of claim 1 , wherein the planar proximal element is without a seal to the stomach.

17. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a restrictor.

18. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a fluid-filled chamber.

19. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a toroidal object.

20. The gastrointestinal implant of claim 1 , wherein the distal element comprises at least one of a catheter and a diagnostic device.

21. The gastrointestinal implant device of claim 1 , wherein the distal element is between 30 mm and 40 mm in diameter.

22. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a length to diameter ratio of at least about one.

23. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a length of between 30 mm and 40 mm.

24. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a length of at most 32 mm.

25. The gastrointestinal implant device of claim 1 , wherein the distal element comprises an anchor of about the same length as the duodenal bulb.

26. The gastrointestinal implant device of claim 1 , wherein at least one of the planar proximal element, the tether and the distal element is covered in an atraumatic material.

27. The gastrointestinal implant device of claim 1 , wherein the tether comprises a suture.

28. The gastrointestinal implant device of claim 1 , wherein the tether is between 10 mm and 50 mm in length.

29. The gastrointestinal implant device of claim 1 , wherein the tether is between 0.5 mm and 5 mm in diameter.

30. The gastrointestinal implant device of claim 29 , wherein the tether is between 1 mm and 2 mm in diameter.

31. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a plurality of spokes, and wherein the tether is coupled to the plurality of spokes.

32. The gastrointestinal implant device of claim 1 , wherein the distal element is configured to change shape upon transmission of force to the distal element by the tether.

33. The gastrointestinal implant device of claim 1 , wherein the distal element comprises a wave anchor, the tether being coupled to at least one crown of the wave anchor.

34. The gastrointestinal implant device of claim 33 , wherein the tether is coupled to a distal crown of the wave anchor, and wherein the wave anchor comprises a diameter of between about 30 mm and about 40 mm.

35. The gastrointestinal implant device of claim 1 , wherein the distal element is configured to open radially outwards upon exertion of tension by the tether.

36. The gastrointestinal implant device of claim 1 , wherein the planar proximal element is loosely attached to the tether, thereby permitting the planar proximal element to rotate independently of the tether.

37. The gastrointestinal implant device of claim 1 , wherein the planar proximal element is coupled to a tie loop to which the tether is coupled.

38. The gastrointestinal implant device of claim 1 , wherein the planar proximal element, distal element and tether are configured to be collapsible into a container for endoscopic delivery into a gastrointestinal tract.

39. The gastrointestinal implant device of claim 1 , wherein at least one of the proximal element and the distal element further comprises a removal drawstring.

40. A method of treatment comprising:

with a planar proximal element in a stomach, resisting distal migration of a proximal portion of a gastrointestinal implant device into an intestine;

with a distal element in the intestine, resisting proximal migration of a distal portion of the gastrointestinal implant device into the stomach; and

with one or more tethers, securing the planar proximal element to the distal element across a pylorus;

wherein the planar proximal element is between 40 mm and 100 mm in size in a first dimension, and is between 0.5 mm and 15 mm in size in a second dimension, orthogonal to the first dimension;

and wherein, in normal use of the implant device, a central longitudinal axis of the planar proximal element, perpendicular to a plane in which the planar proximal element lies, is substantially perpendicular to a central longitudinal axis of a lumen of a pyloric sphincter of the stomach.

41. The method of treatment of claim 40 wherein only a single tether secures the planar proximal element to the distal element.

42. The method of treatment of claim 40 , further comprising sealing the distal element to tissue of the intestine, thereby channeling chyme from the stomach into the intestine.

43. The method of treatment of claim 40 , comprising securing the gastrointestinal implant device without penetrating tissue.

44. The method of treatment of claim 40 , further comprising channeling chyme from the stomach into an unsupported, thin-walled sleeve extending into the intestine from the gastrointestinal implant device.

45. The method of treatment of claim 40 , comprising resisting migration of the planar proximal element into the intestine without sealing the planar proximal element to the stomach.