Shape memory tubular stent

• US 6,635,079 B2
• Filed: 09/27/2001
• Issued: 10/21/2003
• Est. Priority Date: 08/21/1998
• Status: Expired due to Fees

• Current Assignee: John Duncan Unsworth, Thomas Cole Waram
• Original Assignee: John Duncan Unsworth, Thomas Cole Waram
• Inventors: Waram, Thomas Cole, Unsworth, John Duncan
• Primary Examiner(s): Prebilic, Paul B.
• Assistant Examiner(s): GILPIN, CRYSTAL M
• Application Number:
  US09/963,782
• Publication Number:
  US 20020198584A1
• Time in Patent Office: 754 Days
• Field of Search: 623/1.39, 623/1.4, 623/1.44, 623/25, 623/1.11
• US Class Current: 623/1.11
• CPC Class Codes: A61F 2/856 Single tubular stent with a side portal passage
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/954 for placing stents or stent-grafts in a bifurcation
• CPC Class Codes: A61F 2002/065 Y-shaped blood vessels
• 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 2210/0047 heated by light

Abstract

A stent radially expandable from a radially contracted introduction state into a radially expanded position state, in which the final shape of the stent can be controlled by varying the amount and places energy is delivered onto the interior surfaces of the tubes from which the stent is fabricated, and means to seal the opening into the aneurysm, thereby causing the blood therein to clot and preventing the aneurysm from growing or rupturing.

Claims

1. A stent deployment system, comprising:

at least one radially expandable stent means having a proximal end, a distal end and a lumen, each said stent mean comprising a hollow, generally cylindrical member having a side surface comprising a mesh having a plurality of openings, said mesh being formed by at least one elongate member comprised of a material having shape memory characteristics, said at least on elongate member having a memorized shape which is recovered when said elongate ember is heated to a temperature above body temperature, said at least one elongate member having a lumen;

delivery means adapted convey the at least one stent means to a lumen of a vessel;

heating means adapted to heat at least a portion of said at least one elongate member to said temperature above body temperature to at least partially recover said memorized shape, the heating means comprising at least one optical fiber, each said optical fiber extending into the lumen of a respective one of said elongate members and being adapted to transmit photothermal energy onto at least part of an inner surface of the elongate member; and

sealing means to inhibit all or partly the flow of fluids or blood through the walls of the stent;

wherein said memorized shape is selected so that shape recovery of said at least one elongate member results in radial expansion of said at least one stent means inside the lumen of the vessel.

2. The stent deployment system of claim 1, wherein said at least one elongate member comprises a plurality of tubular members each having a proximal end and a distal end, the tubular members extending longitudinally along the stent means.

3. The stent deployment system of claim 2, wherein each of the tubular members is joined at a plurality of points along its length to two other of the tubular members.

4. The stent deployment system of claim 3, wherein the points are regularly spaced.

5. The stent deployment system of claim 4, wherein each of the tubular members defines a regular wave-form having alternating crests and valleys, and wherein the crests of each of the tubular members is joined to the valleys of another of the tubular members.

6. The stent deployment system of claim 5, wherein each tubular member has a memorized shape in which a difference in height between the crests and the valleys of the wave-form is greater than the difference in height when the stent means is in a radially compressed state.

7. The stent deployment system of claim 1, wherein said material having shape memory characteristics comprises a shape memory alloy having a martensite start temperature less than body temperature and an austenite finish temperature greater than human body temperature.

8. The stent deployment system of claim 1, wherein the delivery means comprises a delivery catheter having a proximal end and a distal end, and the at least one stent means is releasably attached to the distal end of the delivery catheter, with the distal end of the catheter extending into the lumen of the at least one stent means.

9. The stent deployment system of claim 8, wherein each said optical fiber enters the delivery catheter at the proximal end thereof and exits the delivery catheter through an orifice provided in the delivery catheter at a distal end thereof, the orifice being longitudinally spaced from the proximal end of the stent means, said catheter having at least one of said orifices.

10. The stent deployment system of claim 9, wherein the stent means is releasably connected to the delivery catheter by said at least one optical fiber, and wherein said at least one optical fiber is retractable into said orifice of the delivery catheter to thereby separate the stent means from the catheter.

11. The stent deployment system of claim 9, wherein said at least one stent means comprises at least two stent means, wherein a first of the stent means is provided longitudinally spaced from a second of the stent means, the first stent means being closer to the proximal end of the catheter than the second stent means.

12. The stent deployment system of claim 11, wherein each of the two stent means is directly connected to the delivery catheter by at least one of said optical fibers, and wherein the optical fibers are retractable into the delivery catheter to separate the stent means from the catheter.

