Methods for delivering, repositioning and/or retrieving self-expanding stents

• US 6,837,901 B2
• Filed: 04/27/2001
• Issued: 01/04/2005
• Est. Priority Date: 04/27/2001
• Status: Expired due to Term

• Current Assignee: Intek Technology LLC (Qorvo, Inc.)
• Original Assignee: Intek Technology LLC (Qorvo, Inc.)
• Inventors: Perelson, Ophir, Morag, Eyal, Rabkin, Dmitry
• Primary Examiner(s): STEWART, ALVIN J
• Application Number:
  US09/845,090
• Publication Number:
  US 20020161427A1
• Time in Patent Office: 1,348 Days
• Field of Search: 623/1.11, 606/192, 606/194, 606/198
• US Class Current: 623/1.11
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 2017/22035 for retrieving or repositioning foreign objects
• CPC Class Codes: A61B 2017/2215 having an open distal end
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/9528 for retrieval of stents
• CPC Class Codes: A61F 2002/9534 for repositioning of stents
• CPC Class Codes: A61F 2210/0023 operated at different temperatures whilst inside or touching the human body, heated or cooled by external energy source or cold supply

Abstract

Methods for delivery and deploying a stent formed of a shape memory alloy to a desired position in a tubular area of the body, and/or for repositioning and/or retrieving a stent formed of a two-way shape memory alloy. An arrangement is provided by which the temperature of the stent is locally adjusted during delivery, repositioning and/or retrieval in a safe and controlled manner by engagement with an expandable and collapsible thermal transfer member situated on a catheter assembly.

Claims

1. The method of delivering a shape memory stent having a transition temperature at or below body temperature to, and deploying the stent at a diseased tubular area in the body utilizing a catheter assembly having a proximal end region and a distal end region, comprising the steps of:

mounting the shape memory stent in a collapsed condition on a thermal transfer device coupled to said catheter assembly at said distal end region thereof, said thermal transfer device including a chamber having an outer transfer thermal wall, such that the heat transfer wall is in local heat transfer relationship with the stent;

delivering the stent in said collapsed condition on said thermal transfer device to a region of the diseased tubular area in the body;

circulating a flow of cooling thermal fluid from said proximal end region of said catheter assembly into said chamber and back to said proximal end region of said catheter assembly, commencing at least as early as the time the stent in its collapsed condition on the thermal transfer device has been delivered to a region of the diseased tubular area;

if necessary, adjusting the position of the stent in said collapsed condition on said thermal transfer device in said narrowing tubular area; and

controlling the expansion of said stent into supporting engagement with the wall of the diseased tubular area by adjusting the temperature and/or rate of the circulation of cooling thermal fluid into said chamber;

releaseably capturing said stent to said catheter assembly at the time of said mounting step;

maintaining said capture of said stent to said catheter assembly during said delivery step;

maintaining said capture of said stent to said catheter assembly during at least a part of said deploying step; and

releasing said stent from capture to said catheter assembly after completion of at least a part of said deploying step;

wherein said catheter assembly comprises a stent-capturing sheath having a distal end;

at least one hook member affixed to said distal end of said stent-capturing sheath; and

an outer sheath having a distal end movably positioned over said stent-capturing sheath; and

wherein said releasing step comprises moving said outer sheath with respect to said stent-capturing sheath whereupon said distal end of said outer sheath cooperates with said at least one hook member to move the same to release said stent.

