Abstract:
The present invention provides apparatuses, systems, methods and kits for fastening sutures or similar devices used in medical surgical procedures. In particular, the present invention is suitable for use with percutaneous or minimally invasive procedures in which sutures are placed with catheter-based devices wherein the tying of knots is particularly challenging. Suture fasteners of the present invention provide for fastening the sutures together in a fixed position at any location along the suture strands. In addition, the fasteners are adjustable to allow repositioning of the fastener after placement to a new desired location along the suture strands. Similarly, such fasteners may be used to hold a single suture strand for various applications.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 10/087,004, filed Mar. 1, 2002, the full disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to medical methods, systems and kits. Particularly, the present invention is related to methods and apparatuses for holding one or more suture strands in a configuration so as to fasten. 
     Sutures are typically used to hold tissue in desired positions, such as to close wounds or to correct malformations. The suture lines are threaded through the tissue any number of times and held in place to maintain the new tissue configuration. In order to hold the suture taught over an extended period of time, a knot is commonly formed in the suture ends. Suturing is often thought of as an art form learned over an extended period of time. There are many types of sutures and knots, each providing certain advantages in a particular operative setting. At least as complicated as the suturing itself is the knot-tying which must occur to secure each of the sutures. Where individual sutures are placed to close a long wound, an individual knot is tied in each place. 
     Knots differ considerably in their configuration, function, complexity and characteristics. By way of example, it will be noted that knots typically involve several throws of the sutures ends relative to each other. In one common knot, three half-hitches are used with the first half-hitch having four throws and each subsequent half-hitch having three throws. In this case, tying of a single knot to close a single suture involves ten throws. The simplest knots may be easier to tie, but in distant locations even the simple knots can be complicated where it is difficult to achieve proximity to the suture site. In these locations, more complicated slip knots have been used. These knots can be tied at a remote location and then slipped down to the surgical site. Except for a few extremely complex knots, slip knots have the undesirable tendency to slip in both directions. As a result, their ease of tying and movement to the surgical site is offset by their tendency to lose their grip at the suture site. 
     From these few examples, it can be appreciated that knots, as a suture-fastening system, are time-consuming, difficult to tie, hard to place, often unreliable as a holding system, difficult to adjust and impossible to relocate. This is particularly the case in the context of percutaneous, endovascular, laparoscopic, minimally invasive or robotic procedures. For these reasons, it would be desirable to provide alternative methods, systems, and kits for fastening sutures or similar devices which overcome at least some of the shortcomings noted above. 
     2. Description of the Background Art 
     Hart et al., U.S. Pat. No. 6,099,553, describes a suture system for closing a wound. The suture system includes a securing mechanism having a plurality of tines wherein the mechanism has a first position for capturing suture ends and a second position for permanently holding the suture ends in a fixed relationship. In a third position, the securing mechanism frictionally engages the suture ends in a sliding relationship. 
     Batra, U.S. Pat. No. 4,510,934, describes a surgical suture which consists of a monofilament core and a braided sheath surrounding the core. The core is later removed whereupon the sheath becomes flexible for tying into a secure knot. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides apparatuses, systems, methods and kits for fastening sutures or similar devices used in medical surgical procedures. In particular, the present invention is suitable for use with minimally invasive procedures in which sutures are placed with catheter-based devices wherein the tying of knots is particularly challenging. Suture fasteners of the present invention provide for fastening the sutures together in a fixed position at any location along the suture strands. In addition, the fasteners are adjustable to allow repositioning of the fastener after placement to a new desired location along the suture strands. Similarly, such fasteners may be used to hold a single suture strand for various applications. 
     In a first aspect of the present invention, the suture fastener for adjustably holding one or more suture strands comprises at least one fastening element comprised of a shape-recovery material or other suitable metal, polymer or combination, wherein the element has a tensioned position for engaging the suture strands while allowing sliding of the element relative to the suture strands and a relaxed shape-recovery position for holding the strands in a fixed position relative to the element or to each other. It may be appreciated that the term “tensioned position” is used to describe a position from which the element converts and assumes the shape-recovery position upon proper activation, such as stimulus or release or force. For example, the element may be placed under tension, compression, extension or any high potential energy state when in the tensioned position. Release of the force holding the element in this state allows the element to assume a relaxed shape-recovery position. Alternatively, the element may be in a tensioned position when no external force is applied but wherein the application of heat or energy transitions the form of the element to a relaxed shape-recovery position. Thus, the term “tensioned position” is not intended to limit the scope of the application to only positions under mechanical tension. In the tensioned position, the element holds the suture strands along a substantially straight path to provide ease of sliding. In the relaxed shape-recovery position, the element holds the suture strands along a tortuous path. In some embodiments, the suture strands are held along the same path and in others, wherein the suture strands comprise a first suture strand and a second suture strand, the first strand follows a first tortuous path and the second strand follows a second tortuous path which differs from the first tortuous path. And, in some embodiments, the tortuous path has a zig zag form or other non-linear form. 
