Clad composite stent

Claim 2

A resilient, body implantable prosthesis, including: a plurality of elongate resilient strands, helically wound in at least two oppositely directed sets of strands arranged in a braided configuration; wherein the strands are age-hardened and substantially uniform in lateral cross-section over respective lengths thereof, and wherein each of the strands includes an elongate core and an elongate tubular case surrounding the core at least substantially over said respective length, a lateral cross-sectional area of the core being at least about ten percent of a lateral cross-sectional area of the strand; wherein one of the core and case is constructed of a first material having a linear attenuation coefficient of at least 25 cm -1 at 100 KeV, the other of the core and case is constructed of a resilient second material, and the first material is more radiopaque than the second material; and wherein said strands, due at least in part to an age-hardening of the resilient second material when the strands are in said braided configuration, exhibit an enhanced modulus of elasticity which is greater than a nominal modulus of elasticity of non-age-hardened but otherwise identical strands by at least about 10 percent, and further has a greater yield strength at 0.2 percent offset and a greater tensile strength as compared to said non-age-hardened but otherwise identical strands.

Claim 3

The prosthesis of claim 1 wherein: the first material forms the core.

Claim 4

The prosthesis of claim 2 wherein: the first material has a direct or equivalent atomic number of at least fifty, and a density of at least 0.5 pounds per cubic inch.

Claim 5

The prosthesis of claim 3 wherein: the first material consists essentially of at least one of the following constituents: tantalum, platinum, gold, iridium, rhenium, tungsten, ruthenium and depleted uranium.

Claim 6

The prosthesis of claim 2 wherein: the case is substantially concentric about the core.

Claim 7

The prosthesis of claim 5 wherein: the second material is body compatible.

Claim 8

The prosthesis of claim 6 wherein: the second material has a yield strength (0.2 percent of offset) of at least 150,000 psi.

Claim 9

The prosthesis of claim 5 wherein: the second material consists essentially of at least one of the following constituents: cobalt, chromium, titanium, aluminum, vanadium, chromium, nickel, molybdenum and iron.

Claim 10

The prosthesis of claim 8 wherein: the second material consists essentially of a cobalt-based alloy.

Claim 11

The prosthesis of claim 9 wherein: the cobalt-based alloy consists essentially of cobalt, chromium, iron, nickel, and molybdenum.

Claim 12

The prosthesis of claim 2 wherein: a lateral cross-sectional area of the core of each strand is in the range of from ten to forty-six percent of the lateral cross-sectional area of the strand.

Claim 13

The prosthesis of claim 1 wherein: the strands in each set are parallel to one another, and the sets of strands cooperate to form a cylinder.

Claim 14

The prosthesis of claim 1 wherein: said second material forms the core.

Claim 15

The prosthesis of claim 1 wherein: said strands, as compared to the non-age-hardened strands, have a yield strength at 0.2 percent offset at least about twenty percent greater, and a tensile strength at least about twenty percent greater.

Claim 16

The prosthesis of claim 1 wherein: the resilient strands of said oppositely directed sets are spaced apart from one another.

Claim 17

The prosthesis of claim 1 wherein: the braided configuration of the helically wound strands is radially self-expanding.

Claim 18

A body implantable prosthesis, including: a plurality of elongate strands, helically wound in at least two oppositely directed sets of strands, arranged in a braided configuration; wherein the strands are age-hardened and substantially uniform in lateral cross-section over respective lengths thereof, and wherein each of the strands includes an elongate core and an elongate tubular case surrounding the core at least substantially over said respective length, a lateral cross-sectional area of the core being at least about ten percent of a cross-sectional area of the core and case, combined; and wherein one of the core and case is constructed of a first material having a linear attenuation coefficient of at least 25 cm -1 at 100 KeV, the other of the core and case is constructed of a second material having a yield strength of at least 150,000 psi at 0.2% offset, the first material is more radiopaque than the second material, and the first and second materials have about the same linear coefficients of thermal expansion; and wherein said strands, due at least in part to an age-hardening of the resilient second material when the strands are in said braided configuration, exhibit an enhanced modulus of elasticity which is greater than a nominal modulus of elasticity of non-age-hardened but otherwise identical strands by at least about 10 percent, and further has a greater yield strength at 0.2 percent offset and a greater tensile strength as compared to said non-age-hardened but otherwise identical strands.

Claim 19

A body implantable prosthesis, including: a plurality of elongate strands, helically wound in at least two oppositely directed sets of strands, arranged in a braided configuration; wherein the strands are age-hardened and substantially uniform in lateral cross-section over respective lengths thereof, and wherein each of the strands includes an elongate core and an elongate tubular case surrounding the core at least substantially over said respective length, a lateral cross-sectional area of the core being at least about ten percent of a cross-sectional area of the core and case, combined; and wherein one of the core and case is constructed of a first material having a linear attenuation coefficient of at least 25 cm -1 at 100 KeV, the other of the core and case is constructed of a second material having a yield strength of at least 150,000 psi at 0.2% offset, the first material is more radiopaque than the second material, and the first and second materials have about the same linear coefficients of thermal expansion; and wherein said strands, due at least in part to an age-hardening of the resilient second material when the strands are in said braided configuration, exhibit an enhanced modulus of elasticity which is greater than a nominal modulus of elasticity of non-age-hardened but otherwise identical strands by at least about 10 percent, and further has a greater yield strength at 0.2 percent offset and a greater tensile strength as compared to said non-age-hardened but otherwise identical strands.

