WO2025137375A1

WO2025137375A1 - Anchor detachment devices, systems, and methods

Info

Publication number: WO2025137375A1
Application number: PCT/US2024/061159
Authority: WO
Inventors: Sarah Louise GARCON; Trevor HUFFAKER; Jonathan Hwan OAKDEN; Jasper Ellington Adamek-Bowers
Original assignee: Shifamed Holdings LLC
Current assignee: Shifamed Holdings LLC
Priority date: 2023-12-19
Filing date: 2024-12-19
Publication date: 2025-06-26
Anticipated expiration: 2026-06-19

Abstract

Apparatuses and methods for delivering a delivery catheter. According to one embodiment, there is a delivery catheter, including: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion, the distal coupler being configured to be releasably coupled to a proximal coupler of a medical device anchor when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft; in which axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume a helical at-rest shape that disengages the proximal coupler from the distal coupler, in which the beveled edge of the distal coupler prevent locking of the distal coupler to the proximal coupler. Other embodiments are disclosed.

Description

ANCHOR DETACHMENT DEVICES, SYSTEMS, AND METHODS

PRIORITY CLAIM

[0001] This patent application claims priority to U.S. provisional patent application no. 63/612,184, entitled “ANCHOR DETACHMENT DEVICES, SYSTEMS, AND METHODS,” and filed on December 19, 2023, which is herein incorporated by reference in its entirety.

CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application is related to International Application No. PCT/US2023/068213, filed on June 9, 2023, entitled “PROSTHETIC HEART VALVE DELIVERY SYSTEM AND METHOD,” the entirety of which is incorporated herein by reference for all purposes.

INCORPORATION BY REFERENCE

[0003] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

BACKGROUND

[0004] Blood flow between heart chambers is regulated by native valves, i.e., the mitral valve, the aortic valve, the pulmonary valve, and the tricuspid valve. Each of these valves is a passive one-way valve that opens and closes in response to differential pressures. Patients with valvular disease have abnormal anatomy and/or function of at least one valve. For example, a valve may suffer from insufficiency, also referred to as regurgitation, when the valve does not fully close, thereby allowing blood to flow retrograde. Valve stenosis can cause a valve to fail to open properly. Other diseases may also lead to dysfunction of the valves.

[0005] The mitral valve, for example, sits between the left atrium and the left ventricle and, when functioning properly, allows blood to flow from the left atrium to the left ventricle while preventing backflow or regurgitation in the reverse direction. Native valve leaflets of a diseased mitral valve, however, do not fully close, causing the patient to experience regurgitation.

[0006] While medications may be used to treat diseased native valves, the defective valve may need to be repaired or replaced at some point during the patient’s lifetime. [0007] Problematically, during valve replacement, the deployment of medical devices such as medical anchor catheters may utilize couplers that become locked or not easily released from other components such as tether assemblies that guide medical devices to a target site, for example via an elongate catheter shaft.

[0008] What is needed is a coupler that facilitates disengagement of a medical device at a target site as the medical device is deployed, for example pursuant to being deployed from an elongate catheter shaft.

SUMMARY OF THE DISCLOSURE

[0009] Described herein are systems, devices, and methods for treatment or replacement of a diseased native valve of the heart, such as the mitral valve, and specifically, apparatuses and methods for anchor detachment of a medical device anchor. According to one embodiment of the present invention, there is a delivery catheter, including: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion, the distal coupler being configured to be releasably coupled to a proximal coupler of a medical device anchor when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft; in which axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume a helical at-rest shape that disengages the proximal coupler from the distal coupler, in which the beveled edge of the distal coupler prevent locking of the distal coupler to the proximal coupler.

[00010] According to another example, the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter.

[0010] According to yet another example, the releasable coupling of the distal coupler with the proximal coupler occurs via interlocking between a distal tooth portion of a second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

[0011] According to yet another example, a distal tooth portion of the first coupling portion of the distal coupler releasably couples with a recess portion of the second coupling portion of the proximal coupler.

[0012] According to yet another example, the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

[0013] According to yet another example, distal and proximal orientations of the couplers are reversed.

[0014] According to another embodiment of the present invention, there is a medical device delivery system, including: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; a medical device anchor adapted to be inserted into the elongate catheter shaft, the anchor having a proximal coupler with a second coupling portion configured to mate with the first coupling portion of the distal coupler, the medical device anchor having a generally elongate delivery configuration when it is disposed within the elongate catheter shaft and a generally curved at-rest configuration when it is deployed from the elongate catheter shaft; in which axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume the generally curved at-rest configuration that disengages the proximal coupler from the distal coupler, in which the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler.

[0015] According to yet another example, the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter.

[0016] According to yet another example, the mating of the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler occurs via interlocking between a distal tooth portion of the second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

[0017] According to yet another example, a distal tooth portion of the first coupling portion of the distal coupler mates with a recess portion of the second coupling portion of the proximal coupler.

