Stent with spiral side-branch support designs

Abstract

An expandable stent may be made having an expandable spiral side branch support section having a spiral configuration and disposed about a center point. The expandable spiral side branch support section is configured to expand outward to allow for the formation of a bifurcated stent with a side branch.

1 . An expandable stent having an exterior surface and an interior surface, an inner diameter and an outer diameter, the inner diameter being constant, there being a longitudinal flowpath through the stent, the stent comprising an expandable spiral side branch support section having a spiral configuration and disposed about a center point, the center point located at a first longitudinal coordinate and circumferential coordinate, the spiral side branch support section comprising at least one spiral arm forming a curve extending at least partially around the center point, the at least one spiral arm having a first end and a second end, the second end positioned closer to the center point than the first end, the stent having no more than one spiral branch support section disposed about a center point located at the first longitudinal coordinate.  
   
   
       2 . The stent of  claim 1 , wherein the distal end of the at least one spiral arm is a free end.  
   
   
       3 . The stent of  claim 1  having only one expandable spiral side branch support section.  
   
   
       4 . The stent of  claim 3  wherein the one expandable spiral side branch support section comprises only one spiral arm.  
   
   
       5 . The stent of  claim 3  wherein the one expandable spiral side branch support section comprises a plurality of spiral arms.  
   
   
       6 . The stent of  claim 5 , wherein each of the spiral arms is attached at one end to a member which forms a circumferential member extending along the exterior surface of the stent, the circumferential member extending only part of the way about the longitudinal axis of the stent.  
   
   
       7 . The stent of  claim 6  wherein the circumferential member includes at least one apex and one valley.  
   
   
       8 . The stent of  claim 7  wherein the circumferential member has a serpentine shape, the serpentine shape having turns.  
   
   
       9 . The stent of  claim 6 , wherein the circumferential member has a locking mechanism.  
   
   
       10 . The stent of  claim 1  having a plurality of expandable spiral side branch sections.  
   
   
       11 . The stent of  claim 10  wherein each of at least two of the expandable spiral side branch sections comprise a plurality of spiral arms.  
   
   
       12 . The stent of  claim 1  having at least one expandable spiral side branch section which comprises a plurality of spiral arms, each of the spiral arms attached at one end to a first member which forms a first closed pathway about the center point and at another end to a second member which forms a second closed pathway about the center point, the first closed pathway being longer than the second closed pathway.  
   
   
       13 . An expandable stent having an exterior surface and an interior surface, an inner diameter and an outer diameter, there being a longitudinal flowpath through the stent, the stent comprising an expandable spiral side branch support section which lies flush with the inner surface of the remainder of the stent, the expandable spiral side branch having a spiral configuration and disposed about a center point, the center point located at a first longitudinal coordinate and circumferential coordinate, the spiral side branch support section comprising at least one spiral arm forming a curve extending at least partially around the center point, the at least one spiral arm having a first end and a second end, the second end positioned closer to the center point than the first end, the stent having no more than one spiral branch support section disposed about a center point located at the first longitudinal coordinate.  
   
   
       14 . The stent of  claim 13  having only one expandable spiral side branch support section.  
   
   
       15 . The stent of  claim 13  wherein the one expandable spiral side branch support section comprises only one spiral arm.  
   
   
       16 . The stent of  claim 13  wherein the one expandable spiral side branch support section comprises a plurality of spiral arms.  
   
   
       17 . A bifurcated stent formed by: 
 providing the expandable stent of  claim 1;     expanding the stent to a first diameter expanding the at least one spiral arm outward to define a second flowpath which branches off the longitudinal flowpath.    
   
   
       18 . The stent of  claim 17  wherein at least one of the expanding steps is accomplished with a balloon.  
   
   
       19 . The stent of  claim 17  wherein at least one of the expanding steps is accomplished by withdrawing a sheath which is disposed over at least a portion of the stent.  
   
   
       20 . In combination, a catheter and an expandable stent having a tubular surface disposed about a longitudinal flowpath, the tubular surface including at least one arm which is arranged along the surface about an opening, the opening having a first size in an unexpanded state of the stent, the at least one arm arranged to define a spiral, the expandable stent disposed about the catheter, the catheter including an elongated member which extends through the opening.