     The suture fastener may take a variety of forms. In some embodiments, the suture fastener comprises a fastening element comprising a coil. In some of the coil embodiments, each turn of the coil has a circular, elliptical, square or triangular shape, to name a few, when the element has the relaxed shape-recovery position. In addition, the coil may further comprise at least one suture retention loop, typically having a circular or elliptical shape. The suture retention loop(s) of each coil turn may be disposed in diametrical opposition when the element has the relaxed shape-recovery position, such as along a long axis of the elliptical shape when so shaped. Alternatively, the suture retention loop(s) may be spaced along each coil turn in a uniform or varied pattern. In other embodiments, each turn of the coil has a figure-eight shape comprising two lobes when the element has the relaxed shape-recovery position and one suture retention loop is disposed within each lobe. The suture retention loops are thus disposed in concentric alignment when the element has the tensioned position. 
     In other embodiments, the suture fastener comprises a fastening element which has a flat shape when in the tensioned position and the element has a curved or bent shape in the relaxed shape-recovery position. For example, the element may comprise an elongate wire, ribbon, rod, filament or shaft having two or more apertures along its length. In preferred embodiments, the element comprises a ribbon having a width in the range of approximately 0.030 to 0.120 inches and a thickness in the range of approximately 0.002 to 0.020 inches. Suture strands are threaded through the apertures so that the element is slidable along the strands in the tensioned position. However, the curved shape of the element in the relaxed shape-recovery position prevents such sliding of the element and fixes the element in place. 
     In further embodiments, the suture fastener comprises two or more elements which interlock when the elements are in the relaxed shape-recovery position. Generally, the elements may be separated, straightened, held open or untwisted in the tensioned position so that the suture strands may be placed within or between them. In this arrangement, the elements may be moved relative to the suture strands to adjust the position of the elements along the strands. When the elements return to the relaxed shape-recovery position, the elements interlock around the strands so that the strands are held in a fixed position relative to the element and each other. 
     In additional embodiments, the suture fastener comprises a fastening element having a first edge having at least one first through hole adjacent thereto and a second edge having at least one second through hole adjacent thereto, wherein the at least one first aperture is concentrically aligned with the at least one second aperture when the element is in the tensioned position and the at least one first aperture is misaligned with the at least one second aperture when the element is in the relaxed shape-recovery position. The at least one pair of through holes may be bounded on all sides in both the tensioned position and the relaxed position. To achieve this, the element has a cylindrical or triangular shape wherein at least part of the first portion overlaps at least part of the second portion when the element is in the tensioned position. In this configuration, suture strands may be threaded through the apertures in a stitching-type fashion. Thus, transition of the element to the relaxed configuration draws the portions apart placing the strands along a tortuous path. 
     In any of the above embodiments, transition from the tensioned position to the relaxed position may be achieved by any means, such as by release of a force on the element or by a change in temperature of the element. 
     In a second aspect of the present invention, a method for securing two or more suture strands together comprises the steps of providing at least one fastening element comprised of a shape-recovery material, wherein the element is in a tensioned position for engaging the suture strands while allowing sliding of the element relative to the suture strands, engaging the suture strands with the element and transitioning the element to a relaxed shape-recovery position wherein the strands are in a fixed position relative to the element or to each other. The engaging step typically comprises positioning the suture strands along a path through at least a portion of the element. In some instances, the engaging step comprises positioning a first suture strand along a first path and a second suture strand along a second path which differs from the first path. When the element comprises a coil where each turn of the coil includes two suture retention loops, the positioning step may include positioning the suture strands through two or more suture retention loops. And when the suture retention loops of each coil turn are disposed in diametrical opposition when the element is in the relaxed shape-recovery position, the positioning step may include positioning the suture strands through successive suture retention loops so that the strands follow a path having a zig zag form when the element is in the relaxed shape-recovery position. 
     The providing step of the methods of the present invention may include loading the element on a loading tool. Alternatively, the element may already be loaded on the loading tool and the providing step comprises providing the element loaded on or within a loading tool. In either situation, the transitioning step comprises releasing the element from the loading tool. 
     When the element comprises an elongate wire, ribbon, rod, filament or shaft, the engaging step may comprise positioning the suture strands near at least two elements so that the elements capture the suture strands during the transitioning step by interlocking with each other. When the element comprises an elongate wire, ribbon, rod, filament or shaft having two or more apertures along its length, the positioning step may comprise positioning the suture strands through at least two apertures, such as in a stitching fashion. Similarly, when the element has a first portion having at least one first aperture and a second portion having at least one second aperture, the positioning step may comprise positioning the suture strands through at least one first aperture and at least one second aperture. This is easily achieved when the element has at least one first aperture concentrically aligned with at least one second aperture and the positioning step comprises positioning the suture strands through apertures in a stitching fashion. 
     With any of the above described embodiments of the fastening elements, the element may be slid along the suture strands to a desired position prior to transitioning to the relaxed shape-recovery position. Once transitioned, the position of the element along the suture strands may be adjusted. The adjusting step may comprise transitioning the element to the tensioned position and moving the element in relation to the suture strands. 
