Patent Publication Number: US-2021186489-A1

Title: Suture clips, deployment devices therefor, and methods of use

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/684,148, filed Aug. 23, 2017, now U.S. Pat. No. 10,939,905, which claims the benefit of U.S. Patent Application No. 62/380,198, filed Aug. 26, 2016. The entire disclosure of each of these prior applications is incorporated by reference for all purposes. 
    
    
     FIELD 
     This disclosure relates generally to suture clips, and to devices and methods for securing sutures using suture clips. 
     BACKGROUND 
     Sutures are used for a variety of surgical purposes, such as approximation of tissue and ligation of tissue. When placing sutures, the strand of suture material to be used typically has a needle affixed to one end which is passed (looped) through the tissue to be approximated or ligated, forming a stitch. The stitch is then tensioned appropriately, and the two free ends of the suture loop, the needle end and the non-needle end, are knotted to retain the desired tension in the stitch. Forming knots in sutures during open surgery is a simple matter, though time-consuming, but forming knots in sutures during endoscopic surgery can require two surgeons to cooperate in a multi-step process that is performed with multiple instruments to pass the needle and suture back and forth to tie the suture knot. 
     Suture locking devices that eliminate the need to tie knots in order to speed up surgical procedures are known. Suture retainers or locks are used in place of suture knots to prevent passage of a suture end into and through tissue and to maintain the tension applied to the suture material during a suturing procedure. 
     When using a method that employs a clip to secure the suture, the clip can be delivered by advancing the clip along a suture line to the area of interest, and then deploying the clip such that the clip secures the suture in place. With the clip thus secured, the excess suture can be cut and removed from the patient. An example of such a clip, as well as methods and devices for use therewith, are disclosed in U.S. Patent Application Publication No. 2007/0005081 A1 and U.S. Pat. No. 7,628,797, the entire contents of which are expressly incorporated by reference herein. 
     Despite the existence of knotless suture locking devices in the art, there is a need for improved devices that enable easy access to the suture, accurate tensioning of the suture, and are simple to use. In light of the foregoing, there is presently a need for improved systems for securing sutures with clips. 
     SUMMARY 
     Disclosed herein are improved suture-clip delivery devices and systems, suture clips that can be used therewith, and their methods of use. The methods can be used, for example, in securing heart valve repair or replacement prostheses in or near the heart. The devices and methods are particularly well suited for traditional surgery or minimally invasive surgery. The devices disclosed herein can eliminate the need for surgical knots, thus reducing surgical time and exposure. Further, the devices can improve the ease of implantation because the clinician need not tie knots in the limited space in and around the heart. 
     Some embodiments of suture clip delivery systems described herein utilize a suture clip having a body with an at least generally flat shape, such as a flat circular or elliptical suture clip, with a suture aperture formed therein, and a handheld device for deploying one or more suture clips. An inner lumen formed in a distal end of the device and the suture aperture of the suture clip can be sized and configured so that one or more lines of suture may pass therethrough. The suture aperture of the suture clip can have an open configuration, wherein the suture aperture is generally unobstructed, and a closed, or crimped, configuration, wherein the suture clip has been plastically deformed so as to frictionally engage the suture line(s) passing therethrough and to prevent them from moving in one or more directions. 
     In a particular embodiment, a suture clip delivery device can include a proximal handle portion that includes an actuation mechanism, such as a trigger. The device can include an outer shaft defining an inner lumen. A crimping assembly can be disposed at least partially within a distal end of the outer shaft. The crimping assembly can be configured to apply a distributed, such as an evenly distributed, radially compressive force to a suture clip. For example, the crimping assembly can be configured to plastically deform the suture clip such that the suture aperture is closed, at least substantially closed, or otherwise secures the suture line(s), while reducing or eliminating bending or buckling of the axial suture clip surfaces. 
     In one implementation, the crimping assembly can include a plurality of crimping members configured to receive and radially compress a suture clip. The actuation mechanism can be configured to move the plurality of crimping members radially inwardly from a first position where the crimping members are configured to receive a suture clip to a second position where the plurality of crimping members are configured to radially compress the suture clip, causing the suture clip to plastically deform. 
     In some implementations, the suture clip delivery device can include an inner shaft at least partially disposed within the inner lumen of the outer shaft. The inner shaft or outer shaft can be moveable with respect to the other, such as by use of the actuation mechanism. For example, the actuation mechanism can be configured to move the inner shaft axially, proximally or distally, relative to the outer shaft. 
     The plurality of crimping members, in some implementations, can be articulated. For example, each of the plurality of crimping members can include an inner hinge member pivotably coupled to an outer hinge member. In a specific example, the inner hinge members can be coupled to an inner shaft of the suture clip delivery device and the outer hinge members can be coupled to the outer shaft of the suture clip delivery device. In further implementations, the plurality of crimping members can be disposed proximate to opposing sides of the distal end of the outer shaft. According to another implementation, each of the plurality of crimping members can include a distal jaw portion configured to receive and radially compress a suture clip. 
     In another aspect, the crimping assembly can include a cutting member configured to sever one or more sutures. In one example, the cutting member can include an annular body defining axial and radial apertures for receiving the one or more sutures. In another example, the suture clip delivery device can include an inner shaft at least partially disposed within the lumen of the outer shaft. The inner shaft can define a pair of radially extending pegs. A radial surface of the cutting member can define a plurality of positioning apertures configured to receive the pegs and an inner suture aperture configured to receive the one or more sutures. 
     The cutting member can be disposed about the inner shaft, such that the pegs are received within the positioning apertures. The positioning apertures can have an axial length larger than the diameter of the pegs, such that the cutting member is axially moveable from a first position where the inner suture aperture and an outer suture aperture formed in the outer shaft are aligned to a second position where the inner suture aperture and the outer suture aperture are at least substantially not aligned. 
     In another implementation, the distal end of the outer shaft can define an axially recessed portion configured to receive a suture clip. 