2. The method of delivering a shape memory stent having a transition temperature at or below body temperature to, and deploying the stent at a diseased tubular area in the body utilizing catheter assembly having a proximal end region and a distal end region, comprising the steps of:

mounting the shape memory stent in a collapsed condition of a thermal transfer device coupled to said catheter assembly at said distal end region thereof, said thermal transfer device including a chamber having an outer transfer thermal wall, such that the heat transfer wall is in local heat transfer relationship with the stent;

delivering the stent in said collapsed condition on said thermal transfer device to a region of the diseased tubular area in the body;

circulating a flow of cooling thermal fluid from said proximal end region of said catheter assembly into said chamber and back to said proximal end region of said catheter assembly, commencing at least as early as the time the stent in its collapsed condition on the thermal transfer device has been delivered to a region of the diseased tubular area;

if necessary, adjusting the position of the stent in said collapsed condition on said thermal transfer device in said narrowing tubular area; and

controlling the expansion of said stent into supporting engagement with the wall of the diseased tubular area by adjusting the temperature and/or rate of the circulation of cooling thermal fluid into said chamber;

releaseably capturing said stent to said catheter assembly at the time of said mounting step;

maintaining said capture of said stent to said catheter assembly during said delivery step;

maintaining said capture of said stent to said catheter assembly during at least a part of said deploying step; and

releasing said stent from capture to said catheter assembly after completion of at least a part of said deploying step;

wherein said thermal transfer device comprises a balloon expandable and collapsible between expanded and collapsed conditions; and

wherein subsequent to the step of deploying said stent into supporting engagement with the wall of diseased tubular area,

performing a balloon angioplasty by expanding said balloon to engage said deployed stent and

forcefully urge said stent against the wall of the diseased tubular area;

10 wherein said catheter assembly comprises inflow passage means through which cooling thermal fluid is infused into said chamber during said infusing step and outflow passage means for providing a controllable outflow of cooling thermal fluid from said chamber, and

wherein said step of performing an angioplasty by expanding the balloon comprises expanding the balloon by inflation under pressure by infusing fluid under pressure into said chamber and controlling the outflow of the fluid from said chamber to inflatingly expand said balloon under internal pressure into an expanded condition to engage said deployed stent end forcefully urge said stent against the wall of the narrowing tubular area;

wherein said step of performing an angioplastyfurther comprises, in conjunction with said inflation of the balloon, actuating mechanical means coupled to said balloon for mechanically expanding the balloon into an expanded condition to engage said deployed stent and forcefully urge said stent against the wall of the diseased tubular area; and

wherein said catheter assembly comprises an inner core catheter and a relatively movable outer core catheter situated over said inner core catheter, said outer core catheter having a distal end which is situated proximally of the distal end of said inner core catheter so that projecting portion of said inner core catheter extends beyond said distal end of said outer core catheter, and a wire frame comprising a plurality of wires, each wire having one end affixed to a distal end of said projecting portion of said inner core catheter, another end affixed to the distal end of said outer core catheter, and a mid-region attached to said expandable balloon; and

wherein said actuating step comprises moving said inner and outer core catheters with respect to each other to bend said wires in an outward direction and thereby expand said balloon.

3. The method of delivering a shape memory stent having a transition temperature at or below body temperature to, and deploying the stent at a diseased tubular areawithin the body utilizing a catheter assembly having proximal end region and a distal end region, comprising the steps of:

mounting the shape memory stent in a collapsed condition on an inflatable balloon in a collapsed condition coupled to said catheter assembly at said distal end region thereof, said balloon having a chamber and having an outer heat transfer wall, such that the heat transfer wall is in local heat transfer relationship with the stent;

delivering the stent in said collapsed condition on said collapsed balloon to a region of the diseased tubular area in the body;

commencing a circulating flow from said proximal end region of said catheter assembly into said chamber of said balloon and back to said proximal end region of said catheter assembly at least as early as the time the stent in its collapsed condition on the collapsed balloon has been delivered to a region of the diseased tubular area;

said circulating flow comprising infusing a flow of cooling thermal fluid from a proximal end of the catheter assembly into said chamber of said balloon, and withdrawing a flow of cooling thermal fluid from said chamber of said balloon back to the proximal end of the catheter assembly;

if necessary, adjusting the position of the stent in said collapsed condition on said collapsed balloon in said diseased tubular area; and

