Patent Publication Number: US-2022211501-A1

Title: Segmented annular reduction systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Non-Provisional Patent Application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 63/134,215, filed Jan. 6, 2021, the entire teachings of which are incorporated herein by reference. 
    
    
     FIELD 
     The present technology is generally related to systems for and methods of reducing annular dimensions such as that of a mitral valve annulus or tricuspid valve annulus. 
     BACKGROUND 
     Generally, the anatomy and physiology of the human heart is well known. Of the four one-way valves in the heart, the two inlet valves are the mitral valve of the left side of the heart, and the tricuspid valve on the right side of the heart. The tricuspid valve is located between the right atrium and the right ventricle. The three leaflets of the tricuspid valve laterally terminate at the tricuspid annulus. Blood flows from the superior and inferior vena cava into the right atrium, then through the tricuspid valve during diastole to fill the right ventricle. During ventricular systole, the tricuspid valve is closed and blood is ejected through the pulmonary valve into the pulmonary artery and hence through the lungs. At the end of ventricular systole the pulmonary valve closes. Leaving the lungs, the now oxygenated blood flows into the left atrium and hence through the mitral valve into the left ventricle during ventricular diastole. Finally, at ventricular systole the mitral valve closes and blood is ejected through the aortic valve into the aorta. However, should the mitral valve become regurgitant due to disease then some percentage of the left ventricular stroke volume will flow backwards through the mitral valve into the left atrium. This regurgitation causes the left atrial pressure to rise, in turn causing pulmonary artery pressure to rise, which is reflected back to the right ventricular pressure. 
     Typically, to treat a patient with functional mitral regurgitation, a physician places an annuloplasty ring on the mitral annulus to reduce the circumference and septal-lateral diameter of the annulus. In degenerative mitral regurgitation patients, annuloplasty rings are utilized to stabilize the mitral annulus, not reduce the annular circumference. 
     The present disclosure addresses problems and limitations associated with the related art. 
     SUMMARY 
     The techniques of this disclosure generally relate to systems for and methods of reducing annular dimensions of an annulus, such as a mitral valve annulus. Such systems and methods can be used to treat functional mitral regurgitation, for example. Various embodiments of the disclosure enable selective plication of annulus tissue and also prevent potential migration of the annuloplasty ring between tissue plications and during post-procedural annular dilation. 
     In one aspect, the present disclosure provides a system that includes an annuloplasty device having a plurality of segments. Each segment includes first and second ends, a flexible body, a pawl at the second end, and a plurality of teeth positioned along the body. At least ones of the pawls and teeth are engaged in a manner such that the plurality of segments form a closed loop. The system can further include a pull wire releasably secured to at least one of the plurality of segments. 
     In another aspect, the disclosure provides a method including the steps of providing a mitral valve annulus of a patient and anchoring a plurality of segments of an annuloplasty device to the mitral valve annulus. The plurality of segments include a first segment and a second segment. Each segment has first and second ends, a flexible body, a pawl at the second end, and a plurality of teeth positioned along the body. Ones of the pawls and teeth are engageable such that the plurality of segments form a closed loop. A pull wire is releasably secured to the second end of the first segment. The method further includes proximally pulling the pull wire to draw the first end of the first segment through the pawl of the second segment. 
     The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a schematic top view of an annuloplasty device. 
         FIG. 1B  is a partial, schematic side view of a system including the annuloplasty device of  FIG. 1A  anchored into tissue with a plurality of anchors and operatively connected to an adjustment catheter. 
         FIG. 1C  is a partial, enlarged, schematic side view of the annuloplasty device of  FIGS. 1A-1B  having two segments in a pre-cinched arrangement. 
         FIG. 1D  is a partial, enlarged, schematic side view of the two segments of  FIG. 1C  in a cinched arrangement. 
         FIG. 2  is a partial, perspective view of the annuloplasty device of  FIGS. 1A-1D  having an alternate anchor. 
         FIG. 3  is a partial, schematic side view of the adjustment catheter of  FIG. 1B  that can be used to cinch the segments of the annuloplasty device of  FIGS. 1A-1D , for example. 
         FIG. 4  is a partial, schematic side view of an alternate adjustment catheter that can be used to cinch the segments of the annuloplasty device of  FIGS. 1A-1D , for example. 
         FIGS. 5A-5B  are partial, schematic side views of another adjustment catheter that can be used to cinch the segments of the annuloplasty device of  FIGS. 1A-1D , for example. 