     In a further aspect, the present disclosure provides a suture clip delivery assembly. The suture clip delivery assembly can include a suture clip delivery device, such as a suture clip delivery device as described above. The suture clip delivery assembly can further include a suture clip and a suture snare assembly. The suture snare assembly can include a suture snare coupled to a handle. The handle can be configured to be inserted through an aperture formed in a distal end of an outer shaft of the suture clip delivery device and through an aperture formed in a radial surface of the outer shaft. The suture snare assembly can further include a retaining member configured to releasably retain the suture snare. In some examples, the retaining member can define a groove, such as a groove formed in a perimeter surface of the retaining member, for receiving the suture snare. In further examples, the retaining member can define one or more notches for helping to release the suture snare from engagement with the retaining member. 
     In another aspect, the present disclosure provides a method for deploying a suture clip onto a suture. A suture clip can be received within a crimping mechanism positioned at a distal end portion of a suture clip deployment device. A free end of the suture can be passed through an aperture formed in the suture clip. A free end of the suture can be passed into a distal end portion of an inner lumen of an outer shaft of the suture clip deployment device. The crimping mechanism can apply a distributed, radially compressive force to the suture clip to plastically deform the suture clip and reduce the aperture to secure the suture within the suture clip. For example, the distributed, radially compressive force can be applied in at least two directions, such as to at least two opposing radial surfaces of the suture clip. In some cases, a distributed force can be sufficient to reduce an aperture of the suture clip, while reducing or eliminating bending or buckling of the axial surfaces of the suture clip. 
     In particular implementations, the suture clip can be radially compressed with a plurality of crimping members coupled to the suture clip deployment device. In some examples, radially compressing the suture clip with a plurality of crimping members can include radially compressing the suture clip at least at opposing radial sides. In another example, radially compressing the suture clip with a plurality of crimping members can include moving an inner shaft or the outer shaft of the suture clip deployment device axially with respect to the other, causing the plurality of crimping members to radially compress the suture clip to secure the suture. 
     In a further example, the plurality of crimping members can be configured to be actuated from a first position where the plurality of crimping members do not plastically deform the suture clip to a second position where the plurality of crimping members plastically deform the suture clip. For instance, when in the second position, the plurality of crimping members can apply a radially inwardly directed force to plastically deform the suture clip, such that an aperture formed in the suture clip can frictionally engage and secure one or more suture lines passing therethrough. In another example, in the first position, the plurality of crimping members can apply a radially inwardly directed force to the suture clip sufficient to secure the suture clip within the plurality of crimping members. 
     The method, in yet further implementations, can include severing one or more suture lines proximate the suture clip, such as proximate a proximal end of the suture clip. For example, the method can include axially moving a cutting member relative to the outer shaft. In a specific example, the one or more suture lines can extend through an aperture formed in the suture clip, through an inner suture aperture formed in the cutting member that is selectively alignable with an outer suture aperture formed in the outer shaft of the suture clip deployment device, and through the outer suture aperture. The suture clip deployment device can be selectively actuated from a first position where the inner and outer suture apertures are at least substantially aligned to a second position where the inner and outer sutures apertures are offset and sever the one or more suture lines passing therethrough. 
     In a further embodiment, the present disclosure provides a suture retaining device, such as a suture clip, that includes a suture retaining body that defines an outer surface and a suture aperture configured to receive and frictionally engage one or more sutures passing therethrough. The suture retaining device can include an atraumatic or biocompatible coating disposed on at least a portion of the outer surface of the suture retaining body. 
     In particular implementations, the suture retaining device, such as a suture clip, can be formed from a plastically deformable material. In some examples, the suture retaining device can be a flat suture clip, such as a flat suture clip having an at least generally circular or elliptical shape. For example, the suture clip can be disk-shaped. 
     In further implementations, the atraumatic or biocompatible coating is a biocompatible coating that can include one or more of heparin, an extracellular matrix, or one or more components of an extracellular matrix. In another implementation, the atraumatic or biocompatible coating is an atraumatic coating that can include one or more of a siloxane polymer, an olefin-based polymer, a copolymer, or a fluorinated polymer. In a specific example, the coating can be a felt, such as an expanded polytetrafluoroethylene felt. In further implementations, the atraumatic or biocompatible coating can encapsulate all or a portion of the suture retaining device, such as within a pillow of encapsulating material. For example, the coating can be coupled to the suture retaining body at least about the edges of the suture aperture such that the encapsulation does not obstruct suture access to the suture aperture. 
     The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of an embodiment of a suture clip delivery assembly, including a suture clip delivery device and a suture snare assembly. 
         FIG. 2  is a cross-sectional view of the suture clip delivery device of  FIG. 1 . 
         FIG. 3  is a detail view of a crimping assembly portion of the suture clip delivery device of  FIG. 2 . 
         FIG. 4  is an exploded view of a crimping assembly portion of the suture clip delivery device of  FIG. 1 . 
         FIG. 5  is perspective view of a crimping assembly portion of the suture clip delivery device of  FIG. 1 , with an outer surface of the crimping assembly portion shown in transparency. 
         FIG. 6  is an elevational view of components of the crimping assembly of the suture clip delivery device of  FIG. 1 , showing the crimping assembly in a first position configured to retain a suture clip. 
         FIG. 7  is an elevational view of components of the crimping assembly of the suture clip delivery device of  FIG. 1 , showing the crimping assembly in a second position configured to plastically deform a suture clip. 
         FIG. 8  is an elevational view of components of the crimping assembly of the suture clip delivery device of  FIG. 1 , showing the crimping assembly in a third position configured to release a suture clip from the crimping assembly and to sever a suture passing through the suture clip. 
         FIG. 9  is a perspective view illustrating the loading of a suture clip into a suture clip delivery device using a suture snare assembly. 
         FIG. 10  is a perspective view illustrating the threading of a suture through a suture clip loaded into a suture clip delivery device using a suture snare. 
         FIG. 11  a perspective view of suture lines secured within a crimped suture clip. 
         FIG. 12  is a perspective view illustrating the loading of a spacer and a suture clip into a suture clip delivery device using a suture snare assembly. 
         FIG. 13  is a perspective view illustrating the threading of a suture through a spacer and a suture clip loaded into a suture clip delivery device using a suture snare. 
