Body lumen closure
Method and apparatus implementing and using techniques for body lumen closure, including use of an implantable medical closure device. The device includes a flexible strand defining an arcuate form. The strand is deformable upon implantation from a large cross-section condition to a small cross-section condition and has at least two anchoring portions disposed along the strand. The anchoring portions are configured to penetrate a wall of a body lumen such that when the strand is deformed to the small cross-section condition, the wall of the body lumen is disposed inwardly.
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This application is a continuation of U.S. application Ser. No. 10/115,552, filed Apr. 3, 2002, the specification of which is incorporated herein by reference.
BACKGROUND A venous valve functions to prevent retrograde flow of blood and allow only antegrade flow of blood to the heart. Referring to
In a first aspect, the invention features an implantable medical closure device. The device includes a flexible strand defining an arcuate form. The strand is deformable upon implantation from a large cross-section condition to a small cross-section condition and has at least two anchoring portions disposed along the strand. The anchoring portions are configured to penetrate a wall of a body lumen such that when the strand is deformed to the small cross-section condition, the wall of the body lumen is disposed inwardly.
The strand can also be deformable from a second small cross-section condition to the large cross-section condition, for example, the strand may be deformed to the second small cross-section condition to facilitate delivery of the strand to a treatment site, where it is then deformed to the large cross-section condition upon implantation. The strand can include free ends, which free ends can include the anchoring portions of the strand. The strand can define an arc, a helix or can include linear leg portions. The strand can be a filament-form or a band and may be corrugated. The strand can deform from the large cross-section condition to the small cross-section condition by, for example, elastic recovery forces or thermal shape-memory effect. The strand can be formed of metal, for example, nitinol. The anchoring portions of the strand can include, for example, a loop or a barb.
In another aspect, the invention features a catheter system, which system includes a catheter for delivery into a lumen. The catheter includes an expander that can be operated between a small cross-section and a large cross-section. The catheter system also includes a closure device positioned about the expander. The closure device is a strand defining an arcuate form and including at least two anchoring portions configured to penetrate a wall of a body lumen. The closure device is deformable by the expander from a first small cross-section condition to a larger cross-section condition to dispose the closure device into engagement with the lumen wall. The closure device is further deformable to a second small cross-section condition, so that the wall of the body lumen is disposed inwardly.
The expander can take any convenient form, including, for example, an inflatable balloon, a mechanical expander or a leveraging device. The mechanical expander can include a two-part axial member having a first inner part connected to a first coiled spring and a second outer part connected to a second coiled spring. The closure device is mounted on the first and second coiled springs, and the first inner part of the axial member is rotatable to expand the first coiled spring and the second outer part of the axial member is rotatable to expand the second coiled spring. Expansion of the first and second coiled springs expands the closure device. Each coiled spring can include a distal end configured to fit within a groove formed on either end of the closure device.
The leveraging device can include a two-part axial member including a first outer part and a second inner part. A splayed cuff is connected to the distal end of the first outer part of the two-part axial member, and at least two flexible legs are connected to the distal end of the second inner part of the two-part axial member. The legs are flared outwardly to contact the distal end of the splayed cuff. The second inner part of the two-part axial member is moveable toward the splayed cuff such that the flexible legs and the splayed cuff expand radially. The closure device is positioned about the flexible legs and expansion of the flexible legs expands the closure device from a first small cross-section condition to a larger cross-section condition. The second inner part of the two-part axial member is also moveable away from the splayed cuff such that the flexible legs and the splayed cuff retract.
In another aspect, the invention features a method of treating a body lumen. The method includes delivering a closure device into a lumen and positioning the strand about the lumen such that a portion of the strand penetrates the wall of the lumen. The method further includes deforming the strand to a smaller cross-section condition such that the wall of the lumen is disposed inwardly. The strand can be positioned about the lumen such that an end of the strand extends through the wall of the lumen. The strand can be disposed on a catheter, which catheter is then delivered into the lumen. The catheter can include an expansion member.
Embodiments may have one or more of the following advantages. Closure of a body lumen can be achieved in a minimally invasive manner by delivery of a closure device to a treatment site using a catheter. The closure device may be partially installed within the lumen but configured to minimize profile and thus reduce impedance to the flow of body fluids through the lumen. The amount of lumen closure can be controlled by selecting the size and/or recovery force of the closure device.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION Referring to
Referring to
The closure device 20, in a radially compacted form, is positioned over the expander 38 in a deflated condition for delivery to the treatment site. Referring as well to
The closure device may be made of a thin elongate, filament form, such as a metal wire. The metal may be selected such that the device is elastically expandable from the compacted condition for delivery into a lumen to an expanded condition for implantation. Once implanted, elastic recovery of the wire contracts the device and the vessel wall. Suitable metals include elastic steels and superelastic alloy materials such as nitinol. The filament may also be a composite material, such as a composite wire. Superelastic metals and composite wires are described in Heath, U.S. Pat. No. 5,725,570, and Mayer, U.S. Pat. No. 5,800,511, the entire contents of both of which are incorporated herein by reference. The metal may also be a temperature-effect shape memory superelastic alloy that conforms to an implanted condition upon exposure to a controlled temperature, e.g. body temperature. Suitable shape memory alloys such as nitinol are discussed in Schetsky MacDonald “Shape Memory Alloys,” Encyclopedia of Chemical Technology (3rd ed) John Wiley and Sons, 1982, vol. 20, p. 726-736. The temperature of the device may be controlled, for example, by heating the expander or by heating the balloon inflation fluid. The wire may also be selected such that the device is plastically deformed from the compacted condition to an expanded condition for embedding the anchoring elements into the vessel wall, with some elastic recovery after the expansion to contract the wall. Alternatively, a mechanical gripper can be used to draw the anchoring portions inward. The filament may also be made of a flexible polymer. The device may be coated with a lubricious polymer or a drug. For example, the anchoring portions may include a tissue sealant to minimize bleeding and enhance vessel wall integrity in the penetration regions.
