Prosthetic Heart Valve Delivery System: Ball-Sliding Attachment

Abstract

Systems, devices, and methods for attaching operator-operable tether(s) to a stent for loading and / or collapsing an expandable stent into a delivery catheter or sheath, translating the collapsed stent along the delivery catheter or sheath, delivering the expandable stent into a target heart chamber, repositioning the expandable stent within the target heart chamber as needed, recapturing or recoating the expandable stent within the delivery catheter or sheath as needed, and deploying the expandable stent in and to the target heart chamber.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Patent Application No. 17 / 158,475, filed January 26, 2021, and entitled "PROSTHETIC HEART VALVE DELIVERY SYSTEM: BALL-SLIDE ATTACHMENT," and U.S. Provisional Patent Application No. 62 / 968,216, filed January 31, 2020, and entitled "PROSTHETIC HEART VALVE DELIVERY SYSTEM: BALL SLIDE ATTACHMENT," both of which are incorporated herein by reference in their entireties.

[0002] [STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT] Not applicable

[0003] [Field of the Invention] The present invention relates to devices and methods for implanting devices within a cardiac chamber. [Background technology]

[0004] [Description of Related Art] Stents in general, and prosthetic heart valves and left atrial appendage occlusion devices in particular, are well known in the art. Native heart valves (e.g., aortic, pulmonary, tricuspid, and mitral valves) are critical for ensuring forward-only flow of blood through the cardiovascular system. These heart valves can lose functionality as a result of congenital, inflammatory, or infectious diseases or conditions, among others. Early intervention has led to repair or replacement of dysfunctional valve(s) during open-heart surgery. More recently, in addition to the open-heart surgical approaches described above, gaining access to a target valve can be achieved percutaneously via at least one of the following known access routes: transapical, transfemoral, transatrial, and transseptal delivery techniques (collectively referred to as transcatheter techniques).

[0005] Generally, in transcatheter techniques, a prosthetic valve is mounted within a stented frame that can achieve a collapsed and expanded state. The device is collapsed and advanced through a sheath or delivery catheter placed within the patient's blood vessel until it reaches the implantation site. The stented frame is generally released from the catheter or sheath and expanded, along with the valve, to an expanded functional size and orientation within the heart by various means. One key issue is the ease of delivery of the prosthetic valve, including the stented frame and valve, across all access routes, including, but not limited to, transapical delivery. More specifically, it would be advantageous to have an improved delivery system for mounting, loading, translating, delivering, repositioning, recoating, and deploying an expandable stent to and within a target heart chamber. The present invention addresses these issues, among others.

[0006] [Description of Related Art] The human heart includes four chambers and four heart valves that aid in the forward (antegrade) flow of blood through the heart. The heart chambers include the left atrium, left ventricle, right atrium, and right ventricle. The four heart valves include the mitral valve, tricuspid valve, aortic valve, and pulmonary valve. See generally FIG. 1.

[0007] The mitral valve, located between the left atrium and left ventricle, helps control the flow of blood from the left atrium to the left ventricle by acting as a one-way valve that prevents backflow into the left atrium. Similarly, the tricuspid valve is located between the right atrium and right ventricle, and the aortic and pulmonary valves are semilunar valves located in the arteries that drain blood from the heart. All valves are one-way valves, with the leaflets opening to allow "antegrade (foregrade) blood flow." Normally functioning, the leaflets close under pressure exerted by reverse blood to prevent blood from flowing back (retrograde) into the chamber from which it just left. For example, when functioning properly, the mitral valve provides a one-way valve between the left atrium and left ventricle, opening to allow antegrade flow from the left atrium to the left ventricle and closing to prevent retrograde flow from the left ventricle to the left atrium. This retrograde flow, when present, is known as mitral regurgitation or mitral regurgitation.

[0008] Native heart valves can be or become dysfunctional for a variety of reasons and / or conditions, including, but not limited to, disease, trauma, congenital malformations, and aging. These types of conditions can cause the valve structures to not close properly, resulting in retrograde flow of blood back into the left atrium from the left ventricle in the case of mitral valve insufficiency.