         FIG. 14A  is a plan view of a suture clip according to an embodiment of the present disclosure. 
         FIG. 14B  is a plan view of a suture clip according to an embodiment of the present disclosure. 
         FIG. 14C  is a plan view of a suture clip according to an embodiment of the present disclosure. 
         FIG. 14D  is a plan view of a suture clip according to an embodiment of the present disclosure. 
         FIG. 14E  is a plan view of a suture clip according to an embodiment of the present disclosure. 
         FIG. 14F  is a plan view of a star-shaped suture clip in an uncrimped state according to an embodiment of the present disclosure. 
         FIG. 14G  is a plan view of the star-shaped suture clip of  FIG. 14F  in a crimped state. 
         FIG. 15  is a plan view of a suture clip according to an embodiment of the present disclosure. 
         FIG. 16A  is an elevational view of an encapsulated suture clip according to an embodiment of the present disclosure. 
         FIG. 16B  is an elevational view of an encapsulated suture clip according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved. 
     Features, integers, characteristics, compounds, chemical moieties, or groups described in conjunction with a particular aspect, embodiment, or example of the present disclosure are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The present disclosure is not restricted to the details of any disclosed embodiment. The present disclosure extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 
     Although the operations of some of the disclosed methods are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods, systems, and apparatus can be used in conjunction with other systems, methods, and apparatus. 
     As used herein, the terms “a,” “an,” and “at least one” encompass one or more of the specified element. That is, if two of a particular element are present, one of these elements is also present and thus “an” element is present. The terms “a plurality of” and “plural” mean two or more of the specified element. 
     As used herein, the term “and/or” used between the last two of a list of elements means any one or more of the listed elements. For example, the phrase “A, B, and/or C” means “A,” “B,” “C,” “A and B,” “A and C,” “B and C,” or “A, B, and C.” 
     As used herein, the term “coupled” generally means physically, magnetically, electrically, or chemically, coupled or linked and does not exclude the presence of intermediate elements between the coupled items absent specific contrary language. Components may be “directly coupled,” in which case the directly coupled components are linked without the presence of intermediate elements. 
     Described herein are suture clips, and devices and methods for securing sutures with suture clips.  FIGS. 1-10  illustrate an embodiment of a suture clip delivery assembly  10  that includes a suture clip deployment device  14  that can be loaded with a suture clip  28 , such as one of the disc-shaped suture clips shown in  FIGS. 14A-14E . While any of the disclosed suture clips can be used to secure a single suture, or can be used to secure plural sutures or suture segments at the same time, this description proceeds with reference to non-limiting examples wherein each suture clip is deployed onto two sutures segments for ease of description only. 
       FIG. 1  shows an example of a suture clip delivery assembly  10  according to one embodiment of the present disclosure. The suture clip delivery assembly  10  can include two main components: a suture clip delivery device or apparatus  14  and a suture snare assembly  16 . The suture snare assembly  16  can be used to thread a suture  18  into the suture clip delivery device  14 . 
     The suture clip delivery device  14  can include a handle portion  22  including a trigger or actuator  24 . An elongate shaft  26  can extend distally from the handle portion  22 , and the proximal end of the elongate shaft  26  can be coupled to the handle portion  22 . In particular implementations, the proximal end of the elongate shaft  26  can be disposed within the handle portion  22 . A suture clip  28  ( FIG. 4 ) can be disposed within a recess formed within the distal end  30  of the elongate shaft  26 . 
     The suture snare assembly  16  can include a suture snare  36 , such as looped length of wire. In particular examples, the suture snare  36  can be formed from a biocompatible flexible material including metals, such as stainless steel, for example 304 stainless steel, a nickel titanium alloy (“nitinol”), or other metals or alloys. In other implementations, the suture snare  36  can be formed from a polymeric material, such as polypropylene, or a natural fiber material. The suture snare  36  can be coupled to a handle  38 . The handle  38  can be curved or otherwise shaped to facilitate grasping or manipulation by a physician. The handle  38  can be made of any suitable material, including metals, such as stainless steel, or suitably rigid plastics. 
     The handle  38  can be configured to be inserted through one or more apertures  42  formed in the distal end  30  of the elongate shaft  26 . The suture snare  36  can pass through an aperture  44  ( FIG. 4 ) formed in the suture clip  28 . Thus, if the handle  38  is moved radially outwardly from the elongate shaft  26 , the suture snare can be drawn through the aperture  44 , through the lumen of the elongate shaft  26 , and radially outwardly from the aperture  42  formed in the elongate shaft  26 . 
     The suture snare  36  and the suture clip  28  can be releasably retained by a retaining member  46 . The retaining member  46  can have generally planar longitudinal surfaces and a thickness, or depth (dimension perpendicular to the page in  FIG. 1 ), relative to its major diameter (left-to-right dimension of the retaining member  46  in  FIG. 1 ). The retaining member  46  generally can be made from a flexible material, such as a plastic or rubber material. 
     The retaining member  46  can be at least generally planar and can define a groove  48  extending about the perimeter of the retaining member  46 . In another implementation, the groove  48  can be omitted, and the suture snare  36  releasably retained by the retaining member  46  by another method. For example, the retaining member  46  can have a thickness sufficient to securely receive the suture snare  36 , which can be maintained in contact with the retaining member  46  by placing the suture snare  36  under tension. In yet another implementation, the retaining member  46  can be made of a material that is resilient or provides enhanced frictional contact with the suture snare  36 . 
     In at least some aspects of the present disclosure, the suture snare  36  can be released from the retaining member  46  by flexing the retaining member. For example, the suture snare  36  can be removed from the retaining member  46  by applying opposing lateral forces to the distal and proximal ends of the retaining member, by twisting or rotating the retaining member, or similar manipulation. In a further implementation, one or more of the faces  50  of the retaining member  46  can define notches or recesses  52  adjacent one or more portions of the groove  48 , which can aid the suture snare  36  in slipping out of engagement with the groove, and thus being released from the retaining member. 
