Stent delivery system and method of manufacturing same

Abstract

Stent delivery system and method of manufacturing same. In one embodiment, the stent delivery system comprises an inner catheter. A handle is disposed at the proximal end of the inner catheter, and an enlarged tip is disposed at the distal end thereof. A stent engaging sleeve coaxially surrounds and is secured to a portion of the inner catheter proximally contiguous to the tip. The stent engaging sleeve is used to frictionally engage a stent mounted thereover in such a way as to prevent the stent, during deployment, from sliding proximally relative to the inner catheter. The system additionally comprises a self-expandable stent of the type comprising a knitted mesh of nitinol wire flexible in both the radial and longitudinal axes. The stent is mounted over the stent engaging sleeve in a longitudinally stretched state and is maintained, until deployment, in the stretched state by a stent restraining sleeve. The stent restraining sleeve, which coaxially surrounds the stent and is appropriately sized to maintain the stent in its stretched state, is a braided tube formed directly over the stent. The system also includes an outer catheter that surrounds much of the distal end of the inner catheter up to its tip, the outer catheter being adapted for axial movement relative to the inner catheter. The distal end of the outer catheter, which is mechanically coupled to the distal end of the stent for axial movement, is provided with an increased inner diameter to accommodate those components positioned between the inner and outer catheters. To facilitate the advancement of the outer catheter over the stent restraining sleeve during the assembly of the system, the outer catheter is fabricated with a longitudinal split extending proximally from its distal end. After the outer catheter has been positioned over the stent restraining sleeve, the split is sealed.

1 . A stent delivery system comprising: 
 (a) an inner catheter;    (b) an outer catheter, said outer catheter surrounding at least a portion of the length of said inner catheter and adapted for axial movement relative to said inner catheter;    (c) a self-expandable stent disposed between said inner catheter and said outer catheter; and    (d) a stent restraining member disposed between said outer catheter and said self-expandable stent, said stent restraining member being dimensioned to maintain said self-expandable stent in a compressed state.    
   
   
       2 . The stent delivery system as claimed in  claim 1  wherein said stent restraining member is a tube surrounding said self-expandable stent.  
   
   
       3 . The stent delivery system as claimed in  claim 2  wherein said tube is mechanically coupled to said outer catheter for axial movement.  
   
   
       4 . The stent delivery system as claimed in  claim 2  wherein said stent restraining member is a coil surrounding said self-expandable stent.  
   
   
       5 . The stent delivery system as claimed in  claim 4  wherein said coil is made from a strong, flexible material having a low coefficient of friction.  
   
   
       6 . The stent delivery system as claimed in  claim 5  wherein said strong, flexible material is selected from the group consisting of wire, thread and ribbon.  
   
   
       7 . The stent delivery system as claimed in  claim 4  wherein said coil is mechanically coupled to said outer catheter for axial movement.  
   
   
       8 . The stent delivery system as claimed in  claim 1  wherein said self-expandable stent is a knitted mesh of nitinol wire flexible in both the radial and longitudinal axes.  
   
   
       9 . The stent delivery system as claimed in  claim 1  further comprising means for deterring said self-expandable stent from sliding proximally relative to said inner catheter during deployment.  
   
   
       10 . The stent delivery system as claimed in  claim 9  wherein said deterring means comprises a stent engaging sleeve fixed to said inner catheter, said stent engaging sleeve being provided with projections on its outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expanding stent from sliding proximally relative thereto.  
   
   
       11 . The stent delivery system as claimed in  claim 1  further comprising a stent engaging sleeve fixed to said inner catheter, said self-expandable stent surrounding said stent engaging sleeve, said stent engaging sleeve having an outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expandable stent from sliding proximally relative thereto.  
   
   
       12 . The stent delivery system as claimed in  claim 1  further comprising a sleeve holding member, said sleeve holding member being fixed to said inner catheter and being secured to the proximal end of said stent restraining member.  
   
   
       13 . A stent delivery system comprising: 
 (a) an inner catheter;    (b) an outer catheter, said outer catheter surrounding at least a portion of the length of said inner catheter and adapted for axial movement relative to said inner catheter; and    (c) a self-expandable stent disposed between said inner catheter and said outer catheter, said self-expandable stent being flexible in both the radial and longitudinal axes, said self-expandable stent being held in a compressed state by said outer catheter.    
   
   
       14 . The stent delivery system as claimed in  claim 13  wherein said self-expandable stent is a knitted mesh of nitinol wire coaxially mounted on said inner catheter.  
   
   
       15 . The stent delivery system as claimed in  claim 14  further comprising means for deterring said self-expandable stent from sliding proximally relative to said inner catheter during deployment.  
   
   
       16 . The stent delivery system as claimed in  claim 15  wherein said deterring means comprises a stent engaging sleeve fixed to said inner catheter, said stent engaging sleeve being provided with projections on its outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expanding stent from sliding proximally relative thereto.  
   
   
       17 . The stent delivery system as claimed in  claim 14  further comprising a stent engaging sleeve fixed to said inner catheter, said self-expandable stent surrounding said stent engaging sleeve, said stent engaging sleeve having an outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expandable stent from sliding proximally relative thereto.  
   