[0009] Mitral regurgitation is a specific problem resulting from a dysfunctional mitral valve that allows at least some retrograde blood flow from the right atrium back into the left atrium. In some cases, the dysfunction results from mitral valve leaflets that prolapse into the left atrium, i.e., above the superior surface of the annulus, instead of connecting or joining to block retrograde flow. This backflow of blood strains the left ventricle with fluid overload and can lead to a series of left ventricular compensatory adaptations and adjustments, including remodeling of the size and shape of the ventricular chamber, which vary significantly during the long-term clinical course of mitral regurgitation.

[0010] Regurgitation can generally be a problem with native heart valves, including the tricuspid, aortic, and pulmonary valves, as well as the mitral valve.

[0011] Thus, native heart valves, such as the mitral valve, generally may require functional repair and / or support, including partial or complete replacement. Such interventions can take several forms, including open-heart surgery and open-heart implantation of a replacement heart valve. See, e.g., U.S. Pat. No. 4,106,129 (Carpentier) for procedures that are highly invasive, involve patient risks, and require not only a lengthy hospital stay but also a very painful recovery period.

[0012] Minimally invasive methods and devices for replacing dysfunctional heart valves are also known, including percutaneous access and catheter-facilitated delivery of replacement valves. Most of these solutions involve a replacement heart valve attached to a structural support, such as a stent, generally known in the art, or other form of wire network designed to expand upon release from a delivery catheter. See, for example, U.S. Pat. No. 3,657,744 (Ersek) and U.S. Pat. No. 5,411,552 (Andersen). Self-expanding variations of support stents help position the valve within a target heart chamber or vessel and hold the expanded device in place. This self-expanding form also presents problems when, as is often the case, the device is not properly positioned on the first positioning attempt and therefore needs to be recaptured and positionally adjusted. This recapture process, for a fully or partially expanded device, requires the operator to retract the collapsed device into the delivery sheath or catheter, adjust the device's entry position, and then redeploy the adjusted device distally from the delivery sheath or catheter, recollapse the device to a point that allows it to re-expand into the proper position. Because expanded stents or wire networks are generally designed to achieve an expanded state that also resists contraction or collapse forces, collapsing an already expanded device is difficult.

[0013] In addition to the open heart surgical approaches described above, gaining access to the target valve may be accomplished percutaneously via one of at least the following known access routes: transapical, transfemoral, transatrial, transaortic, and transseptal delivery techniques.

[0014] Generally, the art has focused on systems and methods that allow for partial delivery of a collapsed valve device using one of the known access routes described above, where one end of the device is released and expanded from a delivery sheath or catheter for initial positioning, and then fully released and expanded when proper positioning is achieved. See, e.g., U.S. Patent Nos. 8,852,271 (Murray, III), 8,747,459 (Nguyen), 8,814,931 (Wang), 9,402,720 (Richter), 8,986,372 (Murray, III), and 9,277,991 (Salahieh), as well as U.S. Patent Application Publication Nos. 2015 / 0272731 (Racehint) and 2016 / 0235531 (Ciobanu).

[0015] Additionally, known "replacement" prosthetic heart valves are intended to completely replace the native heart valve. Therefore, these replacement heart valves physically engage the tissues and / or leaflets within the annular throat, i.e., below the annular plane and superior surface, thereby eliminating all remaining functionality of the native valve and leaving the patient completely dependent on the replacement valve. Generally speaking, maintaining and / or preserving the native function of the heart valve is the preferred solution, and therefore, replacement rather than complete valve replacement is preferred. Clearly, there are cases where the native valve has substantially lost its complete functionality before the interventional implantation procedure, or where the native valve continues to lose functionality after the implantation procedure. The preferred solution is the delivery and implantation of a valve device that can function as an auxiliary and / or supplementary functional valve and completely replace the native function of a valve that has lost or will lose most or all of its functionality. However, the inventive solution described below generally applies to all types and forms of heart valve devices, unless otherwise specified. The present disclosure also applies to stents in general, as those skilled in the art will recognize.

