Expandable polymeric stent with memory and delivery apparatus and method

• US 5,607,467 A
• Filed: 06/23/1993
• Issued: 03/04/1997
• Est. Priority Date: 09/14/1990
• Status: Expired due to Term

• Current Assignee: Michael Froix
• Original Assignee: Michael Froix
• Inventors: Froix, Michael
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/516,091
• Time in Patent Office: 1,350 Days
• Field of Search: 623/1, 623/11, 623/12, 606/191, 606/194, 606/195, 606/198, 600/36
• US Class Current: 623/1.19
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/94 Stents retaining their form, i.e. not being deformable, after placement in the predetermined place
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0042 using a fluid, e.g. circulating
• CPC Class Codes: A61F 2210/0047 heated by light
• CPC Class Codes: A61F 2220/0008 Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 31/041 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 31/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08L 33/06 of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
• CPC Class Codes: Y10S 623/903 Blood vessel
• CPC Class Codes: Y10S 623/921 Blood vessel

Abstract

Self-restrained stent for use in a lumen of a vessel of a patient having a body with the vessel therein, comprising a substantially cylindrical member formed of a plastic material having a built-in elastic predetermined diameter and having a memory provided therein of a diameter greater than the predetermined diameter. The plastic is characterized in that it will attempt to assume the greater diameter in its memory upon occurrence of one or more of the following conditions:

(a) adsorption of heat by the plastic material;

(b) adsorption of a liquid by the plastic material; and

(c) a change in the pH in the liquid in which the plastic member is disposed.

Claims

1. A self-restrained stent for use in the lumen defined by a wall of a vessel having a lumen therein of a patient, comprising a hollow substantially cylindrical member formed of a polymeric composition having an initial predetermined size which is less than the inside diameter of the lumen of the vessel so that the substantially cylindrical member can be inserted into the lumen of the vessel, said polymer composition forming said substantially cylindrical member having a transition characteristic therein whereby when the transition characteristic is activated the substantially cylindrical member will change its dimensions in all directions and assume a greater diameter than the initial predetermined diameter and come into engagement with the wall of the vessel to form a flow passage in the lumen of the vessel.

2. A stent as in claim 1 for use with a liquid wherein said transition characteristic is activated by the adsorption of heat by the polymeric composition.

3. A stent as in claim 1 for use with a liquid wherein the transition characteristic is activated by the adsorption of the liquid by the polymeric composition.

4. A stent as in claim 1 for use with a liquid having a change in pH wherein the transition characteristic is activated by the change in the pH of the liquid in which the polymeric composition is disposed.

5. A stent as in claim 1 wherein said polymeric composition is porous to facilitate the ingrowth of neointimal and endothelial vessel tissues.

6. A stent as in claim 1 together with a medical agent carried by the stent.

7. In the combination of a balloon catheter and a stent, a balloon catheter having a distal extremity with a balloon mounted thereon, the balloon catheter including a balloon inflation lumen for inflating and deflating the balloon, the balloon being in a deflated condition and a stent mounted over the deflated balloon and frictionally engaging the deflated balloon, the stent being characterized in that it is substantially cylindrical and self restrained with a predetermined diameter, said stent being formed of a biocompatible polymeric composition having a transition characteristic therein, whereby when the transition characteristic is activated the stent will change its dimensions in all directions and will attempt to assume a greater diameter than the predetermined diameter.

8. An apparatus as in claim 7 wherein said polymeric composition is porous.

9. An apparatus as in claim 7 together with means for introducing a heated liquid into the balloon for inflating the balloon and for transferring heat to the stent to activate the transition characteristic of the stent.

10. A self-restrained stent for use in a lumen defined by a wall of a vessel having a lumen therein of a patient comprising a hollow substantially cylindrical member formed of a plastic material having an initial built-in elastic predetermined diameter which is less than the diameter of the lumen in the vessel so that the substantially cylindrical member can be inserted into the lumen of the vessel, said plastic material of cylindrical member also having a memory based on a transition provided therein of a diameter greater than the initial built-in elastic predetermined diameter and at least as great as the diameter of the lumen of the vessel, said plastic being characterized in that it will change its dimensions in all directions and will assume the greater diameter in its memory and move into engagement with the wall of the vessel upon the occurrence of one or more of the following conditions selected from the group consisting of:

(a) adsorption of heat by the plastic material;

(b) adsorption of a liquid by the plastic material; and

(c) a change in the pH in the liquid in which the plastic member is disposed.