Patent EA-005172-B1 (EA)
Title: Delivery system having a rapid pusher assembly for self-expanding stent, and stent exchange configuration
Inventor: DORN JURGEN
IPC: A61F2/95
Filed: 2002-07-04
Abstract: 1. A pusher assembly for a delivery system for a self expanding stent, the pusher assembly constituting a catheter shaft with a proximal pusher end to receive an end-wise compressive force and a distal pusher end (8) to deliver said force to a stent (6) to be delivered, the pusher assembly comprising: a pusher strand (16) extending from the proximal pusher end to a distal strand end which is nearer the distal pusher (9) end than the proximal pusher end; and a pusher element (8) which abuts the stent (6) in use to deliver said force to the stent; the pusher assembly further comprising: a transfer shaft (12) having a proximal and a distal end, the proximal end being connected to the distal tube end (22) and the distal end being connected to the pusher element (8); and characterised in that: the pusher element (8) defines a guidewire (2) path, and said transfer shaft (12) lies to one side of said path. 2. Assembly as claimed in claim 1 wherein the transfer shaft (12) is welded to at least one of the pusher element (8) and the pusher strand (16). 3. Assembly as claimed in claim 1 or 2 wherein the pusher element (8) is a cylinder with a distal-facing end face to abut the proximal end of the stent (6). 4. Assembly as claimed in claim 1,2 or 3 wherein the pusher element (8) is a radiopaque marker. 5. Assembly as claimed in any one of the preceding claims wherein the pusher element (8) surrounds a carrier tube (10) itself carried on the pusher element (8) and cantilevered distally from the pusher element (8) to lie in use within the lumen of the stent (6) to be delivered. 6. Assembly as claimed in claim 5 wherein the carrier tube (10) itself carries a radiopaque marker (26) for the distal end of the stent. 7. Assembly as claimed in claim 5 or 6 wherein a proximal portion of the carrier tube (10) extends proximally from the pusher element (8) and flares outwardly proximally. 8. Assembly as claimed in any one of the preceding claims, in which the transfer shaft (12) is present as two shaft portions joined by a connection piece (14). 9. Assembly as claimed in claim 8 wherein the connection piece (14) is a collar. 10. Assembly as claimed in claim 8 or 9 wherein each of the transfer shaft portions is soldered to the connection piece (14). 11. A self-expanding stent deployment system for advancement over a guidewire (2) and having a rapid exchange configuration, comprising: a tubular sheath (4) defining a cavity within which the stent (6) is confined radially inwardly until deployment, the sheath (4) having a distal end and a proximal end and defining an axis of the system; a pipe (18) to pull the sheath (4) proximally to release the stent (6) and having a lumen to transport fluid (F) for delivery to the sheath cavity; a pusher assembly including a pusher element (8) abutting the stent (6) in use and a rod (16) for restraining the pusher element (8) against proximal movement and extending from a proximal rod end proximally beyond the proximal end of the sheath (4) along the lumen of the pipe (18) to a distal rod end, the rod (16) being capable of carrying an endwise compressive stress (C) suffered by the pusher assembly during deployment of the stent (6); an adapter (20) defining at least first (24) and second lumens (22) arranged side by side and parallel with the axis of the system and arranged to transmit forces between the sheath (4) and the pipe (18), wherein the first lumen (24) is a guidewire (2) lumen, and the second lumen (22) communicates with the lumen of the pipe (18) and with the sheath (4) cavity, and characterised in that: the sheath (4) has a tapered tip, distal of the stent (6) cavity which enables the guidewire (2) to pass distally beyond the distal end of the sheath (4). 12. The system according to claim 11, characterised in that the pusher element (8) is a cylinder with a distal facing end face to abut the proximal end of the stent (6). 13. The system according to claim 11 or 12, characterised in that the pusher element (8) constitutes a radiopaque marker. 14. The system according to any one of the claims 11 to 13, characterised by a transfer shaft (12) which lies inside the sheath (4) to one side of the guidewire (2) and is arranged to transmit forces between the pusher element (8) and the rod (16). 15. The system according to claim 14, characterised in that the transfer shaft (12) is welded to at least one of the pusher element (8) and the rod (16). 16. The system according to claims 14 or 15, characterised in that the transfer shaft (12) is present as two shaft portions joined by a connection piece (14). 17. The system according to claim 16, characterised in that the connection piece (14) is a collar. 18. The system according to claims 16 or 17, characterised in that each of the transfer shaft (12) portions is soldered to the connection piece (14). 19. The system according to any one of claims 11 to 18, characterised in that the adapter (20) is made of metal. 20. The system according to any one of claims 11 to 19, characterised in that the connection between the sheath (4) and the adapter (20) is made by means of an adhesive. 21. The system according to any one of claims 11 to 20, characterised in that the sheath (4) comprises an encapsulated metal braid (3). 22. The system according to claim 21, characterised in that the metal braid (3) cooperates with studs (20A) disposed around the circumferential surface of the distal end of the adapter (20). 23. The system according to any one of claims 11 to 23, characterised in that the first lumen (24) is defined by two arcuate segments (23A) and (23B). 24. The system according to any one of claims 11 to 23, characterised in that the pipe (18) is inserted into the first lumen (24) of the adapter (20) until it abuts an end face of a recess provided on the defining walls of the first lumen (24). 25. The system according to any one of claims 11 to 24, characterised in that the pusher element (8) surrounds a carrier tube (10) itself carried on the pusher element (8) and cantilevered distally from the pusher element (8) to lie in use within the lumen of the stent (6) to be delivered. 26. The system according to claim 23, characterised in that the carrier tube (10) itself carries a radiopaque marker (26) for the distal end of the stent (6). 27. The system according to claims 23 or24, characterised in that a proximal portion of the carrier tube (10) extends proximally from the pusher element (8) and flares outwardly proximally.