Stent having adjacent elements connected by flexible webs
A stent incorporating flexible, preferably polymeric, connecting elements into the stent wherein these elements connect adjacent, spaced-apart stent elements. Preferably the spaced-apart adjacent stent elements are the result of forming the stent from a helically wound serpentine wire having space provided between adjacent windings. Other stent forms such as multiple, individual spaced-apart ring-shaped or interconnected stent elements may also be used. The connecting elements are typically web-shaped and result from creating slits or apertures in a covering of graft material applied to the stent and then, for example, applying heat to cause the slits or apertures to enlarge. The remaining graft material forms the interconnecting webs between the adjacent stent elements.
1. A method of making a flexible stent comprising:
a) providing a stent having a length between opposing ends and having metallic stent elements;
b) providing at least a portion of the length of the stent with a polymeric covering;
c) forming slits or apertures through the covering between adjacent stent elements;
d) heating the stent and polymeric covering to cause the slits or apertures to enlarge.
2. The method of claim 1 , wherein said heating step results in the formation of polymeric webs interconnecting said stent elements.
3. The method of claim 2 , wherein the webs comprise ePTFE and fluorinated ethylene propylene.
4. The method of claim 1 , wherein said polymeric covering comprises ePTFE.
5. The method of claim 1 , wherein said polymeric covering comprises fluorinated ethylene propylene.
6. The method of claim 1 , wherein forming slits or apertures through the covering between adjacent stent elements includes puncturing slits or apertures through the covering.
7. The method of claim 1 , wherein forming slits or apertures through the covering between adjacent stent elements includes lasing slits or apertures through the covering.
8. A method of making a flexible stent comprising:
a) providing a stent having a smaller compacted diameter prior to diametrical expansion and a larger diameter following diametrical expansion, said stent having a length between opposing ends and having stent elements;
b) providing at least a portion of the length of the stent with a polymeric covering when the stent is at the smaller compacted diameter;
c) heating the stent and the polymeric covering to bond the covering to the stent elements;
d) forming slits through the covering between adjacent stent elements;
wherein following heating of the flexible stent and the polymeric covering, the polymeric covering shrinks so that said slits form apertures, and wherein after diametrical expansion said apertures become diamond-shaped.
9. The method of claim 8 , wherein forming slits through the covering between adjacent stent elements includes puncturing slits through the covering.
10. The method of claim 8 , wherein forming slits through the covering between adjacent stent elements includes lasing slits through the covering.
11. A medical device comprising:
a frame;
a polymeric film having a multiplicity of slits there-through, said slits having a width;
wherein said film has been heated sufficiently to cause said slits to become apertures by shrinking said film and to cause the film to be bonded to the frame, wherein said apertures have a width greater than the width of said slits; and
wherein the polymeric film defines polymeric webs interconnecting a plurality of stent elements of the device, said polymeric webs defining a length between the stent elements, wherein the polymeric webs are narrower at a middle portion of the length relative to a width of the polymeric webs at a connection point between the polymeric webs and the stent elements.
12. A method of making a flexible stent comprising:
a) providing a stent having a length between opposing ends and having metallic stent elements;
b) providing at least a portion of the length of the stent with a polymeric covering;
c) forming slits or apertures through the covering between adjacent stent elements;
d) heating the stent and polymeric covering to cause the slits or apertures to enlarge, wherein said heating step results in the formation of polymeric webs interconnecting said stent elements.
13. The method of making a flexible stent comprising:
a) providing a stent having a smaller compacted diameter prior to diametrical expansion and a larger diameter following diametrical expansion, said stent having a length between opposing ends and having stent elements;
b) providing at least a portion of the length of the stent with a polymeric covering when the stent is at the smaller compacted diameter;
c) heating the stent and the polymeric covering to bond the covering to the stent elements;
d) forming slits through the covering between adjacent stent elements;
wherein following heating of the flexible stent and the polymeric covering, the polymeric covering shrinks so that said slits form apertures, and wherein after diametrical expansion said slits or apertures become diam and-shaped; and
wherein the polymeric covering defines polymeric webs interconnecting said stent elements.