Stent and method and apparatus for forming and delivering the same
First Claim
1. A stent comprising an elongate body member having a longitudinal axis with a skeletal frame formed to define an elongate chamber which extends through said body member, the body member being formed of thermal shape memory material which operates in response to temperature to expand or contract said skeletal frame between a first expanded configuration and a second compressed configuration, said body member including a plurality of interconnected, open cells forming the skeletal frame of said body member, each of said cells including two substantially parallel, spaced side portions which are substantially parallel to said longitudinal axis and end wall means extending between said side portions at an angle to said longitudinal axis, said end wall means operating to maintain said cell straight side portions substantially parallel to said longitudinal axis in both said first expanded configuration of said skeletal frame and in said second collapsed configuration.
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Accused Products
Abstract
A stent including a wire skeletal frame, the frame being adapted to assume a first condition in which the frame is relatively rigid and substantially tubular in configuration and a second condition in which the frame is flexible, of reduced stress, and collapsible, such that in the second condition walls of the frame are adapted to be positioned against each other to form a stent diameter substantially equal to the combined thickness of the frame walls in abutting engagement with each other, the frame in its second condition being substantially devoid of bias therein urging the frame to assume the first configuration.
722 Citations
32 Claims
- 1. A stent comprising an elongate body member having a longitudinal axis with a skeletal frame formed to define an elongate chamber which extends through said body member, the body member being formed of thermal shape memory material which operates in response to temperature to expand or contract said skeletal frame between a first expanded configuration and a second compressed configuration, said body member including a plurality of interconnected, open cells forming the skeletal frame of said body member, each of said cells including two substantially parallel, spaced side portions which are substantially parallel to said longitudinal axis and end wall means extending between said side portions at an angle to said longitudinal axis, said end wall means operating to maintain said cell straight side portions substantially parallel to said longitudinal axis in both said first expanded configuration of said skeletal frame and in said second collapsed configuration.
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15. A stent for insertion in a body vessel comprising an elongate body means having a longitudinal axis, a first end, a second end, and an elongate chamber extending through said body means between said first and second ends, the body means being formed of thermal shape memory material which is relatively pliable at temperatures below a transition temperature to permit said body means to be collapsed toward said longitudinal axis to a collapsed configuration, for insertion in said body vessel, said thermal shape memory material operating to expand said body means radially outward from said collapsed configuration toward an expanded memory configuration in response to said transition temperature to contact and apply force to said body vessel, said body means operating at said transition temperature to apply less force to said body vessel in the area of at least one of said first and second ends than the force applied by the remainder of said body means to said body vessel at the transition temperature.
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16. A method for forming a stent of thermal shape memory material which becomes pliable to permit the stent to be collapsed at temperatures below a temperature transformation level and which expands the collapsed stent to a preset memory shape at temperatures above the temperature transformation level which includes the steps of
forming a plurality of open cells from thermal shape memory material, fusion welding the thermal shape memory material to form a stent body member with an elongate chamber extending therethrough, and subsequently annealing said body member at a temperature sufficient to set the memory shape of said stent while rendering ductile the fusion welds.
- 19. A stent comprising an elongate body member having a longitudinal axis with a skeletal frame formed to define an elongate chamber which extends through said body member, the skeletal frame being formed to assume a first expanded configuration relative to said longitudinal axis and to be collapsible toward said longitudinal axis to a second collapsed configuration, said skeletal frame further being formed to define a plurality of interconnected open cells with each of said cells including two substantially parallel, spaced side walls which are substantially parallel to said longitudinal axis in both the first expanded configuration and the second collapsed configuration of said skeletal frame and end walls extending between said sidewalls at an angle to said longitudinal axis, said cells being arranged around said elongate chamber with sidewalls of adjacent cells arranged in adjacent coextensive relationship, said cells joined together by an attachment connecting adjacent, coextensive cell sidewalls, this being the only connection between said cells.
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23. A stent comprising an elongate body member having a first section, a second section, a longitudinal axis and an elongate chamber which extends through said body member, the body member being formed of thermal shape memory material having a temperature transformation level above which said body member assumes an expanded configuration relative to said longitudinal axis and below which said body member may be collapsed to a collapsed configuration, the shape memory material in said first section of said body member having a temperature transformation level which differs from the temperature transformation level of the shape memory material in said second section of said body member.
- 24. A stent comprising an elongate body member having a longitudinal axis with a skeletal frame formed to define an elongate chamber which extends through said body member, the body member being formed of thermal shape memory material which has been annealed at a temperature sufficient to set a memory shape for said body member and impart to said shape memory material a temperature transformation level above which said skeletal frame assumes a first expanded configuration relative to said longitudinal axis and below which said skeletal frame will be collapsible toward said longitudinal axis to a second collapsed configuration, said thermal shape memory material being formed to define a plurality of interconnected open cells forming the skeletal frame of said body member with each of said cells including two substantially parallel, spaced side portions which are substantially parallel to said longitudinal axis in both the first expanded configuration and the second collapsed configuration of said skeletal frame and end wall means extending between said side portions at an angle to said longitudinal axis, said cells being joined together only along said side portions by fusion welds formed prior to the annealing of said shape memory material.
- 27. A stent comprising an elongate body member having a longitudinal axis and a skeletal frame formed to define an elongate chamber which extends through said body member, the body member being formed of thermal shape memory material which defines a plurality of interconnected, open cells forming the skeletal frame of said body member, each of said cells including two substantially parallel, spaced, straight side portions which are substantially parallel to said longitudinal axis and end wall means extending between said side portions at an angle to said longitudinal axis, said cells being joined together only along the lengths of said straight side portions, the shape memory material having a temperature transformation level above which said skeletal frame assumes a first expanded configuration relative to said longitudinal axis and below which said cell end wall means permit the space between straight side portions of said cell to decrease to permit movement of said straight portions toward said longitudinal axis to collapse said skeletal frame to a second collapsed configuration, said cell end wall means operating at a temperature above said temperature transformation level when said skeletal frame is in the second collapsed configuration to expand the skeletal frame to the first expanded configuration, and elastomeric sleeve means disposed around said elongate body and operating to expand when said skeletal frame assumes said first expanded configuration and to exert a compressive force on said skeletal frame in said first expanded configuration, said elastomeric sleeve means operating when said skeletal frame is at or below said transition temperature to collapse said skeletal frame to the second collapsed configuration.
- 30. A stent for insertion in a body vessel comprising an elongate body means having a longitudinal axis, a first end, a second end, and an elongate chamber extending through said body means between said first and second ends, the body means being formed of thermal shape memory material which is relatively pliable at temperatures below a transition temperature to permit said body means to be collapsed toward said longitudinal axis to a collapsed configuration for insertion in said body vessel, said thermal shape memory material operating to expand said body means radially outward from said collapsed configuration toward an expanded memory configuration in response to temperatures at or above said transition temperature to contact and apply radial force to said body vessel, said body means including a skeletal frame formed of said thermal shape memory material to define said elongate chamber, the skeletal frame including a plurality of interconnected open cells, each of which includes two substantially parallel, spaced, straight side portions which are substantially parallel to said longitudinal axis and end wall means extending between said side portions at an angle to said longitudinal axis, said cells being joined together only along the lengths of said straight side portions, said skeletal frame including a first area including cells which are designed differently from cells in at least a second area of said skeletal frame to cause different radial forces to be applied to said body vessel by said body means in the expanded memory configuration thereof.
Specification