   
       18 . A method of manufacturing a stent delivery system, said method comprising the steps of: 
 (a) providing an inner catheter;    (b) compressing a self-expandable stent over said inner catheter;    (c) while said self-expandable stent is in a compressed state, positioning a braided tube around said inner catheter and said self-expandable stent, said braided tube being dimensioned to maintain said self-expandable stent in said compressed state; and    (d) positioning an outer catheter around said braided tube, said outer catheter being adapted for axial movement relative to said inner catheter.    
   
   
       19 . The method as claimed in  claim 18  wherein said inner catheter and said self-expandable stent are coaxially disposed, wherein said self-expandable stent is flexible in both the longitudinal and radial axes, wherein said compressing step comprises stretching said self-expandable stent longitudinally, wherein said outer catheter is a solid tube, said outer catheter positioning step comprising sliding said outer catheter over said braided tube, and wherein said braided tube positioning step comprises forming a braided tube over said self-expandable stent and said inner catheter, said method further comprising mechanically coupling said outer catheter to said braided tube for axial movement.  
   
   
       20 . The method as claimed in  claim 18  wherein said inner catheter and said self-expandable stent are coaxially disposed, wherein said self-expandable stent is flexible in both the longitudinal and radial axes, wherein said compressing step comprises stretching said self-expandable stent longitudinally, wherein said outer catheter is provided with a longitudinal slit extending at least a part of the length thereof, and wherein said braided tube positioning step comprises forming a braided tube over said self-expandable stent and said inner catheter, said method further comprising, after said outer catheter positioning step, the step of sealing said longitudinal slit, and mechanically coupling said outer catheter to said braided tube for axial movement.  
   
   
       21 . The method as claimed in  claim 18  wherein said braided tube positioning step comprises sliding a pre-formed braided tube over said inner catheter and said self-expandable stent.  
   
   
       22 . The method as claimed in  claim 18  wherein said braided tube positioning step comprises sliding a pre-formed braided tube over said inner catheter and said self-expandable stent, wherein said inner catheter and said self-expandable stent are coaxially disposed, wherein said self-expandable stent is flexible in both the longitudinal and radial axes and wherein said compressing step comprises stretching said self-expandable stent longitudinally, said method further comprising the step of mechanically coupling said outer catheter to said braided tube for axial movement.  
   
   
       23 . The method as claimed in  claim 22  wherein said outer catheter is a solid tube.  
   
   
       24 . The method as claimed in  claim 23  further comprising, before said outer catheter positioning step, the steps of fixing a braid holding sleeve to said inner catheter and securing the proximal end of said braided tube to said braid holding sleeve.  
   
   
       25 . The method as claimed in  claim 22  further comprising, before said compressing step, the step of fixing a stent engaging sleeve to said inner catheter, said self-expandable stent surrounding said stent engaging sleeve, said stent engaging sleeve having an outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expandable stent from sliding proximally relative thereto.  
   
   
       26 . A method of manufacturing a stent delivery system, said method comprising the steps of: 
 (a) providing an inner catheter;    (b) compressing a self-expandable stent over said inner catheter;    (c) while said self-expandable stent is in a compressed state, wrapping a helical restraint around said inner catheter and said self-expandable stent, said helical restraint being dimensioned to maintain said self-expandable stent in said compressed state; and    (d) positioning an outer catheter around said helical restraint, said outer catheter being adapted for axial movement relative to said inner catheter.    
   
   
       27 . The method as claimed in  claim 26  wherein said helical restraint is a made from a strong, flexible filamentary or ribbon-like material having a low coefficient of friction.  
   
   
       28 . The method as claimed in  claim 27  further comprising the step of mechanically coupling said outer catheter to said helical restraint for axial movement.  
   
   
       29 . The method as claimed in  claim 28  wherein said inner catheter and said self-expandable stent are coaxially disposed, wherein said self-expandable stent is flexible in both the longitudinal and radial axes and wherein said compressing step comprises stretching said self-expandable stent longitudinally.  
   
   
       30 . The method as claimed in  claim 29  wherein said outer catheter is provided with a longitudinal slit extending at least a part of the length thereof, said method further comprising, after said outer catheter positioning step, the step of sealing said longitudinal slit.  
   
   
       31 . The method as claimed in  claim 30  further comprising, before said compressing step, the step of fixing a stent engaging sleeve to said inner catheter, said self-expandable stent surrounding said stent engaging sleeve, said stent engaging sleeve having an outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expandable stent from sliding proximally relative thereto.  
   
   
       32 . A method of manufacturing a stent delivery system, said method comprising the steps of: 
 (a) providing an inner catheter;    (b) compressing a self-expandable stent over said inner catheter, said self-expandable stent being flexible in both the radial and longitudinal axes; and    (c) positioning an outer catheter around said self-expandable stent, said outer catheter being adapted for axial movement relative to said inner catheter and being dimensioned to maintain said self-expandable stent in a compressed state.    
   
   
       33 . The method as claimed in  claim 32  wherein said self-expandable stent is a knitted mesh of nitinol wire.  
   
   
       34 . The method as claimed in  claim 32  wherein said outer catheter is provided with a longitudinal slit extending at least a part of the length thereof, said method further comprising, after said outer catheter positioning step, the step of sealing said longitudinal slit.  
   
   
       35 . The method as claimed in  claim 34  further comprising, before said compressing step, the step of fixing a stent engaging sleeve to said inner catheter, said self-expandable stent surrounding said stent engaging sleeve, said stent engaging sleeve having an outer surface adapted to engage said self-expandable stent in such a way as to deter said self-expandable stent from sliding proximally relative thereto.