Method of insitu bypass to hold open venous valves

• US 5,843,171 A
• Filed: 01/24/1997
• Issued: 12/01/1998
• Est. Priority Date: 01/29/1996
• Status: Expired due to Term

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Laguna, Alvaro J., Campbell, Carey V., Pond, Daniel B., Kovach, Larry J., Chastain, James H.
• Primary Examiner(s): Prebilic, Paul B.
• Application Number:
  US08/788,628
• Time in Patent Office: 676 Days
• Field of Search: 623/1, 623/2, 623/12, 606/191, 606/195, 606/198, 600/29, 600/30, 600/31
• US Class Current: 606/198
• CPC Class Codes: A61B 17/12022 Occluding by internal devices, e.g. balloons or releasable wires plugging an opening in the wall of an organ A61B17/0057; occluders for the cervical canal A61F6/146; vas deferens occluders A61F6/20
• CPC Class Codes: A61B 17/12109 in a blood vessel
• CPC Class Codes: A61B 17/12131 characterised by the type of occluding device
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: B29D 23/001 Pipes; Pipe joints pleated hoses B29D23/18
• CPC Class Codes: B29K 2027/18 PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29L 2031/753 Medical equipment; Accessories therefor bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/1372 Randomly noninterengaged or randomly contacting fibers, filaments, particles, or flakes
• CPC Class Codes: Y10T 428/139 Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1397 Single layer [continuous layer]

Abstract

A tube of porous PTFE having at least two first and at least two second regions wherein the at least two first regions have a greater density than the at least two second regions. For tubes of porous expanded PTFE having a microstructure of nodes interconnected by fibrils, the at least two first regions have a mean fibril length that is less than that of the at least two second regions. Preferably the regions are arranged in the form of ring-shaped segments of the tube wherein denser segments alternate along the length of the tube with less dense segments. Other arrangements between the different regions are possible; for example, the regions may be oriented in a spiral relationship with each other along the length of the tube. The porous PTFE tubes of the present invention have excellent radial compression resistance without requiring additional exterior reinforcing members due to the presence of the denser regions that are provided with a circumferential orientation. Tubes of this type are anticipated to be useful as vascular grafts and particularly as intraluminal vascular grafts. When provided as an intraluminal graft, the tube may also optionally be manufactured to be circumferentially distensible to a larger diameter up to a maximum diameter beyond which it will not distend during normal use; such a tube can also be made to recoil minimally on the release of the distending force. The tube may be used in in situ bypass procedures to hold venous valves open and to occlude tributary branches.

Claims

1. A method of performing an in situ bypass, comprising:

a. transecting a vein to form a vein segment;

b. inserting a circumferentially distensible intraluminal graft into the vein segment and into at least one venous valve within the vein segment;

c. circumferentially distending the intraluminal graft, thereby holding open the at least one venous valve; and

d. anastomosing the vein segment to adjacent arteries;

wherein the intraluminal graft comprises a porous PTFE tube having a microstructure of nodes interconnected by fibrils, said tube having a luminal surface, at least two first regions and two second regions wherein said second regions have a greater mean fibril length than said first regions when fibril lengths are measured at the luminal surface of the tube.

3. A method according to claim 1 wherein the intraluminal graft occludes at least one tributary branch of the venous segment.

2. A method of holding leaflets of a venous valve in an open condition, comprising inserting a circumferentially distensible intraluminal graft into a segment of a vein and into a venous valve within the vein, and circumferentially distending the intraluminal graft, thereby holding open the leaflets of the venous valve, wherein the intraluminal graft comprises a porous PTFE tube having a microstructure of nodes interconnected by fibrils, said tube having a luminal surface, at least two first regions and two second regions having fibril lengths wherein said second regions have a greater mean fibril length than said first regions when fibril lengths are measured at the luminal surface of the tube.

4. A method according to claim 2 wherein the intraluminal graft occludes at least one tributary branch of the venous segment.