[0016] Furthermore, for example, known solutions for mitral valve replacement systems, devices, and methods are dual-chamber solutions, i.e., requiring the involvement and engagement of a replacement valve device implanted in both the left atrium and the left ventricle. Generally, these solutions include a radially expanding stent in the left atrium, with anchoring or tethering portions (placed inferiorly through the native annulus or annular throat) connecting inferiorly through the annular throat from the stent device, with the subannular surface within the left ventricle, the left ventricular chordae tendineae, and even the left ventricular wall surface(s). See, for example, MitraClip®, marketed by Abbott Group and currently the only repair device approved in the United States. With MitraClip®, a catheter containing the MitraClip® is inserted into the femoral vein. The device enters the heart through the inferior vena cava and into the right atrium, where it is delivered transseptally. The MitraClip® passes through the annulus into the left ventricle and sits beneath the valve leaflets, lowering them and reducing regurgitation.

[0017] Such dual-chamber and native annulus solutions are unnecessarily bulky and therefore, from a strictly structural standpoint, more difficult to deliver and position / recapture / reposition. Furthermore, dual-chamber solutions present difficulties with making the ventricular fixation and / or tethering connections required to maintain position. Furthermore, these solutions disrupt native valve functionality as described above because the device portion positioned within the left ventricle must be routed through the native annulus and / or annular throat and the native mitral valve, thereby disrupting any remaining coaptation ability of the native valve leaflets. Additionally, dual-chamber solutions generally require invasive fixation of portions of the native tissue, resulting in unnecessary trauma and potential complications.

[0018] It will be further recognized that dual chamber mitral solutions precisely require sub-annular and / or ventricular engagement with fixation portions, anchoring portions, etc., as the atrial portion of the device cannot adequately anchor itself to the atrial cavity and / or above the annulus. Again, some or portions of the embodiments described herein are readily applicable to single or dual chamber solutions, unless otherwise indicated.

[0019] Finally, known prosthetic heart valves consist of two or three leaflets arranged to act as one-way valves, allowing fluid to flow antegradely while preventing retrograde flow. The native mitral valve is located posterior to the fourth costal cartilage and consists of an annulus connected to the anterior and posterior leaflets, chordae tendineae, papillary muscles, ventricular walls, and atria. Each native leaflet is supported by chordae tendineae attached to a papillary muscle, which is in tension with each ventricular contraction, maintaining valve function. Both the anterior and posterior leaflets of the native valve are attached to both the anterolateral and posteromedial papillary muscles via primary, secondary, and tertiary chordae tendineae. Breakage of either papillary muscle in the setting of myocardial injury can result in insufficiency of either the anterior or posterior leaflet of the mitral valve. Other mechanisms can result in insufficiency of one or both native mitral valve leaflets. In the case of single mitral valve insufficiency, regurgitation can take the form of a non-central eccentric jet of blood returning into the left atrium. Other leaflet disorders may include more focused regurgitant jets. Known prosthetic valve replacements generally include leaflets arranged to mimic the native valve structure, which over time may become susceptible to similar regurgitant outcomes.

[0020] Applications of collapsible and expandable stents are not limited to implantation of prosthetic heart valves: vascular stents are commonly used, and are generally collapsible to facilitate delivery through the lumen of a delivery catheter to a work site where the stent is translated out of the lumen of the catheter and expanded by self-expanding means or by an expansion mechanism such as an expandable balloon, among others. [Prior art documents] [Patent documents]

[0021] [Patent Document 1] U.S. Patent No. 4,106,129 [Patent Document 2] U.S. Patent No. 3,657,744 [Patent Document 3] U.S. Patent No. 5,411,552 [Patent Document 4] U.S. Patent No. 8,852,271 [Patent Document 5] U.S. Patent No. 8,747,459 [Patent Document 6] U.S. Patent No. 8,814,931 [Patent Document 7] U.S. Patent No. 9,402,720 [Patent Document 8] U.S. Patent No. 8,986,372 [Patent Document 9] U.S. Patent No. 9,277,991 [Patent Document 10] US Patent Application Publication No. 2015 / 0272731 [Patent Document 11] US Patent Application Publication No. 2016 / 0235531 Summary of the Invention [Problem to be solved by the invention]

[0022] As discussed above, known delivery methods and devices include expandable prosthetic valve stents and vascular stents that are collapsed during delivery via a delivery catheter. Some problems with known systems, devices, and methods include easily attaching an operator-operable tether(s) to the stent for loading and / or collapsing the expandable stent into a delivery catheter or sheath, translating the collapsed stent along the delivery catheter or sheath, delivering the expandable stent into a target heart chamber, repositioning the expandable stent within the target heart chamber as needed, recapturing or recoating the expandable stent within the delivery catheter or sheath as needed, and deploying the expandable stent in and within the target heart chamber. [Means for solving the problem]