     In a third aspect of the present invention, a system for adjustably holding one or more suture strands comprises at least one fastening element comprised of a shape-recovery material, wherein the element has a tensioned position for engaging the suture strands while allowing sliding of the element relative to the suture strands and a relaxed shape-recovery position for holding the strands in a fixed position relative to the element or to each other, and a loading tool having a proximal end, a distal end and a lumen therethrough, wherein the element is loadable on the loading tool. In some embodiments, the loading tool further comprises a shaft near the distal end. In such instances, the element may comprise a coil which is mountable on the shaft. When each turn of the coil includes at least one suture retention loop, the coil may be loadable on the loading tool by inserting the shaft through at least one of the suture retention loops. 
     The system may further comprise at least one suture strand which is engageable by the element. Here, the loading tool may comprise a shaft near the distal end which houses at least a portion of the lumen through which the suture strand is threadable. 
     In a fourth aspect of the present invention, a suture fastening system for adjustably holding one or more suture strands comprises a delivery catheter comprising a proximal end, a distal end, and a lumen therethrough; and a suture fastener loadable on the distal end of the delivery catheter, said fastener comprising a ratcheting mechanism which is adapted to hold a suture strand at a first location and then release the strand and hold the strand at a second location upon adjustment, wherein the first and second locations are a predetermined distance apart. In some embodiments, the system further comprises at least one suture strand, wherein the strand has at least a first protuberance disposed near the first location and a second protuberance disposed near the second location. The suture strand may comprise a fiber, thread, filament, wire or cord and at least one protuberance may be selected from the group consisting of knots, beads, balls, ribs, and spokes. Further, the suture strand or at least one protuberance may be comprised of a material selected from the group consisting of stainless steel, nitinol, metal, polymer, silicone, latex, epoxy, cotton, nylon, polyester, and polytetrafluoroethylene-. In some embodiments, the ratcheting mechanism comprises at least two flexible arms having stoppers mounted thereon which are engageable with the protuberance. In most of these instances, the suture fastener may be loadable within the lumen of the delivery catheter. 
     In a fifth aspect of the present invention, a method for adjustably holding a suture strand comprises the steps of providing a delivery catheter comprising a proximal end, a distal end, and a lumen therethrough, loading a suture fastener on the distal end of the delivery catheter, said fastener comprising a ratcheting mechanism which is adapted to hold the suture strand at a first location and then hold the strand at a second location upon adjustment, wherein the first and second locations are a predetermined distance apart, and engaging the suture fastener with the suture strand at the first location. In some embodiments where the suture strand has at least a first protuberance disposed near the first location, wherein the ratcheting mechanism comprises at least two flexible arms each having a stopper mounted thereon which are engageable with the first protuberance, the loading step comprises positioning the suture strand so that the stopper engages the first protuberance. The method may further comprise adjusting the suture strand by advancing the strand through the fastener so that the fastener engages the strand at the second location. Thus, when the suture strand has at least a second protuberance disposed near the second location, wherein the ratcheting mechanism comprises at least two flexible arms each having a stopper mounted thereon which are engageable with the second protuberance, the loading step may comprise advancing the suture strand so that the stopper engages the second protuberance. 
     The methods, systems and apparatuses of the present invention may be provided in one or more kits for such use. The kits may comprise at least one fastening element comprised of a shape-recovery material, wherein the element has a tensioned position for engaging the suture strands while allowing sliding of the element relative to the suture strands and a relaxed shape-recovery position for holding the strands in a fixed position relative to the element or to each other, and instructions for use. Or, kits may comprise a ratcheting mechanism which is adapted to hold a suture strand at first location and then release the strand and hold the strand at a second location upon adjustment, wherein the first and second locations are a predetermined distance apart, and instructions for use. Optionally, such kits may further include any of the other system components described in relation to the present invention and any other materials or items relevant to the present invention. 
     It may be appreciated that in all embodiments of the methods of the present invention, the suture strand(s) held by the fastener may be cut at any distance from the fastener. In this way, the suture strands and fastener may be left in place as a temporary or permanent implant. Cutting of the sutures may be achieved by any suitable means. For instance, a cutting blade may be included in the delivery catheter which deploys the fastener. Or, a separate cutting catheter, tool, instrument or device may be used. Thus, such a cutting means may be included in any of the systems, apparatuses or kits of the present invention. 
     Other objects and advantages of the present invention will become apparent from the detailed description to follow, together with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-2  illustrate an embodiment of a suture fastener. 
         FIGS. 3-5  depict side views of a loading tool having a suture fastener loaded therein or thereon. 
         FIGS. 6A-6C  illustrate usage of a suture fastener in fixing valve leaflets together. 
         FIGS. 7A-7B  illustrate cross-sectional views of a fastening element having a coil shape. 
         FIG. 8  depicts a perspective view of a fastening element having a coil shape. 
         FIG. 9  illustrates a fixture for fabricating a fastening element having a coil shape. 
         FIG. 10  illustrates a cross-sectional view of a fastening element having a FIG.- 8  shape. 