     As will be described in more detail, the suture  18  can be inserted through the opening in the suture snare  36 , and the suture snare can be drawn through the aperture  44  of the suture clip  28  and the aperture  42  of the elongate shaft  26 . As the handle  38  continues to move radially outwardly from the elongate shaft  26 , the suture  18  can be drawn through the aperture  44  of the suture clip  28  and the aperture  42  of the elongate shaft  26 . When the suture  18  extending distally from the distal end  30  of the elongate shaft  26  has reached a desired length, the suture clip  28  can be crimped or otherwise secured against movement relative to the suture  18 , and the suture can be cut proximally relative to the suture clip  28 . 
       FIG. 2  is a cross-sectional view of the suture clip delivery device  14 . The elongate shaft  26  can include an elongate outer shaft  58  and an elongate inner shaft  60  disposed within a lumen of the outer shaft  58 . A crimping assembly  64  can be disposed at the distal end  30  of the elongate outer shaft  58 . 
     The inner shaft  60  can be moveable axially relative to the outer shaft  58 . For example, one or more pins  68  may be formed on, or coupled to, the inner shaft and extend radially outwardly therefrom. Each of the one or more pins  68  can be coupled to a distal end of a biasing member  70 , such as a spring. When the suture clip delivery device  14  includes more than one pin  68 , the suture clip delivery apparatus  14  can include a corresponding number of biasing members  70 . In other aspects, the outer shaft  58  and the inner shaft  60  may be configured differently. For example, the outer shaft  58  may be made moveable relative to a fixed inner shaft  60 , or both the outer shaft and the inner shaft may be moveable relative to one another. 
     A proximal end of the biasing member  70  can be coupled to a pivot member  74  that can be disposed about a pin  76 . The pin  76  can assist in securing the biasing member  70  within the handle  22 , while allowing the pivot member  74  to rotate with respect to the pin. The biasing member  70  can be selected to provide a desired of resistance, and proximally directed force, on the inner shaft  60 , when the pivot member  74  is in a resting position. 
     The pivot member  74  can define a stop  80  configured to engage an edge  82  of the handle  22 , which can limit the rotation (counterclockwise, as shown) of the pivot member, and thus distal movement of the inner shaft  60 . Similarly, the pivot member  74  can define a notch  88  that can allow for rotation (clockwise, as shown) of the pivot member, and thus proximal movement of the inner shaft  60 , until a bottom surface  90  of the notch contacts the edge  82 . 
     In at least some embodiments, the pivot member  74  may be disposed proximally adjacent to a support member  94 . The support member  94  can help provide structural integrity to the pivot member  74  during actuation of the actuator  24 . The support member  94  can, in at least some implementations, also be used to maintain appropriate resting and actuated positions for the pivot member  74 . For example, the support member  94  can be coupled to the handle  22  or shaped so as to limit rotation of the pivot member  74 . 
     The support member  94  can, in some implementations, be coupled to a biasing member  96 . The biasing member  96  can be coupled to an aperture  98  of the support member  94  and an anchor  100  coupled to or formed in the handle  22 . The biasing member  96  can be selected to apply an opposing biasing force to the biasing member  70 . In various examples, the biasing member  96  can be coupled to the support member  94  or the handle  22  in a different manner, or the biasing member  96  can be omitted. 
     With reference to  FIGS. 3-5 , the crimping assembly  64  can include two crimping members  104  disposed partially within apertures  106  formed in the upper and lower radial surfaces of the outer shaft  58 . Each of the crimping members  104  can include an inner hinge member  108  and an outer hinge member  110 . The inner hinge members  108  can be disposed within triangular recesses  112  formed in the upper and lower radial surfaces of the inner shaft  60 , as shown in  FIG. 3 . The inner hinge members  108  can include an inner aperture  114  formed in the radial surface of the inner hinge members  108 . Pins  116  (see  FIG. 3 ) can be inserted through the inner apertures  114  and corresponding inner apertures  118  (see  FIG. 4 ) formed in the radial surfaces of the inner shaft  60 . 
     As shown in  FIG. 4 , the proximal end of each of the outer hinge members  110  can define a mounting fork  120  configured to receive an outer end of an inner hinge member  108 . Apertures  122  can be defined in the lateral surfaces of the mounting fork  120 . A pin  124  ( FIG. 3 ) can be inserted through the apertures  122  and an aperture  126  formed in the outer end of an inner hinge member  108 . 
     The outer hinge members  110  can extend into the apertures or recessed portions  106  formed in the outer shaft  58 . The outer hinge members  110  can be formed with a bent configuration, where a proximal portion has an obtuse angle relative to the axis of the outer shaft  58 , and a distal portion has an acute angle, or is straight, relative to the axis of the outer shaft. Apertures  130  ( FIG. 4 ) can be formed in the radial surfaces of the outer hinge members  110 , such as at or proximate an inflection point in the longitudinal surface of the outer hinge members. The outer hinge members  110  can be secured in the apertures or recessed portions  106  by inserting pins  132  ( FIG. 3 ) through the apertures  130  and corresponding apertures  134  formed in the radial surface of the outer shaft  58  ( FIG. 4 ). 
     The distal ends of the outer hinge members  110  can include jaw portions  140  extending laterally from the sides of the outer hinge members. The jaw portions  140  can be dimensioned to receive the suture clip  28 . For example, the jaw portions  140  are shown as arcuate to receive a circular suture clip  28 . If the suture clip has non-arcuate edges, or for other reasons, the jaw portions  140  can have non-arcuate shapes, including varying shapes (e.g., jagged or scalloped). The jaw portions  140  can help distribute a compressive force about the radial surface of the suture clip  28 . This distribution of force can help close the aperture  44  of the suture clip  28  while reducing bending, buckling, or other types of deformation of the surface of the suture clip. For example, it may be helpful to maintain more flat, or planar, axial surfaces of the suture clip  28 , as it may allow the suture clip  28  to be placed flush with devices, such as heart valve repair or replacement prostheses, or help reduce trauma to surrounding tissue by providing an even surface. The distribution of force can also provide for more reliable securement of one or more sutures  18  within the aperture  44 , as the compressive forces can be directed to closing the aperture  44 , rather than bending the suture clip  28 . 