     
    
    
     DETAILED DESCRIPTION 
     Specific embodiments of the present disclosure are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to the treating clinician. “Distal” or “distally” are a position distant from or in a direction away from the clinician. “Proximal” and “proximally” are a position near or in a direction toward the clinician. 
       FIGS. 1A-1D  collectively illustrate a system  5  including an annuloplasty device  10  formed of a plurality of interconnected segments  12   a,    12   b,    12   c,    12   d,    12   e,    12   f,    12   g  (“ 12   a - 12   g ”). The number of segments can vary, as desired. As shown, the annuloplasty device  10  has seven segments  12   a - 12   g,  however, fewer or greater segments are envisioned. Each segment  12   a - 12   g  includes a flexible body  14   a,    14   b  having a first end  16   a,    16   b  and a second end  18   a,    18   b.  Only a first segment  12   a  and a second segment  12   b  are fully referenced in the figures for ease of illustration. Each segment  12   a - 12   f  can be identically configured or can vary, as desired. A plurality of teeth or engagement features  20   a,    20   b  (generally referenced) are positioned along one side of the body  14   a,    14   b  between the first end  16   a,    16   b  and second end  18   a,    18   b.  Each tooth  20   a,    20   b  includes a protrusion or is angled with respect to the body  14   a,    14   b.  The first end  16   a,    16   b  is a free end and the second end  18   a,    18   b  includes a pawl  22   a,    22   b.  In one example, the pawls are integrally formed with the respective body (e.g., pawl  22   a  is integrally formed with the body  14   a ). As is best shown in  FIG. 2 , each pawl  20   a,    20   b  has a longitudinal opening  24   a,    24   b  extending from one side of the pawl  20   a,    20   b  to the other. Each longitudinal opening  24   a,    24   b  is configured to receive the first end  16   a,    16   b  of an adjacent segment in one direction but not the opposing direction. For example, the opening  24   a  of the pawl  22   a  of the first segment  12   a  is sized and configured to receive the body  14   b  of the second segment  12   b  and upon insertion of the second segment body  14   b  into the opening  24   a  of the first segment  12   a,  the body  14   b  of the second segment  12   b  cannot be pulled back in the opposite direction. Generally, the plurality of teeth  20   b  of the second segment  12   b  and the pawl  22   a  of the first segment  12   a  collectively form a ratchet. With this configuration, the plurality of segments  12   a - 12   g  can be interconnected, forming a ring or closed loop that can be reduced and maintained in dimension, which can prevent potential migration of the annuloplasty ring between tissue plications and during any potential post-procedural annular dilation. Once two adjacent segments are interconnected, they are essentially locked in the interconnected fashion. Each pawl and adjacent plurality of teeth can be configured similarly and function in a similar way. In one example, the plurality of teeth  20   a,    20   b  extend along an entire length of the respective body  14   a,    14   b  at specified intervals, to allow for more intermediate control and locking of annular ring size/cinch amount between two adjacent pawls  22   a,    22   b.    
     It is envisioned that the annuloplasty device  10  can be anchored or otherwise secured to a valve annulus (see also,  FIGS. 5A-5B  and related disclosure), such as a mitral valve annulus in a variety of manners. In one example, the annuloplasty device  10  is secured to the valve annulus prior to cinching of the annuloplasty device  10 . In various embodiments, the annuloplasty device is secured with one or more anchors that can be provided as part of system  5  or annuloplasty device  10 . The anchors can have a variety of configurations including barbs, prongs, shape memory elements or helical members. In the example of  FIG. 1B , one anchor  30   a,    30   b  is positioned at each pawl  22   a,    22   b.  In various embodiments, each anchor  30   a,    30   b  is secured to one pawl  22   a,    22   b.    FIG. 1B  illustrates anchors  30   a,    30   b  each having a plurality of shape memory prongs that can be inserted into tissue in an elongated (i.e. generally linear arrangement) and then the prongs will spring into the illustrated natural arrangement once released into the tissue. In other embodiments, such as that of  FIG. 2 , one or more anchors  30   a ′ may be helical for rotational advancement into tissue. In instances where the anchor is rotatably advanced into tissue, each segment (e.g., segments  12   a - 12   g ) may be anchored or attached to the valve annulus or other tissue prior to being formed into an interconnected ring or loop. In other words, segments  12   a - 12   g  can be anchored to tissue individually and disconnected from each other. In various methods, once the annuloplasty device  10  is secured to the valve annulus, one or more segments  12   a - 12   g  are independently cinched to a desired degree and are automatically locked or maintained in the cinched arrangement upon cinching due to the one-way movement restriction of the ratchet configuration formed by respective pawls and teeth. 
