Overlapped stents for scaffolding, flexibility and MRI compatibility

Abstract

A tubular insert for a vessel comprises an inner stent and an outer stent. At least a portion of the inner stent is disposed within the outer stent. The outer stent has a longitudinal axis and is constructed to be free of any closed loops which are electrically conductive and which are disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop. The inner stent has a longitudinal axis and is constructed so as to be free of any closed loops which are electrically conductive and which are disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop. There is a substantially electrically non-conductive connection between the inner and outer stents. Desirably, a wall surface is defined by the outer and inner stents, and there are no closed, electrically conductive loops in the wall surface of the tubular insert.

1 . A tubular insert for a bodily vessel comprising an inner stent, and an outer stent, at least a portion of the inner stent disposed within the outer stent, the outer stent having a longitudinal axis and constructed so as to be free of any closed loops which are 
 1) electrically conductive; and    2) disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop;    the inner stent having a longitudinal axis and constructed so as to be free of any closed loops which are    1) electrically conductive; and    2) disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop;    wherein there is a substantially electrically non-conductive connection between the inner stent and the outer stent.    
     
     
         2 . The tubular insert of  claim 1  wherein there are a plurality of substantially electrically non-conductive connections between the inner stent and the outer stent.  
     
     
         3 . The tubular insert of  claim 2  wherein the inner stent is a helical stent and the outer stent is a helical stent.  
     
     
         4 . The tubular insert of  claim 1  wherein the inner stent is a helical stent and the outer stent is a helical stent.  
     
     
         5 . The tubular insert of  claim 1  wherein the electrically non-conductive connection comprises plastic.  
     
     
         6 . The tubular insert of  claim 1  wherein the electrically non-conductive connection comprises adhesive.  
     
     
         7 . The tubular insert of  claim 1  wherein the electrically non-conductive connection comprises ceramic.  
     
     
         8 . The tubular insert of  claim 3  wherein the electrically non-conductive connections comprise plastic.  
     
     
         9 . The tubular insert of  claim 3  wherein the electrically non-conductive connection comprise adhesive.  
     
     
         10 . The tubular insert of  claim 3  wherein the electrically non-conductive connection comprise ceramic.  
     
     
         11 . The tubular insert of  claim 3  wherein one of the outer stent and inner stent extends generally clockwise about the longitudinal axis of the stent from one end of the stent to another and the other of the outer stent and inner stent extends in a generally counterclockwise direction about the longitudinal axis of the stent.  
     
     
         12 . The tubular insert of  claim 1  wherein at least one of the outer stent and the inner stent is made from a magnetic resonance compatible material.  
     
     
         13 . The tubular insert of  claim 1  wherein the outer stent and the inner stent are made from a magnetic resonance compatible material.  
     
     
         14 . The tubular insert of  claim 4  wherein the outer stent and the inner stent are made from a magnetic resonance compatible material.  
     
     
         15 . The tubular insert of  claim 1  wherein the outer stent includes a plurality of interconnected loops which extend at an oblique or perpendicular angle relative to the longitudinal axis of the outer stent, the loops extending only part of the way about the longitudinal axis of the outer stent and the inner stent includes a plurality of interconnected loops which extend at an oblique or perpendicular angle relative to the longitudinal axis of the inner stent, the loops extending only part of the way about the longitudinal axis of the inner stent.  
     
     
         16 . The tubular insert of  claim 2  having a plurality of cells, each cell defined by a portion of the outer stent, a portion of the inner stent and at least two connections between the outer stent and the inner stent.  
     
     
         17 . The tubular insert of  claim 2  wherein the inner and outer stents are both made of a conductive material with an electrically non-conductive material disposed thereabout.  
     
     
         18 . The tubular insert of  claim 1  wherein a wall surface is defined by the outer and inner stents, there being no closed, electrically conductive loops in the wall surface of the tubular insert.  
     
     
         19 . The tubular insert of  claim 2  wherein a wall surface is defined by the outer and inner stents, there being no closed, electrically conductive loops in the wall surface of the tubular insert.  
     
     
         20 . The tubular insert of  claim 1  wherein portions of the inner and outer stents are made of metal.  
     
     
         21 . A method of imaging a tubular medical device, the tubular medical device being in the form of an outer stent and an inner stent, at least a portion of the inner stent disposed within the outer stent, the outer stent having a longitudinal axis and constructed so as to be free of any closed loops which are 
 1) electrically conductive; and    2) disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop;    the inner stent having a longitudinal axis and constructed so as to be free of any closed loops which are    1) electrically conductive; and    2) disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop;    wherein there is a substantially electrically non-conductive connection between the inner stent and the outer stent, the method comprising the steps of:    a) disposing the tubular medical device within a magnetic resonance imager;    b) using the magnetic resonance imager to obtain a magnetic resonance image of the tubular medical device; and    c) removing the tubular medical device from the magnetic resonance imager.    
     