[0023] Systems, devices, and methods for attaching operator-operable tether(s) to a stent for loading and / or collapsing an expandable stent into a delivery catheter or sheath, translating the collapsed stent along the delivery catheter or sheath, delivering the expandable stent into a target heart chamber, repositioning the expandable stent within the target heart chamber as needed, recapturing or recoating the expandable stent within the delivery catheter or sheath as needed, and deploying the expandable stent in and to the target heart chamber. Embodiments of the delivery system described herein apply to single-chamber prosthetic heart valves, as well as prosthetic heart valves requiring fixation outside of a single chamber. [Brief explanation of the drawings]

[0024] [Figure 1] Certain features of the heart are shown in cross section. [Figure 2] 1 shows a perspective view of an exemplary stent. [Figure 3A] 3 shows a bottom view of one embodiment of a transition section of the exemplary stent of FIG. 2. [Figure 3B] 3 shows a bottom view of one embodiment of a transition section of the exemplary stent of FIG. 2. [Figure 3C] 3 shows a bottom view of one embodiment of a transition section of the exemplary stent of FIG. 2. [Figure 4] 1 illustrates one embodiment of attachment features defined on an exemplary stent. [Figure 5A] 3 illustrates one embodiment of an attachment feature defined in a transition portion of the exemplary stent of FIG. 2. [Figure 5B] 3 illustrates one embodiment with three attachment features defined in the transition portion of the exemplary stent of FIG. 2. [Figure 6A] 1 illustrates one embodiment of a wire with a distal ball. [Figure 6B] 6B illustrates one embodiment of a notched tube for slidably receiving the wire with the distal ball of FIG. 6A. [Figure 6C] 6C illustrates one embodiment of an outer tube for receiving the notched tube of FIG. 6B. [Figure 6D] 6A-6C show an embodiment of an assembled tether comprising a wire with a distal ball, a notched tube, and an outer tube. [Figure 7A] 1 illustrates one embodiment of an assembled tether with the ball in a partially retracted position. [Figure 7B] 1 illustrates one embodiment of an assembled tether in a released position. [Figure 7C] 1 illustrates one embodiment of an assembled tether in a fully retracted position. [Figure 8] 1 illustrates one embodiment of three spaced apart tether assemblies extending distally from a delivery catheter or sheath. [Figure 9] 3 illustrates one embodiment of three spaced apart tether assemblies attached to three attachment features defined in the transition section of the exemplary stent of FIG. 2. [Figure 10A] FIG. 10 shows three exemplary tether assemblies attached to three attachment features of an exemplary stent frame without displacement from the longitudinal axis. [Figure 10B]1 shows three exemplary tether assemblies attached to three attachment features of an exemplary stent frame, displaced in a first direction relative to the longitudinal axis. [Figure 10C] 10 shows three exemplary tether assemblies attached to three attachment features of an exemplary stent frame, displaced in a second direction relative to the longitudinal axis. [Figure 11A] 10 shows exemplary handles and mechanisms for adjusting (reducing) the extension of each tether assembly distally from the distal end of the delivery catheter or sheath. [Figure 11B] 10 shows exemplary handles and mechanisms for adjusting (increasing) the extension of each tether assembly distally from the distal end of the delivery catheter or sheath. [Figure 12A] 10 shows an exemplary handle and mechanism for releasing one of the tether assemblies from attachment to an exemplary attachment feature of the stent. [Figure 12B] 10 shows an exemplary handle and mechanism for releasing one of the tether assemblies from attachment to an exemplary attachment feature of the stent. DETAILED DESCRIPTION OF THE INVENTION

[0025] Generally, various embodiments of the present invention are directed to devices and methods for loading and / or folding an expandable stent into a delivery catheter or sheath, translating the folded stent along the delivery catheter or sheath, delivering the expandable stent into a target heart chamber, repositioning the expandable stent within the target heart chamber as needed, recapturing or recoating the expandable stent within the delivery catheter or sheath as needed, and attaching an operator-operable tether(s) to the stent for deploying the expandable stent in and to the target heart chamber.