     The outer shaft  58  can define an annular recessed portion  142  ( FIG. 4 ) surrounding a distal aperture  144  of the outer shaft  58 . The jaw portions  140  of the outer hinge members  110  can extend into the annular recessed portion  142 . The longitudinal portion of the outer hinge members  110  can extend through notches  146  formed in the upper and lower axial surfaces of the recessed portion  142 . The annular recessed portion  142  can be dimensioned to receive a suture clip  28 , such that the suture clip  28  can be releasably engaged by the jaw portions  140  of the outer hinge members  110 . 
     The crimping assembly  64  can further include an annular cutting member  150  disposed about the inner shaft  60 . The cutting member  150  can include axially elongate, such as oval-shaped, apertures  152  formed in opposing radial surfaces of the cutting member and a radial aperture  158 . The apertures  152  can receive pegs  156  radially extending from opposing radial surfaces of the inner shaft  60 . The length of the apertures  152  can be longer than the radius of the pegs  156 , which can allow the cutting member  150  to move proximally and distally with respect to the inner shaft  60 . The radial surface of the cutting member  150  can further define an inner suture aperture  158 . The inner suture aperture  158  can be configured to be selectively alignable with a radial aperture  154  of the inner shaft  60  and an outer suture aperture  162  formed in the radial surface of the outer shaft  58 . If desired, the sides of the inner suture aperture  158 , or the outer suture aperture  162 , can be sharpened, such as being provided with a cutting edge, to help sever the suture  18  when it extends through the inner and outer suture apertures  158 ,  162 . 
       FIGS. 6-8  illustrate the operation of the crimping assembly  64  as the inner shaft  60  is moved proximally with respect to the outer shaft  58  as the actuator  24  is actuated.  FIG. 6  illustrates the crimping assembly  64  in a resting position, prior to actuation of the actuator  24 . The inner hinge members  108  can be located proximally within the apertures  112 . The outer hinge members  110  can be angled such that, when the inner hinge members  108  are proximally located, the jaw portions  140  of the outer hinge members  110  are biased radially inwardly. When a suture clip  28  is positioned within the jaw portions  140 , the jaw portions can exert a radially inwardly directed force, which can help retain the suture clip  28  within the suture clip delivery device  14  while a suture  12  is being inserted proximally into the aperture  44  of the suture clip and radially outwardly through the inner suture aperture  158  and the outer suture aperture  162 . 
     The pegs  156  of the inner shaft  60  can be positioned at distal ends of the apertures  152  of the cutting member  150 , which can place the aperture  158  of the cutting member  150  in alignment with the suture aperture  162  of the outer shaft  58 . Thus, in the resting position shown in  FIG. 6 , the crimping assembly  64  can be configured to receive and retain a suture clip  28  within the jaw portions  140  of the outer hinge members  110 . A suture  18  can be received through the aperture  44  of the suture clip  28 , through the inner suture aperture  158  of the cutting member  150 , and radially outwardly through the outer suture aperture  162  of the outer shaft  58 . 
     As shown in  FIG. 7 , as the inner shaft  60  is moved proximally with respect to the outer shaft  58  (see  FIGS. 4 and 5 ), proximal movement of the pins  116  can cause the inner hinge members  108  to rotate distally about the pins, applying a radially outwardly directed force to the outer hinge members  110  through the pins  124 . In turn, the distal ends of the outer hinge members  110  can rotate radially inwardly about the pins  132 . As the distal ends of the outer hinge members  110  rotate radially inwardly, the jaw portions  140  can exert a compressive force on the suture clip  28 , which can cause the suture clip to plastically deform and the aperture  44  of the suture clip to narrow. If a suture  18  is inserted through the aperture  44 , the suture can be secured against movement relative to the suture clip  28  (e.g.,  FIG. 11 ). During this initial clamping motion ( FIG. 6  to  FIG. 7 ), the pegs  156  of the inner shaft  60  can move proximally relative to the apertures  152  of the cutting member  150 . However, the alignment between the inner suture aperture  158  and the outer suture aperture  162  can be maintained. 
     Referring to  FIG. 8 , when the inner shaft  60  is moved further proximally from the position of  FIG. 7 , the inner hinge members  108  can continue to rotate distally about the pins  116 . The distal movement of the inner hinge members  108  can cause the inner hinge members to exert a radially inwardly directed force on the outer hinge members  110  through the pins  124 , which can cause the distal ends of the outer hinge members  110  to rotate radially outwardly about the pins  132 . The radially outward rotation of the distal ends of the outer hinge members  110  can cause the jaw portions  140  to be released from engagement with the suture clip  28 , which can allow the suture clip and the suture  18  to be released from the recess  142  of the outer shaft  58 . 
     As the inner shaft  60  moves proximally, the pegs  156  can move proximally within the apertures  152  (e.g., from  FIG. 6  to  FIG. 7 ), contacting the proximal lip of the apertures  152 . Further proximal motion of the inner shaft  60  (e.g., from  FIG. 7  to  FIG. 8 ) causes the cutting member  150  to move proximally along with the inner shaft  60  relative to the outer shaft  58 . As the cutting member  150  moves proximally, the inner suture aperture  158  can move proximally with respect to the outer suture aperture  162  ( FIG. 5 ), which can sever a suture  18  inserted through the inner suture aperture  158  and the outer suture aperture  162 . 
     After the actuator  24  is no longer activated, the inner shaft  60  can move distally relative to the outer shaft  58 , returning to the resting position illustrated in  FIG. 6 . 
     It should be appreciated that changes can be made to the crimping assembly  64  without departing from the scope of the present disclosure. For example, if desired, the cutting member  150  can be configured to cut the suture  18  while the suture aperture  44  is being compressed. Although two crimping members  104  are illustrated, the crimping assembly  64  can include a larger number of crimping members  104 , which may be used to further distributed the radially compressive force applied to the suture clip  28 . In another example, the crimping assembly  64  can include a single crimping member that is configured to apply a distributed, radially compressive force to the suture clip  28 . 