     Cinching of each segment  12   a - 12   g  can be conducted, for example, by actively pulling a respective pull wire (e.g., pull wires  32   a,    32   b ) releasably secured to one respective segment (e.g., segments  12   a,    12   b ) and provided as part of system  5 . In one example, the pull wire  32   a,    32   b  includes a hook  34   a,    34   b  that can be configured to releasably engage the first end of the body of an adjacent segment. In operation, each pull wire is threaded through the longitudinal opening in the pawl adjacent the respective second end so that proximal pulling of the pull wire will correspondingly pull the body through the pawl. For example, as shown in  FIGS. 1C-1D , pull wire  32   a  is threaded through the opening  24   a  in the pawl  22   a  of the first segment  12   a.  The pull wire  32   a  is releasably engaged with the second end  18   a  of the second segment  12   b.  Upon proximal retraction of the pull wire  32   a,  the second segment  12   b  is drawn through the opening  24   a  to shorten the distance between the pawl  22   a  of the first segment  22   a  and the pawl  22   b  of the second segment  12   b,  effectively “cinching” the second segment  12   b  and tissue anchored proximate thereto (see also  FIGS. 5A-5B  and related disclosure). 
     The pull wires  32   a,    32   b  can be protected and housed within an adjustment catheter  38  (best shown in  FIG. 1B ), which can be provided as part of system  5 . In one example, the adjustment catheter  38  can include one stem catheter  40  that distally terminates at a branch  42   a,    42   g,    42   f  for each pull wire  32   a,    32   g,    32   f,  which directs one respective pull wire  32   a,    32   g,    32   f  to one respective pawl (see pull wires  32   a,    32   f,    32   g  and pawls  22   a,    22   f,    22   g  in  FIG. 1B ; only three branches, pull wires and segments are shown for ease of illustration, however, the remaining branches, pull wires and segments can be similarly configured and operated in an identical manner). Each branch  42   a,    42   f,    42   g  terminates at a distal end  44   a,    44   f,    44   g.  In the example of  FIG. 1B , each distal end  44   a,    44   f,    44   g  can be positioned proximally and over one pawl  22   a,    22   f,    22   g.  In this example, a pivot-point of each pull wire  32   a,    32   f,    32   g  is above (in the perspective shown) each anchor  30   a,    30   f,    30   g  and pawl  22   a,    22   f,    22   g.    
     In one example method, the annuloplasty device is provided and anchored to a mitral valve annulus so that the annuloplasty device circumscribes the annulus and cannot move with respect to the annulus. An adjustment catheter of any of the types disclosed herein houses at least one pull wire, each of which is releasably secured to a second end of a second segment and passing through the pawl of a first segment. One or more pull wires are pulled proximally to pull the respective second end of the segment into the pawl until the desired amount of shortening between the pawl and adjacent pawl at the first end of the segment is achieved. Once the desired shortening of the respective segment is achieved, the pull wire is disengaged from the respective first end. Turning again to the example of  FIGS. 1C-1D , once the desired amount of cinching of the second segment  12   b  has been conducted, the pull wire  32   b  can be selectively detached from the body  14   b  by unhooking the hook  34   a  from the first end  16   b.  Any other releasable attachment methods that provide similar function are considered within the scope of the present disclosure. It is envisioned that the excess portion  15  of body  14   b  pulled through the pawl  22   a  can remain attached. In some embodiments, the excess portion  15  of the body  14   b  can be severed and removed. The pull wire can be directed to another pawl with the adjustment assembly and the process can be repeated until the desired adjustment of the annuloplasty ring is achieved. In one embodiment, multiple pull wires are provided and used to adjust multiple segments separately, either simultaneously or in sequence. 
     In another example shown in  FIG. 3 , during cinching, the distal end  44   a,    44   b,    44   g  of each branch  42   a,    42   b,    42   g  can be positioned adjacent the opening  24   a,    24   b  of the pawl  22   a,    22   b,    22   g  so that a pull force vector of each pull wire  32   a,    32   b,    32   g  is parallel to the valve annulus and will not apply a dehiscence force to the anchor  30   a,    30   b,    30   g.  As at least partially indicated with like reference numerals, the embodiment of  FIG. 3  can be identically configured, function and be implanted in the same manner as other embodiments disclosed herein except as explicitly stated. 