[0018] According to yet another example, the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

[0019] According to yet another example, distal and proximal orientations of the couplers are reversed.

[0020] These and other examples are described herein. [0021] All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein.

[0022] In some aspects, a delivery catheter is provided, comprising: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion, the distal coupler being configured to be releasably coupled to a proximal coupler of a medical device anchor when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft; wherein axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume a curved at-rest shape that disengages the proximal coupler from the distal coupler, wherein the beveled edge of the distal coupler prevents locking or binding of the distal coupler to the proximal coupler.

[0023] In some aspects, the curved at-rest shape comprises a helical shape.

[0024] In other aspects, a proximal protrusion of the proximal coupler is configured to be received within the first coupling portion of the distal coupler adjacent to the beveled edge when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft.

[0025] In one aspect, the proximal protrusion of the proximal coupler rotates into a space provided by the beveled edge of the distal coupler when the distal coupler is advanced beyond the distal end.

[0026] In additional aspects, the elongate catheter shaft comprises an anchor control catheter disposed within an inner steerable catheter, which is disposed within an outer steerable catheter.

[0027] In some aspects, the anchor control catheter is configured to be translated axially beyond a distal end of the inner steerable catheter.

[0028] In other aspects, the anchor control catheter assumes a helical configuration when translated axially beyond the distal end.

[0029] In one aspect, the anchor control catheter is configured to be used as an encircling tool which decouples the medical device anchor from directly encircling a target anatomy. [0030] A medical device delivery system is also provided, comprising: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; a medical device anchor adapted to be inserted into the elongate catheter shaft, the anchor having a proximal protrusion configured to mate with the first coupling portion of the distal coupler, the medical device anchor having a generally elongate delivery configuration when it is disposed within the elongate catheter shaft and a generally curved at-rest configuration when it is deployed from the elongate catheter shaft; wherein axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume the generally curved at-rest configuration that disengages the proximal coupler from the distal coupler, wherein the beveled edge of the distal coupler prevents locking or binding of the distal coupler to the proximal coupler. [0031] In some aspects, the curved at-rest shape comprises a helical shape.

[0032] In other aspects, a proximal protrusion of the proximal coupler is configured to be received within the first coupling portion of the distal coupler adjacent to the beveled edge when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft.

[0033] In one aspect, the proximal protrusion of the proximal coupler rotates into a space provided by the beveled edge of the distal coupler when the distal coupler is advanced beyond the distal end.

[0034] In additional aspects, the elongate catheter shaft comprises an anchor control catheter disposed within an inner steerable catheter, which is disposed within an outer steerable catheter.

[0035] In some aspects, the anchor control catheter is configured to be translated axially beyond a distal end of the inner steerable catheter.

[0036] In other aspects, the anchor control catheter assumes a helical configuration when translated axially beyond the distal end.

[0037] In one aspect, the anchor control catheter is configured to be used as an encircling tool which decouples the medical device anchor from directly encircling a target anatomy. [0038] A method of delivering a delivery catheter is also provided, the method comprising: slidably disposing a tether assembly in an elongate catheter shaft having an opening at a distal end thereof, wherein the tether assembly has a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; constraining the distal coupler to a proximal coupler of a medical device inside the elongate shaft, wherein the constraining releasably couples the distal coupler to a proximal coupler of a medical device anchor; moving, via axial movement, the distal coupler beyond the distal end of the elongate catheter shaft, wherein the movement of the distal coupler beyond the distal end allows the medical device anchor to assume a helical at-rest shape; and disengaging the proximal coupler from the distal coupler via the medical device anchor assuming the helical at-rest shape, wherein the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler. [0039] In some aspects, the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter. [0040] In other aspects, the releasable coupling of the distal coupler with the proximal coupler occurs via interlocking between a distal tooth portion of a second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

[0041] In some aspects, a distal tooth portion of the first coupling portion of the distal coupler releasably couples with a recess portion of the second coupling portion of the proximal coupler.

[0042] In one aspect, the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

[0043] In additional aspects, distal and proximal orientations of the couplers are reversed.

[0044] A method of delivering a medical device is also provided, the method comprising: slidably disposing a tether assembly in an elongate catheter shaft having an opening at a distal end thereof, wherein the tether assembly has a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; disposing a medical device anchor into the elongate catheter shaft, the anchor having a proximal coupler with a second coupling portion configured to mate with the first coupling portion of the distal coupler, the anchor having a generally elongate delivery configuration when disposed within the elongate shaft and a generally curved at-rest configuration when it is deployed from the elongate catheter shaft; mating the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler of the tether assembly; moving, via axial movement, the distal coupler beyond the distal end of the elongate catheter shaft, wherein the movement of the distal coupler beyond the distal end allows the medical device anchor to assume the generally curved at-rest configuration; and disengaging the proximal coupler from the distal coupler via the medical device anchor assuming the generally curved at-rest configuration, wherein the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler.

