Methods and apparatus for luminal stenting

Abstract

A stent delivery system, a core assembly, and methods of operating the same are provided. The delivery system can comprise a catheter and the core assembly. The core assembly can comprise a constraining member, protruding member, a core member, and a stent extending along the core member. The tubular constraining member can be spaced apart from the core member and define a capture area. The protruding member can be disposed along the core member at least partially distal of the capture area. The stent can have a first portion disposed within the capture area and a second portion, distal to the first portion, extending across or over an outer surface of the protruding member so that the protruding member and the constraining member cooperate to inhibit expansion of the first portion of the stent.

What is claimed is: 
     
         1 . A core assembly for a stent delivery system, the assembly comprising:
 a core member extending in a longitudinal direction, the core member having a distal section and a proximal section;   a tubular constraining member having an inner lumen and disposed along the core member and having a distal portion (i) spaced apart from the core member and (ii) defining a capture area in the lumen;   a radially extending protruding member disposed along the core member at least partially distal of the capture area, the protruding member having an outer surface, the protruding member being disposed between the distal section and the proximal section of the core member; and   a stent having (i) a first portion disposed within the capture area and (ii) a second portion, distal to the first portion, extending across or over the protruding member outer surface, such that the protruding member and the constraining member cooperate to inhibit expansion of the stent first portion.   
     
     
         2 . The assembly of  claim 1 , further comprising a distal cover coupled to the core member distal section, the distal cover at least partially covering a stent distal portion, such that when the core assembly is slidably disposed within a catheter, the distal cover is disposed between the stent distal portion and a catheter inner wall. 
     
     
         3 . The assembly of  claim 1 , wherein the core assembly is operative to engage the stent in both a delivery position and a resheathing position, and wherein the constraining member distal portion is axially spaced apart from a stent distal portion in both the delivery position and the resheathing position. 
     
     
         4 . The assembly of  claim 1 , wherein the constraining member comprises a sheath having a distal end and an inner lumen. 
     
     
         5 . The assembly of  claim 4 , wherein the protruding member has a cross-sectional outer profile that is sized about equal to or greater in size than a cross-sectional profile of the constraining member lumen. 
     
     
         6 . The assembly of  claim 1 , wherein the core member distal section is a distal tapering section. 
     
     
         7 . The assembly of  claim 1 , wherein the core member comprises a wire. 
     
     
         8 . The assembly of  claim 1 , wherein the protruding member and the constraining member secure the stent by inducing a variable diameter in the stent between the first portion and the second portion. 
     
     
         9 . The assembly of  claim 1 , wherein the protruding member comprises a generally cylindrical outer surface, and the capture area is defined between an outer surface of the core member and an inner surface of the tubular constraining member, and wherein the protruding member outer surface is radially offset from the core member outer surface. 
     
     
         10 . The assembly of  claim 9 , wherein the protruding member outer surface is radially offset from the constraining member inner surface. 
     
     
         11 . The assembly of  claim 10 , wherein the protruding member outer surface is spaced radially between the core member outer surface and the constraining member inner surface. 
     
     
         12 . The assembly of  claim 1 , wherein the stent second portion is supported on the protruding member outer surface. 
     
     
         13 . The assembly of  claim 1 , wherein the stent is engaged between the protruding member and the constraining member in a press fit to inhibit expansion of the stent first end. 
     
     
         14 . The assembly of  claim 1 , wherein the stent is engaged between the protruding member and the constraining member in an interference fit to inhibit expansion of the stent first end. 
     
     
         15 . The assembly of  claim 1 , wherein the protruding member is rotatably mounted on the core member. 
     
     
         16 . The assembly of  claim 1 , wherein the protruding member comprises an annular ring supported on the core member. 
     
     
         17 . The assembly of  claim 1 , wherein the capture area is defined between the constraining member distal portion and the core member. 
     
     
         18 . The assembly of  claim 1 , wherein the protruding member is axially spaced apart from the constraining member distal portion. 
     