[0026] The support structure or stent has multiple functions that aid in the treatment of heart valve regurgitation (mitral or tricuspid valve). These functions include its function as a scaffold for a functioning prosthetic valve, apposition to the atrial anatomy, optimized radial force for compatibility with atrial dilation, the ability to load and deploy from a minimally invasive delivery system, and a geometry to support mitigation against paravalvular leak (PVL). The design features of the stent are adapted to fulfill one or more of the above-identified functions. Specific design features and attributes of exemplary stents are discussed in detail below to aid in understanding the utility of the funnel loading device and related methods. As those skilled in the art will recognize, the present invention is not limited to prosthetic heart valves with a stent support structure, but may also be applied to collapsible and expandable stents, such as those typically used in endovascular procedures. Additionally, those skilled in the art will recognize the utility of the disclosed invention for use in implanting stent designs of certain exemplary embodiments intended to support minimally invasive procedures for the treatment of valvular regurgitation or other dysfunction in at least the mitral, tricuspid, and aortic valves.

[0027] Stents may be self-expandable (e.g., nitinol or similar materials) or balloon-expandable (e.g., cobalt chrome or similar materials). Stents are typically made from cells, which may be open-cell diamond-like or continuous structures, with working cell elements. Stents may also be constructed using tubes, wires, braids, or similar structures. Exemplary stent transitions are described below.

[0028] 2-3C, one embodiment of an exemplary expandable stent 100 for use with the present invention comprises an outer portion 102 (which may be generally circular, but need not be a perfectly round circular structure when fully and / or partially expanded) and an inner support portion 104 (which may be cylindrical, but need not be cylindrical with a constant diameter, and which is adapted to support and retain a prosthetic valve leaflet (not shown in FIG. 2 ) within the inner support portion 104, most preferably at a point located above the native valve annulus, e.g., the mitral valve annulus), although other attachment points for the prosthetic leaflet are within the scope of the present invention. Additionally, as discussed above, the stent 100 may be configured to supplement and / or replace the function of a tricuspid valve. A preferred configuration comprises prosthetic leaflets positioned above the native leaflets, attached and spaced sufficiently far (above) from the native leaflets so as not to physically interfere with or interact with them. However, certain embodiments contemplate some interaction with the native leaflets.

[0029] The individual cells C that form the outer portion 102 of the stent 100 O are visible in FIG. 2 as open cell areas defined by the material used to form the exemplary expandable stent 100.

[0030] The individual cells C that form the inner valve support 104 I are also illustrated as open cell regions formed within an inner region R defined by outer portion 102, with the inner valve support extending radially upward into inner region R. As illustrated, the individual cells C I is the individual cell C O may be different sizes and have different shapes.

[0031] The region of the stent 100 that facilitates the transition radially inward of the stent 100 from the outer portion 102 to the inner portion 104 of the stent 100 is the transition or cell region 106. The transition cell region 106 is the outer portion cell C O and / or inner cell C I Cell C may contain cells of different size and / or shape than eitherT The outer and / or inner regions 102, 104, and / or transition cell region 106 of the stent 100 may be constructed from one continuous structure, or two or more structures may be combined to achieve an intended design goal. The transition cell region 106 includes a generally radially upward turn to allow the inner valve support 104 to reside within the inner region 102, as shown in FIG. 2. In some embodiments, the cell C of the transition cell region 106 T The lower portion of the inner valve support 104, that portion of the inner valve support 104 that connects with the inner region 102, may also include a curved shape to facilitate and / or complete the radially upward turn into the inner region 102.

[0032] Transition Cell C T The geometry and / or shape of the transition cell region 106 may be substantially straight line segments when expanded, as in Figure 3A below, or may incorporate an offset or twist within the stent cell pattern when expanded to allow for controlled compression of the stent, as shown in Figure 3B. An exemplary cross-sectional shape of the transition cell region 106 as viewed from the bottom of the stent 100 is shown schematically in Figures 3A and 3B.

[0033] This transition cell region 106 of the stent 100 may be a strut, a full cell portion, or a partial cell portion. The transition cell region 106 can have any number of struts (a minimum of three) or cells generally required to meet design needs. Transition Cell C T Alternatively, the struts may be formed by substantially straight, evenly spaced struts 108, as shown in FIG. 3A, which extend away from the inner valve support 104 with equal angles α on either side of the strut 108 and equal angles β on either side of the strut 108 to intersect or merge with the outer support 102.