[0045] In some aspects, the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter. [0046] In other aspects, the mating of the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler occurs via interlocking between a distal tooth portion of the second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

[0047] In some aspects, a distal tooth portion of the first coupling portion of the distal coupler mates with a recess portion of the second coupling portion of the proximal coupler. [0048] In other aspects, the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

[0049] In one aspect, distal and proximal orientations of the couplers are reversed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] A better understanding of the features and advantages of the methods and apparatuses described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments, and the accompanying drawings of which:

[0051] FIG. 1 illustrates an example schematic prosthetic mitral valve in place in a patient’s heart.

[0052] FIGS. 2A-2B illustrate an example anchor delivery subsystem.

[0053] FIGS. 3A and 3B illustrate an example of a spiral guide arm.

[0054] FIGS. 4A and 4B illustrate an example of a helical guide arm.

[0055] FIGS. 5A-5B illustrate details of an example anchor.

[0056] FIG. 6A illustrates a coupled tether assembly and medical device anchor disposed in an elongate catheter shaft.

[0057] FIG. 6B illustrates uncoupling of a medical device anchor from a tether assembly upon exiting an elongate catheter shaft.

[0058] FIGS. 6C-6D show additional views of a coupled tether assembly and medical device anchor.

[0059] FIG. 7 is a flow chart depicting a method for delivering a delivery catheter.

[0060] FIGS. 8A-8B is a flow chart depicting a method of delivering a medical device.

[0061] FIGS. 9A-9B illustrate one example of the anchor coupling and decoupling from the tether assembly facilitated by the beveled edge of the distal tether connector.

DETAILED DESCRIPTION

[0062] This disclosure is directed to a delivery system for a prosthetic heart valve that has two main components: an anchor adapted to be disposed in a ventricle adjacent a native valve of a patient’s heart and a frame supporting prosthetic valve leaflets adapted to be delivered after delivery of the anchor and then expanded within the anchor. In particular, the valve is a prosthetic mitral valve, and the delivery system of this invention delivers the valve’s two components transeptally. In use, the delivery system advances distally from an entry point in the patient’s femoral vein, enters the right atrium of the heart, and passes through the septum into the left atrium to implant the anchor and then expand the valve frame inside the anchor.

[0063] Because the anatomy of the heart may differ from patient to patient, it may be desirable to be able to control the movement, position, and/or orientation of the delivery system while delivering and implanting the anchor and the valve frame. It may also be necessary to retrieve the anchor and/or the valve during implantation if their position is not quite right. The prosthetic valve delivery system of this invention therefore provides mechanisms for navigating the anchor and the valve and for controllably releasing the anchor and the valve when they have been correctly placed.

[0064] Specifically, prior to releasing the anchor, the anchor may be reversibly coupled to a tether assembly and delivered via axial movement to a target site within an elongate catheter shaft. Upon reaching the targe site, the anchor may exit the elongate catheter shaft and its release facilitated by the anchor assuming a helical or curved at-rest shape outside of the catheter shaft that disengages the anchor from the tether assembly. Release of the anchor may be further facilitated by a beveled edge or other contours on the tether assembly that prevent locking or catching of the anchor during release.

[0065] FIG. 1 shows an exemplary prosthetic mitral valve 10 in place in a patient’s heart. Valve 10 includes an anchor 12 and a valve frame 14. Moveable leaflets (not shown) attached to the valve frame take the place, and perform the function, of the native valve leaflets. As shown, anchor 12 has been placed around chordae tendinae (“chordae” or “chords”) 20 and/or portions of native leaflets in the left ventricle 18. Valve frame 14 extends between the left atrium 16 and the left ventricle 18 through the native valve annulus 22.

[0066] The anchor 12 and valve frame 14 of valve 10 are implanted separately. Anchor 12 is delivered first and placed around the chordae 20. Valve frame 14 is thereafter delivered and expanded within anchor 12. In order to advance the valve components from an opening in the patient’s groin to the heart, the delivery system might need to be pushed, bent, and/or rotated to navigate the anatomy of the intervening vasculature. [0067] Because the anchor and the frame are delivered separately, the delivery system described herein has two main subsystems: an anchor delivery subsystem and a valve frame delivery subsystem.

[0068] FIGS. 2A-2B show aspects of an anchor delivery subsystem 30 having a proximal controller 32 and three nested catheters: An outer steering catheter 34, an inner steering catheter 36 movably disposed within the lumen of the outer steering catheter 34, and an anchor control catheter 38 movably disposed within the lumen of the inner steering catheter. A guide arm (not shown in FIGS. 2A-2B) extends from a distal end of the anchor control catheter, as described below. Also shown is a tether 42 releasably connected at its distal end to an anchor (not shown) movably disposed within the inner steering catheter 36. Outer steering catheter 34, inner steering catheter 36, and anchor control catheter 38 are all operatively connected to the proximal controller 32. While the proximal controller 32 is shown as a single component for ease of illustration, it should be understood that each of the nested catheters can include their own proximal controllers. An introducer sheath (not shown) may be used to introduce the three nested catheters into the patient’s vasculature. The introducer sheath can gain access to the left atrium over a guidewire.