     
         19 . A method of operating a stent delivery system, comprising:
 moving a core assembly through a catheter to a treatment site, the core assembly comprising (i) a stent having a proximal section and a distal section, (ii) a core member having a distal section and a proximal section, (iii) a protruding member disposed along the core member between the distal section and the proximal section, and (iv) a constraining member axially spaced apart from the protruding member and the stent distal portion, the constraining member extending over a first portion of the stent proximal section with the protruding member seated under a second portion of the stent proximal section, distal to the first portion, such that the stent is secured between a distal end of the constraining member and a proximal end of the protruding member in a delivery position;   proximally retracting the catheter relative to the core assembly until the constraining member distal end and the stent first portion are positioned distally beyond a catheter distal end while maintaining the stent first portion in a collapsed state by securement of the stent between the constraining member distal end and the protruding member proximal end in the delivery position with the core member distal section extending distally relative to the stent; and   expanding a distal portion of the stent into apposition with a vessel wall while maintaining the stent first portion in the collapsed state in the delivery position.   
     
     
         20 . The method of  claim 19 , further comprising proximally withdrawing the core assembly into the catheter to resheath the stent within the catheter after the stent distal portion has been expanded. 
     
     
         21 . The method of  claim 19 , wherein expanding the stent distal portion comprises unfurling a distal cover that at least partially covers the stent distal portion. 
     
     
         22 . The method of  claim 21 , further comprising everting the distal cover, such that a free first end of the distal cover moves from a proximally oriented position to a distally oriented position. 
     
     
         23 . The method of  claim 19 , wherein expanding the stent distal portion comprises automatically expanding the stent distal portion as the stent distal portion exits the catheter. 
     
     
         24 . The method of  claim 19 , further comprising releasing the stent first portion to allow the stent first portion to expand into apposition with the vessel wall. 
     
     
         25 . The method of  claim 24 , wherein releasing the stent first portion comprises proximally retracting the constraining member relative to the protruding member to allow the stent first portion to expand into apposition with the vessel wall. 
     
     
         26 . The method of  claim 25 , further comprising proximally retracting the core assembly from the catheter to remove the core assembly from the catheter. 
     
     
         27 . The method of  claim 26 , further comprising inserting a second core assembly into the catheter for delivering a second stent at the treatment site. 
     
     
         28 . A stent delivery system comprising:
 a catheter having a distal end; and   a core assembly comprising:
 a tubular constraining member comprising a lumen and a distal portion; 
 a stent having a proximal portion disposed within the lumen and a distal portion disposed outside of the lumen; 
 a core member extending within the lumen and distally beyond the stent distal portion; 
 a radially protruding member coupled to the core member and being disposed distal of the constraining member distal portion within the stent distal portion; and 
   wherein the constraining member and the protruding member collectively form a gripping mechanism that engages the stent proximal portion in a collapsed state, the gripping mechanism being operative to (i) exert a distal pushing force on the stent to distally advance the stent relative to the catheter until the stent proximal portion is distally beyond the catheter distal end and (ii) exert a proximal pulling force on the stent to proximally withdraw the stent into the catheter when the stent proximal portion is distally beyond the catheter distal end and the stent is at least partially expanded into apposition with a vessel wall.   
     
     
         29 . The system of  claim 28 , wherein the gripping mechanism is configured to exert the distal pushing force and the proximal pulling force on its own without the cooperation of other components or structures. 
     
     
         30 . The system of  claim 28 , wherein the gripping mechanism is collectively formed by the constraining member distal portion and a protruding member proximal portion. 
     
     
         31 . The system of  claim 28 , wherein an arcuate tip of the core member extends distal of the protruding member. 
     
     
         32 . The system of  claim 28 , wherein when the assembly is oriented substantially straight, the protruding member does not press the stent against a catheter inner surface. 
     
     
         33 . The system of  claim 28 , wherein the protruding member comprises a generally cylindrical outer surface that is radially spaced apart from a catheter inner surface, such that when the assembly is oriented substantially straight, the protruding member does not press the stent against the catheter inner surface. 
     
     
         34 . The system of  claim 28 , wherein the protruding member comprises a generally cylindrical outer surface that is radially spaced apart from a catheter inner surface, such that when the assembly is oriented substantially straight, a radial distance between the protruding member outer surface and the catheter inner lumen is sized greater than a stent thickness.