         FIG. 11  depicts a perspective view of a fastening element having a FIG.- 8  shape. 
         FIG. 12  illustrates a fixture for fabricating a fastening element having a FIG.- 8  shape. 
         FIG. 13  illustrates suture strands held by a FIG.- 8  shaped element in a relaxed shape-recovery position. 
         FIG. 14  illustrates suture strands held by a FIG.- 8  shaped element in a relaxed shape-recovery position wherein each strand is held separately by the suture retention loops along separate paths. 
         FIGS. 15A-15C  illustrate a suture fastener comprising interlockable elements. 
         FIGS. 16A-16B  illustrate a suture fastener comprising an element having a flat shape when in a tensioned position and a curved shape when in a relaxed shape-recovery position. 
         FIGS. 17A-17B  illustrate a cylindrically shaped element having first and second portions with apertures for positioning suture strands. 
         FIGS. 18A-18B  illustrate a triangularly shaped element having first and second portions with apertures for positioning suture strands. 
         FIG. 19  illustrates an embodiment of a delivery catheter for delivery and deployment of a fastening element. 
         FIGS. 20A-20B  depict textured suture strands. 
         FIGS. 21A-21B  illustrate embodiments of a ratchet for use with textured suture strands. 
         FIG. 22  illustrates a housing having a flange wherein the ratchet of  FIGS. 21A-21B  is housed within. 
         FIG. 23  illustrates a pair of valve leaflets fixed together by a textured suture strand and ratcheted fasteners. 
         FIGS. 24A-24B  illustrate a pair of valve leaflets fixed together by a textured suture strand and a single ratcheted fastener. 
         FIG. 25  illustrates a kit in accordance with the present invention. 
         FIGS. 26A-26B ,  27 A- 27 B,  28 A- 28 B illustrate additional embodiments of an element which holds suture strands, wherein each turn of the coil has various numbers and arrangements of suture retention loops. 
         FIG. 29  illustrates an embodiment wherein a suture strand is threaded through the suture retention loops in a pattern that does not follow the shape of the coil. 
         FIG. 30  illustrates an embodiment of an element wherein the coil is formed by alternating the direction of the wind. 
         FIGS. 31-32  illustrate turns of a coil having shapes other than circular or oval. 
         FIG. 33A  illustrates an embodiment of an element in a tensioned position having portions which are overlapped so that at least one aperature is concentrically aligned with another aperture. 
         FIG. 33B  illustrates the embodiment of  FIG. 33A  in a relaxed position wherein the apertures are misaligned. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-2 , an embodiment of a suture fastener  100  is illustrated to provide an overview of the general features of the present invention. Here, the suture fastener  100  is comprised of a fastening element  102  having a coil shape. The element  102  is comprised of a shape-recovering material so that the element is able to return to a desired shape under certain conditions. For example, the shape-recovering material may be comprised of a shape-memory alloy, such as nitinol, or a spring-tempered steel. In this case, the element  102  may be placed in a tensioned position to form a first desired shape and release of the tension would allow the element  102  return to a relaxed shape-recovering position to form a second desired shape. These different shapes are useful in holding, adjusting and fastening one or more sutures. 
     For example,  FIG. 1  illustrates a first suture strand  104  and a second suture strand  106  engaged by a fastening element  102 . The element  102  has a coil shape wherein the suture strands  104 ,  106  are threaded through loops  108  of the coil while the element is maintained in a tensioned position. In this position, the loops  108  are generally aligned so that the suture strands  104 ,  106  are held along a substantially straight path. Thus, the element  102  may be slid back and forth, as indicated by arrows, relative to the suture strands  104 ,  106 . Such sliding allows the element  102  to be advanced along the suture to a desired position for anchoring or fastening. Tension on the element  102  may then be released so that the element returns to a shape-recovering position. An example of such a position is shown in  FIG. 2 . Here, the element  102  holds the suture strands  104 ,  106  along a tortuous path having a zig zag form. In this position, the element  102  is not able to slide along the sutures as the tortuous path creates significant friction and resistance to sliding or slippage. Thus, the suture strands  104 ,  106  are fastened in place. 
     The suture fastener  100  may be introduced and deployed in a desired location with the use of a loading tool. In some embodiments, shown in  FIGS. 3-5 , the loading tool  200  has a proximal end (not shown), a distal end  202  and a lumen  204  therethrough. In each of these cases, suture strands  104 ,  106  are typically inserted through the lumen  204  as shown. Referring to  FIG. 3 , the fastener  100  may be loaded within the lumen  204  so that the suture strands  104 ,  106  are threaded through the fastener  100 . The fastener  100  may then be deployed by pushing the fastener  100  out of the distal end  202  of the loading tool  200 . Referring to  FIG. 4 , the fastener  100  may be loaded or mounted on the outside of the loading tool  200 . Here, the fastener  100  is shown coiled around a shaft  203  of the loading tool  200  which houses the lumen  204  containing suture strands  104 ,  106 . Thus, the fastener  100  may then be deployed by pushing the fastener  100  off the distal end  202  of the loading tool  200  so that the fastener  100  engages the suture strands  104 ,  106  at a desired location. Similarly,  FIG. 5  illustrates a fastener  100  loaded on the outside of the loading tool  200 . However, in this case the fastener  100  is shown coiled around the distal end  202  of the loading tool in a more compressed fashion. Such compression is desirable with some fastener  100  designs. Again, the fastener  100  may then be deployed by pushing the fastener  100  off the distal end  202  of the loading tool  200  so that the fastener  100  engages the suture strands  104 ,  106  at a desired location. It may be appreciated that the loading tool  200  may comprise a number of designs with the suture fastener  100  and/or suture strands  104 ,  106  having a number of arrangements for deployment and function of the suture fastener  100 . 
