Stent having helical elements

Abstract

An expandable stent comprised of a plurality of helical segments is disclosed. In one embodiment, the stent is generally cylindrical in shape having a cylindrical axis, and comprises a first and second set of helical segments. The helical segments in the first set are substantially parallel and have a first pitch forming a first helical angle with respect to the cylindrical axis. The helical segments in the second set are also generally parallel to each other and form a second pitch that differs from the first pitch, thereby forming a second helical angle with respect to the cylindrical axis. In an alternative embodiment, the stent comprises one set of helical segments and a plurality of circumferential elements that are joined together by the helical segments to form a plurality of cylindrical elements which are joined together to form a stent body. The stent may also have endzones.

1 . An expandable stent comprising:
 a generally cylindrically shaped main body having a cylindrical axis, the main body including:   a plurality of adjacent cylindrical elements having cylindrical axes collinear with the main body cylindrical axis,   the cylindrical main body elements comprising a plurality of first expandable circumferential segments having a circumferential dimension; and a plurality of second expandable circumferential segments having a circumferential dimension that is less than the first expandable segment circumferential dimension, each of the second expandable segments connected to two first expandable segments via substantially H-shaped connecting segments; and   wherein the substantially H-shaped connecting segments and second expandable circumferential segments of adjacent cylindrical main body elements form a plurality of generally parallel helixes.   
   
   
       2 . The stent of  claim 1 , further comprising a first non-helical endzone at one end of the main body, and a second non-helical endzone at an opposite end of the main body. 
   
   
       3 . The stent of  claim 2 , wherein each endzone is attached to the main body by a plurality of struts. 
   
   
       4 . The stent of  claim 2 , wherein each endzone comprises a ring formed from a plurality of contiguous segments. 
   
   
       5 . The stent of  claim 4 , wherein the contiguous segments comprise linear and curved segments joined together to form a repeating pattern. 
   
   
       6 . The stent of  claim 1 , wherein at least a portion of the stent is radiopaque. 
   
   
       7 . The stent of  claim 1 , wherein at least two of the plurality of helixes are 180 degrees apart. 
   
   
       8 . The stent of  claim 1 , wherein the first expandable circumferential element comprises a plurality of linear and curved segments joined together to form a repeating pattern that resembles generally a square wave form having curved peaks and valleys. 
   
   
       9 . The stent of  claim 1 , wherein the second expandable element comprises a plurality of linear and curved segments joined together and wherein the linear segments form an angle relative to the cylindrical axis of the stent that is approximately equal to the helical angle of at least one of the helixes in the main body. 
   
   
       10 . An expandable stent that, when in an unexpanded state, comprises:
 a cylindrical main body defining a cylindrical axis,   the main body comprising: a plurality of cylindrical elements having collinear cylindrical axes, the cylindrical elements being adjacent to one another and connected to one another by helical segments comprising expandable circumferential segments and substantially H-shaped connecting segments,   wherein the helical segments comprise a plurality of first expandable helical segments having a first pitch and a plurality of second expandable helical segments having a second pitch different from the first pitch, and wherein the first helical segments cross the second helical segments and the first and second helical segments are attached to each other via substantially H-shaped connecting segments.   
   
   
       11 . The stent of  claim 10 , wherein the second pitch has a value that is approximately twice that of the first pitch. 
   
   
       12 . The stent of  claim 10 , further comprising a plurality of generally cylindrical shaped endzones having cylindrical axes that are collinear with the main body cylindrical axis. 
   
   
       13 . The stent of  claim 12 , wherein the endzones have square outer edges. 
   
   
       14 . The stent of  claim 10 , wherein the first helical segments are comprised of a plurality of circumferential segments joined together to form a helix. 
   
   
       15 . The stent of  claim 14 , wherein the circumferential segments comprise a plurality of linear and curved segments joined together. 
   
   
       16 . The stent of  claim 15 , wherein the linear segments lie at an angle between 0 and 45 degrees with respect to the cylindrical axis of the stent. 
   
   
       17 . The stent of  claim 10 , wherein the second helical segments are comprised of a plurality of second circumferential elements joined together to form a second helix. 
   
   
       18 . An expandable stent comprising:
 a plurality of first expandable segments;   a plurality of second expandable segments;   a plurality of adjacent cylindrical elements having collinear cylindrical axes, the cylindrical main body elements formed by connecting first expandable segments with second expandable segments via substantially H-shaped connecting segments;   a plurality of first helical segments having a pitch, the first helical segments formed by connecting first expandable segments from adjacent cylindrical elements with each other; and   a plurality of second helical segments formed by connecting second expandable segments from adjacent cylindrical elements with each other,   wherein the second helical segments have a pitch that differs from the pitch of the first helical segments.   
   
   
       19 . The stent of  claim 18 , further comprising a first and second endzone, each endzone straddling a cylindrical element. 
   
   
       20 . The stent of  claim 18 , wherein at least one helical segment forms an angle of approximately 40 degrees relative to the cylindrical axis.