Intravascular stent

Claim 2

A stent designed to be carried on the balloon of a balloon catheter to a target site in a vessel, comprising a series of expandable, strip-like segments, each adapted for movement, in a substantially radial direction, between a closed, high-curvature condition and an expanded, low-curvature condition, upon exposure to a selected stimulus, said segments being joined along offsetting side regions, such that with the segments in their high-curvature condition, the stent is adapted to form a flexible, cylindrical sleeve on such balloon, and upon exposure to such stimulus, the segments in the stent expand toward their low-curvature condition until such movement is constrained by the walls of such vessel.

Claim 3

The stent of claim 1, wherein said segments form a linear unitary strip when said stent is in its memory condition.

Claim 4

The stent of claim 1, wherein said segments form a V-shaped unitary strip when said stent is in its memory condition.

Claim 5

The stent of claim 1, wherein said strip segments are formed of a memory polymer.

Claim 6

The stent of claim 4, wherein said strip segments are formed of a thermoplastic polymer.

Claim 7

The stent of claim 4, wherein said strip segments are formed of a crosslinked thermoplastic polymer.

Claim 8

The stent of claim 4, wherein said strip segments are formed of a thermoplastic polymer blend.

Claim 9

The stent of claim 4, wherein said strip segments are formed of a crosslinked thermoplastic polymer blend.

Claim 10

The stent of claim 4, wherein said memory polymer is a methacrylate-containing polymer.

Claim 11

The stent of claim 4, wherein said memory polymer is an acrylate-containing polymer.

Claim 12

The stent of claim 4, wherein said memory polymer is biodegradable.

Claim 13

The stent of claim 4, wherein said segments contain a therapeutic agent for controlled release of said agent to the target site.

Claim 14

The stent of claim 1, wherein said segments are formed of a memory polymer having a polymer-state transition that is activated by one of the following stimuli: (a) adsorption of heat by said polymer; (b) adsorption of liquid by said polymer; and (c) a change in pH in a liquid in contact with said polymer.

Claim 15

The stent of claim 1, wherein said segments are formed of a memory polymer having a thermally-activated polymer-state transition selected from the group consisting of: (a) a melting point of the polymer; (b) a glass-transition of the polymer; (c) a liquid crystal transition; and (d) a local mode molecular transition.

Claim 16

The stent of claim 14, wherein said transition is a glass transition between about 25° and 65° C.

Claim 17

The stent of claim 14, wherein said transition is a crystalline melting point between about 25° and 65° C.

Claim 18

The stent of claim 1, wherein said segments in their open, low-curvature condition have an outer diameter of between about 0.1 mm to 5 cm.

Claim 19

The stent of claim 1, wherein said segments have an expansion ratio of between about 2-2,000.

Claim 20

A balloon-catheter apparatus for delivering a stent to a target site in a vessel, comprising a balloon catheter having at one end a balloon that can be filled with a liquid; a stent, formed of a series of expandable, strip-like segments, each adapted for movement, in a substantially radial direction, between a closed, high-curvature condition and an expanded, low-curvature condition, upon exposure to said liquid; said segments being joined along offsetting side regions, such that with the segments in their high-curvature condition, the stent is adapted to form a flexible, cylindrical sleeve on said balloon, and upon exposure to said liquid, the segments in the stent expand toward their low-curvature condition until such movement is constrained by the walls of such vessel.

Claim 21

A balloon-catheter apparatus for delivering a stent to a target site in a vessel, comprising a balloon catheter having at one end a balloon that can be filled with a liquid; a stent, formed of a series of expandable, strip-like segments, each adapted for movement, in a substantially radial direction, between a closed, high-curvature condition and an expanded, low-curvature condition, upon exposure to said liquid; said segments being joined along offsetting side regions, such that with the segments in their high-curvature condition, the stent is adapted to form a flexible, cylindrical sleeve on said balloon, and upon exposure to said liquid, the segments in the stent expand toward their low-curvature condition until such movement is constrained by the walls of such vessel.

Claim 22

The apparatus of claim 19, wherein said stent is formed of a memory polymer having a polymer-state transition that is activated by one of the following: (a) adsorption of heat by said polymer; (b) adsorption of liquid by said polymer; and (c) a change in pH in a liquid in contact with said polymer.

Claim 23

The apparatus of claim 20, wherein said liquid is heated to a temperature of between 25°-100°C., and said transition is a thermal transition, activated by adsorption of heat from said liquid, selected from one of the following: (a) a melting point of the polymer; (b) a glass-transition of the polymer; (c) a liquid crystal transition; and (d) a local mode molecular transition.

Claim 24

The stent of claim 20, wherein said transition is a glass transition between about 25° and 65° C.

Claim 25

The stent of claim 20, wherein said memory polymer is a methacrylate-containing polymer.

Claim 26

The stent of claim 20, wherein said memory polymer is an acrylate-containing polymer.

Claim 27

The stent of claim 20, wherein said memory polymer is biodegradable.

Claim 28

The stent of claim 20, wherein said strip segments are formed of a thermoplastic polymer.

Claim 29

The stent of claim 20, wherein said strip segments are formed of a crosslinked thermoplastic polymer.

Claim 30

The stent of claim 20, wherein said strip segments are formed of a thermoplastic polymer blend.

Claim 31

The stent of claim 20, wherein said strip segments are formed of a crosslinked thermoplastic polymer blend.

Claim 32

The stent of claim 20, wherein said segments contain a therapeutic agent for controlled release of said agent to the target site.