       FIGS. 6A-6C  illustrate a possible application for usage of the suture fastener  100 . Here, valve leaflets LF are shown sutured together for treatment of valvular regurgitation. The first suture strand  104  and the second suture strand  106  are each attached to a valve leaflet LF by any suitable means. Rather than tying the suture strands  104 ,  106  together with a knot, a suture fastener  100  is used to fasten the strands  104 ,  106  together. In this example, the treatment procedure is performed with minimally invasive techniques wherein the valve leaflets are remotely accessed through the vascular system with the use of catheters. Thus, the loading tool  200  comprises a catheter which has been advanced through the vascular system to the leaflets LF. As shown in  FIG. 6A , the loading tool  200 , having the suture fastener  100  loaded within, approaches the site of the suture and the free ends of the suture strands  104 ,  106  are positioned within the lumen  204  of the loading tool  200 . Referring now to  FIG. 6B , the suture fastener  100  is then deployed at a desired location to hold the strands  104 ,  106  in a fixed position relative to the fastener  100  and/or to each other. The position of the fastener  100  may then be adjusted by sliding the fastener  100  along the suture strands  104 ,  106  to another desired location, such as closer to the leaflets LF as shown in  FIG. 6C . Such adjustment is achieved by placing the fastener  100  in a tensioned position wherein the suture strands  104 ,  106  are engaged but not fixed, moving the fastener  100  along the strands  104 ,  106  and then returning the fastener  100  to a relaxed shape-recovery position to hold the strands  104 ,  106  in a fixed position. Once the fastener  100  has reached its final position, the strands  104 ,  106  may be cut and the fastener  100  left in place, as illustrated in  FIG. 6C . 
     As mentioned, the suture fastener  100  is comprised of at least one fastening element  102  comprised of any type of shape-recovery material. This includes but is not limited to nitinol wire, spring-tempered steel, polymers, Elgiloy® (Elgin, Ill.) and the like. Likewise, the material may take any suitable form, such as round wire, flat wire, ribbon, hypotube, braid or cable. In many embodiments, the fastener  100  is comprised of 0.004-0.012 inch wire, preferably 0.008 inch superelastic nitinol wire. In some cases, the fastener  100  is heat-set by baking at approximately 450-560° C. for around 5-10 min, preferably approximately 7 min, followed by cool water quenching. The shape-recovery material allows the element  102  to have a tensioned position for engaging the suture strands while allowing sliding of the element relative to the suture strands and a relaxed shape-recovery position for holding the strands in a fixed position relative to the element or to each other. It may be appreciated that the element  102  is transitionable between the tensioned and relaxed position by application and release of force on the element  102 , by a change in temperature of the element or by any other applicable means. 
     The fastening element  102  may take any number of forms suitable for holding suture strands along various paths, including substantially straight to various degrees of tortuous. In some embodiments, the element  102  comprises a coil  250 . As shown in cross-section in  FIGS. 7A-7B , each turn of the coil  250  may have, for example, an oval or elliptical shape,  FIG. 7A , or a circular shape,  FIG. 7B . In addition, each turn of the coil  250  may include at least one suture retention loop  252 . Or, various turns of the coil  250  may include one or more suture retention loops  252  and other turns may include no suture retention loops. The suture retention loops  252  are often disposed in diametrical opposition when the element  102  is in the relaxed shape-recovery position.  FIG. 8  provides a perspective view of the element  102  in the relaxed shape-recovery position, the element  102  having four turns of the coil  250 , each turn having two diametrically opposed suture retention loops  252 . During loading on or in the loading tool or at any other time when the element  102  is in the tensioned position, the suture retention loops  252  are disposed in concentric alignment. The element can undergo such deflection for loading on the loading tool with little or no permanent deformation due to the construction of the element  102 , in particular the presence of the arched coil turn connecting the suture retention loops. Since the arches assume the deflection, the individual suture retention loops do not have as much strain placed on them and thus are able to more easily keep their shape. Concentric alignment of the loops  252  allows the suture strands  104 ,  106  to be advanced through the loops  252  along a substantially straight path for loading or repositioning of the element  102 . Upon relaxation of the element  102 , the strands are thus held along a tortuous path. 