[0069] FIGS. 3 A-4B are embodiments of guide arm 82 positioned at the distal end of anchor control catheter. In various embodiments, guide arm 82 can assume a spiral configuration (FIGS. 3A and 3B) and/or helical configuration (FIGS. 4A and 4B), such as the configuration it would controllably assume after emerging from the anchor control catheter in the left atrium of the heart. The geometry of the guide arm 82 provides a consistent selfassembly with a proven encircling geometry. As will be described in more detail, the anchor control catheter is used as an encircling tool which decouples the anchor itself from (e.g., direct) encircling. The anchor is then deployed from the guide arm into the anatomy.

[0070] FIGS. 5A-5B show details of anchor 88. When loaded into the anchor control catheter, anchor 88 assumes a generally straightened shape. In its unconstrained state after delivery from the anchor control catheter, as shown, anchor 88 assumes a ring-like, spiral, or helical shape, extending from a distal tip 124 to a proximal connector 126, where it releasably attaches to the tether of the anchor control catheter as described above.

[0071] FIG. 5B shows the anchor of FIG. 5 A including one or more layers of expanded polytetrafluoroethylene (ePTFE) disposed over the anchor, including at least partially over the distal tip 124 and the proximal connector 126 to provide a lubricious and biologically inert coating that protects the anatomy from damage or abrasions that could otherwise be caused by uncoated metal. While ePTFE is used in this embodiment, it should be understood that other similar materials can be used with the anchor. [0072] FIG. 6 A shows a schematic diagram of anchor control catheter 38 with tether 42 disposed therein and distal connector 630 bottomed out and abutting the anchor control catheter. FIG. 6B shows the proximal connector 626 of the anchor. Referring to FIGS. 6A- 6B, the distal connector 630 can include a first coupling portion 636, which can comprise, for example, a recess, groove, or indentation between distal protrusion 639 and beveled edge 638. The first coupling portion 636 can be configured to receive a corresponding proximal protrusion 637 of the proximal connector 626 of the anchor, while the distal protrusion 639 of the distal connector is received within second coupling portion 641 of the proximal connector.

[0073] As will be discussed in FIGS. 6C-6D, deployment of anchor 88 out of guide arm 82 of the anchor control catheter allows the anchor 88 to assume a pre-set or biased shape (e.g., a ring-like, spiral, or helical delivery configuration), causing release/decoupling of anchor 88 from the tether and the anchor delivery catheter system. This results in the anchor 88 being deployed and anchored around chordae and/or leaflets of the left ventricle with no connection to any other system component (e.g., no tether or other linkage is left behind when the anchor 88 is deployed). When the anchor is still contained within the anchor control catheter, the proximal connector 626 of the anchor (corresponding to proximal connector 126 in FIG. 5A) is connected to, coupled to, or attached to a distal connector of the tether of the anchor control catheter. The proximal connector of the anchor is designed and configured to release from the distal connector of the tether without binding to allow for a smooth delivery of the anchor into the anatomy.

[0074] FIG. 6C illustrates a coupling or attachment between distal connector 630 of the tether of the delivery subsystem and proximal connector 626 of the anchor. The coupling between these two connectors is shown disposed within the shaft of the anchor control catheter 38 or guide arm 82. According to one example, the coupling is accomplished via the distal connector 630 having a first coupling portion 636 that couples or interlocks with proximal protrusion 637 of the proximal connector 626 of the anchor. According to certain examples, first coupling portion 636 of distal connector 630 may be a recess, groove, or indentation to receive proximal protrusion 637, which may be a raised portion, a tooth-shaped portion, a hook shaped portion, or any other projection. According to yet other examples, different or additional connection points may exist between distal connector 630 and the proximal connector 626 of the anchor. For example, distal protrusion 639 of distal connector 630 may be configured to couple to or slot within a second coupling portion 641 of the proximal connector 626, such as a recess on the proximal connector of the anchor. [0075] When the distal connector of the tether is coupled to the proximal connector of the anchor, the proximal and distal connectors can maintain coupling when they are confined or constrained within a lumen of an inner lumen of the anchor control catheter, the guide arm, and/or the inner or outer catheters described above. In one example, once coupling has occurred, the tether and distal connector 630 may be translated within the lumen, with respect to the anchor control catheter, to push or pull the proximal connector 626 and the anchor in a desired direction. Arrow 606 represents forward axial movement 806 through the lumen within the anchor control catheter 38 and/or guide arm 82.

