Patent Publication Number: US-2022211500-A1

Title: Tissue remodeling system and methods

Description:
BACKGROUND 
     Field 
     The present disclosure relates to systems and methods for remodeling tissue. In particular, the present disclosure relates to systems and methods for heart valve remodeling, such as mitral valve remodeling. 
     Description of Related Art 
     Heart valves lie at the exit of each of the four heart chambers. Heart valves work as one-way valves to prevent blood from flowing in the wrong direction. Each valve has a set of flaps, called leaflets or cusps. Valve regurgitation is when blood leaks through an incompletely closed valve, allowing blood flow in two directions during contraction. Regurgitation may be caused either due to an abnormality of the leaflets themselves (called primary regurgitation), such as valve prolapse, damaged chordae, rheumatic fever, endocarditis, trauma or congenital heart defects. On the other hand, in secondary regurgitation, the valve itself is intact and only the surrounding structures the valve leaflets insert into are abnormal, resulting in regurgitation. Examples for secondary regurgitation are history of heart attack, cardiomyopathy, prolong use of certain drugs, radiation, atrial fibrillation, etc. Regurgitation can result in congestive heart failure, which is the most common hospital admission diagnosis in the United States. Symptoms of congestive heart failure include fatigue, shortness of breath, swelling of feet and legs. Valve regurgitation leads to a vicious cycle of heart failure, arrhythmias, and worsening cardiomyopathy (weakening of the heart muscle), which results in more regurgitation. 
     Historically, open surgical valve repair or replacement is performed to treat diseases such as regurgitation. More recently, catheter-based technologies have been developed and introduced into clinical practice for the repair of the mitral valve. In general, repair is deemed superior to valve replacement to restore coaptation of the leaflets. 
     SUMMARY 
     The systems, methods and devices described herein have innovative aspects, no single one of which is indispensable or solely responsible for their desirable attributes. Without limiting the scope of the claims, some of the advantageous features will now be summarized. 
     An aspect of the present disclosure involves a system for mitral valve remodeling that includes a first tissue anchor and a second tissue anchor. The first tissue anchor is configured to be implanted into tissue at a first location at or near an annulus of a mitral valve of a patient. The first tissue anchor comprises an anchor portion, a drive portion and a suture mount portion. The anchor portion engages the tissue and is implanted by rotation about a longitudinal axis of the first tissue anchor. The drive portion is rotatably fixed with respect to the anchor portion and is configured to removably engage with a drive member of a catheter. The suture mount portion is rotatable relative to the anchor portion and the drive portion and is located between the drive portion and the anchor portion along the longitudinal axis. The second tissue anchor is configured to be implanted into tissue at a second location at or near the annulus of the mitral valve across from the first location. The second tissue anchor comprises an anchor portion, a drive portion and a suture mount portion. The anchor portion engages the tissue and is implanted by rotation about a longitudinal axis of the second tissue anchor. The drive portion is rotatably fixed with respect to the anchor portion and is configured to removably engage with the drive member of the catheter. The suture mount portion is rotatable relative to the anchor portion and the drive portion and is located between the drive portion and the anchor portion along the longitudinal axis. A suture has a tensioned portion that extends between a first suture mount location on the suture mount portion of the first tissue anchor and a second suture mount location on the suture mount portion of the second tissue anchor. The suture mount portions of the first and second tissue anchors rotate to align with one another in response to tension applied to the suture. 
     In an embodiment, each of the first and second suture mount locations of the first and second tissue anchors comprises a passage that accommodates the suture, wherein the tensioned portion of the suture extends from an end of the passage relatively closer to the anchor portion. 
     In an embodiment, a suture lock is configured to secure a portion of the suture relative to the second tissue anchor to fix a length of a tensioned portion of the suture between the first tissue anchor and the second tissue anchor. 
     In an embodiment, the suture lock comprises a first portion and a second portion movable relative to the first portion, wherein a lock portion of the suture is captured between the first portion and the second portion. 
     In an embodiment, the first portion comprises a passage, wherein the lock portion of the suture passes through the passage. 
     In an embodiment, the first portion of the suture lock is configured to contact the suture mount portion of the second tissue anchor to fix the length of the tensioned portion of the suture. 
     In an embodiment, the passage of the suture lock is aligned with a passage of the second suture mount location of the second tissue anchor when the suture lock is in contact with the second tissue anchor. 
     In an embodiment, the first portion of the suture lock is rotationally fixed relative to the second portion. 
     In an embodiment, a threaded fastener is configured to move the first portion of the suture lock relative to the second portion. 
     In an embodiment, the threaded fastener is configured to move the first portion of the suture lock toward and away from the second portion. 
     In an embodiment, a suture cutter is configured to cut the suture. 
     In an embodiment, the suture cutter comprises a tip having an axial slot and a radial passage, wherein the axial slot intersects the radial passage, wherein the suture passes through the radial passage, the suture cutter further comprising a blade that is movable within the slot to cut the suture. 
