CA2512311C - Improved tissue supporting devices - Google Patents

Abstract

A new multiple component stent which allows for initial self-expansion and subsequent deformation to a final enlarged size. In one embodiment, stent comprises a first relilient element and a second deformable element. In another embodiment, stent is made of a first austenite component and a second mertensite component.

Claims (15)

1. A stent comprising:
a plurality of annular elements, each annular element having a compressed state and an expanded state, wherein each annular element has a longitudinal dimension which is smaller in the radially expanded state than in the compressed state; and at least one connecting member connecting adjacent annular elements, the connecting member having a longitudinal dimension that increases upon expansion of the stent.

2. The stent of claim 1, wherein each annular element comprises a plurality of alternating struts and apices connected to each other to form a substantially annular configuration.

3. The stent of claim 2, wherein the connecting members are connected to the apices of the adjacent annular members.

4. The stent of claim 2, wherein the plurality of struts comprises left and right struts, with each pair of left and right struts connected to each other at an apex.

5. The stent of claim 2, wherein each strut has a longitudinal dimension which is smaller when the annular elements are in the expanded state than in the compressed state.

6. The stent of claim 2, wherein each strut has a longitudinal dimension which is larger when the annular elements are in the compressed state than in the expanded state.

7. The stent of claim 2, wherein at least one of the annular elements is closed such that the plurality of alternating struts and apices are connected to each other to form a closed annular element.

8. The stent of claim 7, wherein at least one of the annular elements are open such that the plurality of alternating struts and apices are not connected at at least one location.

9. The stent of claim 1, wherein at least one connecting member has a plurality of alternating segments.

10. The stent of claim 9, wherein the at least one connecting member has a plurality of alternating and angled straight segments.

11. The stent of claim 1, wherein the stent is made from a shape memory alloy.

12. The stent of claim 11 wherein the shape memory alloy is nitinol.

13. The stent of claim 1, wherein the annular elements and connecting members define an alternating longitudinal pattern of annular elements and connecting members.

14. The stent of claim 1 comprising, at about normal body temperatures, a shape memory, superelastic, austenitic alloy portion and a shape memory, martensitic alloy portion, the superelastic austenitic alloy portion having a transition temperature from martensite to austenite less than body temperature while the martensitic alloy portion has a transition temperature from martensite to austenite greater than body temperature, the martensitic alloy portion and superelastic austenitic alloy portion being constructed, arranged and associated with respect to each other in comprising the stent such that the two alloy portions act in combination to allow, upon transformation of the austenitic alloy portion to martensite at a temperature below the transition temperature, constraint of the stent to a deployment diameter smaller than the predetermined fabricated diameter and upon transformation of the austenite alloy portion from martensite back to austenite to self-expand the stent back to about the predetermined fabricated diameter at temperatures in excess of the transition temperature of the austenitic superelastic portion, the shape memory of the superelastic austenitic portion tending to form the stent to a larger diameter due to its shape memory but being restrained therefrom by the martensitic alloy portion whereby the austenitic alloy portion can be deformed by external force without plastic deformation along with the martensitic portion to an enlarged stent diameter beyond that of the self-expanded diameter.

15. A stent comprising:
a plurality of annular elements, each annular element having a compressed state and an expanded state, wherein each annular element has a longitudinal dimension which is smaller in the radially expanded state than in the compressed state; and at least one connecting member connecting adjacent annular elements, wherein the annular elements and connecting members are made of nitinol, with each connecting member preset with an elasticity which causes the connecting member to elongate longitudinally when the annular elements are transformed from the compressed state to the expanded state.