     In yet another example shown in  FIG. 4 , a distal end  44   a ′,  44   b ′,  44   g ′ of each branch  42   a ′,  42   b ′,  42   g ′ can be curved so that the branch  42   a ′,  42   b ′,  42   g ′ is non-linear along its length. The distal end  44   a ′,  44   b ′,  44   g ′ is curved to lead the respective pull wire  32   a,    32   b,    32   g  into the respective pawl opening (e.g.,  24   a,    24   b;  see also  FIG. 2 ) so that the direction of the pull-force vector would avoid anchor dehiscence. In this embodiment, the distal ends  44   a ′,  44   b ′,  44   g ′ of each branch  42   a ′,  42   b ′,  42   g ′ can also be configured to serve as a backstop for each respective anchor  30   a,    30   b,    30   g  to provide a reactional force to allow the second end of the body to move though the pawl opening without the anchor  30   a,    30   b,    30   g  moving with the body. For example, the distal ends of  44   a ′ of the branch  42   a ′ serves as a backstop for the anchor  30 a to provide a reactional force to allow the first end  16   b  of the body  14   b  of the second segment  12   b  to move though the pawl opening  24   a  without the anchor  30   a  moving with the body  14   b.  As at least partially indicated with like reference numerals, the embodiment of  FIG. 4  can be otherwise identically configured, function and be implanted in the same manner as other embodiments disclosed herein except as explicitly stated. 
     Referring in addition to  FIGS. 5A-5B , which illustrate an alternate adjustment catheter  38 ″ and methods utilizing only two branches  42   a,    42   b  extending from the stem  40 . Each branch  42   a,    42   b  can optionally take the configuration of branches  42   a ′,  42   b ′ disclosed above. In one example, a single pull wire  32   a  could be inserted through one branch  42   a  while adjacent branch  42   b  can receive pawl  22   b  to provide support as the pull wire  32   a  is proximally pulled. In one example, a single pull wire  32   a  could be moved sequentially from one branch  42   a  to the other branch  42   b  to adjust the respective segment(s) (e.g., segments  12   a - 12   f ) in a manner such as that disclosed above. The branches  42   a,    42   b  can then be repositioned at additional pawls to interconnect the pull wire  32   a  to additional segments for cinching. In another example, segment  12   b  is cinched to correspondingly cinch portion P of tissue T secured thereto. Such cinching is accomplished by reducing a distance D 1  between adjacent pawls  22   a,    22   b  to a smaller/reduced distance D 2 ). The excess portion  15  can be either severed outside of the respective branch  42   a  or can be drawn into the respective branch  42   a  be severed and removed from the patient through the adjustment catheter  38 ″. Or, the excess portion  15  can be left in place. The adjustment catheter  38 ″ could then be repositioned at a second set of pawls, and then a third set of pawls, and so on, as desired, to selectively cinch desired segments. In some embodiments the distal end  44   b  of the branch  42   b  that is opposite the pull wire can receive the adjacent pawl  22   b  to provide support during cinching. As at least partially indicated with like reference numerals, the embodiment of  FIGS. 5A-5B  can be identically configured, function and be adjusted in the same manner as other embodiments disclosed herein except as explicitly stated. 
     In yet another example of the disclosure, the adjustment catheter  38 ″ can include a single branch  42   a  that can be a continuous extension of stem  40  or angled with respect to stem  40 . In this example, since branch  42   b  would not be provided to lend additional stabilizing support to the system during cinching, stabilization and support can be achieved by abutting the distal end  44   a  of the branch  42   a  against a proximal end of the respective pawl (as previously described, to provide a reactionary force), either in embodiments having curved distal end (e.g.,  FIG. 4 ) or non-curved distal end (e.g.,  FIG. 3 ). In various examples of the disclosure, one or more flexible segments (e.g., flexible segment  12   b ) is already partially threaded through one pawl (e.g., pawl  22   a ), so the pull wire  32   a  only needs to hook onto the end of the flexible segment  12   b  for cinching of each flexible segment, without having to also weave all the way through one respective pawl to reach the respective flexible segment. Similarly, in the multi-branch embodiments shown in  FIGS. 1A-4 , the pull wires can optionally be woven through respective pawls outside of the patient pre-implantation, but with a single-arm or dual-arm “tool-style” catheter that moves around and cinches each flexible segment in a serial fashion. It is envisioned that pre-threading of the flexible segments at least partially through the pawls may ease navigation and technical feasibility of implantation of such embodiments. 
     Aspects of the disclosure provide numerous advantages over known devices and techniques. Particularly, aspects of the disclosure allow for variable localized cinch amounts of the device around the annulus that provide a more patient-specific and tailored treatment corresponding with varying amounts of annulus dilatation. Further, aspects of the disclosure provide systems to simultaneously cinch and locking, rather than locking needing to be accomplished in a separate step. Simultaneous cinching and locking reduces procedural complexity and time. 
     It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.