     In an embodiment, the anchor portion comprises one or more barbs. 
     In an embodiment, each of the barbs comprises a tubular element having an angled end with a tip of the angled end located radially outward. 
     An aspect of the present disclosure involves a system for implanting a tissue anchor in heart tissue of a patient. The system includes a delivery catheter comprising an anchor delivery tip. The tip comprises a stationary portion and a rotatable portion. The stationary portion comprises a suture passage having a first end and a second end. The rotatable portion comprises a drive portion. The system further includes a tissue anchor comprising an anchor portion, a drive portion and a suture mount portion. The anchor portion engages the heart tissue and is implanted by rotation about a longitudinal axis of the tissue anchor. The drive portion is rotatably fixed with respect to the anchor portion and is configured to removably engage with the drive portion of the catheter. The suture mount portion is rotatable relative to the anchor portion and the drive portion. A suture is secured to the suture mount portion. The tissue anchor is configured to be engaged with the delivery catheter with the drive portion of the tissue anchor engaged with the drive portion of the delivery catheter. The suture extends through the suture passage of the tip of the delivery catheter such that the suture can be tensioned to restrain the suture mount portion of the tissue anchor from rotating as the rotatable portion of the tip of the delivery catheter is rotated to rotate the drive portion and the anchor portion of the tissue anchor to thereby implant the tissue anchor into the heart tissue. 
     In an embodiment, the suture passage of the stationary portion is located radially outward of the rotatable portion. 
     In an embodiment, the suture mount portion is located between the drive portion and the anchor portion. 
     In an embodiment, the delivery catheter comprises a distal tip cover configured to surround the tissue anchor prior to deployment. 
     In an embodiment, the distal tip cover comprises a slot through which the suture passes from exterior the distal tip cover to interior the distal tip cover such that the suture can be secured to the suture mount portion. 
     In an embodiment, the distal tip cover comprises a slit that extends from the slot to a distal end of the distal tip cover, wherein the slit is configured such that the suture can move from the slot, pass through the slit, and be separated from the distal tip cover when the tissue anchor is deployed from the delivery catheter. 
     In an embodiment, the anchor portion comprises one or more barbs. 
     In an embodiment, each of the barbs comprises a tubular element having an angled end with a tip of the angled end located radially outward. 
     An aspect of the present disclosure involves a tissue anchor including an anchor portion comprising a helical thread configured to be implanted into bodily tissue by rotation about a longitudinal axis of the tissue anchor. The tissue anchor further includes a drive portion that is rotatably fixed with respect to the anchor portion. The drive portion is configured to removably engage with a drive member of a catheter such that rotation of the drive member rotates the drive portion and the anchor portion of the tissue anchor. The tissue anchor further includes a suture mount portion is rotatable relative to the anchor portion and the drive portion. The suture mount portion is configured to connect to a suture at a suture mount location. The suture mount portion is configured to rotate to align the suture mount location with a direction of force of the suture. The suture mount portion is located between the drive portion and the anchor portion along the longitudinal axis. 
     In an embodiment, the helical thread of the anchor portion is a helical coil defining a hollow interior space. 
     In an embodiment, the helical coil comprises a circular cross-sectional shape. 
     In an embodiment, the drive portion defines a radially outward-facing drive surface that is configured to engage the drive member of the catheter. 
     In an embodiment, the drive portion comprises a square cross-sectional shape that defines the radially outward-facing drive surface. 
     In an embodiment, the suture mount portion has a peripheral surface surrounding the longitudinal axis of the tissue anchor, the peripheral surface defining a geometric center of the suture mount portion, wherein an axis of rotation of the suture mount portion is spaced from the geometric center. 
     In an embodiment, the suture mount location is on an opposite side of the geometric center from the axis of rotation. 
     In an embodiment, the suture mount location comprises a passage extending through the suture mount portion in a direction substantially aligned with the longitudinal axis of the tissue anchor. 
     In an embodiment, a length of the anchor portion along the longitudinal axis is greater than a length of one or both of the drive portion and the suture mount portion. 
     In an embodiment, the length of the drive portion is greater than the length of the suture mount portion. 
     In an embodiment, the anchor portion comprises one or more barbs. 
     In an embodiment, each of the barbs comprises a tubular element having an angled end with a tip of the angled end located radially outward. 
