Radiopaque super-elastic intravascular stent
View Patent ↗The intravascular stent is formed from a composite wire includes an inner core of radiopaque metal, a polymer layer coaxially disposed about the inner core, and an outer metal layer coaxially disposed about the polymer layer. The intermediary polymer layer acts as a barrier material between the inner core and the outer sheath, so that the inner core and outer sheath may be made of dissimilar metallic layers, and the intermediary polymer layer will prevent a galvanic reaction between the inner core and the peripheral metal layer. The intravascular stent has ends flared radially outwardly to prevent radially and longitudinally inward deformation of the ends of the stent when the stent is disposed in a desired location in a patient's vasculature.
1. A composite wire, comprising:
a single wire having a first free end, a second free end, and a main body length therebetween for forming a vascular interventional device, said single wire including:
an elongated inner core having a selected length and formed from a radiopaque metal;
an outer metal layer disposed around said elongated inner core along the length of said elongated inner core, wherein said elongated inner core and said outer metal layer are made of dissimilar metals; and
a continuous intermediate polymer layer disposed between said outer metal layer and said elongated inner core, said continuous intermediate polymer layer being configured to insulate said elongated inner core and said outer metal layer from galvanic corrosion between said elongated inner core and said outer metal layer, and said continuous intermediate polymer layer being formed from a polymer selected from the group consisting of poly-para-xylylene, a fluorine substituted poly-para-xylylene and combinations thereof; and
a segment of tubing joining the first free end of said single wire and the second free end of said single wire together, said first and second free ends of said single wire being in close proximity to each other such that said segment of tubing joining the first free end of said single wire and the second free end of said single wire together is configured to prevent said first and second free ends of said single wire from extending away from the main body length of said single wire.
2. The composite wire of claim 1 , wherein the radiopaque metal is selected from the group consisting of platinum, tantalum, gold, and combinations thereof.
3. The composite wire of claim 1 , wherein the inner core is cylindrical.
4. The composite wire of claim 1 , wherein the inner core is disposed centrally along a longitudinal axis of the composite wire.
5. The composite wire of claim 1 , wherein the outer metal layer is formed of a superelastic alloy.
6. The composite wire of claim 1 , wherein the outer metal layer is formed of a nickel-titanium alloy.
7. The composite wire of claim 1 , wherein the composite wire is formed as a cylindrical wire.
8. A composite wire, comprising:
a single wire having a first free end, a second free end, and a main body length therebetween for forming a vascular interventional device, said single wire including:
an elongated inner core having a selected length and formed from a first metal, said elongated inner core disposed centrally along a longitudinal axis of said single wire, and said first metal being radiopaque;
an outer metal layer coaxially disposed around said elongated inner core along the length of said elongated inner core, said outer metal layer being formed of a second metal different from said first metal; and
a continuous intermediate polymer layer coaxially disposed between said outer metal layer and inner core, said continuous intermediate polymer layer being operative to insulate said elongated inner core and said outer metal layer from galvanic corrosion between said elongated inner core and said outer metal layer, said continuous intermediate polymer layer being formed from a polymer selected from the group consisting of poly-para-xylylene, a fluorine substituted poly-para-xylylene, and combinations thereof; and
a segment of heat shrink tubing capturing the first free end of said single wire and the second free end of said single wire within the segment of heat shrink tubing to join the first free end of said single wire and the second free end said single wire together, said first and second free ends of said single wire overlapping in close proximity to each other such that said segment of tubing joining the first free end of said single wire and the second free end of said single wire together is configured to prevent said first and second free ends of said single wire from extending away from the main body length of said single wire.
9. The composite wire of claim 8 , wherein the first metal is selected from the group consisting of platinum, tantalum, gold, and combinations thereof.
10. The composite wire of claim 8 , wherein the inner core is cylindrical.
11. The composite wire of claim 8 , wherein said second metal is a superelastic alloy.
12. The composite wire of claim 1 , wherein said second metal is a nickel-titanium alloy.
13. The composite wire of claim 1 , wherein the composite wire is formed as a cylindrical wire.
14. A composite wire, comprising:
a single wire having a first free end, a second free end, and a main body length therebetween for forming a vascular interventional device, said single wire including:
an elongated inner core having a selected length and formed from a first metal selected from the group consisting of platinum, tantalum, gold, and combinations thereof, said elongated inner core disposed centrally along a longitudinal axis of said single wire, and said first metal being radiopaque;
an outer metal layer coaxially disposed around said elongated inner core along the length of said elongated inner core, said outer metal layer being formed of a superelastic second metal different from said first metal; and
a continuous intermediate polymer layer selected from the group consisting of poly-para-xylylene, a fluorine substituted poly-para-xylylene, and combinations thereof, said continuous intermediate polymer layer coaxially disposed between said outer metal layer and said elongated inner core, said continuous intermediate polymer layer being operative to insulate said elongated inner core and said outer metal layer from galvanic corrosion between said elongated inner core and said outer metal layer; and
a segment of heat shrink tubing capturing the first and second free ends of said single wire within the segment of heat shrink tubing to join the first and second free ends of said single wire together, the first and second free ends of said single wire being in close proximity to each other, and said first and second free ends of said single wire overlapping such that said segment of tubing joining the first free end of said single wire and the second free end of said single wire together is configured to prevent said first and second free ends of said single wire from extending away from the main body length of said single wire.
15. The composite wire of claim 14 , wherein the inner core is cylindrical and said composite wire is cylindrical.
16. The composite wire of claim 14 , wherein said superelastic second metal is a nickel-titanium alloy.
17. The composite wire of claim 14 , wherein said superelastic second metal is nitinol.