Flexible expandable stent

Abstract

A stent for implanting in the body to hold open a blood vessel includes cells with facing loops and the curved flexible links disposed and adapted to cooperate so that, when unexpanded, the stent can flex as it is moved through curved blood vessels to a site where it is to be expanded and so that, when the stent is expanded in a curved vessel, at that site, as compared to each other, cells on the outside of the curve are open in length, but narrow in width as compared to cells on the inside of the curve which are short in length but increased in width to result in a more constant stent cell area between the inside and the outside of the curve than would otherwise occur causing the stent, when coated with a medicine, to apply a more even dose to the inside wall of the lumen, avoiding the possibility that a toxic dose is supplied at one area while a less than effective dose is applied to another area.

1 - 25 . (canceled) 
   
   
       26 . An expandable stent formed of a cylindrical unitary tube suitable for insertion into a lumen in which the stent may be expanded, comprising:
 a plurality of continuous serpentine sections extending circumferentially around the stent;   a plurality of flexible connectors connecting said serpentine sections forming generally uniform cells wherein the length of each of said connectors is longer than the distance between adjacent serpentine sections each of said connectors being elongatable.   
   
   
       27 - 41 . (canceled) 
   
   
       42 . The stent according to  claim 26  wherein, after expansion, the flexible connectors are staggered between neighboring adjacent serpentine sections along the longitudinal length of the stent. 
   
   
       43 . The stent according to  claim 26  wherein, before expansion, the flexible connectors are horizontally aligned between neighboring adjacent serpentine sections along the longitudinal length of the stent. 
   
   
       44 . The stent according to  claim 26 , wherein the flexible connectors further include straight portions and curved portions, the straight portions being connected to the neighboring adjacent sections. 
   
   
       45 . The stent according to  claim 44  wherein the curved portions of the flexible connectors have an open end and a closed end, the open end of the connectors facing the same direction within each continuous serpentine section circumferentially around the stent, and alternate in the opposite direction along the longitudinal axis of the stent. 
   
   
       46 . The stent according to  claim 43 , wherein the flexible connectors are connected to peaks of neighboring adjacent serpentine sections. 
   
   
       47 . The stent according to  claim 46 , wherein the flexible connectors are attached to all the peaks of neighboring adjacent serpentine sections. 
   
   
       48 . A stent comprising:
 a plurality of flexible connectors connecting loops of adjacent vertical meander patterns of the stent to form generally uniform cells, the flexible connector including an elongatable member wherein the length of the member is greater than the distance between points of attachment of the member to the adjacent vertical meander patterns, said connector being elongatable.   
   
   
       49 . The flexible connectors of  claim 48  wherein, after expansion, the connectors are staggered between neighboring adjacent vertical meander patterns along the longitudinal length of the stent. 
   
   
       50 . The flexible connector of  claim 48  wherein, before expansion, the connectors are horizontally aligned between neighboring adjacent vertical meander patterns along the longitudinal length of the stent. 
   
   
       51 . A stent formed of a unitary tube having a patterned shape for insertion into a lumen in which it may be expanded, comprising:
 a. even first meander patterns having axes extending in a first direction;   b. odd first meander patterns also having axes extending in said first direction, wherein said odd first meander patterns are 180° out of phase with said even first meander patterns and occur between every two even first meander patterns;   c. second meander patterns having axes extending in a second direction, different than said first direction, wherein said second meander patterns intersect with said even and odd first meander patterns to form generally uniform cells structure;   d. wherein said first and said second meander patterns comprise loops;   e. wherein at least one loop of each of said second meander patterns is between each odd and even first meander pattern;   f. said loops of said second meander patterns containing at least a portion having a smaller width.   
   
   
       52 . The stent according to  claim 51  wherein said second meander patterns are connected to said even and odd first meander patterns so as to leave loops of the first meander patterns between adjacent second meander patterns. 
   
   
       53 . The stent according to  claim 51 , wherein said second meander patterns have straight and curved portions. 
   
   
       54 . The stent according to  claim 53 , wherein each curved portion of said second meander patterns further includes an open end and a closed end, wherein the open end alternates in direction along the longitudinal axis of the stent. 
   
   
       55 . A stent formed of a unitary tube having a patterned shape for insertion into a lumen in which it may be expanded, comprising:
 a. even first meander patterns having axes extending in a first direction;   b. odd first meander patterns also having axes extending in said first direction, wherein said odd first meander patterns are 180° out of phase with said even first meander patterns and occur between every two even first meander patterns;   c. second meander patterns having axes extending in a second direction, different than said first direction, wherein said second meander patterns intersect with said even and odd first meander patterns to form generally uniform cells;   d. wherein said first and said second meander patterns comprise loops;   e. wherein at least one loop of each of said second meander patterns is between each odd and even first meander pattern;   f. wherein at least some of said loops of said second meander patterns are more flexible than the loops of said first meander patterns, so that a distance between first meander patterns is maintained upon expansion.   
   
   
       56 . An expandable stent for supporting a vessel, wherein in the expanded and deployed state, the stent consists of:
 a. first meander patterns having loops, the first meander patterns being longitudinally spaced from each other and having axes extending in a first direction; and   b. second meander patterns having loops, the second meander patterns having axes extending in a second direction, different than the first direction;   c. wherein the first and second meander patterns are interconnected to form a tubular structure;   d. wherein the first meander patterns are connected to the second meander patterns so as to leave at least one loop of each of the second meander patterns in the space between each pair of adjacent first meander patterns;   e. wherein the second meander patterns are connected to the first meander patterns so as to leave no more than two loops of each of the first meander patterns between each pair of adjacent second meander patterns; and   f. wherein said first and second meander patterns are adapted to cooperate so that, when the expanded stent is in a curved vessel, on the outside of the curve, a circumferential compression and horizontal expansion of the loops in said second meander pattern substantially compensates for a horizontal compression and circumferential expansion of the loops in said first meander pattern and on the inside of the curve.   
   
   
       57 . A stent according to  claim 56 , wherein on the outside of the curve, the loops in said second meander pattern are more open and the loops in the first meander pattern more closed, and on the inside of the curve, the loops in said second meander pattern are more closed and the loops in the first meander pattern more open. 
   
   
       58 . A stent according to  claim 56  wherein the compensation maintains a density of stent element area which is more constant on the inside and on the outside of the curve than it would without the compensation. 
   
   
       59 . A stent according to  claim 56  wherein the compensation maintains a stent area which is more constant on the inside and on the outside of the curve than it would without the compensation. 
   
   
       60 . A stent according to  claim 58  wherein said stent is coated with a medicine and said more constant density of stent elements results in a more even dose being applied to the inside wall of the lumen, lowering the probability that a toxic dose is supplied at one area while a less than effective dose is supplied to another area. 
   
   
       61 . A stent according to  claim 59  wherein said stent is coated with a medicine and said more constant density of stent elements results in a more even dose being applied to the inside wall of the lumen, lowering the probability that a toxic dose is supplied at one area while a less than effective dose is supplied to another area. 
   
   
       62 . The stent according to  claim 56 , wherein the shape of the loops provides radial strength to the stent to enable the stent to maintain a blood vessel at a desired inner diameter. 
   
   
       63 . The stent according to  claim 56 , wherein the stent defines a plurality of enclosed spaces, with each longitudinal end of the enclosed space being formed by loops of the first meander pattern.