Stent and method for manufacturing the stent
A stent includes a stent body having a circumference and struts disposed helically about the circumference in turns. At least two of the struts have respective strut ends. At least two paddle-shaped markers extend away from a respective one of the strut ends. The markers have respective marker extreme ends and different overall longitudinal lengths substantially aligning the marker extreme ends approximately along a single circumference of the stent body. A method for manufacturing a helical stent includes the steps of providing a stent body with struts disposed about the circumference thereof in turns and with bridges connecting the struts in adjacent turns. The stent body is expanded and, thereafter, some of the bridges, in particular, sacrificial bridges, are removed.
1 . A stent, comprising:
a stent body having:
a circumference;
struts disposed helically about said circumference in turns, at least two of said struts having respective strut ends; and
at least two paddle-shaped markers extending away from a respective one of said strut ends, said markers having respective marker extreme ends and different overall longitudinal lengths substantially aligning said marker extreme ends approximately along a single circumference of said stent body.
2 . The stent according to claim 1 , wherein:
said stent body has a longitudinal axis; and
said single circumference is substantially orthogonal to said axis.
3 . The stent according to claim 1 , wherein:
said stent body has a longitudinal axis; and
said markers extend away from a respective one of said strut ends substantially parallel to said longitudinal axis.
4 . The stent according to claim 1 , wherein:
said marker has a body with a first imaging characteristic, said body has at least one portion with a second imaging characteristic different from said first imaging characteristic;
said first and second imaging characteristics are selected from the group consisting of ultrasound imaging characteristics, fluoroscopy imaging characteristics, x-ray imaging characteristics, and magnetic resonance imaging characteristics.
5 . The stent according to claim 4 , wherein said portion is a structure selected from at least one of the group consisting of a depression, a hole, a recess, a notch, a slot, a cylinder, a coating, a filling, a sphere, a texture, a porosity, a second material attached to said marker, and a particle.
6 . The stent according to claim 1 , wherein said marker extreme ends are substantially flat in a circumferential direction and are shaped to receive a deployment catheter.
7 . The stent according to claim 1 , wherein said struts are disposed in a single helix having one start at a proximal end of said helix and one end at a distal end of said helix.
8 . The stent according to claim 1 , wherein:
said stent body has a proximal end and a distal end; and
said struts are disposed in a multiple helix with at least two helices each having one start at said proximal end and one end at said distal end.
9 . The stent according to claim 8 , wherein said multiple helix has 4 helices each having one start at said proximal end and one end at said distal end.
10 . The stent according to claim 7 , wherein:
said struts are s-shaped struts; and
said helix has a continuous repetition of said s-shaped struts throughout a length of said helix.
11 . The stent according to claim 8 , wherein:
said struts are s-shaped struts; and
each of said helices has a continuous repetition of said s-shaped struts throughout a length of said helices.
12 . The stent according to claim 1 , wherein said struts have curved segments and said markers extend away from said curved ends.
13 . The stent according to claim 1 , wherein said markers are radiopaque markers.
14 . The stent according to claim 13 , wherein said radiopaque markers are of a material selected from at least one of the group consisting of tungsten, tantalum, molybdenum, platinum, gold, zirconium oxide, barium salt, bismuth salt, hafnium, and bismuth subcarbonate.
15 . The stent according to claim 1 , wherein said markers are ultrasound markers.
16 . The stent according to claim 15 , wherein said ultrasound markers are features selected from at least one of a group consisting of abrasions, holes, voids, porous materials, porous coatings, hollow balloons, and layered materials having different sonic properties.
17 . The stent according to claim 15 , wherein said ultrasound marker is a hole 0.50 millimeters in diameter filled with a composite of glass microballoons and tungsten powder suspended in an epoxy matrix.
18 . The stent according to claim 1 , wherein said markers are magnetic resonance imaging markers.
19 . The stent according to claim 18 , wherein said magnetic resonance imaging markers are of materials selected from at least one of the group consisting of paramagnetic, diamagnetic, and ferromagnetic.
20 . The stent according to claim 18 , wherein said magnetic resonance imaging markers are of at least one of the group consisting of gadolinium, gadolinium salts, gadolinium foil, gadolinium powder, hematite, oxides, nanocrystalline iron oxide, and iron powder.
21 . The stent according to claim 1 , wherein said markers are ultrasonic markers.
22 . The stent according to claim 21 , wherein said ultrasonic markers are of glass or ceramic microballoons
23 . The stent according to claim 1 , wherein said markers are combinations of radiopaque, ultrasound, and magnetic resonance imaging markers.
24 . The stent according to claim 1 , wherein one of said markers has a relatively shorter extension portion adjacent an end of said helix turn and others of said markers have a relatively larger extension portion increasing in size along said helix turn in a direction away from said relatively shorter extension portion.
25 . The stent according to claim 24 , wherein said markers have paddle portions with aligned ends.
26 . The stent according to claim 24 , wherein:
said stent body has a longitudinal axis; and
said markers have paddle portions with ends opposite said extension portions defining a circumferential plane substantially orthogonal to said longitudinal axis.
27 . The stent according to claim 24 , wherein said extension portions have a given width in a circumferential direction of said stent body and said paddle portions have a width in said circumferential direction greater than said given width.
28 . The stent according to claim 24 , wherein said extension portions have a given width in a circumferential direction of said stent body and said paddle portions have a width in said circumferential direction equal to said given width.
29 . The stent according to claim 25 , wherein said paddle portions are non-circular.
30 . The stent according to claim 1 , wherein said extreme ends of adjacent ones of said markers are separated by a distance no greater than 18 microns.
31 . The stent according to claim 1 , wherein:
said struts have a reduced state and first expanded state defining an outer circumferential cylinder with a first circumference;
at least two of said struts have respective strut ends;
at least two of said paddle-shaped markers extend away from a respective one of said strut ends and have respective marker extreme ends; and
said markers have a second expanded state in which a second circumference defined by said marker extreme ends is greater than said first circumference.
32 . A stent, comprising:
a stent body having:
a circumference;
struts disposed helically about said circumference in turns, at least two of said struts having respective strut ends; and
at least two paddle-shaped markers extending away from a respective one of said strut ends, said markers having respective circumferentially flat extreme ends and different overall longitudinal lengths substantially aligning said flat extreme ends of said markers along approximately a single circumference of said stent body.
33 . The stent according to claim 32 , wherein:
said stent body has a longitudinal axis; and
said single circumference is substantially orthogonal to said axis.
34 . The stent according to claim 32 , wherein:
said stent body has a longitudinal axis; and
said single circumference is at an angle to said axis.
35 . A stent, comprising:
a stent body having:
a circumference;
struts disposed helically about said circumference in turns and having a reduced state and first expanded state defining an outer circumferential cylinder with a first circumference, at least two of said struts having respective strut ends;
at least two paddle-shaped markers extending away from a respective one of said strut ends and having respective marker extreme ends; and
said markers having a second expanded state in which a second circumference defined by said marker extreme ends is greater than said first circumference.