       FIG. 9  illustrates a possible fixture  260  for fabricating the element  102 . As shown, two 0.024 in stainless steel mandrels  280  are press fit into holes  282  in a base  284  and trimmed to about 1 cm extension. The shape-recovery wire  286  is then wrapped around the fixture  260  as shown. Since each loop  252  is made with the wire  286  starting on the outside of the mandrels  280  and then returning to the outside of the mandrels  280 , the suture would be trapped on the inside of the loop  252  and cannot slip out. Consequently, each loop  252  can be made with only one wind to keep the suture contained. 
     As shown in cross-section in  FIG. 10 , each turn of the coil  250  may have, for example, a FIG.- 8  shape having two lobes  255 . In addition, each turn of the coil  250  may include at least one suture retention loop  252  disposed within each lobe  255 . Again, such loops  252  are typically disposed in diametrical opposition when the element  102  is in the relaxed shape-recovery position.  FIG. 11  provides a perspective view of the element  102  in the relaxed shape-recovery position, the element  102  having four turns of the coil  250 , each turn having two diametrically opposed suture retention loops  252 . It may be appreciated that the suture retention loops  252  may be absent from some turns of the coil to allow for greater deflection or strain in the tensioned position. During loading on or in the loading tool or at any other time when the element  102  is in the tensioned position, the suture retention loops  252  are disposed in nearly concentric alignment. Such alignment of the loops  252  allows the suture strands  104 ,  106  to be advanced through the loops  252  along a substantially straight path for loading or repositioning of the element  102 . Upon relaxation of the element  102 , the strands are thus held along a tortuous path.  FIG. 12  illustrates a possible fixture  280  for fabricating the element  102 . As shown, two 0.024 in stainless steel mandrels  280  are press fit into holes  282  in a base  284  and trimmed to about 1 cm extension. The shape-recovery wire  286  is then wrapped around the fixture  260  as shown. 
       FIGS. 13-14  illustrate suture strands  104 ,  106  held by the element  102  along tortuous paths in the relaxed shape-recovery position. Referring to  FIG. 13 , the element  102  has a FIG.- 8  shape as described in relation to  FIGS. 10-12 . Here, the first suture strand  104  and the second suture strand  106  are shown held together by suture retention loops  252  in each turn of the coil  250 . When the element  102  is in the relaxed shape-recovery position, as shown, the strands  104 ,  106  are held together along a tortuous zig zag path. Referring to  FIG. 14 , the element  102  again has a FIG.- 8  shape but here the first suture strand  104  and the second suture strand  106  are held separately by suture retention loops  252 . Thus, when the element  102  is in the relaxed shape-recovery position, the first strand  104  follows a first tortuous path and the second strand  106  follows a second tortuous path which differs from the first tortuous path. 
       FIGS. 26A-26B ,  27 A- 27 B,  28 A- 28 B illustrate additional embodiments of the element  102  wherein each turn of the coil  250  has various numbers and arrangements of suture retention loops  252 . In one embodiment shown in cross-section in  FIG. 26A , each turn of the coil  250  has three suture retention loops  252 .  FIG. 26B  provides a perspective view of the element  102  in the relaxed shape-recovery position, the element  102  having three turns of the coil  250 , each turn having three suture retention loops  252 . Also shown is a suture strand  104  threaded through the suture retention loops  252 . In another embodiment shown in cross-section in  FIG. 27A , each turn of the coil  250  has four suture retention loops  252 .  FIG. 27B  provides a perspective view of the element  102  in the relaxed shape-recovery position, the element  102  having three turns of the coil  250 , each turn having four suture retention loops  252 . Also shown is a suture strand  104  threaded through the suture retention loops  252 . And, in yet another embodiment shown in cross-section in  FIG. 28A , each turn of the coil  250  has five suture retention loops  252 .  FIG. 28B  provides a perspective view of the element  102  in the relaxed shape-recovery position, the element  102  having four turns of the coil  250 , each turn having five suture retention loops  252 . Again, also shown is a suture strand  104  threaded through the suture retention loops  252 . Thus, generally, the more suture retention loops present, the more closely the threaded suture strand  104  follows the shape of the coil. However, as shown in  FIG. 29 , the suture strand  104  may be threaded through the loops  252  in a pattern that does not follow the shape of the coil  250 , and additionally the suture strand  104  may not be threaded through all of the loops  252 . It may be appreciated that each turn of the coil may have any number of retention loops and the suture retention loops  252  may be absent from some turns of the coil to allow for greater deflection or strain in the tensioned position. 
       FIG. 30  illustrates an embodiment of the element  102  wherein the coil  250  is formed by alternating the direction of the wind. As shown, the coil  250  reverses direction of the wind at reverse points  251 . This provides a slightly different relaxed shape-recovery position from the standard coil shape and responds differently when in the tensioned position. As shown, the suture retention loops  252  may still be located within each turn of the coil. 
     It may also be appreciated that the turns of the coil  250  may be shaped other than circular or oval. For example, as shown in  FIG. 31 , each turn of the coil  250  may be square or, as shown in  FIG. 32 , each turn of the coil  250  may be triangular. Suture retention loops  252  may be located along each turn, as shown, and a suture strand  104  is then threaded through the loops  252 . Again, it may be appreciated that loops  252  may not be located along every turn of the coil and the suture strand  104  may be threaded through some or all of the loops in any configuration. 