13. The stent deployment system of claim 11, wherein the first stent means is releasably connected to the delivery catheter by said at least one optical fiber, and wherein said at least one optical fiber extends through the distal end of the first stent means and into the proximal end of the second stent means, thereby releasably connecting the first and second stent means to one another, the at least one optical fiber being retractable into the delivery catheter to separate the stent means from the catheter.

14. The stent deployment system of claim 13, wherein the first and second stent means are connected by at least one tubular member extending from the proximal end of the first stent means to the distal end of the second stent means.

15. The stent deployment system of claim 3, wherein the sealing means comprises one or more plates or a membrane, wherein the plates or the membrane are provided on an external surface of the side surface of the stent means and at least partially the openings.

16. The stent deployment system of claim 14 adapted to be received at a branch of said vessel, further comprising a third stent means having a distal end, a proximal end and a lumen, the proximal end of the third stent means positioned at a gap between said first and second stent means, said distal end of said catheter extending through said gap outwardly of the lumen of the third stent means, such that a longitudinal axis of said third stent means is angled relative to a longitudinal axis of the first and second stent means,

wherein said third stent means comprises a generally cylindrical member having a side surface comprising a mesh having a plurality of openings, said mesh being formed by at least one elongate member comprised of a material having shape memory characteristics, said at least one elongate member having a memorized shape which is recovered when said elongate member is heated to a temperature above body temperature,

wherein said third stent means is releasably connected to said distal end of said catheter by at least one of said optical fibers.

17. A stent deployment system, comprising:

at least one radically expandable stent means having a proximal end, a distal end and a lumen, each said stent means comprising a hollow, generally cylindrical member having a side surface comprising a mesh having a plurality of openings, said mesh being formed by at least one elongate member comprised of a material having shape memory characteristics, said at least one elongate member is heated to a temperature above body temperature said at least one elongate member having a lumen;

delivery means adapted to heat at least one stent means to a lumen of a vessel; and

heating means adapted to heat at least a portion of said at least one elongate member to said temperature above body temperature above body temperature to at least partially recover said memorized shape;

wherein said memorized shape is selected so that shape recovery of said at least one elongate member results in radical expansion of said at least one stent means inside the lumen of the vessel; and

wherein the heating means comprises at least one set of electrical contacts located inside the lumen of said at least one elongate member, each set of electrical contacts coming into contact with different parts of an inner surface of one of the elongate members and delivering an electrical potential between the said parts of contact to produce resistive heating of the elongate member approximately between the parts of contact.

19. The stent deployment system of claim 17, further comprising sealing means to inhibit all or partly the flow of fluids or blood through the walls of the stent.

20. The stent deployment system of claim 19, wherein the sealing means comprises one or more plates or a membrane, herein the plates or the membrane are provided on an external surface of the side surface of the stent means and at least partially cover the openings.

21. The stent deployment of claim 17, wherein each said set of contacts comprises a pair of contacts.

22. The stent deployment system of claim 17, wherein the contacts are attached to the inner surfaces of the at least on elongate member.

23. The stent deployment system of claim 17, wherein the contacts are slidable along the inner surfaces of the at leas one elongate member.

24. The stent deployment system of claim 17, wherein each said set of electrical contacts is attached to a flexible probe such that the contacts of each set are held in position relative to each other.

18. A method for sealing off aneurysms from the blood flow through a blood vessel having a lumen, thereby causing the blood or fluid within the aneurysm to clot and help prevent further damage to bodily tissue, the method comprising:

(a) providing a stent deployment system comprising;

at least one radially expandable stent means having a proximal end, a distal end and a lumen, each said stent means comprising a hollow, generally cylindrical member having a side surface comprising a mesh having a plurality of openings, said mesh being formed by at least one elongate member comprised of a material having shape memory characteristics, said at least one elongate member having a memorized shape which is recovered when said elongate member is heated to a temperature above body temperature, said at least one elongate member having a lumen;

delivery means adapted to convey the at least one stent means to a lumen of a vessel;

heating means adapted to heat at least a portion of said at least one elongate member to said temperature above body temperature to at least partially recover said memorized shape, the heating means being selected from the group consisting of at least one optical fiber located extending into the lumen of said at least one elongate member, and at least one set of electrical contacts located inside the lumen of said at least one elongate member; and

sealing means to inhibit all or partly the flow of fluids or blood through the walls of the stent;

herein said memorized shape is selected so that shape recovery of said at least one elongate member results in radial expansion of said at least one stent means inside the lumen of a blood vessel;

(b) using said delivery means to convey the stent means inside the lumen of the vessel to the aneurysm;

(c) using said heating means to heat at least a portion of the at least one elongate member to said temperature above body temperature, to at least partially recover said memorized shape and cause radial expansion of the stent means inside the lumen of the vessel so as to block off the aneurysm from the normal flow of blood through the vessel.