[0076] When the tether and distal connector 630 are advanced axially beyond a distal opening of the guide arm 82, the proximal and distal connectors are no longer constrained together by the lumen of the anchor control catheter/guide arm. This allows the anchor to assume its pre-biased shape (e.g., a ring-like shape, a spiral, or helical shape). Since the anchor assumes a linear or elongated shape when constrained within the anchor control catheter, movement towards the pre-biased shape causes the proximal connector of the anchor to curve or bend radially inwards towards this pre-biased shape.

[0077] According to certain examples, the distal connector 630 of the tether may have a beveled edge 638, which according to certain examples may be proximal to first coupling portion 636 of distal connector 630 and proximal to the proximal protrusion 637 of the proximal connector 626. Beveled edge 638 may assist or allow for uncoupling of the proximal connector 626 of the anchor from distal connector 630 of the tether by preventing locking or obstruction of proximal connector 626 of the anchor when the anchor transitions from the elongated or linear delivery configuration towards the pre-biased curved, ring-like, spiral, or helical shape. The beveled edge provides additional room or space for the distal connector to bend or release from the proximal connector. Without the beveled edge, the distal connector can bind or become stuck inside the proximal connector, preventing release, and therefore preventing deployment or disconnection of the anchor and proximal connector from the distal connector.

[0078] While the beveled edge 638 is shown on the distal connector of the tether, it should be understood that in other embodiments the beveled edge could be on the proximal connector of the anchor, or alternatively on both the proximal connector and the distal connector.

[0079] FIG. 6D illustrates uncoupling 612 of the proximal connector 626 of the anchor from distal connector 630 of the tether upon exiting the guide arm 82. As shown here, axial movement 808 of the tether in the anchor control catheter moves distal connector 630 and proximal connector 626 of the anchor outside of the guide arm 82, and into, for example, a target delivery site. According to certain examples, the anchor may assume a ring-like, helical, spiral, or curved at-rest shape when implanted in the anatomy. Assuming such a shape when the anchor is moved outside of the guide arm 82 causes the proximal connector 626 of the anchor to deflect or arc away from the distal connector of the tether (as shown by arrow 612), releasing or uncoupling the proximal connector 626 of the anchor from the distal connector 630, thus releasing the anchor from the guide arm and anchor delivery catheter. According to certain examples, beveled edge 638 of distal connector 630 may facilitate uncoupling by preventing locking or catching of proximal protrusion 637 of the proximal connector 626 within first coupling portion 636 of the distal connector 630.

[0080] To deliver an anchor to a patient’s heart with the systems described above, the outer steerable catheter and inner steerable catheter are used to navigate the delivery system within a sheath to the patient’s right atrium RA and through the septum to the left atrium LA. The anchor control catheter includes flexibility and smooth rotational control of the catheter across the septum. The guide arm of the anchor control catheter is then advanced out of the distal end of the inner steerable catheter where it assumes a spiral shape or helical shape under the control of the shape set of the intermediate part of control arm and the control of the distal part of control arm by actuation catheter (not shown). The anchor also fully selfassembles and assumes it is at-rest shape within the guide arm of the anchor control catheter within the left atrium. When positioned with its distal end generally adjacent to the distal end of the anchor control catheter, the smaller radius or profile of the anchor with respect to the distal arm radius drives a smaller self-assembly envelope of the anchor control catheter within the left atrium.

[0081] Using the inner steerable catheter for steering under fluoroscopic visualization, the spiral or helical portion of the anchor control catheter is then advanced through the leaflets of the native valve into the left ventricle LV. Using the actuation catheter to extend the distal tip of guide arm radially outwards from the guide arm, the anchor control catheter is rotated within the left ventricle to advance guide arm between the chordae and the heart wall with the anchor still inside the anchor control catheter. The chordae can then be encircled with the guide arm for at least the full length of the anchor (e.g., approximately 1.5 full turns). To fully deploy the anchor in the left ventricle, the anchor control catheter is withdrawn from the anchor while holding tether (not shown) stationary. The anchor control catheter (not shown) is withdrawn into the inner steerable catheter (not shown) until the distal end clears the proximal end of the anchor. The tether is then decoupled from the anchor without binding due to the beveled edge on the distal connector of the tether of the anchor control catheter, the inner steerable catheter is withdrawn into the outer steerable catheter, and the anchor delivery subsystem is withdrawn from the patient. The anchor does not lose chordae and remains stable during anchor control catheter retraction. The anchor control catheter retraction is a simple process.

[0082] FIG. 7 is a flow chart depicting a method for delivering a delivery catheter 700.

[0083] Method 700 begins at block 705, with a tether assembly being slidably disposed in an elongate catheter shaft having an opening at a distal end thereof, in which the tether assembly has a distal coupler with a first coupling portion and a beveled edge near the first coupling portion.

