Flexible stent
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. A 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, 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,
wherein said strut portions and/or said helical portions can have a varied axial length over a length of said stent;
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, and every other one of said peaks of said strut elements are connected by a respective one of said helical elements;
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; and
wherein one of said strut portions has less strut elements than a second of said strut portions, said one of said strut portions has half as many strut elements as the second of said strut portions.
2. The stent of claim 1 wherein said helical elements of each of said helical portions are wound in the same direction.
3. The stent of claim 1 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.
4. The stent of claim 3 wherein said at least of said one strut portions is at either end of said stent.
5. The stent of claim 1 wherein at least one of said helical portions has a larger diameter than at least one of said strut portions.