Flexible stent

Abstract

A flexible stent structure includes a plurality of axially spaced strut portions defining generally tubular axial segments of the stent and constructed to be radially expandable. A helical portion is interposed axially between two strut portions and has a plurality of helical elements connected between circumferentially spaced locations on the two strut portions. The helical elements extend helically between those locations and the length of a helical element is sufficient so that, when the stent is in a radially expanded state, it can simultaneously withstand repeated axial compression or expansion and bending.

1 . Flexible stent comprising:
 a helical portion comprising a plurality of side-by-side, individual helical elements helically wound about an axis of said stent, said helical portion being expandable radially upon deployment and compressible, expandable and bendable in a deployed state; and a strut portion on either side of said helical portion, each of said strut portions comprising axially aligned strut elements having a first end connected to said helical elements of said helical portion, said strut portions being radially expandable upon deployment.   
     
     
         2 . The stent of  claim 1  wherein said helical elements are wound at least 90 degrees between said strut elements connected to said helical elements in said deployed state. 
     
     
         3 . The stent of  claim 1  wherein said helical elements are wound at least 360 degrees between said strut elements connected to said helical elements in said deployed state. 
     
     
         4 . The stent of  claim 1  further comprising one or more additional said helical portions and one or more additional said strut portions wherein one of said one or more additional said helical portions is connected to a second end of one of said strut portions, said one or more additional said helical portions being connected respectively to said one or more additional said strut portions such that each of said helical portions is interposed between a pair of said strut portions. 
     
     
         5 . The stent of  claim 4  wherein said helical elements of each of said helical portions are wound in the same direction. 
     
     
         6 . The stent of  claim 4  wherein said helical elements of at least one of said helical portions are wound in a direction opposite to said helical elements of another of said helical portions. 
     
     
         7 . The stent of  claim 1  wherein one or more pairs of helical portions are separated and flanked by said strut portions, said helical elements of one portion of said pair being wound in a direction opposite to said helical elements of the other portion of said pair. 
     
     
         8 . The stent of  claim 1  wherein said strut elements of said strut portion have a wave pattern of individual wave portions, each individual wave portion having a peak. 
     
     
         9 . The stent of  claim 8  wherein each of said helical elements is connected to a respective one of said peaks of said strut elements. 
     
     
         10 . The stent of  claim 8  wherein some of said helical elements are connected to some of said peaks of said strut elements. 
     
     
         11 . The stent of  claim 8  wherein every other one of said peaks of said strut elements are connected by a respective one of said helical elements. 
     
     
         12 . The stent of  claim 8  wherein said strut portion comprises a plurality of said strut elements and peaks of said individual wave members being connected to one another by a link. 
     
     
         13 . The stent of  claim 4  wherein at least one of said strut portions comprises a plurality of said strut elements, said strut elements of said strut portion have a wave pattern of individual wave portions, each individual wave portion having a peak and peaks of said individual wave members being connected to one another by a link. 
     
     
         14 . The stent of  claim 13  wherein said at least of said one strut portions is at either end of said stent. 
     
     
         15 . The stent of  claim 1  wherein said helical elements extend helically in a first direction from a first said strut element to a peak and then in an opposite direction from said peak to a second said strut element. 
     
     
         16 . The stent of  claim 1  further comprising one or more additional said helical portions and one or more additional said strut portions wherein one of said one or more additional said helical portions is connected to a second end of one of said strut portions, said one or more additional said helical portions being connected respectively to said one or more additional said strut portions such that each of said helical portions is interposed between a pair of said strut portions and at least one of said helical portions comprise helical elements which extend helically in a first direction from a first said strut portion to a peak and then in an opposite direction from said peak to a second said strut portion. 
     
     
         17 . The stent of  claim 16  wherein at least one of said helical portions comprises said helical elements being wound in a direction opposite to said helical elements of another of said helical portions. 
     
     
         18 . The stent of  claim 1  wherein said helical portion has a larger diameter than said strut portions. 
     
     
         19 . The stent of  claim 4  wherein at least one of said helical portions has a larger diameter than at least one of said strut portions. 
     
     
         20 . The stent of  claim 1  wherein said helical portion has a smaller diameter than said strut portion. 
     
     
         21 . The stent of  claim 4  wherein at least one of said helical portions has a smaller diameter than at least one of said strut portions. 
     
     
         22 . The stent of  claim 1  further comprising a biocompatible graft material covering an outside surface of said stent. 
     
     
         23 . The stent of  claim 1  further comprising a biocompatible graft material covering an inside surface of said stent. 
     
