Stents having a hybrid pattern and methods of manufacture
An intravascular stent and method of making an intervascular stent having a hybrid pattern a. The hybrid pattern comprises a plurality of circumferentially self-expansible members comprising a plurality of interconnected, geometrically deformable closed cells, adjacent self-expansible members interconnected by a plurality of bridge members linking a first interconnection between two closed cells in a first self-expansible member to a second interconnection between two closed cells in a second self-expansible member, wherein the second interconnection is circumferentially offset and non-adjacent to the first interconnection.
1. A method of making an intravascular stent, comprising the steps of:
a. vacuum depositing a metal hypotube onto a cylindrical substrate;
b. patterning a stent pattern onto the deposited metal hypotube, wherein the pattern comprises a plurality of longitudinally extending struts defining a plurality of interconnected closed cells connected to each other along a first circumferential axis of the metal hypotube by interconnection points, and a plurality of elongate struts defining a plurality of bridge struts, each of the plurality of bridge struts extending along a second circumferential axis and having opposing ends that interconnect at the interconnection points between adjacent pairs of the plurality of interconnected closed cells at each opposing end of each of the plurality of bridge struts; and
c. removing the stent pattern from the cylindrical substrate.
2. The method of claim 1 , wherein the step of patterning further comprises patterning each of the plurality of bridge struts to be separated by at least two interconnected closed cells of the first plurality of interconnected closed cells along the first circumferential axis of the first plurality of interconnected closed cells.
3. The method of claim 2 , wherein the step of vacuum depositing a metal hypotube onto a substrate further comprises the step of vacuum depositing a metal ribbon and winding the metal ribbon around a cylindrical substrate.
4. The method of claim 3 , after the step of removing the stent pattern from the cylindrical substrate, further comprising the steps of:
winding the ribbon around a mandrel;
shaping the wound ribbon into a desired stent frame shape; and
joining sections of the wound ribbon.
5. The method of claim 4 , further comprising the step of patterning at least one surface of the thin ribbon, prior to or simultaneous with the step of winding around the mandrel.
6. The method of claim 4 , wherein the step of patterning further comprises laser patterning to impart at least one feature on the at least one surface of the ribbon.
7. The method of claim 4 , wherein the step of patterning further comprises forming a plurality of grooves on the at least one surface of the ribbon.
8. The method of claim 4 , further comprising polishing the ribbon, prior to or simultaneous with the step of winding around the mandrel.
9. The method of claim 4 , further comprising laser cutting a stent strut pattern into the thin ribbon, prior to, after, or simultaneous with the step of winding around the mandrel.
10. The method of claim 9 , wherein the step of laser cutting is an athermal process characterized by low slag formation.
11. The method of claim 1 , wherein the step of patterning comprises laser patterning to impart at least one feature on the at least one surface of the deposited metal.
12. The method of claim 11 , wherein the laser patterning is an athermal process characterized by low slag formation during laser patterning.
13. The method of claim 1 wherein the metal hypotube is made of a material selected from the group consisting of of elemental titanium, vanadium, aluminum, nickel, tantalum, zirconium, chromium, silver, gold, silicon, magnesium, niobium, scandium, platinum, cobalt, palladium, manganese, molybdenum and alloys thereof.
14. The method of claim 1 wherein the step of patterning a stent onto the deposited metal hypotube and forming a first plurality of interconnected closed cells or forming a second plurality of interconnected closed cells further comprises forming each closed cell of the first plurality or second plurality of interconnected closed cells into a diamond expanded shape, circular expanded shape, elliptical expanded shape, triangular expanded shape, rectangular expanded shape, or square.
15. The method of claim 1 , wherein the step of vacuum depositing further includes the step of providing a pre-patterned planar substrate and the step of patterning includes forming the pattern by vacuum depositing the thin film onto the pre-patterned planar substrate.
16. The method of claim 1 , wherein the step of vacuum depositing metal onto a substrate further comprises the step of vacuum depositing a thin film metal having a thickness between 1 and about 1000 microns.
17. The method of claim 1 , wherein the step of vacuum depositing metal onto a substrate further comprises the step of vacuum depositing layers of dissimilar metals.
18. The method of claim 1 , further comprising the step of forming a plurality of grooves on a surface of the stent pattern.
19. The method of claim 1 , further comprising removing oxide from the stent pattern.
20. The method of claim 1 , further comprising electropolishing the stent pattern.
21. The method of claim 1 , further comprising shape setting the stent pattern.
22. The method of claim 1 , wherein the step of vacuum depositing a metal hypotube onto a cylindrical substrate further comprises the steps of vacuum depositing plural layers of metal to form laminated layers of metal.
23. The method of claim 1 , wherein the first plurality of interconnected closed cells, the second plurality of interconnected closed cells, and the plurality of bridge members are configured in a pattern having blood flow diversion properties.