Expandable stent

Abstract

There is described a novel stent design which has flexibility characteristics superior to currently available stent structures. Further, once the present stent is expanded, it exhibits an inherent tendency to maintain the shape of the lumen in which it is deployed. This is a significant advantage over many currently available stents which, upon expansion, tend to stretch and deform the lumen from its natural longitudinal orientation as the stent tends to straighten. The present stent is characterized by a porous surface having a repeating pattern generally in the shape of a “butterfly”.

What is claimed is:  
     
         1 . An unexpanded stent comprising a proximal end and a distal end in communication with one another, a tubular wall disposed between the proximal end and the distal end, the tubular wall having a longitudinal axis and a porous surface defined by a plurality of interconnected circumferential rows of a repeating pattern, the repeating pattern comprising a concave-shaped wall and a convex-shaped wall aligned substantially along an axis substantially orthogonal to the longitudinal axis.  
     
     
         2 . The stent defined in  claim 1 , wherein the repeating pattern is substantially free of straight sections.  
     
     
         3 . The stent defined in  claim 1 , wherein the tubular wall has a substantially circular cross-section.  
     
     
         4 . The stent defined in  claim 1 , wherein the tubular wall is constructed of a plastically deformable material.  
     
     
         5 . An unexpanded stent comprising a proximal end and a distal end in communication with one another, a tubular wall disposed between the proximal end and the distal end, the tubular wall having a longitudinal axis and a porous surface defined by a plurality of interconnected circumferential rows of a repeating pattern, the repeating pattern comprising a concave-shaped wall and a convex-shaped wall aligned in manner such that individual repeating patterns in the a circumferential row are interlocked with respect to one another.  
     
     
         6 . The stent defined in  claim 5 , wherein the concave-shaped wall and the convex-shaped wall are interconnected by a pair of S-shaped walls.  
     
     
         7 . The stent defined in  claim 5 , wherein each S-shaped wall comprises at least one S-shaped section having an axis passing through an initial point and an end point of the S-shaped section.  
     
     
         8 . The stent defined in  claim 7 , wherein S-shaped section comprises an asymmetric pair of curved sections.  
     
     
         9 . The stent defined in  claim 8 , wherein each curved section comprises an arc of at least about 180°.  
     
     
         10 . The stent defined in  claim 6 , wherein each S-shaped wall comprises: a first S-shaped section having a first axis passing through an initial point and an end point of the first S-shaped section and a second S-shaped section having a second axis passing through an initial point and an end point of the-second S-shaped section.  
     
     
         11 . The stent defined in  claim 10 , wherein each of the first axis and the second axis are angled with respect to the longitudinal axis.  
     
     
         12 . The stent defined in  claim 10 , wherein the first axis and the second axis are acutely angled with respect to one another.  
     
     
         13 . The stent defined in  claim 5 , wherein the repeating pattern is substantially free of straight sections.  
     
     
         14 . The stent defined in  claim 5 , wherein the tubular wall has a substantially circular cross-section.  
     
     
         15 . The stent defined in  claim 5 , wherein the tubular wall is constructed of a plastically deformable material.  
     
     
         16 . An unexpanded stent comprising a proximal end and a distal end in communication with one another, a tubular wall disposed between the proximal end and the distal end, the tubular wall having a longitudinal axis and a porous surface defined by a plurality of interconnected circumferential rows of a repeating pattern, the repeating pattern comprising four S-shaped sections orientated such that, for at least two pairs of the S-shaped sections, one S-shaped section is a mirror image of the other S-shaped section along an axis orthogonal to the longitudinal axis.  
     
     
         17 . The stent defined in  claim 16 , wherein each of the four S-shaped sections has substantially the same shape.  
     
     
         18 . The stent defined in  claim 16 , wherein each of the four S-shaped sections comprises an asymmetric pair of curved sections.  
     
     
         19 . The stent defined in  claim 18 , wherein each curved section comprises an arc of at least about 180°.  
     
     
         20 . The stent defined in  claim 16 , wherein each of a first pair of S-shaped sections comprises a first axis passing through an initial point and an end point of the S-shaped section to define a pair of first axes in substantially parallel alignment.  
     
     
         21 . The stent defined in  claim 16 , wherein each of a second pair of S-shaped sections comprises a second axis passing through an initial point and an end point of the S-shaped section to define a pair of second axes in substantially parallel alignment.  
     
     
         22 . The stent defined in  claim 16 , wherein: 
 (i) each of a first pair of S-shaped sections comprises a first axis passing through an initial point and an end point of the S-shaped section to define a pair of first axes in substantially parallel alignment; and    (ii) each of a second pair of S-shaped sections comprises a second axis passing through an initial point and an end point of the S-shaped section to define a pair of second axes in substantially parallel alignment.    
     
     
         23 . The stent defined in  claim 20 , wherein each of the first axis and the second axis are angled with respect to the longitudinal axis.  
     
     
         24 . The stent defined in  claim 20 , wherein the first axis and the second axis are acutely angled with respect to one another.  
     
     
         25 . The stent defined in  claim 16 , wherein the repeating pattern is substantially free of straight sections.  
     
     
         26 . The stent defined in  claim 16 , wherein the tubular wall has a substantially circular cross-section.  
     
     
         27 . The stent defined in  claim 16 , wherein the tubular wall is constructed of a plastically deformnable material.  
     
     
         28 . An expandable stent comprising a proximal end and a distal end in communication with one another, a tubular wall disposed between the proximal end and the distal end, the tubular wall having a longitudinal axis and a porous surface defined by a plurality of interconnected circumferential rows of a repeating pattern, the repeating pattern being substantially free of straight sections and having a multi-lobed shaped perimeter and being oriented in place by at least six 3-point junctions.  
     
     
         29 . The stent defined in  claim 28 , wherein the tubular wall has a substantially circular cross-section.  
     
     
         30 . The stent defined in  claim 28 , wherein the tubular wall is constructed of a plastically deformable material.