     
         24 . The stent of  claim 1  further comprising a biocompatible graft material covering and an outside surface and an inside surface of said stent. 
     
     
         25 . The stent of  claim 1  further comprising a biocompatible graft material attached to at least one of said strut portions, said graft material covering said strut portions and said helical portion. 
     
     
         26 . The stent of  claim 1  further comprising a plurality of sections of biocompatible graft material, each of said sections of graft material being attached to one of said strut portions and covering the attached said strut portion and a portion of an adjacent said helical portion wherein a gap is provided between each of said sections of graft material. 
     
     
         27 . The stent of  claim 26  wherein said gap is less than about 20% of a length of said helical portion. 
     
     
         28 . The stent of  claim 1  further comprising a plurality of sections of a biocompatible graft material, each of said sections of graft material being attached to one of said strut portions and covering the attached said strut portion and an adjacent said helical portion wherein said graft material of adjacent sections of graft material is overlapped. 
     
     
         29 . The stent of  claim 28  wherein said overlap is less than about 40% of a length of said helical portion. 
     
     
         30 . The stent of  claim 1  further comprising a biocompatible graft material, said graft material being attached to at least one of said strut portions, said graft material covering said strut portions and said helical portion and said graft material having a bulge at said helical portion. 
     
     
         31 . The stent of  claim 1  further comprising a biocompatible graft material, said graft material being attached to at least one of said strut portions, said graft material covering said strut portions and said helical portion and said graft material having a plurality longitudinal openings in said graft material over said helical portion. 
     
     
         32 . The stent of  claim 1  further comprising a biocompatible graft material, said graft material being attached to at least one of said strut portions and covering said strut portions and said helical portion, said graft material having a bulge at said helical portion and said graft material having a plurality of longitudinal openings in said graft material over said helical portion. 
     
     
         33 . The stent of  claim 32  further comprising a biocompatible graft material, said graft material being attached to at least one of said strut portions and covering said strut portions and said helical portion, said graft material having a plurality of helical openings corresponding to a pitch of said helical elements. 
     
     
         34 . The stent of  claim 1  further comprising a plurality of sections of biocompatible graft material each of said sections being attached to either said strut portion or said helical portion. 
     
     
         35 . The stent of  claim 34  wherein a gap is provided between each of said sections of said graft material. 
     
     
         36 . The stent of  claim 35  wherein said gap is less than about 20% of a length of said helical portion. 
     
     
         37 . The stent of  claim 1  further comprising a plurality of sections of biocompatible graft material each of said sections being attached to either said strut portion or said helical portion wherein adjacent sections of graft material are overlapped. 
     
     
         38 . The stent of  claim 37  wherein said overlap is less than about 40% of a length of said helical portion. 
     
     
         39 . The stent of  claim 1  wherein a gap between adjacent helical elements of a helical portion is about the same in a compressed state of said stent. 
     
     
         40 . The stent of  claim 39  wherein said gap is in a range of between 0 and a size of a gap between adjacent helical elements of a helical portion in said deployed state. 
     
     
         41 . The stent of  claim 1  wherein adjacent helical elements of a helical portion contact one another in a compressed state. 
     
     
         42 . The stent of  claim 1  wherein a gap between adjacent helical elements of a helical portion varies along the length of said helical portion in a compressed state. 
     
     
         43 . The stent of  claim 42  wherein said gap is in a range of between 0 and a size of a gap between adjacent helical elements of a helical portion in said deployed state. 
     
     
         44 . The stent of  claim 4  wherein said strut portions and/or said helical portions can have a varied axial length over a length of said stent. 
     
     
         45 . The stent of  claim 44  wherein said strut elements of said strut portion have a wave pattern of individual wave portions, each individual wave portion having a peak and each of said helical elements is connected to a respective one of said peaks on one side of said side strut elements and some of said helical elements are connected to some of said peaks on the other side of said side strut elements. 
     
     
         46 . The stent of  claim 45  wherein every other one of said peaks of said strut elements are connected by a respective one of said helical elements. 
     
     
         47 . The stent of  claim 4  wherein one of said helical portions has a higher ratio of a sum of gap lengths to a length of the helical portion than a second one of said helical portions. 
     
     
         48 . The stent of  claim 4  wherein one of said strut portions has less strut elements than a second of said strut portions. 
     
     
         49 . The stent of  claim 48  wherein said one of said strut portions has half as many strut elements as the second of said strut portions. 
     