     In other embodiments, the suture fastener  100  comprises two or more elements  300  which are interlockable, an example of which is illustrated in  FIGS. 15A-15C . Referring to  FIG. 15A , the fastener  100  is comprised of two elements  300  which are curved so that they interlock as shown when the element is in the relaxed shape-recovery position. Each element  300  may be comprised of an elongate wire, ribbon, rod, filament, shaft, braid, strand, cable, hypotube, weave, or mesh, to name a few. As shown in  FIG. 15B , the elements  300  may be separated, straightened, held open or untwisted in the tensioned position so that suture strands  104 ,  106  may be placed within or between them. In this arrangement, the strands  104 ,  106  may be moved or adjusted relative to the elements  300  or each other. When the elements  300  return to the relaxed shape-recovery position, the elements  300  interlock around the strands, as shown in  FIG. 15C , so that the suture strands  104 ,  106  are held in a fixed position relative to the element  300  and each other. Similarly, in another embodiment, the fastener  100  is comprised of one element which has a straight configuration in the tensioned position and a curved configuration in the relaxed shape-recovery position so that the curved configuration can hold suture strands  104 ,  106  in a fixed position. 
     In additional embodiments, the suture fastener  100  comprises an element  400  which has a flat shape when in the tensioned position and a curved or bent shape when in the relaxed shape-recovery position, an example of which is illustrated in  FIGS. 16A-16B . Referring to  FIG. 16A , the element  400  is comprised of elongate wire, ribbon, rod, filament, shaft, mesh or woven sheet, to name a few, having two or more apertures  402  along its length. In a preferred embodiment, the element  400  comprises a ribbon having a width in the range of approximately 0.030 to 0.120 inches and a thickness in the range of approximately 0.002 to 0.010 inches. The suture strands  104 ,  106  are threaded through the apertures  402  in an alternating fashion as shown. Alternatively, the strands  104 ,  106  may be threaded in another arrangement which engages the strands  104 ,  106  with the element  400  yet allows the strands  104 ,  106  to slide relative to the element  400 , as illustrated by arrows. When the element  400  forms the relaxed shape-recovery position, shown in  FIG. 16B , the element  400  forms a curved or bent shape which prevents the strands  104 ,  106  from sliding relative to the element  400 . Thus, the strands  104 ,  106  are fixed in place. 
     In still further embodiments, illustrated in  FIGS. 17A-17B  and  FIGS. 18A-18B , the suture fastener  100  comprises an element  500  which has a first portion  502  having at least one first aperture  504  and a second portion  506  having at least one second aperture  508 . Referring to  FIG. 17A , the element  500  may have a cylindrical shape wherein the portions  502 ,  506  comprise end flaps as shown. By placing the element  500  in the tensioned position, the portions  502 ,  506  are overlapped so that at least one first aperture  504  is concentrically aligned with at least one second aperture  508 . Suture strands  104 ,  106  threaded through the apertures  504 ,  508 , as shown, may thus slide in relation to the element  500  for adjustment of the position of the element  500 . When the element  500  is placed in the relaxed shape-recovery position, shown in  FIG. 17B , the at least one first aperture  504  is then misaligned with the at least one second aperture  508 . In this configuration, it is much more difficult for the suture strands  104 ,  106  to slide relative to the element  500  so the strands  104 ,  106  are essentially fixed in place. Similarly, as shown in  FIGS. 18A-18B , the element  500  may have a triangular shape wherein the portions  502 ,  506  comprise end flaps as shown. In this embodiment, the element  500  functions as in  FIGS. 17A-17B  respectively. 
     In another embodiment, illustrated in  FIGS. 33A-33B , the element  500  again has a first portion  502  having at least one first aperture  504  and a second portion  506  having at least one second aperture  508 . Referring to  FIG. 33A , the element  500  may have a cylindrical shape wherein the portions  502 ,  506  comprise end flaps as shown. By placing the element  500  in the tensioned position, the portions  502 ,  506  are overlapped so that at least one first aperture  504  is concentrically aligned with at least one second aperture  508 . The element may be held in the tensioned position by the insertion of a mandrel  505 , as shown, or by any other suitable means. Suture strands  104 ,  106  threaded through the apertures  504 ,  508 , as shown, may thus slide in relation to the element  500  for adjustment of the position of the element  500 . When the mandrel  505  is removed element  500  is placed in the relaxed shape-recovery position, shown in  FIG. 33B , the at least one first aperture  504  is then misaligned with the at least one second aperture  508  by inward recoiling of the element  500 . In this configuration, it is much more difficult for the suture strands  104 ,  106  to slide relative to the element  500  so the strands  104 ,  106  are essentially fixed in place. 
