Internal restraint for delivery of self-expanding stents

Abstract

A medical device delivery system comprises a catheter having a catheter shaft with a proximal region and a distal region. The catheter shaft has a pull wire lumen therein. An expandable medical device is disposed about medical device receiving region of the catheter shaft. The expandable medical device has a reduced configuration and an expanded configuration. The system further comprises a retractable retaining wire, at least a portion of which is coiled about the expandable medical device and retains the expandable medical device in the reduced configuration. One end of the retractable retaining wire terminates in a pull-wire. The pull-wire extends into the pull-wire lumen to the proximal region of the catheter shaft.

1 . A delivery system for delivering a medical device to a body location, the delivery system comprising: 
 a catheter, the catheter having a catheter shaft having a proximal region and a distal region, the catheter shaft defining a pull-wire lumen, at least a portion of the distal region defining a medical device receiving region;    an expandable medical device disposed about the medical device receiving region, the expandable medical device having a reduced configuration and an expanded configuration, the expandable medical device further having proximal and distal device ends;    at least one retractable retaining wire, at least a portion of the at least one retractable retaining wire coiled about at least a portion of the expandable medical device and retaining the expandable medical device in the reduced configuration, one end of the at least one retractable retaining wire terminating in at least one pull-wire, the at least one pull-wire extending into the pull-wire lumen to the proximal region of the catheter shaft.    
     
     
         2 . The delivery system of  claim 1  wherein the at least one retractable retaining wire is characterized as one or more ribbons.  
     
     
         3 . The delivery system of  claim 1  wherein the at least one retractable retaining wire is constructed from a shape memory material.  
     
     
         4 . The delivery system of  claim 1  wherein the at least one retractable retaining wire is constructed from at least one material of the group consisting of nitinol, acrylate-based polymers, polyurethane-based polymers, polynorbornene-based polymers, polylactide-based polymers, platinum, tungsten, titanium, stainless steel, nickel and any combinations thereof.  
     
     
         5 . The delivery system of  claim 1  wherein the medical device is a stent.  
     
     
         6 . The delivery system of  claim 5  wherein the stent comprises a plurality of interconnected struts, the at least one retractable retaining wire being threadingly coiled about selected struts of the stent.  
     
     
         7 . The delivery system of  claim 1  wherein the medical device receiving region comprises a medical balloon, the delivery system further comprising an inflation lumen, the inflation lumen in fluid communication with the medical balloon.  
     
     
         8 . The delivery system of  claim 7  wherein the medical device is balloon expandable.  
     
     
         9 . The delivery system of  claim 1  wherein the catheter shaft includes a side wall, the side wall defining at least one lumen port, the at least one pull-wire extending proximally from the proximal end of the at least one retractable retaining wire and passing through the at least one lumen port to enter into the pull-wire lumen.  
     
     
         10 . The delivery system of  claim 1  wherein the at least one retractable retaining wire is constructed and arranged to uncoil from the medical device when the at least one pull-wire is retracted.  
     
     
         11 . A delivery system for delivering a medical device to a body location, the delivery system comprising: 
 a catheter, the catheter having an outer member and a retractable inner member, the catheter having a proximal region and a distal region, at least a portion of the distal region of the inner member defining a medical device receiving region;    an expandable medical device having a reduced configuration and an expanded configuration, the expandable medical device disposed about the medical device receiving region of the inner member in the reduced configuration, the expandable medical device comprising a plurality of interconnected struts;    one or more flexible members, each of the one or more flexible members having a first end and a second end, each end of the one or more flexible members being engaged to one or more struts, each of the one or more flexible members being looped about the medical device receiving region of the inner member, thereby retaining the medical device in the reduced configuration thereabout.    
     
     
         12 . The delivery system of  claim 11  wherein the expandable medical device is expanded from the reduced configuration to the expanded configuration when the retractable inner member is proximally retracted from within the medical device.  
     
     
         13 . The delivery system of  claim 11  wherein the medical device is a self-expanding stent.  
     
     
         14 . The delivery system of  claim 11  wherein the inner member is a wire.  
     
     
         15 . The delivery system of  claim 11  wherein the medical device mounting region of the retractable inner member includes a lubricious surface.  
     
     
         16 . An expandable medical device having a reduced configuration and being expandable to an expanded configuration, the expandable medical device comprising: 
 a plurality of interconnected struts, the plurality of interconnected struts defining an internal tubular passage,    one or more flexible members, each of the one or more flexible members having a first end and a second end and extending into the internal tubular passage, each end of the one or more flexible members being engaged to a strut.    
     
     
         17 . The expandable medical device of  claim 16  wherein each of the one or more flexible members is constructed and arranged to removably engage a catheter member and retain the expandable medical device in the reduced state about the catheter member.  
     
     
         18 . The expandable medical device of  claim 17  in combination with a catheter member, the expandable medical device disposed about the catheter member, each of the one or more flexible members at least partially and removably disposed about the catheter member, the flexible members being of sufficient length to allow the expandable medical device to expand to the expanded configuration when the catheter member is removed from within the expandable medical device.  
     
     
         19 . The expandable medical device of  claim 18  in the form of a self-expanding stent.  
     
     
         20 . A delivery system for delivering a medical device to a body location, the delivery system comprising: 
 a catheter member, the catheter member having a proximal region and a distal region, at least a portion of the distal region of the catheter member defining a medical device receiving region; and    an expandable medical device having a reduced configuration and an expanded configuration, in the reduced configuration the medical device being disposed about the medical device receiving region of the catheter member, the expandable medical device further having one or more engagement members, each of the one or more engagement members having a first end and a second end, the first end of each of the one or more engagement members engaged to a location on the expandable medical device, in the reduced configuration the second end of each of the one or more engagement members releasably engaged to the medical device receiving region of the catheter member or to another of the one or more engagement members.    
     