Claim 20

The prosthesis of claim 17 wherein: the first material forms the core.

Claim 21

The prosthesis of claim 18 wherein: the first material has a direct or equivalent atomic number of at least fifty, and a density of at least 0.2 pounds per cubic inch.

Claim 22

The prosthesis of claim 19 wherein: the first material consists essentially of at least one of the following constituents: tantalum, platinum, gold, iridium, rhenium, tungsten, ruthenium and depleted uranium.

Claim 23

The prosthesis of claim 17 wherein: the second material consists essentially of a cobalt-based alloy.

Claim 24

The prosthesis of claim 21 wherein: the cobalt-based alloy consists essentially of cobalt, chromium, iron, nickel and molybdenum.

Claim 25

The prosthesis of claim 18 wherein: a lateral cross-sectional area of the core of each strand is in the range of from 10 to 46 percent of the lateral cross-sectional area of the core and case, combined.

Claim 26

The prosthesis of claim 17 wherein: said second material forms the core.

Claim 27

The prosthesis of claim 17 wherein: the first material and the second material have respective linear coefficients of thermal expansion within the range of about 3×10 -6 per degree F. to about 9×10 -6 per degree F.

Claim 28

The prosthesis of claim 17 wherein: the strands in each of said sets are substantially parallel to one another.

Claim 29

The prosthesis of claim 17 wherein: said strands, as compared to the non-age-hardened strands, have a yield strength at 0.2 percent offset at least about twenty percent greater, and a tensile strength at least about twenty percent greater.

Claim 30

The prosthesis of claim 17 wherein: the elongate strands of said oppositely directed sets are spaced apart from one another.

Claim 31

The prosthesis of claim 17 wherein: the braided configuration of the helically wound strands is radially self-expanding.

Claim 32

A resilient, body implantable prosthesis, including: a plurality of elongate resilient strands, helically wound in at least two oppositely directed sets of strands interwoven with one another; wherein the strands are age-hardened and substantially uniform in lateral cross-section over respective lengths thereof, and wherein each of the strands includes an elongate core and an elongate tubular case surrounding the core at least substantially over said respective length, a lateral cross-sectional area of the core being at least about ten percent of a cross-sectional area of the core and case, combined; and wherein said core is constructed of a core material having a linear attenuation coefficient of at least 25 cm -1 at 100 KeV, the case is constructed of a resilient case material, the core material is more ductile and more radiopaque than the case material; and wherein said strands, due at least in part to an age-hardening of the case material when the strands are interwoven with one another, exhibit an enhanced modulus of elasticity which is greater than a nominal modulus of elasticity of non-age-hardened but otherwise identical strands, by at least about 10 percent.

Claim 33

A resilient, body implantable prosthesis, including: a plurality of elongate resilient strands, helically wound in at least two oppositely directed sets of strands interwoven with one another; wherein the strands are age-hardened and substantially uniform in lateral cross-section over respective lengths thereof, and wherein each of the strands includes an elongate core and an elongate tubular case surrounding the core at least substantially over said respective length, a lateral cross-sectional area of the core being at least about ten percent of a cross-sectional area of the core and case, combined; and wherein said core is constructed of a core material having a linear attenuation coefficient of at least 25 cm -1 at 100 KeV, the case is constructed of a resilient case material, the core material is more ductile and more radiopaque than the case material; and wherein said strands, due at least in part to an age-hardening of the case material when the strands are interwoven with one another, exhibit an enhanced modulus of elasticity which is greater than a nominal modulus of elasticity of non-age-hardened but otherwise identical strands, by at least about 10 percent.

Claim 34

The prosthesis of claim 30 wherein: the core material has a direct or equivalent atomic number of at least fifty, and a density of at least 0.5 pounds per cubic inch.

Claim 35

The prosthesis of claim 31 wherein: the core material consists essentially of at least one of the following constituents: tantalum, platinum, gold, iridium, rhenium, tungsten, ruthenium and depleted uranium.

Claim 36

The prosthesis of claim 30 wherein: the case material is body compatible, and has a yield strength at 0.2 percent offset of at least 150,000 psi.

Claim 37

The prosthesis of claim 33 wherein: the case material consists essentially of at least one of the following constituents: cobalt, chromium, titanium, aluminum, vanadium, nickel, molybdenum and iron.

Claim 38

The prosthesis of claim 33 wherein: the case material consists essentially of a cobalt-based alloy.

Claim 39

The prosthesis of claim 35 wherein: the cobalt-based alloy consists essentially of cobalt, chromium, iron, nickel, and molybdenum.

Claim 40

The prosthesis of claim 30 wherein: the strands in each set are parallel to one another, and the sets of strands cooperate to form a cylinder.

Claim 41

The prosthesis of claim 30 wherein: The core and case materials have about the same linear coefficients of thermal expansion.

Claim 42

The prosthesis of claim 30 wherein: the strands, as compared to the non-age-hardened strands, have a yield strength at 0.2 percent offset at least about 20 percent greater, and a tensile strength at least about 20 percent greater.

Claim 43

The prosthesis of claim 30 wherein: the resilient strands of said oppositely directed sets are spaced apart from one another.

Claim 44

The prosthesis of claim 30 wherein: the oppositely directed sets of strands are interwoven into a self-expanding structure.