Stents with increased flexibility

Abstract

Stents that are adapted to be balloon-expanded and include a plurality of rings of repeating cells, wherein adjacent rings are connected by s-shaped or omega-shaped crosslink connectors or a combination of both connectors. The configurations, materials, and/or dimensions of these devices, including the unit cells and/or crosslink connectors allow the stents to be expanded to a greater extent (e.g., up to or greater than 12 mm of diameter), and optionally with reduced foreshortening and without increasing the strain on the materials forming the crosslink connectors and unit cells. The biphasic arrangement of trapezoidal unit cells, as well as the configuration and arrangement of the s-shaped connectors, may allow these stents to expand while maintaining their radial compression strength and longitudinal compression strength with minimal recoil and stent foreshortening.

What is claimed is: 
     
         1 . A stent device, the device comprising:
 a plurality of adjacent rings arranged transverse to a length of the device in a proximal to distal direction, wherein each ring comprises a repeating pattern of alternating flattened tops and flattened bottoms extending transverse to the length of the device, wherein the flattened tops are connected to the flattened bottoms by sigmoid-shaped connectors so that each flattened top forms part of a proximal-facing U-shape and each flattened bottom forms part of a distal-facing U-shape.   a plurality of crosslink connectors connecting adjacent rings, wherein each crosslink connector connects a region between one of the flattened tops and one of the sigmoid-shaped connectors on one of the rings to a region between one of the fattened bottoms and one of the sigmoid-shaped connectors on an adjacent ring;   wherein the crosslink connectors form a helically winding arrangement around the length of the device, further wherein the cross-link connectors comprises one of: omega-shaped crosslink connectors or s-shaped crosslink connectors; and   wherein the stent device has a first configuration in which the plurality of adjacent rings has a first diameter, and the stent device has a second configuration in which the plurality of adjacent rings has a second diameter that is greater than the first diameter, and wherein the flattened tops and the flattened bottoms remain parallel to each other as the stent device is expanded from the first configuration to the second configuration.   
     
     
         2 . The device of  claim 1 , wherein the repeating pattern of alternating flattened tops and flattened bottoms comprises a repeating pattern of biphasic cells, wherein each biphasic cell includes a first open trapezoidal portion having a first side, a second side and a third side forming a proximal-facing opening and a second open trapezoidal portion having a fourth side, a fifth side and a sixth side forming a distal-facing opening, wherein the second side forms a flattened top and the fifth side forms a flattened bottom, further, wherein the first and third sides are parallel and wherein the fourth and sixth sides are not parallel. 
     
     
         3 . The device of  claim 1 , wherein each ring of the plurality of adjacent rings comprises between 1 and 3 omega-shaped crosslink connectors. 
     
     
         4 . The device of  claim 1 , wherein each of the crosslink connectors connecting the plurality of adjacent rings is oriented in the same direction. 
     
     
         5 . The device of  claim 1 , further comprising a maximum of 2 crosslink connectors between adjacent rings. 
     
     
         6 . The device of  claim 1 , wherein the flattened tops of each ring are radially offset from the flattened bottoms. 
     
     
         7 . The device of  claim 6 , wherein the radial offset increases as the stent device transitions from the first configuration to the second configuration. 
     
     
         8 . The device of  claim 1 , wherein the first diameter is between 0.5 mm and 4 mm and the second diameter is between 2 mm and 12 mm. 
     
     
         9 . The device of  claim 1 , wherein the cross-link connectors comprise sigmoid-shaped crosslink connectors and further wherein each flattened top and a portion of each of two sigmoid-shaped connectors to which it is attached forms a first open trapezoidal portion having a proximal-facing opening and each flattened bottom and a portion of each of two sigmoid-shaped connectors to which it is attached forms a second open trapezoidal portion having a distal-facing opening. 
     
     
         10 . The device of  claim 1 , wherein the length of the device is between about 12 mm and about 80 mm. 
     
     
         11 . The device of  claim 1 , wherein the device comprises one or more of: an alloy of chromium cobalt, a stainless steel and a magnesium alloy. 
     
     
         12 . The device of  claim 1 , further comprising a sleeve comprising a polymeric matrix in which the plurality of rings is encapsulated. 
     
     
         13 . The device of  claim 12 , wherein the sleeve comprises a porous material. 
     
     
         14 . The device of  claim 1 , wherein the flattened tops and the flattened bottom comprise rounded edges. 
     
     
         15 . The device of  claim 1 , wherein the device foreshortens less than about 8.5% when expanding from the first configuration to the second configuration. 
     
     
         16 . The device of  claim 1 , wherein the stent device is configured to bend at least 90 degrees in the first configuration without kinking. 
     
     
         17 . A stent device having a length extending in a distal to proximal direction, the device comprising:
 a plurality of adjacent rings arranged transverse to the length of the device, wherein each ring comprises a length of material arranged radially around the length of the stent device as a plurality of repeating biphasic cells, each biphasic cell comprising a first open trapezoidal portion having a first side, a second side and a third side forming a proximal-facing opening, and a second open trapezoidal portion having a fourth side, a fifth side and a sixth side forming a distal-facing opening, wherein the second side and the fifth side are parallel, further wherein the first open trapezoidal portion is radially offset from the second open trapezoidal portion and the third side of the first open trapezoidal portion is connected to the fourth side of the second open trapezoidal portion by a first connector region, and wherein the first side of the first open trapezoidal portion connects to a sixth side of an adjacent biphasic cell in the ring by a second connector;   between one and three s-shaped connectors connecting each ring that is adjacent to a more distal ring to the more distal ring, wherein each s-shaped connector connects between the first side and the second side of one of the first open trapezoidal portions of the plurality of biphasic cells in the ring that is adjacent to the more distal ring to between the fifth side and sixth side of one of the second open trapezoidal portions of the plurality of biphasic cells of the more distal ring,   wherein the device has a first configuration in which a first diameter of the plurality of adjacent rings is between 0.5 mm and 4 mm, and a second configuration in which a second diameter of the plurality of adjacent rings is between 2 mm and 12 mm, and wherein the second side and the fifth side remain parallel as the stent device expands from the first configuration to the second configuration.   
     
     
         18 . The device of  claim 17 , wherein the first and third sides are parallel and wherein the fourth and sixth sides are not parallel. 
     
     
         19 . The device of  claim 17 , wherein each ring of the plurality of adjacent rings comprises between 1 and 6 s-shaped crosslink connectors. 
     
     
         20 . The device of  claim 17 , wherein each of the crosslinks connectors connecting the plurality of adjacent rings are oriented in the same direction. 
     
     
         21 . The device of  claim 17 , wherein the first diameter is between 0.5 mm and 4 mm and the second diameter is between 2 mm and 12. 
     
     
         22 . The device of  claim 17 , wherein each flattened top and a portion of each of two s-shaped connectors to which it is attached forms a first open trapezoidal portion having a proximal-facing opening and each flattened bottom and a portion of each of two sigmoid-shaped connectors to which it is attached forms a second open trapezoidal portion having a distal-facing opening. 
     
     
         23 . The device of  claim 17 , further comprises a sleeve comprising a polymeric matrix in which the plurality of rings is encapsulated in a sandwich configuration. 
     
     
         24 . The device of  claim 17 , wherein the flattened tops and the flattened bottom comprise rounded edges. 
     
     
         25 . The device of  claim 17 , wherein the device foreshortens less than about 4.5-8.5% when expanding from the first configuration to the second configuration. 
     
     
         26 . The device of  claim 17 , wherein each crosslink connector has a width that is smaller than a width of the length of material forming the biphasic cells.