     
         22 . The method of  claim 21  wherein the tubular medical device is located within a living body when it is disposed within the magnetic resonance imager.  
     
     
         23 . The method of  claim 21  wherein the tubular medical device is not located within a living body when it is disposed within the magnetic resonance imager.  
     
     
         24 . The method of clam  22  wherein the inner stent is a helical stent and the outer stent is a helical stent.  
     
     
         25 . The method of clam  23  wherein the inner stent is a helical stent and the outer stent is a helical stent.  
     
     
         26 . The method of  claim 24  wherein one of the inner stent and the outer stent extends in a generally clockwise direction about the longitudinal axis of the stent and the other stent extends in a generally counterclockwise direction about the longitudinal axis of the stent.  
     
     
         27 . The method of  claim 25  wherein one of the inner stent and the outer stent extends in a generally clockwise direction about the longitudinal axis of the stent and the other stent extends in a generally counterclockwise direction about the longitudinal axis of the stent.  
     
     
         28 . The method of  claim 22  wherein the connection between the outer stent and the inner stent comprises a material selected from the group consisting of ceramic materials, plastic materials and adhesive materials.  
     
     
         29 . The method of  claim 21  wherein the outer stent includes a plurality of interconnected loops which extend at an oblique or perpendicular angle relative to the longitudinal axis of the outer stent, the loops extending only part of the way about the longitudinal axis of the outer stent and the inner stent includes a plurality of interconnected loops which extend at an oblique or perpendicular angle relative to the longitudinal axis of the inner stent, the loops extending only part of the way about the longitudinal axis of the inner stent.  
     
     
         30 . The method of  claim 21  having a plurality of cells, each cell defined by a portion of the outer stent, a portion of the inner stent and at least two connections between the outer stent and the inner stent.  
     
     
         31 . The method of  claim 21  wherein the inner and outer stents are both made of a conductive material with an electrically non-conductive material disposed thereabout.  
     
     
         32 . The method of  claim 21  wherein a wall surface is defined by the outer and inner stents, there being no closed, electrically conductive loops in the wall surface of the tubular medical device.  
     
     
         33 . A method of manufacturing a tubular medical device, comprising the steps of: 
 a) providing a first stent, the first stent having a longitudinal axis and constructed so as to be free of any closed loops which are    1) electrically conductive; and    2) disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop;    b) providing a second stent, the second stent having a longitudinal axis and constructed so as to be free of any closed loops which are    1) electrically conductive; and    2) disposed about the longitudinal axis such that the longitudinal axis passes through the closed loop;    wherein there is a substantially electrically non-conductive connection between the first stent and the second stent;    c) disposing at least a portion of the second stent within the first stent;    d) connecting the first stent and the second stent together via a connection which is substantially electrically non-conductive.    
     
     
         34 . The method of  claim 33  wherein the first stent is a helical stent and the second stent is a helical stent.  
     
     
         35 . The method of  claim 33  wherein the first stent includes a rib which runs along the length of the first stent and a plurality of first arms extending therefrom, the first arms extending only part of the way about the circumference of the first stent and the second stent includes a rib which runs along the length of the second stent and a plurality of second arms extending therefrom, the second arms extending only part of the way about the circumference of the second stent.  
     
     
         36 . The method of  claim 33  wherein the first stent includes a plurality of interconnected loops which extend at an oblique or perpendicular angle relative to the longitudinal axis of the first stent, the loops extending only part of the way about the longitudinal axis of the first stent and the second stent includes a plurality of interconnected loops which extend at an oblique or perpendicular angle relative to the longitudinal axis of the second stent, the loops extending only part of the way about the longitudinal axis of the second stent  
     
     
         37 . The method of  claim 33  wherein the tubular medical device has a plurality of cells, each cell defined by a portion of the first stent, a portion of the second stent and at least two connections between the first stent and the second stent.  
     
     
         38 . The method of  claim 33  wherein the first and second stents are both made of a conductive material with an electrically non-conductive material disposed thereabout.  
     
     
         39 . The method of  claim 33  wherein a wall surface is defined by the first and second stents, there being no closed, electrically conductive loops in the wall surface of the tubular medical device.  
     
     
         40 . An expandable member for implantation in a bodily vessel, the expandable member comprising a multilayer tubular wall surface formed of a plurality of interconnected struts disposed at different distances from a centerline which runs along a longitudinal axis of the stent, the struts defining a plurality of interconnected cells, each cell including an electrically conducting portion and an electrically non-conductive portion, the tubular member including pathways which form closed paths about the circumference of the stent, each closed path including at least one substantially electrically non-conducting portion and one electrically conducting portion.  
     
     
         41 . An expandable member comprising a first stent and a second stent, the first stent formed of a member which winds from a proximal end of the first stent to a distal end of the first stent and back again to the proximal end, the second end formed of a member which winds from a distal end of the second stent to a proximal end of the second stent and back again to the distal end, whereon one of the first and second stents is disposed within the other of the first and second stents.