[0084] Method 700 continues at block 710 with constraining the distal coupler to a proximal coupler of a medical device inside the elongate shaft, wherein the constraining releasably couples the distal coupler to a proximal coupler of a medical device anchor.

[0085] Next, at block 715, the distal coupler is moved, via axial movement, beyond the distal end of the elongate catheter shaft, in which the movement of the distal coupler beyond the distal end of the elongate catheter shaft allows the medical device anchor to assume a helical at-rest shape.

[0086] Finally, at block 720, the proximal coupler is disengaged from the distal coupler via the medical device anchor assuming the helical at-rest shape, in which the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler.

[0087] According to another embodiment of method 700, the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter.

[0088] According to yet another embodiment of method 700, the releasable coupling of the distal coupler with the proximal coupler occurs via interlocking between a distal tooth portion of a second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

[0089] According to yet another embodiment of method 700, a distal tooth portion of the first coupling portion of the distal coupler releasably couples with a recess portion of the second coupling portion of the proximal coupler.

[0090] According to yet another embodiment of method 700, the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

[0091] According to yet another embodiment of method 700, distal and proximal orientations of the couplers are reversed. [0092] FIGS. 8A-8B is a flow chart depicting a method of delivering a medical device 800-801.

[0093] Method 800-801 begins at block 805 by slidably disposing a tether assembly in an elongate catheter shaft having an opening at a distal end thereof, in which the tether assembly has a distal coupler with a first coupling portion and a beveled edge near the first coupling portion.

[0094] Method 800-801 continues at block 810 with disposing a medical device anchor into the elongate catheter shaft, the anchor having a proximal coupler with a second coupling portion configured to mate with the first coupling portion of the distal coupler, the anchor having a generally elongate delivery configuration when disposed within the elongate shaft and a generally curved at-rest configuration when it is deployed from the elongate catheter shaft.

[0095] Method 800-801 continues at block 815 with mating the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler of the tether assembly.

[0096] Next, method 800-801 continues at block 820 with moving, via axial movement, the distal coupler beyond the distal end of the elongate catheter shaft, in which the movement of the distal coupler beyond the distal end allows the medical device anchor to assume the generally curved at-rest configuration.

[0097] Method 800-801 continues at FIG. 8B.

[0098] At block 825, method 800-801 disengages the proximal coupler from the distal coupler via the medical device anchor assuming the generally curved at-rest configuration, in which the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler.

[0099] According to another embodiment of method 800-801, the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter.

[00100] According to yet another embodiment of method 800-801, the mating of the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler occurs via interlocking between a distal tooth portion of the second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

[00101] According to yet another embodiment of method 800-801, a distal tooth portion of the first coupling portion of the distal coupler mates with a recess portion of the second coupling portion of the proximal coupler. [00102] According to yet another embodiment of method 800-801, the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

[00103] According to yet another embodiment of method 800-801, distal and proximal orientations of the couplers are reversed.

[00104] FIGS. 9A-9B illustrate one example of the anchor coupling and decoupling from the tether assembly facilitated by the beveled edge of the distal tether connector 930. As shown in FIG. 9 A, when the anchor begins to detach or decouple from the distal connector of the tether, the anchor and proximal connector 926 can begin to rotate relative to the tether, causing the proximal connector of the anchor to rotate into the beveled edge of the distal connector. Referring to FIG. 9B, this rotation is more relevant as the axis of the proximal connector is rotated more relative to the distal connector. This beveled edge allows for free release of the anchor from the tether, allowing the anchor to be delivered and left behind in the desired anatomy.

[00105] The valve delivery subsystem is a low profile valve delivery system that allows control of valve position until the very end of the delivery procedure. The valve delivery subsystem is a true 28Fr delivery profile with steerability that allows for familiar and easy positioning of the valve frame in the target location. The valve delivery subsystem allows for deployment of the collapsed or compressed valve frame within an already deployed anchor. Expansion of the valve frame structure captures the anchor and controls the final anchor position. Emphasis has been provided above that it is desirable to have the anchor deployed in a “high” position towards the left atrium so as to avoid LVOTO. While the anchor position can be controlled with the anchor delivery subsystem, it should also be understood that the anchor position can be adjusted or pulled upwards with the valve delivery subsystem after the valve has been allowed to expand within the anchor.

[00106] This disclosure provides details around a forgiving mitral valve replacement procedure and system specifically designed for the mitral anatomy. The systems and methods disclosed herein solve for an unmet need by providing a delivery system and delivery procedure that is familiar to physicians with a small learning curve, an implant that is adaptable and applicable to all anatomies, and an implant that reliable eliminates mitral regurgitation (MR) without the risk of complications associated with other mitral valve replacement devices on the market.

[00107] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[00108] The process parameters and sequence of steps described and/or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and/or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed. The various example methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

[00109] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected,” "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected,” "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature. [00110] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a,” "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as "/".