controlling the expansion of said stent into supporting the engagement of the wall of the diseased tubular area by adjusting the temperature and/or rate of the inflow of cooling thermal fluid into said chamber;

wherein subsequent to the step of deploying said stent into supporting engagement with the wall of the diseased tubular area, performing a balloon angioplasty by expanding said balloon into an expanded condition to engage said deployed stent, and forcefully urging said stent against the wall of the diseased tubular area; and

wherein said catheter assembly comprises inflow passage means through which cooling thermal fluid is infused into said chamber during said infusing step and outflow passage means for providing a controllable outflow of cooling thermal fluid from said chamber, and

wherein said step of performing an angioplasty by expanding the balloon comprises expanding the balloon by inflation under pressure by infusing fluid under pressure into said chamber and controlling the outflow of the fluid from said chamber to inflatingly expand said balloon under internal pressure into an expanded condition to engage said deployed stent and forcefully urge said stent against the wall of the narrowing tubular area; and

wherein said step of performing an angioplasty further comprises, in conjunction with said inflatingly expanding the balloon, actuating mechanical means coupled to said balloon for mechanically expanding the balloon into an expanded condition to engage said deployed stent and forcefully urge said stent against the wall of the diseased tubular area; and

wherein said catheter assembly comprises an inner core catheter and relatively movable outer core catheter situated over said inner core catheter, said outer core catheter having a distal end which is situated proximally of the distal end of said inner core catheter so that projecting portion of said inner core catheter extends beyond said distal end of said outer core catheter, and a wire frame comprising a plurality of wires, each wire having one end affixed to a distal end of said projecting portion of said inner core catheter, another end affixed to the distal end of said outer core catheter, and a central region attached to said expandable balloon; and

wherein said actuating step comprises moving said inner and outer core catheters with respect to each other to bend said wires in an outward direction and thereby expand said balloon.

4. The method of delivering a shape memory stent having a transition temperature at or below body temperature to, and deploying the stent at, a diseased tubular area within the body utilizing a catheter assembly having proximal end region and a distal end region, comprising the steps of:

mounting the shape memory stent in a collapsed condition on an inflatable balloon in a collapsed condition coupled to said catheter assembly at said distal end region thereof, said balloon having a chamber and having an outer heat transfer wall, such that the heat transfer wall is in local heat transfer relationship with the stent;

delivering the stent in said collapsed condition on said collapsed balloon to a region of the diseased tubular area in the body;

commencing a circulating flow from said proximal end region of said catheter assembly into said chamber of said balloon and back to said proximal end region of said catheter assembly at least as early as the time the stent in its collapsed condition on the collapsed balloon has been delivered to a region of the diseased tubular area;

said circulating flow comprising infusing a flow of cooling thermal fluid from a proximal end of the catheter assembly into said chamber of said balloon and withdrawing a flow of cooling thermal fluid from said chamber of said balloon back to the proximal end of the catheter assembly;

if necessary, adjusting the position of the stent in said collapsed condition on said collapsed balloon in said diseased tubular area; and

controlling the expansion of said stent into the engagement of the wall of the diseased tubular area by adjusting the temperature and/or the temperature of the inflow of cooling thermal fluid into said chamber;

releasably capturing said stent to said catheter assembly at the time of said mounting step;

maintaining said capture of said stent to said catheter assembly during said delivery step;

maintaining said capture of said stent to said catheter assembly during at least a part of said deploying step; and

releasing said stent from capture to said catheter assembly after completion of at least part of the deployment step;

wherein said catheter assembly comprises a stent capturing sheath having a distal end;

at least one hook member affixed to said distal end of said stent-capturing sheath; and

an outer sheath having a distal end movably positioned over said stent-capturing sheath; and

wherein said releasing step comprises moving said outer sheath with respect to said stent-capturing sheath whereupon said distal end of said outer sheath cooperates with said at least one hook member to move the same to release said sheath.