     
         21 . The delivery system of  claim 20  wherein the expandable medical device expands from the reduced configuration to the expanded configuration when the second end of the one or more engagement members is released from the medical device receiving region of the catheter member or from another of the one or more engagement members.  
     
     
         22 . The delivery system of  claim 20  wherein the one or more engagement members are constructed from at least one material of the group consisting of nitinol, acrylate-based polymers, polyurethane-based polymers, polynorbornene-based polymers, polylactide-based polymers, platinum, tungsten, titanium, stainless steel, nickel and any combinations thereof.  
     
     
         23 . The delivery system of  claim 21  wherein the one or more engagement members are at least partially constructed from a temperature sensitive shape memory material.  
     
     
         24 . The delivery system of  claim 22  wherein the second end of each of the one or more engagement members is constructed at least partially from the temperature sensitive shape memory material.  
     
     
         25 . The delivery system of  claim 24  wherein the catheter member includes a lumen therein.  
     
     
         26 . The delivery system of  claim 25  wherein the lumen has a heating element therein, the heating element constructed and arranged to increase the temperature of the second end of each of the one or more engagement members.  
     
     
         27 . The delivery system of  claim 25  wherein the heating element is selected from at least one member of the group consisting of a fiber optic wire, an electrically conductive wire, an electrically resistive wire, a saline bolus, and any combination thereof.  
     
     
         28 . The delivery system of  claim 20  wherein the catheter member is a heat conductive wire.  
     
     
         29 . The delivery system of  claim 21  wherein the one or more engagement members are at least partially constructed from a pH sensitive shape memory material.  
     
     
         30 . The delivery system of  claim 29  wherein the second end of each of the one or more engagement members is constructed at least partially from the pH sensitive shape memory material.  
     
     
         31 . The delivery system of  claim 30  wherein the catheter member includes a lumen therein.  
     
     
         32 . The delivery system of  claim 31  wherein the lumen is constructed and arranged to deliver a pH-buffered bolus of saline to the distal region of the catheter member.  
     
     
         33 . A delivery system for delivering a medical device to a body location, the delivery system comprising: 
 a catheter member, the catheter member having a proximal region and a distal region, at least a portion of the distal region of the catheter member defining a medical device receiving region;    an expandable medical device having a reduced configuration and an expanded configuration, in the reduced configuration the medical device being disposed about the medical device receiving region of the catheter member; and    one or more engagement members, each of the one or more engagement members having a first end and a second end, in the reduced configuration the first end of each of the one or more engagement members being releasably engaged to a location on the expandable medical device or to another of the one or more engagement members, the second end of each of the one or more engagement members engaged to the medical device receiving region of the catheter member.    
     
     
         34 . The delivery system of  claim 33  wherein the expandable medical device expands from the reduced configuration to the expanded configuration when the first end of the one or more engagement members is released from the location on the expandable medical device or from another of the one or more engagement members.  
     
     
         35 . The delivery system of  claim 33  wherein the one or more engagement members are constructed from at least one material of the group consisting of nitinol, acrylate-based polymers, polyurethane-based polymers, polynorbornene-based polymers, polylactide-based polymers, platinum, tungsten, titanium, stainless steel, nickel and any combinations thereof.  
     
     
         36 . A delivery system for delivering a medical device to a body location, the delivery system comprising: 
 a catheter member, the catheter member having a proximal region and a distal region, at least a portion of the distal region of the catheter member defining a medical device receiving region;    an expandable medical device having a reduced configuration and an expanded configuration, the expandable medical device disposed about the medical device receiving region of the catheter member in the reduced configuration;    one or more engagement members, each of the one or more engagement members having an engaged state and a released state, each of the one or more engagement members having a first end and a second end, the first end of each of the one or more engagement members engaged to a location on the expandable medical device and in the reduced configuration the second end of each of the one or more engagement members being engaged to a location on the medical device receiving region of the catheter member or to another engagement member;    the expandable medical device being expanded from the reduced configuration to the expanded configuration when the one or more engagement members are transformed from the engaged state to the released state thereby causing the second ends of the one or more engagement members to be released from the medical device receiving region or the another engagement member.    
     
     
         37 . The delivery system of  claim 36  wherein the one or more engagement members are constructed from at least one material of the group consisting of nitinol, acrylate-based polymers, polyurethane-based polymers, polynorbornene-based polymers, polylactide-based polymers, platinum, tungsten, titanium, stainless steel, nickel and any combinations thereof.  
     
     
         38 . An expandable medical device having a reduced configuration and being expandable to an expanded configuration, the expandable medical device comprising: 
 one or more engagement members, each of the one or more engagement members having a first end and a second end, the first end of each of the one or more engagement members engaged to a location on the expandable medical device, the second end of each of the one or more engagement members extending radially inward from the first end and constructed and arranged to releasably engage a medical device receiving region of a catheter member.    
     
     
         39 . The expandable medical device of  claim 38  wherein the one or more engagement members are at least partially constructed from a temperature sensitive shape memory material.  
     
     
         40 . The expandable medical device of  claim 38  wherein the second end of each of the one or more engagement members is constructed at least partially from a temperature sensitive shape memory material.  
     
     
         41 . The expandable medical device of  claim 38  wherein the one or more engagement members are constructed from at least one material of the group consisting of nitinol, acrylate-based polymers, polyurethane-based polymers, polynorbornene-based polymers, polylactide-based polymers, platinum, tungsten, titanium, stainless steel, nickel and any combinations thereof.  
     
     
         42 . The expandable medical device of  claim 38  wherein the medical device is a self-expanding stent.