[0034] In one embodiment, the struts 108 of the transition section 106 may be straight, as in FIG. 3A , or may have unequal angles relative to the inner valve support section 104 and the outer support section 102, as shown in FIG. 3C . Here, the straight struts 108 are angled to provide a smaller angle α and a larger angle α′ relative to the inner valve support section 104. Similarly, a smaller angle β′ and a larger angle β are provided relative to the outer support section 102. This allows for compressed nesting of the angled struts 108 of the transition section 106.

[0035] In another preferred embodiment, the transition cell region 106 may include transition cell struts 108' that have offsets, i.e., are not straight, but are twisted and / or curved, forming transition cells C T The degree of offset and / or twist and / or curvature of the struts 108′ and, therefore, the resulting expanded cell C T The size and / or shape of may vary depending on the number of cells / struts in the transition cell region 106, the packing density when the stent is collapsed, and the stress / strain distribution limits of the transition cell region 106.

[0036] Referring now to FIG. 4, an attachment feature 402 is defined along one of the struts 108, preferably within the transition cell region 106 of the expandable stent 102, as described above in FIGS. 2-3B. However, one skilled in the art will recognize that the attachment feature 402 may also be defined along a strut or struts that are not within the transition cell region 106. Additionally, while the attachment feature 402 is shown as circular, other shapes are certainly possible and within the scope of the present invention. Additionally, the attachment feature 402 may be defined on a strut of the stent frame that is downstream (of normal blood flow through the prosthetic heart valve) of the stent frame when implanted. Alternatively, the attachment feature 402 may be defined on the lowest downstream strut of the prosthetic heart valve frame.

[0037] FIG. 5A illustrates an exemplary circular attachment feature 402 positioned and defined along a stent strut, while FIG. 5B illustrates the location of three attachment features 402 around the transition cell region 106 of an exemplary expandable stent 102. As shown, there is substantially equal spacing or separation between adjacent attachment features 402 along and / or around the transition cell region 106. Those skilled in the art will recognize that unequal spacing or separation between the locations of attachment features 402 may also be employed. Additionally, at least one attachment feature 402 may be used. It is preferable to have at least two, and more preferably at least three, attachment features 402 defined as described herein.

[0038] 6A-7A, there is shown one embodiment of a tether assembly 410 operably connected at its proximal end to an operating handle H, as will be further described. The tether assembly 410 further comprises an outer tube 404, a notched tube 406, and a wire having a distal dilation element 408, the tether assembly having a length that allows for proximal connection with the handle H and a sufficient extension length from the distal end of the delivery catheter or sheath to, among other things, facilitate translation and deployment of the subject heart valve prosthesis, as will be further described herein. The wire distal dilation element 408 is not limited to a wire but may include equivalent structures such as, but not limited to, a tube, a rod which may be hollow or solid.

[0039] An outer tube 404 is provided having a lumen L1 therethrough. A notched tube 406 is sized to be slidably received within lumen L1 and includes a distal flexible tab 407 extending distally from lumen L2 of the notched tube, as shown.

[0040] A wire having a distal enlarged element 408, in which an enlarged distal element 409 is shown as a ball, is adapted to be slidably received within lumen L2 to create a nested arrangement as shown in FIG. 6D for tether assembly 410.

[0041] 7A-7C illustrate the operation and relationship of the components of the tether assembly 410 during certain steps of the prosthetic heart valve loading, translation, repositioning, recapture, deployment, and release during the implantation process.

[0042] FIG. 7A shows a distal dilation element 409 of the wire, which is pulled proximally back into the distal flexible tabs 407 of the notched tube 406, deforming the tabs 407 and creating a compression or friction fit therein. Additionally, the distance between the tabs 407 when deformed as shown is greater than the distance between the tabs when the ball 409 is not sandwiched between them. This configuration allows an enlarged distal element, such as the illustrated ball 409, having a diameter smaller than the minimum diameter of the attachment feature 402, and distal flexible tabs 407 that also have a maximum undeformed length between the tabs 407 smaller than the minimum diameter of the attachment feature 402, to be inserted through the attachment feature. The insertion position is as shown in FIG. 6D, with the distal dilation element 409, shown as a ball, positioned distal to the distal flexible tabs 407. Once the distal expansion element 409 and distal flexible tab 407 are inserted through the attachment feature 402, the operator can then retract the wire with the expansion distal element 408 proximally to engage and deform the distal flexible table 407 with the distal expansion element 409, as shown in FIG. 7A, increasing the distance between the tabs 407 to a length greater than the diameter of the attachment feature, thereby attaching the tether assembly 410 to the stent 102, preferably at the transition point described above. This process step is repeated for each of the at least one tether assembly 410 to attach the tether assembly 410 to the stent 102.