[00111] Spatially relative terms, such as "under,” "below,” "lower,” "over,” "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly,” "downwardly,” "vertical,” "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[00112] Although the terms “first” and “second” may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.

[00113] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise,” and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

[00114] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and/or steps may alternatively be exclusive, and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps. [00115] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, a numeric value may have a value that is +/- 0.1% of the stated value (or range of values), +/- 1% of the stated value (or range of values), +/- 2% of the stated value (or range of values), +/- 5% of the stated value (or range of values), +/- 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[00116] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[00117] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

[00118] In operation, a prosthetic valve system according to embodiments of the present disclosure is delivered and implanted as follows. An anchor delivery catheter that carries the anchor in a delivery configuration is advanced transeptally to the left atrium. The distal portion (e.g., guide arm) of the anchor delivery catheter, along with the anchor contained therein, self-assemble into an encircling configuration. The anchor delivery catheter is advanced through the valve into the ventricle of the heart. The clinician is provided with independent control of rotation, radial extent (“reach”), and axial position (“height”) of the guide arm to encircle native tissue (e.g., leaflets and/or chordae). Upon determination of satisfactory encircling, the anchor delivery catheter is removed and the anchor is left in place (e.g., solely in the ventricle) with the encircled tissue contained (e.g., radially) therein. In some embodiments, the anchor is (e.g., fully) deployed from the delivery system into the heart, the anchor is completely released with no tether or other connection to other devices prior to valve deployment. The anchor is stably positioned by circumscribing and gently gathering chordae/leaflets in the ventricle, while being completely free from (e.g., anchor) delivery system interaction once deployed. The inner diameter of the untethered anchor provides a target through which a guidewire is placed, with the valve delivery system advanced along the guidewire. All of the above features provide fine-tuned control of encircling device, and easy reversibility and safety and re-encircling without undue risk to patient tissue. The valve is deployed in a stepwise or piecewise manner. For example, first the ventricular portion of the frame is expanded into the anchor, allowing engagement between the outflow and/or central waist portion of the frame and the anchor. This allows the clinician to “pull” or raise the anchor (and optionally the valve) up into or towards the annulus. Then the atrial side of the frame is self-expanded, firmly fixing the prosthetic valve into the anatomy in combination with the anchor positioned about a waist of the prosthetic valve. The open (free) ends of the anchor enable it to resize as the self-expanding valve is expanded therein. The stiffness of the anchor in its (e.g., initial) deployed state is selected to be such that the expansion force of the self-expanding valve can modify the (e.g., radial) dimension of the anchor to ensure the valve achieves its target size. For example, the radial dimension of the deployed anchor can increase to accommodate and conform to the self-expanded valve perimeter. Further, the anchor interaction with the expanding valve is such that, during partial deployment of the valve, an axial position of the anchor with respect to the valve body (and/or the native anatomy) can be altered, with no appreciable friction or resistance to the valve body and/or native anatomy. Upon full expansion of the valve into the anchor and anatomy, the anchor is securely coupled to firmly hold its position and maintain chordae/leaflets containment (e.g., encircling) against the valve frame. Separating the anchor delivery from the frame delivery provides a purpose-built system for mitral replacement, achieving a true 28F delivery system.

Claims

CLAIMS What is claimed is:

1. A delivery catheter, comprising: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion, the distal coupler being configured to be releasably coupled to a proximal coupler of a medical device anchor when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft; wherein axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume a curved at-rest shape that disengages the proximal coupler from the distal coupler, wherein the beveled edge of the distal coupler prevents locking or binding of the distal coupler to the proximal coupler.

2. The delivery catheter of claim 1, wherein the curved at-rest shape comprises a helical shape.

3. The delivery catheter of claim 1, wherein a proximal protrusion of the proximal coupler is configured to be received within the first coupling portion of the distal coupler adjacent to the beveled edge when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft.

4. The delivery catheter of claim 3, wherein the proximal protrusion of the proximal coupler rotates into a space provided by the beveled edge of the distal coupler when the distal coupler is advanced beyond the distal end.

5. The delivery catheter of claim 1, wherein the elongate catheter shaft comprises an anchor control catheter disposed within an inner steerable catheter, which is disposed within an outer steerable catheter.

6. The delivery catheter of claim 5, wherein the anchor control catheter is configured to be translated axially beyond a distal end of the inner steerable catheter.

7. The delivery catheter of claim 6, wherein the anchor control catheter assumes a helical configuration when translated axially beyond the distal end.

8. The delivery catheter of claim 7, wherein the anchor control catheter is configured to be used as an encircling tool which decouples the medical device anchor from directly encircling a target anatomy.