The anchoring portions can also take a number of different forms that permit the ends of the closure device to penetrate the wall of the blood vessel, and restrain the ends from re-entering the vessel. In the embodiment illustrated above, the device 20 is formed of an open-ended strand in the shape of an arc. This shape facilitates deflection of the ends of the strand so that they can be embedded in the vessel wall and also provides a small profile within the vessel, so that blood flow is not substantially impeded. As illustrated above, the body of the device, within the vessel, closely conforms to the inner wall of the lumen.
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The mechanical expander 135 expands by rotating the inner rod 134 to expand the first coil 129 and rotating the outer tube 133 to expand the second coil 128. The coils 128, 129 expand radially in opposite directions, exerting a radial force on the closure device 125, causing the anchoring portions 126 to penetrate a vessel wall. Once the closure device 125 is secured to the vessel wall, the mechanical expander 135 can be disengaged from the closure device 125 by sliding the mechanical expander 135 axially away from the closure device 125. The mechanical expander 135 is contracted by rotating the inner rod and outer tube in the opposite directions used for expansion, and is withdrawn from the vessel. Optionally, a retractable sheath can enclose the mechanical expander 135 and closure device 125 while positioning the assembly at the treatment site, which sheath is then retracted.
Referring to
Other embodiments are within the scope of the following claims. For example, a closure device may be used to treat vascular vessels at locations without a valve to constrict the vessel at a desired location and other body lumens outside the vascular system.
Claims
1. An implantable medical closure device, comprising:
- a flexible strand defining a continuous arcuate form having a first half with a first anchoring end and a second half with a second anchoring end, the first half and the second half being opposed relative a center line bisecting the flexible strand, where in a first state the flexible strand adjacent the first anchoring end and the second anchoring end provide for a tangential line that is parallel with the center line, and in a second state the flexible strand adjacent the first anchoring end and the second anchoring end provide for lines that are no longer parallel with the center line.
2. The device of claim 1, where the flexible strand is formed of a material that can provide a force to move the first anchoring end and the second anchoring end toward the first state.
3. The device of claim 2, where the material is a metal.
4. The device of claim 3, where the metal is nitinol.
5. The device of claim 1, where the strand is a filament-form.
6. The device of claim 1, where the first anchoring end and the second anchoring end include a barb.
7. The device of claim 1, where the flexible strand is a flexible polymer.
8. The device of claim 1, where the flexible strand defines at least one loop for the continuous arcuate form.
9. An implantable medical closure device, comprising:
- a flexible member having a first half and a second half that extend from a center line in a continuous arcuate form, and having a first anchoring end and a second anchoring end opposed to the first anchoring end across the center line, where in a first state the flexible strand adjacent the first anchoring end and the second anchoring end provide for a tangential line that is parallel with the center line, and in a second state the flexible strand adjacent the first anchoring end and the second anchoring end provide for lines that are no longer parallel with the center line.
10. The device of claim 9, where the flexible strand is formed of a material that can provide a force to move the first anchoring end and the second anchoring end toward the first state.
11. The device of claim 10, where the material is nitinol.
12. The device of claim 9, where the first anchoring end and the second anchoring end include a barb.
13. The device of claim 9, where the flexible strand defines at least one loop for the continuous arcuate form.
14. A catheter system, comprising:
- a catheter for delivery into a lumen, the catheter including an expander that can be operated between a small cross-section and a large cross-section; and
- a closure device positioned about the expander, the closure device comprising a flexible strand defining a continuous arcuate form having a first half and a second half that extend from a center line, the first half having a first anchoring end and the second half having a second anchoring end, where when the closure device is positioned on the expander in the small cross-section the flexible strand adjacent the first anchoring end and the second anchoring end provide for a tangential line that is parallel with the center line, and when the closure device is positioned on the expanded in the large cross-section, relative the small cross-section, the flexible strand adjacent the first anchoring end and the second anchoring end provide for lines that are no longer parallel with the center line.
15. The catheter system of claim 14, where the expander comprises an inflatable balloon.
16. The catheter system of claim 14, where the expander comprises a mechanical expander.
17. The catheter system of claim 14, where the expander comprises a leveraging device.
18. The catheter system of claim 17, where the leveraging device comprises:
- a two-part axial member including a first outer part and a second inner part;
- a splayed cuff connected to the distal end of the first outer part of the two-part axial member; and
- at least two flexible legs connected to the distal end of the second inner part of the two-part axial member and flared outwardly to contact the distal end of the splayed cuff.
19. The catheter system of claim 17, where the closure device is positioned about the flexible legs;
- the second inner part of the two-part axial member is moveable in a first direction such that the flexible legs are pressed against the splayed cuff causing the flexible legs and the splayed cuff to expand radially; and
- expansion of the flexible legs expands the closure device from the first small cross-section condition to the larger cross-section condition.
20. The catheter system of claim 19, where the second inner part of the two-part axial member is moveable in a second direction such that the flexible legs move away from the splayed cuff causing the flexible legs and the splayed cuff to retract.
Type: Application
Filed: Dec 7, 2005
Publication Date: Apr 20, 2006
Applicant:
Inventor: Sally Thornton (Marlborough, MA)
Application Number: 11/296,590
International Classification: A61F 2/24 (20060101);