Prosthesis delivery system with dilating tip

• US 5,902,333 A
• Filed: 08/21/1995
• Issued: 05/11/1999
• Est. Priority Date: 04/13/1993
• Status: Expired due to Term

• Current Assignee: Boston Scientific Corporation
• Original Assignee: Boston Scientific Corporation
• Inventors: Roberts, George T., Andersen, Erik
• Primary Examiner(s): Prebilic, Paul B.
• Application Number:
  US08/517,456
• Time in Patent Office: 1,359 Days
• Field of Search: 604/104, 604/105, 604/106, 606/151, 606/191, 606/192, 606/194, 606/197, 606/198, 606/199, 606/200, 623/1, 623/11, 623/12
• US Class Current: 606/191
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/966 with relative longitudinal movement between outer sleeve and prosthesis, e.g. using a push rod
• CPC Class Codes: A61F 2002/044 Oesophagi or esophagi or gullets

Abstract

This invention provides prosthesis delivery systems with tips constructed to permit both easier advance into the body and easier removal from the body after expanding the prosthesis. The tip includes a distal taper that can gently widen a lumen during advance in instances where the lumen is narrower than the tip and a proximal taper that can gently widen the lumen on retraction in instances where the prosthesis does not immediately expand the lumen to provide clearance for the larger diameter tip.

Claims

1. A system for delivering a prosthesis into a body lumen of a patient, comprising:

an elongated catheter with a catheter shaft defining an axis and having a proximal end that remains outside the body, a distal end, and a supporting portion for supporting a prosthesis configured in a radially compact form for delivery of the prosthesis to a desired location inside the body,

a bi-directional, rigid dilating tip fixed to said catheter at a point distal of said prosthesis, said tip having a distal dilating portion, a proximal dilating portion, and a maximum diameter portion therebetween,

said maximum diameter portion having a diameter that is about equal to or greater than the radially compact form of said prosthesis,

said distal dilating portion extending distally over an axial length to a smaller diameter and having a smooth profile that is free of sharp edges, said smaller diameter being about equal to the diameter of the catheter shaft, and said axial length being greater than the diameter of said maximum diameter portion of said tip, and

said proximal dilating portion extending proximally over an axial length to a smaller diameter and having a smooth profile that is free of sharp edges, said smaller diameter being about equal to the diameter of the catheter shaft, and said axial length being greater than the diameter of said maximum diameter portion of said tip, said proximal dilating portion constructed for gradually dilating said lumen during proximal motion of said catheter while withdrawing the catheter after releasing said prosthesis, said proximal dilating portion of said tip including a shelf-portion of constant diameter over an axial length, said shelf portion having a diameter corresponding to the inner diameter of said sheath such that distal portions of said sheath can engage said shelf portion when extended over said prosthesis to protect said prosthesis against exposure to body fluids, said shelf portion comprising a compressible polymer o-ring fitted into a groove in said shelf portion, and

a thin walled retractable protective sheath sized to be coaxially disposed about and closely conform to said prosthesis when supported on said catheter in said radially contracted form during said delivery to said desired site, and

said tip further constructed in cooperation with said sheath such that said sheath engages said tip when said sheath is coaxially disposed about said prosthesis and the outer diameter of said sheath is no greater than the diameter of said maximum diameter portion of said tip to protect said sheath during said distal motion while delivering said prosthesis.

2. A method for delivering a prosthesis into the esophagus of a patient, comprising:

providing an elongated catheter with a shaft defining an axis and having a proximal end that remains outside the body, a distal end, and a supporting portion for supporting a prosthesis configured in a radially compact form, said catheter further including a bi-directional dilating tip fixed to said catheter at a point distal of said prosthesis, said tip having a distal dilating portion, a proximal dilating portion, and a maximum diameter portion therebetween, a prosthesis carried upon said catheter,

said maximum diameter portion having a diameter that is about equal to or greater than the radially compact form of said prosthesis,

said distal dilating portion extending distally over an axial length and with a smooth profile that is free of sharp edges to a smaller diameter, said smaller diameter being about equal to the diameter of the catheter shaft, and said axial length being greater than the diameter of said maximum diameter portion of said tip, and

said proximal dilating portion extending proximally over an axial length and with a smooth profile that is free of sharp edges to a smaller diameter, said smaller diameter being about equal to the diameter of the catheter shaft, and said axial length being greater than the diameter of said maximum diameter portion of said tip,

placing said catheter into a body lumen and positioning said prosthesis at a desired location,

expanding said prosthesis to a diameter no larger than said maximum diameter of said tip,

withdrawing said catheter to engage the proximal dilating portion of the tip and the prosthesis, and

continuing to withdraw said catheter so said tip widens the passage through the prosthesis so the catheter can be removed from the body immediately after deployment.

3. The method of claim 2 comprising,

selecting a self-expanding prosthesis to provide axial force to the interior of said lumen to fully expand said lumen after an extended period of time, and

withdrawing said catheter prior to fully expanding said prosthesis.

4. The method of claim 2 or 3 comprising crossing a region of a lumen constricted to a diameter smaller than the maximum diameter of the tip by urging the distal or proximal portion of said tip against said region to widen said region.

5. The method of claim 2 or 3 wherein the lumen being treated has a diameter of about 1 cm or more.