Prosthesis delivery

• US 5,824,058 A
• Filed: 07/21/1997
• Issued: 10/20/1998
• Est. Priority Date: 05/20/1993
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Corporation
• Inventors: Roberts, George T., Ravenscroft, Adrian C.
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/897,944
• Time in Patent Office: 456 Days
• Field of Search: 623/1, 623/11, 623/12, 606/194, 606/195, 606/196, 606/197, 606/198, 606/199, 604/104, 604/8, 604/96
• US Class Current: 623/1.11
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2002/9505 having retaining means other than an outer sleeve, e.g. male-female connector between stent and instrument
• CPC Class Codes: A61F 2002/9511 the retaining means being filaments or wires
• CPC Class Codes: A61F 2210/0019 operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers

Abstract

This invention provides smooth delivery and accurate positioning of prostheses in the body. In embodiments, systems are provided that include elongate members extending generally along the axis of a supporting catheter to a free ends. The elongate members extend through openings in the prosthesis to maintain the position of the prosthesis on the catheter. The prosthesis can be released from the catheter by relative axial motion of the catheter and the elongate members such that the free ends are removed from the openings in the prosthesis. In embodiments, the elongate members hold the distal end of a self-expanding stent at a desired axial location and in radial compaction as a restraining sheath is withdrawn. The friction between the sheath and stent puts the stent under tension, which reduces the radial force on the sheath wall, allowing smoother retraction. Proximal portions of the stent radially expand and axially shorten. The distal end, however, is maintained at the desired axial location and released from the catheter to contact the body lumen wall without substantial axial shortening.

Claims

1. A system for positioning a self-expanding prosthesis in contact with tissue within a patient, comprising:

a self-expanding prosthesis having a proximal end and a distal end and a tissue-engaging body therebetween,

a catheter having a portion supporting a prosthesis in a radially compact form,

said portion of said catheter supporting said prosthesis including members positioned to engage the distal end of said prosthesis to maintain corresponding portions of the prosthesis compact at a fixed axial position with respect to the catheter while other portions of said prosthesis are radially expanded to engage tissue,

said distal end of said prosthesis engaged by said members being releasable from said catheter at said fixed axial position by relative axial motion between said members and said prosthesis, so that said members disengage from said prosthesis,

a retractable sheath positioned over and in contact with said prosthesis when said prosthesis is in the compact form, and

a tensioning element applying an axial force to said prosthesis to reduce frictional force between said sheath and said prosthesis while retracting said sheath to expose said prosthesis.

2. A method of positioning a prosthesis in the body, comprising:

providing a system for positioning a prosthesis in contact with tissue on the wall of a lumen of a patient, comprising;

a tubular prosthesis having a proximal and distal end and a tissue-engaging body therebetween,

said prosthesis having a radially compact form for delivery into the patient, and, being radially expandable along its body for engaging tissue, the length of said prosthesis varying in dependence on expansion of said body, and

said prosthesis being formed of a patterned filament and including a series of openings through the tissue-engaging body of said prosthesis about the circumference of said prosthesis, near the distal end, and

said system further including a catheter having a portion for supporting said prosthesis coaxially about said portion in said compact form for delivery into the patient and constructed for expanding said prosthesis into contact with tissue,

said portion including a series of elongate members arranged about the circumference of said catheter, fixed to said catheter, and extending generally along the axis of the catheter to free ends positioned to pass through corresponding openings about the circumference of the tissue-engaging body of said prosthesis, said members maintaining corresponding portions of said prosthesis radially compact at a predetermined axial location, while proximal portions of said prosthesis are radially expanded to engage tissue,

said portion of said prosthesis corresponding to said openings releasable from said catheter at an axial location substantially corresponding to said predetermined location by moving said catheter proximally so the free ends of said members are removed from said openings.