       FIGS. 9 and 10  illustrate a method of using the suture clip delivery assembly  10 . The handle  38  of the suture snare  36  can be inserted through the aperture  144  in the distal end of the outer shaft  58 , through the inner suture aperture  158  ( FIG. 4 ) of the cutting member  150 , and radially outwardly through the outer suture aperture  162 . As shown in  FIG. 9 , the suture clip  28  can be in contact with a longitudinal end surface  170  of the retaining member  46 . The longitudinal surface  170  can be, at least in some examples, formed on a laterally protruding support member  172 . The laterally protruding support member  172  can, for example, help support the suture snare  36 , and the groove  48  may extend through the longitudinal surface of the laterally protruding support member  172 . 
     In some cases, the suture clip  28  can rest adjacent the longitudinal surface  170  until the suture clip is inserted into the recess  142  of the outer shaft  58 . In other cases, the longitudinal surface  170  can include features to help maintain the suture clip  28  in contact with the retaining member  46 . For example, an annular recess (not shown), or a recess otherwise dimensioned to at least partially receive the suture clip  28 , may be formed in the longitudinal surface  170 . The recess may be configured to exert a slight compressive force on the suture clip  28  in order to retain the suture clip until the suture clip is transferred to the recess  142  of the outer shaft  58  and received within the jaw portions  140  of the outer hinge members  110 . 
     When the suture clip  28  has been transferred into the recess  142 , the suture snare  36  can be released from the retaining member  46  by appropriate manipulation, such as flexing, of the retaining member, including releasing the portions of the suture snare proximate the notches  52 . 
     Referring now to  FIG. 10 , the suture snare  36  can be pulled through the aperture  44  of the suture clip  28 , through the inner suture aperture  158  of the cutting member  150 , and then radially outwardly through the outer suture aperture  162  of the outer shaft  58 . Continued application of a radially outwardly directed force to the handle  38  can pull the suture  18 , threaded through the suture snare  36 , through the aperture  44  of the suture clip  28 , through the inner suture aperture  158  of the cutting member  150 , and then radially outwardly through the outer suture aperture  162  of the outer shaft  58 . 
     When the suture  18  is at the desired position, such as proximate tissue to be approximated or ligated with the suture, a physician can activate the actuator  24 , causing the crimping assembly  64  to crimp the suture clip  28 , which can cause the suture clip to plastically deform, reducing the size of the aperture  44 , to secure the suture within the suture clip, as described above with reference to  FIGS. 6-8 , and as illustrated in  FIG. 11 . 
     According to a further embodiment, the present disclosure can provide for one or more members to be disposed between tissue to be approximated or ligated with a suture and a suture retaining device such as a suture clip. In a particular implementation, a spacer, such as a bushing, can be disposed between the suture retaining device and the tissue. For example, the bushing can be disposed between a suture clip and the sewing ring of a prosthetic heart valve. Using a spacer intermediate the suture retaining device and the tissue to be approximated or ligated (including a spacer adjacent a medical device to be secured to the tissue) can help provide flexibility about the suture point, particularly if the spacer is formed from a resilient material. In other cases, the spacer can be constructed from a material that has improved biocompatibility compared with the suture retaining device, which can in turn improve the biocompatibility of the suture retaining device. Similarly, the spacer can help reduce trauma to tissue or a medical device proximate the suture retaining device, particularly if the suture retaining device may have any sharp or irregular surfaces. 
       FIGS. 12 and 13  are generally similar to  FIGS. 9 and 10 , but include a spacer  190 , such as a bushing. In some cases, the spacer  190  can be sized or shaped similarly to the suture clip  28 . In other cases, the spacer  190  can have a different size and/or shape than the suture clip  28 . In a particular example, a disc-shaped spacer  190  can be used with a non-disc shaped suture clip  28 . 
     With reference to  FIG. 12 , the spacer  190  can be disposed on the longitudinal end surface  170  of the retaining member  46 . The suture clip  28  can be disposed adjacent the spacer  190 . The suture clip  28  can then be loaded into the suture clip delivery device  14  as described with respect to  FIG. 9 . 
     Referring now to  FIG. 13 , the suture snare  36  can be pulled through an aperture  192  of the spacer  190 , through the aperture  44  of the suture clip  28 , through the inner suture aperture  158  of the cutting member  150 , and then radially outwardly through the outer suture aperture  162  of the outer shaft  38 . As the handle  38  is continued to be moved radially outwardly from the outer shaft  58 , the suture  18  can be pulled through the aperture  192  of the spacer  190 , through the aperture  44  of the suture clip  28 , and through the outer suture aperture  162  of the outer shaft  58  in a similar manner as the handle  38 . The suture clip  28  can be crimped and secured to the suture  18  as described above with reference to  FIG. 10 . Although the suture clip  28  can be maintained within the jaw portions  140  during the process of threading the suture  18  through the suture clip  28  and suture clip delivery device  14 , the spacer  190  can remain outside of the jaw portions  140 , and thus can be moveable over the suture snare  36  and the suture while the suture clip is being crimped to the suture. 
       FIGS. 14A-14G  illustrate plan views of various examples of suture clips  28  that may be used with the suture clip delivery device  14 . Generally, the suture clips  28  can have a thin thickness, or depth, (dimension perpendicular to the page in  FIGS. 14A-14G ) relative to their major dimension, or diameter. The thickness can be relatively uniform for the whole suture clip  28 , and can be substantially smaller relative to the diameter of the suture clip  28  (left-to-right dimension in  FIGS. 14A-14G ), such as less than 25% of the diameter, less than about 15% of the diameter, less than about 10% of the diameter, and/or less than about 5% of the diameter. 
     The suture clips  28 , and other suture clip embodiments, can be made from a variety of materials including, for example, stainless steel, titanium, titanium alloys or other metal alloys, various plastics, and other biologically-compatible materials. 