     
         50 . Flexible stent comprising:
 a helical portion comprising a plurality of side-by-side, individual helical elements helically wound about an axis of said stent, said helical portion being expandable radially upon deployment and compressible, expandable and bendable in a deployed state; and a strut portion on either side of said helical portion, each of said strut portions comprising helically aligned strut elements having a first end connected to said helical elements of said helical portion, said strut portions being radially expandable upon deployment.   
     
     
         51 . The stent of  claim 50  wherein each of said helical elements extends for one or more complete rotations of 360 degrees about an axis of said stent. 
     
     
         52 . The stent of  claim 50  wherein each of said helical elements extends for at least  90  degrees about an axis of said stent. 
     
     
         53 . A method for minimizing or eliminating foreshortening of a flexible stent comprising rotating a plurality of side-by-side individual helical elements, said helical elements being helically wound about an axis of said stent to form a helical portion, said helical portion being expandable radially upon deployment and compressible, expandable and bendable in a deployed state and a strut portion on either side of said helical portion, each of said strut portions comprising axially aligned strut elements having a first end connected to said helical elements of said helical portion, said strut portions being radially expandable upon deployment. 
     
     
         54 . The method of  claim 53  wherein an axial length of said stent in said deployed state is the same as an axial length of said stent in a crimped state. 
     
     
         55 . The stent of  claim 53  wherein a gap between said side-by-side helical elements of said helical portion is about the same in a crimped state of said stent. 
     
     
         56 . The stent of  claim 53  wherein said side-by-side helical elements of said helical portion contact one another in a crimped state of said stent. 
     
     
         57 . The method of  claim 56  wherein an axial length of said stent in said deployed state is the same as an axial length of said stent in a crimped state. 
     
     
         58 . The method of  claim 53  wherein an axial length of said stent in a crimped state is less than an axial length of said stent in said deployed state. 
     
     
         59 . A method for crimping a flexible stent comprising elongating a plurality of side-by-side individual helical elements to a crimped state, said helical elements being helically wound about an axis of said stent to form a helical portion, said helical portion being expandable radially upon deployment and compressible, expandable and bendable in a deployed state and a strut portion on either side of said helical portion, each of said strut portions comprising axially aligned strut elements having a first end connected to said helical elements of said helical portion, said strut portions being radially expandable upon deployment. 
     
     
         60 . The stent of  claim 59  wherein a gap between said side-by-side helical elements of said helical portion varies along a length of said helical portion in said crimped state. 
     
     
         61 . The method of  claim 59  wherein an axial length of said stent in said deployed state is less than an axial length of said stent in said crimped state. 
     
     
         62 . A method for placing a flexible stent within a mammal in a body lumen comprising placing one or more stents at said site, said flexible stent comprising a helical portion comprising a plurality of side-by-side, individual helical elements helically wound about an axis of said stent, said helical portion being expandable radially upon deployment and compressible, expandable and bendable in a deployed state; and a strut portion on either side of said helical portion, each of said strut portions comprising axially aligned strut elements having a first end connected to said helical elements of said helical section, said strut portions being radially expandable upon deployment. 
     
     
         63 . The method of  claim 62  wherein the mammal is a human and the body lumen is a vessel or duct. 
     
     
         64 . The method of  claim 62  wherein the mammal is a human and the body lumen is a super femoral artery. 
     
     
         65 . The method of  claim 62  wherein said stent further comprises a biocompatible graft material covering an outside surface of said stent and/or an inside surface of said stent. 
     
     
         66 . A method of treating a diseased vessel or duct comprising the steps of:
 guiding a catheter to a target site;   advancing through the catheter a flexible stent, said flexible stent comprising a helical portion comprising a plurality of side-by-side, individual helical elements helically wound about an axis of said stent, and a strut portion on either side of said helical portion, each of said strut portions comprising axially aligned strut elements having a first end connected to said helical elements of said helical section;   expelling the stent from the catheter at the target site, causing the helical portion to expand radially and said strut portions to expand radially, said helical portion being compressible, expandable and bendable in a deployed state.   
     
     
         67 . The method of  claim 66  wherein said target site is a vascular site. 
     
     
         68 . The method of  claim 66  wherein the target site is a super femoral artery. 
     
     
         69 . The method of  claim 66  wherein said target site is a lesion. 
     
     
         70 . The method of  claim 66  wherein said target site is an aneurysm. 
     
     
         71 . The method of  claim 66  wherein said stent further comprises a biocompatible graft material covering an outside surface of said stent and/or an inside surface of said stent. 
     
     
         72 . The method of  claim 66  wherein said stent further comprises a coating of a polymer and/or drug eluting material.