9. A medical device delivery system, comprising: an elongate catheter shaft having an opening at a distal end thereof; and a tether assembly slidably disposed in the elongate catheter shaft and having a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; a medical device anchor adapted to be inserted into the elongate catheter shaft, the anchor having a proximal protrusion configured to mate with the first coupling portion of the distal coupler, the medical device anchor having a generally elongate delivery configuration when it is disposed within the elongate catheter shaft and a generally curved at-rest configuration when it is deployed from the elongate catheter shaft; wherein axial movement of the distal coupler beyond the distal end allows the medical device anchor to assume the generally curved at-rest configuration that disengages the proximal coupler from the distal coupler, wherein the beveled edge of the distal coupler prevents locking or binding of the distal coupler to the proximal coupler.

10. The medical device delivery system of claim 9, wherein the curved at-rest shape comprises a helical shape, a ring-like shape, or a spiral shape.

11. The medical device delivery system of claim 9, wherein a proximal protrusion of the proximal coupler is configured to be received within the first coupling portion of the distal coupler adjacent to the beveled edge when the distal coupler and the proximal coupler are constrained together inside the elongate catheter shaft.

12. The medical device delivery system of claim 11, wherein the proximal protrusion of the proximal coupler rotates into a space provided by the beveled edge of the distal coupler when the distal coupler is advanced beyond the distal end.

13. The medical device delivery system of claim 9, wherein the elongate catheter shaft comprises an anchor control catheter disposed within an inner steerable catheter, which is disposed within an outer steerable catheter.

14. The medical device delivery system of claim 13, wherein the anchor control catheter is configured to be translated axially beyond a distal end of the inner steerable catheter.

15. The medical device delivery system of claim 14, wherein the anchor control catheter assumes a helical configuration when translated axially beyond the distal end.

16. The medical device delivery system of claim 15, wherein the anchor control catheter is configured to be used as an encircling tool which decouples the medical device anchor from directly encircling a target anatomy.

17. A method of delivering a delivery catheter, the method comprising: slidably disposing a tether assembly in an elongate catheter shaft having an opening at a distal end thereof, wherein the tether assembly has a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; constraining the distal coupler to a proximal coupler of a medical device inside the elongate shaft, wherein the constraining releasably couples the distal coupler to a proximal coupler of a medical device anchor; moving, via axial movement, the distal coupler beyond the distal end of the elongate catheter shaft, wherein the movement of the distal coupler beyond the distal end allows the medical device anchor to assume a helical at-rest shape; and disengaging the proximal coupler from the distal coupler via the medical device anchor assuming the helical at-rest shape, wherein the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler.

18. The method of claim 17, wherein the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter.

19. The method of claim 17, wherein the releasable coupling of the distal coupler with the proximal coupler occurs via interlocking between a distal tooth portion of a second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

20. The method of claim 19, further wherein a distal tooth portion of the first coupling portion of the distal coupler releasably couples with a recess portion of the second coupling portion of the proximal coupler.

21. The method of claim 19, wherein the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

22. The method of claim 17, wherein distal and proximal orientations of the couplers are reversed.

23. A method of delivering a medical device, the method comprising: slidably disposing a tether assembly in an elongate catheter shaft having an opening at a distal end thereof, wherein the tether assembly has a distal coupler with a first coupling portion and a beveled edge near the first coupling portion; disposing a medical device anchor into the elongate catheter shaft, the anchor having a proximal coupler with a second coupling portion configured to mate with the first coupling portion of the distal coupler, the anchor having a generally elongate delivery configuration when disposed within the elongate shaft and a generally curved at-rest configuration when it is deployed from the elongate catheter shaft; mating the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler of the tether assembly; moving, via axial movement, the distal coupler beyond the distal end of the elongate catheter shaft, wherein the movement of the distal coupler beyond the distal end allows the medical device anchor to assume the generally curved at-rest configuration; and disengaging the proximal coupler from the distal coupler via the medical device anchor assuming the generally curved at-rest configuration, wherein the beveled edge of the distal coupler prevents locking of the distal coupler to the proximal coupler.

24. The method of claim 23, wherein the elongate catheter shaft is part of a delivery catheter, the tether assembly is an anchor catheter, and the medical device catheter is an anchor control catheter.

25. The method of claim 23, wherein the mating of the second coupling portion of the proximal coupler of the medical device anchor with the first coupling portion of the distal coupler occurs via interlocking between a distal tooth portion of the second coupling portion of the proximal coupler and a counterpart recess portion of the first coupling portion of the distal coupler adjacent to the beveled edge.

26. The method of claim 25, further wherein a distal tooth portion of the first coupling portion of the distal coupler mates with a recess portion of the second coupling portion of the proximal coupler.

27. The method of claim 25, wherein the beveled edge of the distal coupler of the tether assembly is inferior and lateral to the counterpart recess portion of the first coupling portion of the distal coupler, wherein the beveled edge forms a wall lateral to the distal tooth portion of the second coupling portion of the proximal coupler.

28. The method of claim 23, wherein distal and proximal orientations of the couplers are reversed.