     The suture clip  200  of  FIG. 14A  can include a tapered aperture  202  with a notch  204  formed in a first end  206  of the aperture  202 , the first end of the aperture being wider than, and tapering to, a second end  208  of the aperture. The outer radial surface  210  of the suture clip  200  can include a notch  212  proximate to, and nested within, the notch  204  of the aperture  202 . The notches  204 ,  212  can make the side of the suture clip  200  proximate the notches  204 ,  212  more susceptible to being bent or radially compressed when compressive forces are applied to radial sides of the suture clip  200 , perpendicular to the longitudinal axis of the aperture  202 . 
       FIG. 14B  illustrates a suture clip  220  that can have a generally circular outer surface  222  and defines a generally elliptical aperture  224 , with arcuate or rounded portions  226  defined at the vertices of the aperture. The arcuate portions  226  can help reduce stress at the vertices of the aperture  224  when the suture clip  220  is crimped. 
     The suture clip  230  of  FIG. 14C  can have an at least generally elliptical radial outer surface  232  and can define an at least generally elliptical aperture  234 . The at least generally elliptical radial outer surface  232  can allow the suture clip  230  be crimped with lower compressive forces than, for example, suture clips  28  having a circular shape. 
       FIG. 14D  illustrates a suture clip  240  that can have an at least generally circular outer surface  242  and defines an aperture  244  that can have an irregular or jagged perimeter including angled protruding sections  246  and angled recesses  248 . When crimped, the angled protruding sections  246  and angled recessed portions  248  can be placed into contact with one another, which can provide a roughened surface or tortuous path that can help prevent the suture  18  from slipping axially or radially with respect to the suture clip  240 . 
     The suture clip  250  of  FIG. 14E  can have a generally annular radial surface  252  defining a generally annular aperture  254 . The diameter of the aperture  254  can be selected to provide a desired degree of resistance to crimping of the suture clip  250 . That is, a larger diameter aperture  254  may be easier to crimp, as there can be less material to deform. 
     A star-shaped suture clip  260  is shown in  FIG. 14F . The suture clip  260  can define a plurality of outer triangular points  262  and corresponding outer triangular recesses  264 , and a plurality of inner triangular points  266  and corresponding triangular recesses  268  of a central aperture  270 . As shown, each of the outer triangular points  262  is aligned with an inner triangular recess  268 . Similarly, each of the outer triangular recesses  264  is aligned with an inner triangular point  266 . Although the suture clip  260  is shown with seven outer triangular points  262 , outer triangular recesses  264 , inner triangular points  266 , and outer triangular recesses  268 , in other implementations, the suture clip  260  can have another number of points  262 ,  266  and/or recesses  264 ,  268 . In addition, the shape of the suture clip  260  can be varied, such as having scalloped, rather than triangular, points and recesses. 
     When used with the crimping assembly  64  (e.g.,  FIGS. 3-4 ), the jaw portions  140  can be shaped to apply a radially-inwardly directed crimping force to the outer triangular recesses  264 , and in turn to the inner triangular points  266 .  FIG. 14G  illustrates the suture clip  260  in a crimped state. As the crimping force is applied, the width of the inner triangular recesses  268  can reduce, which can trap suture  18  in the inner triangular recesses, or within the central aperture  270  of the suture clip  260 . The size of the central aperture  270  can also be reduced as the crimping force is applied to the suture clip  260 . The pattern of the points  262 ,  266  and recesses  264 ,  268  can facilitate crimping of the suture clip  260 , as well as allowing the suture clip to be compressed symmetrically. 
       FIG. 15  illustrates an embodiment of a suture clip  300  shown in a crimped state, or otherwise configured to secure a suture  18 . The suture clip  300  can be generally disk shaped with two suture engagement flaps  304  that project inwardly toward each other and define a suture engagement slot  306 . The suture engagement slot  306  can include a tortuous portion  308  at either end to prevent sutures that are pinched between the flaps  304  in the suture engagement slot  306  from sliding laterally out of the slot into either of the arcuate slots  310  that extend from the ends of the slot. The arcuate slots  310  space the flaps  304  from an outer annular portion  312  of the clip  300  and allow the flaps  304  to articulate out of the plane of  FIG. 15  while the outer annular portion  312  stays generally in or near the plane of the  FIG. 15 . The arcuate slots  310  can include enlarged, rounded end portions  314  that can reduce stress concentrations in the clip material around them when the flaps  304  are resiliently deformed out of plane.  FIG. 15  also shows two tabs  316  at diametrically opposite sides of the clip  300 . 
     In some embodiments, the suture clips  300  can be formed from nitinol (e.g., with an alloy of nickel at about 54.5-57% by weight with titanium accounting for the balance except for residual amounts (less than 0.05% each) of oxygen, carbon, and hydrogen) or another shape memory and/or pseudoelastic material, with the suture clips  300  formed so that the clip assumes its closed position (e.g., the flat position shown in  FIG. 15 ) when in the austenite condition (e.g., when generally unstressed at body temperature). The nitinol can have an austenite finish temperature selected to match the particular application. For example, an austenite finish temperature of from about −5 degrees to about +15 degrees Celsius may be selected. 
     A suture clip, such as the suture clip  300 , can be formed from material that will assume its martensite condition when subjected to sufficient stress, such as the stress applied to the clip&#39;s engagement flaps  304  and annular outer body  312  when the suture clip  300  is mounted for deployment. In such an embodiment, the stress applied to the engagement flaps  304  can be sufficient to force the engagement flaps to open wide enough to allow one or more suture lines through the slot  306 . The stressed material, including the bent material where the engagement flaps  304  join the annular outer body  312 , is forced into its martensite condition. When the stress is removed, such as when the clip  300  is deployed, the material can return to its austenite condition so that the annular outer body  312  and the engagement flaps  304  can assume their flat shape shown in  FIG. 15 . 
