STENT HAVING HELICAL ELEMENTS
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 having an unexpanded state, the unexpanded stent comprising:
a body defining a cylindrical axis, the body including a helical segment having a substantially H-shaped portion defining two generally parallel linear portions being angled with respect to the cylindrical axis, the helical segment including a substantially S-shaped portion defining at least one generally linear portion being angled with respect to the cylindrical axis.
2 . The stent of claim 1 , wherein the angle between the linear portions of the H-shaped segment and the cylindrical axis is greater than 0 degrees.
3 . The stent of claim 2 , wherein the angle between the linear portions of the H-shaped segment and the cylindrical axis is less than 90 degrees.
4 . The stent of claim 1 , wherein the angle between the linear portion of the S-shaped portion and the cylindrical axis is greater than 0 degrees.
5 . The stent of claim 4 , wherein the angle between the linear portion of the S-shaped portion and the cylindrical axis is less than 90 degrees.
6 . The stent of claim 1 , further comprising a plurality of cylindrical elements disposed about the cylindrical axis.
7 . The stent of claim 6 , wherein each cylindrical element comprises: (1) a first plurality of the expandable circumferential segments and (2) a second plurality of circumferential segments, wherein the first and second pluralities of circumferential segments are joined to each other by at least one of the S-shaped portion and H-shaped segment.
8 . The stent of claim 7 , wherein the first and second pluralities of circumferential segments comprise a majority of the circumference of each cylindrical element.
9 . The stent of claim 7 , wherein the first circumferential segments alternate with the second circumferential segments.
10 . An expandable stent having an unexpanded state, the unexpanded stent comprising:
a cylindrical main body defining a cylindrical axis, the main body including a plurality of helical segments, each helical segment including a substantially H-shaped segment defining two generally parallel linear portions being angled with respect to the cylindrical axis, each helical segment including a substantially S-shaped segment defining at least one generally linear portion being angled with respect to the cylindrical axis.
11 . The stent of claim 10 , wherein the angle between the linear portions of the H-shaped segment and the cylindrical axis is greater than 0 degrees.
12 . The stent of claim 11 , wherein the angle between linear portions of the H-shaped segment and the cylindrical axis is less than 90 degrees.
13 . The stent of claim 10 , wherein each helical segment includes a plurality of substantially S-shaped segments alternating with a plurality of substantially H-shaped segments.
14 . An expandable stent having an unexpanded state, the unexpanded stent comprising:
a main body having a plurality of cylindrical elements disposed about a cylindrical axis, the main body including a helical segment including a substantially S-shaped segment and a substantially H-shaped segment, the H-shaped segment defining two generally parallel linear portions nonparallel to the cylindrical axis.
15 . The stent of claim 14 , the linear portions are not perpendicular to the cylindrical axis.
16 . The stent of claim 14 , wherein each helical segment includes a plurality of substantially S-shaped segments alternating with a plurality of substantially H-shaped segments.
17 . The stent of claim 14 , wherein each cylindrical element comprises: (1) a first plurality of the expandable circumferential segments and (2) a second plurality of circumferential segments, wherein the first and second pluralities of circumferential segments are joined to each other by at least one of the S-shaped portion and H-shaped segment.
18 . The stent of claim 17 , wherein the first and second pluralities of circumferential segments comprise a majority of the circumference of each cylindrical element.
19 . The stent of claim 18 , wherein the first circumferential segments alternate with the second circumferential segments.