5. The method of delivering a shape memory stent having a transition temperature at or below body temperature to, and deploying the stent at, a diseased tubular area in the body utilizing a catheter assembly having proximal end region and a distal end region comprising the steps of:

mounting the shape memory stent in a collapsed condition on an inflatable balloon in a collapsed condition coupled to said catheter assembly at said distal end region thereof, said balloon having a chamber having an outer thermal transfer wall, such that the thermal transfer wall is in local heat transfer relationship with the stent;

delivering the stent in said collapsed condition on said collapsed balloon to a region of the narrowing tubular area in the body;

commencing a circulating flow from said proximal end region of said catheter assembly into said balloon and back to said proximal end region of said catheter assembly at least as early as the time the stent in its collapsed condition on the collapsed balloon has been delivered to a region of the diseased tubular area, said circulating flow comprising an inflow of cooling thermal fluid from said proximal end region of the catheter assembly into said chamber of said balloon, and an outflow from the chamber of said balloon back to the proximal end of the catheter assembly;

if necessary, adjusting the position of the stent in said collapsed condition on said balloon in said diseased tubular area; and

controlling the expansion of said stent into the engagement of the wall of the diseased tubular area by adjusting the rate and/or the temperature of the inflow of cooling thermal fluid into said chamber; and

during said controlled expansion step, at least partially expanding the balloon;

wherein said step of expanding the balloon comprises controlling a circulating flow of fluid to and from the chamber of said balloon; and

wherein said step of expanding the balloon comprises expanding a frame assembly on said catheter assembly and to which said balloon is attached.

6. The method of claim 5 wherein the catheter assembly comprises an inner core catheter and a relatively moveable outer core catheter situated over said inner core catheter, said outer core catheter having a distal end which is situated proximally of the distal end of said inner core catheter so that a projecting portion of said inner core catheter extends beyond said distal end region of said outer core catheter, and wherein said frame assembly comprises a plurality of wires, each wire having one end fixed to a distal end of said projecting portion of said inner core catheter, another end fixed to the distal end of said outer core catheter, and a central region attached to said expandable balloon.

7. The method of delivering a shape memory stent having a transition temperature at or below body temperature to, and deploying the stent at, a diseased tubular area in the body utilizing a catheter assembly having a proximal end region and a distal end region comprising the steps of:

mounting the shape memory stent in a collapsed condition on an inflatable balloon in a collapsed condition coupled to said catheter assembly at said distal end region thereof, said balloon having a chamber having an outer thermal transfer wall, such that the thermal transfer wall is in local heat transfer relationship with the stent;

delivering the stent in said collapsed condition on said collapsed balloon to a region of the narrowing tubular area in the body;

commencing a circulating flow from said proximal end region of said catheter assembly into said balloon and back to said proximal end region of said catheter assembly at least as early as the time the stent in its collapsed condition on the collapsed balloon has been delivered to a region of the diseased tubular area, said circulating flow comprising an inflow of cooling thermal fluid from said proximal end of the catheter assembly into said chamber of said balloon, and an outflow from the chamber of said balloon to the proximal end region of the catheter assembly;

if necessary, adjusting the position of the stent in said collapsed condition on said balloon in said diseased tubular area; and

controlling the expansion of the stent into supporting engagement with the wall of the diseased tubular area by adjusting the rate and/or the temperature of the inflow of cooling thermal fluid into said chamber; and

during said controlled expansion step, at least partially expanding the balloon;

wherein during said mounting step, releaseably capturing said stent in said collapsed condition to said catheter assembly by capturing means moveably affixed to said catheter assembly and coupled to said balloon; and

wherein said step of expanding the balloon during deployment causes movement of said capturing means to maintain connection between said catheter assembly and said stent expands; and

wherein subsequent to deployment, releasing said capturing means from said stent by collapsing said balloon.