     According to another aspect, the present disclosure provides suture retaining devices, such as clips, that can have atraumatic or biocompatible properties. These suture retaining devices can include, for example, a suture clip  28  as previously described (e.g., the suture clips  200 ,  220 ,  230 ,  240 ,  250 ,  260  of  FIGS. 14A-14G ), the suture clip  300  ( FIG. 15 ), or other types of suture clips or suture securing or retaining devices, including crimp able cylinders or suture retaining devices made from plastically deformable materials, or from shape memory and/or pseudoelastic materials, such as nitinol. Suitable suture retaining devices are disclosed in U.S. Pat. Nos. 6,626,930; 9,017,347; 8,753,373; 8,777,968; 7,628,797; U.S. Patent Application Publication No. US 2007/0005079 A1; and U.S. Patent Application Publication No. US 2014/0031864 A1; the entire contents of each of these documents are expressly incorporated by reference.  FIG. 11  illustrates a suture clip  28  having an atraumatic or biocompatible coating  180 . 
     According to one implementation, the suture retaining devices can be coated with a polymer that can help reduce trauma to tissues placed into contact with a suture retaining device or improve the biocompatibility of the suture retaining device, such as by making the surface of the suture retaining device less rigid. The polymer can be a biocompatible polymer, including various types of medical grade elastomers. Suitable elastomers can include silicone rubbers, for example, a siloxane polymer such as a polydimethylsiloxane polymer, a medical grade olefin-based elastomer, or copolymers, such as ethyl vinyl acetate. In specific examples, the polymer is a silicone elastomer, for example SILASTIC® (Dow Corning Corp., Midland, Mich.) polymer. In other examples, the polymer can be a fluorinated polymer, such as poly(tetrafluoroethylene) (PTFE). When a suture clip  28  is used with a spacer  190 , the spacer  190  may be formed from, or coated with, a biocompatible polymer, instead of, or in addition to, coating or treating the suture clip  28 . 
     The polymer can be applied in various forms, including coatings of various thicknesses, in expanded forms (such as ePTFE), including felts or pillows. In a specific example, the suture retaining device can be fully or partially encapsulated by the polymer, such as being encapsulated by a pillow formed from the polymer. In some cases, the encapsulating material can be secured to the suture retaining device in a manner than does not inhibit suture access to a suture aperture of the suture retaining device. For example, the encapsulating material can be secured to suture retaining device about the perimeter of the suture aperture. In another example, the encapsulating material can be bonded to the suture retaining device, and one or more slits aligned with the suture aperture may be formed in the encapsulating material. 
       FIG. 16A  illustrates an encapsulated suture retaining device  350 . The encapsulated suture retaining device  350  can include a suture retaining device  354  defining a suture aperture  356 . The suture retaining device  354  can be surrounded by a layer of encapsulating material  358 . The encapsulating material  358  can be bonded to the suture retaining device  354 , such as being mechanically, chemically, or thermally bonded to the suture retaining device. One or more slits  360  can be formed in the faces  362  of the encapsulating material  354 , such as a slit being formed in each face. The slits  360  can cooperate with the suture aperture  356  to define an opening through which one or more sutures may pass. If desired, excess encapsulating material  354  may be trimmed, such as shown in the encapsulated suture retaining device  370  of  FIG. 16B , which can be otherwise similar to the encapsulated suture retaining device  350  of  FIG. 16A . 
     According to one method of forming an encapsulated suture retaining device, such as the encapsulated suture retaining device  350  or the encapsulated suture retaining device  370 , a suture retaining device can be placed on a layer of encapsulating material. The encapsulating material can be folded over the suture retaining device. Alternatively, the suture retaining device can be inserted into a pouch of encapsulating material. 
     The edges of the encapsulating material, such as an end of a pouch or edges of folded encapsulating material, can be sealed to fully encapsulate the suture retaining device. Suitable sealing methods include mechanical, thermal, or chemical sealing. For example, edges of the encapsulating material can be sealed together, and optionally to surfaces of the suture retaining device, using an adhesive. 
     A slit can be formed in the encapsulating material to cooperate with an aperture of the suture retaining device to define an opening through which one or more lines of suture material may be inserted. Optionally, excess encapsulating material can be trimmed so that the encapsulated suture retaining device is dimensioned more similarly to a non-encapsulated suture retaining device, which may be useful, for example, in using an encapsulated suture retaining device with a suture retaining device delivery device. 
     In another implementation, the suture retaining devices can be coated or otherwise treated with a polymer or other material to improve biocompatibility, including hemocompatibility. For example, a suture retaining device can be treated with a material that can repel materials that might foul the surface of the suture retaining device, such as proteins, platelets, or cells, and be nonthrombogenic. One suitable class of materials can be hydrogel materials. The surface treatment can include biological materials, including biological materials to help the suture retaining device be nonthrombogenic, to encourage tissue ingrowth to help the suture retaining device become incorporated into surrounding tissue, or to otherwise improve biocompatibility. When a suture clip  28  is used with a spacer  190 , the spacer  190  can be coated or otherwise treated with such a biocompatible material, in addition to, or instead of, coating the suture clip  28 . 
     In a particular example, the suture retaining device can be coated with heparin or a material that incorporates heparin. For example, heparin, or components thereof, may be incorporated into a polymer that is then used to surface treat the suture retaining device. In other examples, the surface treatment can include treatment with an extracellular matrix (such as from a decellularized tissue scaffold) or components of the extracellular matrix, such as heparin, chondroitin, keratin, hyaluronic acid, collagen, elastin, fibronectin, laminin, or galectin. 
     In particular implementations, the suture retaining device can be coated with multiple materials. For example, a first polymer may be coated with a second polymer, where the second polymer can improve the biocompatibility of the first polymer. In a further example, the first or second polymer can incorporate a biologically active material, such as heparin. In yet another example, a polymer can be coated with a biologically active material, such as heparin, one or components of the extracellular matrix, an extracellular matrix, or combinations thereof. 
     In some implementations, surface treatments can be applied to a portion of a suture retaining device, such as to one side of a suture clip. In further implementations, surface treatments can be applied to multiple portions, or all, of the suture retaining device, such as both sides of a suture clip. When surface treatments are applied to multiple portions of a suture retaining device, the surfaces treatments can be the same, in some examples, while in other examples the surface treatments can be different. 
     The technologies from any example can be combined with the technologies described in any one or more of the other examples. In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the disclosed technology. We therefore claim all that comes within the scope of the following claims.