[0043] Those skilled in the art will appreciate that although the preferred embodiment includes a ball-shaped distal enlargement element 409 and a circular attachment feature 402, other shapes may be used for the ball-shaped distal enlargement element 409 and / or the attachment feature 402. Some of these shapes may be complementary, e.g., a square element instead of a distal ball-shaped distal enlargement element 409 and a square attachment feature 402. However, complementary features are not required as long as the distal element, e.g., the illustrated ball 409, can fit through the attachment feature 402 and be drawn distally to deform the flexible distal tab 407 and achieve attachment.

[0044] Those skilled in the art will also understand that the paravalvular leak mitigation skirt or fabric may cover at least a portion of the expandable stent 102, including, but not limited to, the transition cell region. In such a case, the tether assembly 410 may extend through the skirt or fabric to reach, attach to, and release from the attachment feature 402.

[0045] Once attached to the stent frame in this manner, the tether assembly(ies) 410 can be used to collapse the self-expanding stent frame 102 into the proximal end of the lumen of the delivery catheter or sheath and assist in distally translating the collapsed stent frame 102 through the delivery catheter or sheath to the distal end of the delivery catheter of a sheath previously placed in the target heart chamber. At this point, the collapsed stent frame 102 is at least partially released from the delivery catheter or sheath and begins to self-expand. The attached tether assembly(ies) 410 can be used to assist this process by manipulating the tether assembly(ies) 410 to move the at least partially expanded stent frame 102 to an appropriate position within the target heart chamber. In certain cases, it can be advantageous to reposition the at least partially expanded stent frame comprising the prosthetic heart valve by retracting one or more of the tether assembly(ies) 410 proximally to move the stent frame 102 into a desired orientation and position within the heart valve relative to anatomical landmarks. Figures 10A-10C show one embodiment with three tether assemblies 410, with Figure 10A being a default position, with the stent frame 102 aligned substantially symmetrically with the longitudinal axis of the delivery sheath. Figures 10B and 10C illustrate the ability to retract (or push) one or more tether assemblies 410 to move the connected stent frame 102 away from symmetric alignment of the longitudinal axis into an asymmetric position to assist in positioning and deployment of the stent frame 102.

[0046] 11A and 11B and 12A and 12B provide embodiments of an operating handle H to which the distal end of each tether assembly 410 is connected. As shown, the length of extension of the tether assemblies 410 away from the distal end of the delivery sheath can be manipulated by moving an attached push / pull and release mechanism 430 proximally or distally at the handle H. This may be done for a combined set of tether assemblies, or individual tether assemblies 410 may be selected to selectively extend (push distally) or shorten (retract proximally) relative to the other tether assemblies 410, and / or the components of each tether assembly 410, including the outer tube 404, notched tube 406, and enlarged distal element 408, may each be independently pushed proximally and / or retracted distally. Each tether assembly 410 has its own length and release mechanism 430 attached to the handle H.

[0047] Each push / pull and release mechanism 430 further comprises a lever that can be locked and unlocked, allowing for manipulation of the individual components of the tether assembly 410. When locked, the associated tether assembly 410 is attached to the attachment feature 402, as described above. Releasing the tether assembly 410 from the attachment feature 402 is achieved by unlocking the lever (actuating the lever as shown), as shown in FIGS. 12A-12B , and then retracting the unlocked portion of the assembly distally, i.e., by retracting the associated component of the tether assembly (i.e., notched tube 406, enlarged distal element 408) distally to release it from attachment engagement with the attachment feature 402. It will be apparent to one skilled in the art that this same mechanism 430 can be used to advance and / or retract the components of the tether assembly 410 to accomplish attachment and / or detachment from the attachment feature 402.