8. The method of capturing a two-way shape memory stent having first and second transition temperatures which is already deployed in supporting engagement with a vessel wall at a first position for repositioning or retrieval utilizing a catheter assembly having a proximal end region and a distal end region comprising the steps of:

providing an expandable and collapsible thermal transfer device in a collapsed condition on said catheter assembly at said distal end region thereof, said expandable thermal transfer device including a chamber having a thermal wall;

introducing said expandable thermal transfer device in its collapsed condition on said catheter assembly into the lumen of the deployed stent;

expanding the expandable thermal transfer device until its thermal transfer wall is in local thermal transfer relationship with the deployed stent;

circulating a cooling thermal fluid from said proximal end region of said catheter assembly into said chamber of said expandable thermal transfer device and from said chamber of said thermal transfer device back to said proximal end region of said catheter assembly to thereby cool said deployed stent in local thermal transfer relationship with said thermal transfer wall to cause the temperature of the stent to decrease to or below the second transition temperature to thereby become at least partially collapsed, soft and pliable; and

capturing said at least partially collapsed and softened stent by stent-capturing means to capture the stent to the catheter assembly;

wherein said step of expanding said thermal transfer device comprises actuating a mechanical frame assembly at said distal end of said catheter assembly coupled to said thermal transfer device until said heat transfer wall of said thermal transfer device is in local thermal transfer relationship with said deployed stent.

9. The method of claim 8 wherein said catheter assembly comprises an inner core catheter and a relatively movable outer core catheter situated over said inner core catheter, said outer core catheter having a distal end which is situated proximally of the distal end of said inner core catheter so that a projecting portion of said inner core catheter extends beyond said distal end of said outer core catheter, and a wire frame comprising a plurality of wires, each wire having one end affixed to a distal end of said projecting portion of said inner core catheter, another end affixed to the distal end of said outer core catheter, and a central region attached to said expandable balloon;

and

wherein said actuating step comprises moving said inner and outer core catheters with respect to each other to bend said wires in an outward direction and thereby expand said balloon.

10. The method of capturing a two-way shape memory stent having first and second transition temperatures which is already deployed in supporting engagement with a vessel wall at a first position for repositioning or retrieval utilizing a catheter assembly having a proximal end region and a distal end region comprising the steps of:

providing an expandable and collapsible thermal transfer device in a collapsed condition on said catheter assembly at said distal end region thereof, said expandable thermal transfer device including a chamber having a thermal transfer wall;

introducing said expandable thermal transfer device in its collapsed condition on said catheter assembly into the lumen of the deployed stent;

expanding the expandable thermal transfer device until its thermal transfer wall is in local thermal transfer relationship with the deployed stent;

circulating a cooling thermal fluid from said proximal end region of said catheter assembly into said chamber of said expandable thermal transfer device and from said chamber of said thermal transfer device back to said proximal end region of said catheter assembly to thereby cool said deployed stent in local thermal transfer relationship with said thermal transfer wall to cause the temperature of the stent to decrease to or below the second transition temperature to thereby become at least partially collapsed, soft and pliable;

capturing said at least partially collapsed and softened stent by stent-capturing means to capture the stent to the catheter assembly; and

partially collapsing said thermal transfer device after said softened stent has been captured by said stent capturing means and wherein said stent remains in constant local thermal transfer relationship with said thermal transfer wall of said thermal transfer device;

wherein said catheter assembly comprises an inner core catheter and a relatively movable outer core catheter situated over said inner core catheter, said outer core catheter having a distal end which is situated proximally of the distal end of said inner core catheter so that projecting portion of said inner core catheter extends beyond said distal end of said outer core catheter, and a wire frame comprising a plurality of wires, each wire having one end affixed to a distal end of said projecting portion of said inner core catheter, another end affixed to the distal end of said outer core catheter, and a central region attached to said expandable balloon; and

wherein said actuating step comprises moving said inner and outer core catheters with respect to each other to bend said wires in an outward direction and thereby expand said thermal transfer device.