       FIG. 19  illustrates an embodiment of a delivery catheter  520  for delivery and deployment of the element  500 . Here, the delivery catheter  520  comprises a push rod  522 , having a slot  524  therethrough, surrounded by an outer tube  526 . The element  500  is loaded, in the compressed or tensioned position, within the outer tube  526  distal to the push rod  522 . Suture strands  104 ,  106  are threaded through the element  500 , as previously described in relation to  FIGS. 17A-17B  and  FIGS. 18A-18B , and through the slot  524  in the push rod  522 . Once the sutures  104 ,  106  are positioned in the tissue (not shown), such as through valve leaflets wherein anchors  530  at the ends of the sutures  104 ,  106  rest against the underside of the leaflets, the element  500  may be positioned at a desired location along the suture strands  104 ,  106 . Once in this position, the element  500  is deployed from the catheter  520  by pushing the element  500  out of the outer tube  526  with the push rod  522 . A cutting mechanism  532  may also be integral with the push rod  522  to cut the suture strands  104 ,  106  and leave the element  500  in place. 
     In additional embodiments, the suture fastener  100  comprises a ratcheting mechanism  600  for securing a textured suture strand  602 . Typically, such suture strands  602  are comprised of a fiber, thread, filament, wire or cord and may be textured by any means to provide a surface having protuberances  603  for securing with the ratcheting mechanism  600 . Protuberances may include knots, beads, balls, ribs and spokes. For example, an embodiment of a suture strand  602  having a ribbed texture is shown in  FIG. 20A , and an embodiment having a beaded texture is shown in  FIG. 20B . The suture strand  602  or at least one protuberance  603  may be comprised of any suitable material, such as stainless steel, metal, polymer, silicone, latex, epoxy, cotton, nylon, polyester and Teflon, to name a few. For example, the suture strands  602  may be formed by extruding the desired texture with a rigid polymer over a stainless steel core wire. Alternatively, knots may be tied in increments along a flexible suture strand to provide a suitable texture. 
       FIGS. 21A-21B  illustrate embodiments of the ratcheting mechanism  600  for use with the textured suture strand  602 . As shown in  FIGS. 21A-21B , the ratcheting mechanism  600  may include a cylindrical tube  604  having flexible arms  606  thereattached. Stoppers  608  are attached near the distal end of the arms  606  as shown. The stoppers  608  are used to nestle between the protuberances  603  of the suture strand  602  and hold the strand  602  in place. For example, the ratcheting mechanism  600  may be adapted to hold the suture strand  602  at a first location and then release the strand  602  and hold the strand  602  at a second location upon adjustment, wherein the first and second locations are a predetermined distance apart. Referring to  FIG. 22 , the suture fastener  100  may further comprise a housing  610  having a flange  612  for tissue contact wherein the ratcheting mechanism  600  is housed within. The fastener  100  may be mounted on the distal end  622  of a delivery catheter  520  for placement in a desired location along a suture strand  602 . As shown in  FIG. 23 , valve leaflets LF may be fixed together by a suture strand  602 . Suture fasteners  100  may be positioned along the suture strand  602 , as shown, so that the flanges  612  contact the surfaces of the leaflets LF. The position of the fasteners  100  may be adjusted by advancing the suture strand  602  through the ratcheting mechanism  600 . The suture strand  602  is then held in place by action of the stoppers  608  in the protuberances  603  as described above. Similarly, as shown in  FIGS. 24A-24B , one suture fastener  100  may be used to fix a pair of leaflets together. In  FIG. 24A , the suture strand  602  is passed through each of the leaflets LF wherein one end of the strand  602  forms a loop  624  through which the other free end  626  of the strand  602  is passed. The fastener  100  is then positioned along this free end  626  and adjusted and/or secured as described in relation to  FIG. 23 . In  FIG. 24B , the suture strand  602  is passed through each of the leaflets LF so that both free ends  626  are on one side of the leaflets LF. The fastener  100  is then positioned along both free ends  626 , as shown, and adjusted and/or secured as described in relation to  FIG. 23 . 
     Referring now to  FIG. 25 , kits  700  according to the present invention comprise at least a suture fastener  100  and instructions for use IFU. Such kits may include more than one suture fastener which may include different features, such as element  102  or ratcheting mechanism  600 . Optionally, the kits may further include one or more of any of the other system components described above, such as a loading tool  200 , a suture strands  104 ,  106 , a textured suture strand  602 , and/or a delivery catheter  520 . In addition, other items may be included related to the medical procedure, such as catheters, guidewires, introducers, dilators, and needles, to name a few. The instructions for use IFU will set forth any of the methods as described above, and all kit components will usually be packaged together in a pouch  702  or other conventional medical device packaging. Usually, those kit components, such as suture fasteners  100 , which will be used in performing the procedure on the patient will be sterilized and maintained within the kit. Optionally, separate pouches, bags, trays or other packaging may be provided within a larger package, where the smaller packs may be opened separately to separately maintain the components in a sterile fashion. 
     Although the foregoing invention has been described in some detail by way of illustration and example, for purposes of clarity of understanding, it will be obvious that various alternatives, modifications and equivalents may be used and the above description should not be taken as limiting in scope of the invention which is defined by the appended claims.