[0048] 12A-12B provide a mechanism by which the tether assemblies 410 can be individually released from the stent frame and retracted proximally as in FIGS. 7B and 7C.

[0049] In some cases, it may be advantageous to at least partially restore, re-cover, and / or recapture the at least partially expanded stent frame 102 by retracting it proximally into the lumen of the delivery catheter or sheath and then resuming the release and deployment steps.

[0050] 7B and 7C , once the stent frame including the prosthetic heart valve is properly positioned, the enlarged distal elements 409 of the wires with enlarged distal elements 408 are pushed away from the distal flexible tabs 407, causing the distal flexible tabs 407 to return to their undeformed shape allowing the notched tubes 406 and the wires with distal enlarged elements 408 to be withdrawn from the attachment features 402, thereby separating the tether assemblies 410 from the stent frame 102. Once each provided tether assembly 410 is detached from the stent frame 102, the tether assembly(ies) 410 may be withdrawn from the heart chamber.

[0051] 8 and 9 provide further details about a preferred embodiment comprising three tether assemblies (410).

[0052] As explained, the preferred access route for the disclosed delivery system includes a transapical approach, however, all other delivery access routes can be successfully navigated using the disclosed invention(s).

[0053] The description of the invention and its applications set forth herein is illustrative and is not intended to limit the scope of the invention. Features of various embodiments may be combined with other embodiments within the spirit of the invention. Variations and modifications of the embodiments disclosed herein are possible, and practical substitutes and equivalents to the various elements of the embodiments will be apparent to those skilled in the art upon review of this patent document. These and other variations and modifications of the embodiments disclosed herein may be made without departing from the scope and spirit of the invention.

Claims

1. 1. A delivery system for an expandable prosthetic heart valve for delivering and / or manipulating the position of a self-expanding stent frame at an anatomical location, said delivery system comprising: at least one tether assembly operably connected at a distal end to a push / pull and release mechanism of the operating handle, each of the at least one tether assembly comprising: an outer tube having a lumen therethrough; a notched tube slidably received within the lumen of the outer tube and including a lumen therethrough and two flexible tabs extending from a distal end of the lumen of the notched tube, the two flexible tabs being capable of extending distally from the lumen of the outer tube; a wire having an enlarged distal element attached to a distal end of the wire and slidably received within the lumen of the notched tube, the enlarged distal element being capable of extending distally from the lumen of the outer tube and from the lumen of the notched tube; A delivery system comprising:

2. 2. The delivery system of claim 1, wherein the self-expanding stent frame comprises at least one attachment feature defined on at least one strut of the self-expanding stent frame, and the enlarged distal element of the wire having the enlarged distal element is adapted to translate through and releasably engage the attachment feature.

3. The delivery system of claim 2 , wherein the enlarged distal element comprises a ball.

4. The delivery system of claim 2 , wherein the at least one attachment feature is defined on at least one lowermost downstream strut of the self-expanding stent frame.

5. The delivery system of claim 2 , wherein the attachment features are formed on transition cell regions of the self-expanding stent frame.

6. The delivery system of claim 2 , wherein the enlarged distal element and the at least one attachment feature comprise complementary shapes.

7. The delivery system of claim 2 , wherein the enlarged distal element and the at least one attachment feature do not comprise complementary shapes.

8. 3. The delivery system of claim 2, wherein one of the at least one tether assemblies is adapted to be attached to and released from one of the at least one attachment features.

9. 2. The delivery system of claim 1, wherein the push / pull and release mechanism is adapted to translate the at least one tether assembly proximally and / or distally relative to a distal end of a delivery catheter along which the at least one tether assembly is translated.

10. 2. The delivery system of claim 1, wherein the push / pull and release mechanism is adapted to selectively translate the outer tube, the notched tube, and / or the wire having the enlarged distal element relative to each other, relative to the distal end of the delivery catheter, and, if there are at least two of the at least one tether assembly, relative to any other one of the at least two tether assemblies.

11. 10. The delivery system of claim 1, adapted for use in delivering a prosthetic heart valve to treat one or more of the group consisting of a native mitral valve, a native tricuspid valve, and a native aortic valve.

12. 10. The delivery system of claim 1, adapted for use in delivering a prosthetic heart valve along one or more of the transcatheter access routes in the group consisting of transapical, transfemoral, transatrial, and transseptal delivery techniques.

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