     An aspect of the present disclosure involves a tissue anchor including an anchor portion comprising a helical thread configured to be implanted into bodily tissue by rotation about a longitudinal axis of the tissue anchor. The tissue anchor further includes a drive portion that is rotatably fixed with respect to the anchor portion. The drive portion is configured to removably engage with a drive member of a catheter such that rotation of the drive member rotates the drive portion and the anchor portion of the tissue anchor. The tissue anchor further includes a suture mount portion that is rotatable relative to the anchor portion and the drive portion. The suture mount portion is configured to connect to a suture at a suture mount location. The suture mount portion is configured to rotate to align the suture mount location with a direction of force of the suture. The suture mount portion is located above the anchor portion along the longitudinal axis. The suture mount portion has a first end surface and a second end surface opposite the first end surface. The second end surface is closer to the anchor portion than the first end surface along the longitudinal axis. The suture mount portion is configured such that suture extends from the tissue anchor at or below the second end surface. 
     In an embodiment, the suture mount portion is located immediately adjacent the anchor portion. 
     In an embodiment, the helical thread of the anchor portion is a helical coil defining a hollow interior space. 
     In an embodiment, the helical coil comprises a circular cross-sectional shape. 
     In an embodiment, the drive portion defines a radially outward-facing drive surface that is configured to engage the drive member of the catheter. 
     In an embodiment, the drive portion comprises a square cross-sectional shape that defines the radially outward-facing drive surface. 
     In an embodiment, the suture mount portion has a peripheral surface surrounding the longitudinal axis of the tissue anchor, the peripheral surface defining a geometric center of the suture mount portion, wherein an axis of rotation of the suture mount portion is spaced from the geometric center. 
     In an embodiment, the suture mount location is on an opposite side of the geometric center from the axis of rotation. 
     In an embodiment, the suture mount location comprises a passage extending through the suture mount portion from the first end surface to the second end surface in a direction substantially aligned with the longitudinal axis of the tissue anchor. 
     In an embodiment, a length of the anchor portion along the longitudinal axis is greater than a length of one or both of the drive portion and the suture mount portion. 
     In an embodiment, the length of the drive portion is greater than the length of the suture mount portion. 
     In an embodiment, the anchor portion comprises one or more barbs. 
     In an embodiment, each of the barbs comprises a tubular element having an angled end with a tip of the angled end located radially outward. 
     An aspect of the present disclosure involves a suture lock for a tissue remodeling system. The suture lock includes a first portion comprising a base flange and a hub extending in an axial direction from the base flange. The base flange comprises a suture passage configured to accommodate a suture of the tissue remodeling system. The suture lock also includes a second portion comprising an end wall and at least one side wall defining a space to slidably engage the hub of the first portion. The end wall and the at least one side wall are configured to prevent rotation of the first portion when the hub is positioned within the space. The second portion further comprising a clamping surface located adjacent an end of the suture passage of the base flange and configured to clamp a portion of the suture against the base flange to fix the suture relative to the suture lock. The second portion is movable toward and away from the first portion to selectively clamp and release the suture. 
     In an embodiment, the at least one sidewall comprises a first side wall and a second side wall, wherein the first and second side walls are parallel and spaced apart from one another to receive the hub therebetween. 
     In an embodiment, the first portion comprises a threaded cavity extending in the axial direction within the hub and the second portion comprises an opening within the end wall, the suture lock further comprising a threaded fastener that passes through the opening and threadably engages the threaded cavity, wherein the threaded fastener is configured to move the first portion toward the second portion in response to rotation in a first direction and to allow the first portion to move away from the second portion in response to rotation in a second direction. 
     An aspect of the present disclosure involves a method of remodeling a mitral valve. The method includes implanting, using at least one catheter, a first tissue anchor at a first location at or near an annulus of a mitral valve of a patient. The method further includes implanting, using the at least one catheter, a second tissue anchor at a second location at or near the annulus of the mitral valve of the patient across from the first location. The method also includes extending a suture between the first tissue anchor and the second tissue anchor and using the suture to move the first tissue anchor and the second tissue anchor toward one another. The method includes fixing a tension length of the suture between the first tissue anchor and the second tissue anchor using a suture lock that is lockable using the at least one catheter. The method further includes observing the function of the mitral valve and, if desired, unlocking the suture lock, increasing or decreasing the tension length of the suture, and relocking the suture lock. 
     In an embodiment, the method further comprises cutting an excess portion of the suture using a suture cutter. 
     An aspect of the present disclosure involves a method of tensioning a suture of a mitral valve remodeling system. The method includes slidably engaging a suture lock with a suture that has an end fixed to a first tissue anchor implanted at a first location at or near an annulus of the mitral valve and is slidably engaged with a second tissue anchor implanted at a second location at or near the annulus of the mitral valve. The method further includes sliding the suture lock along the suture toward the second tissue anchor using a catheter until the suture lock contacts the second tissue anchor. The method also includes applying a pulling force to the suture while holding the suture lock in contact with the second tissue anchor to tension a portion of the suture extending between the first tissue anchor and the second tissue anchor. 
     In an embodiment, the method further includes locking the suture lock on the suture to maintain the tension of the portion of the suture extending between the first tissue anchor and the second tissue anchor. 
     In an embodiment, the method further includes disengaging the catheter from the suture lock after the suture lock is locked on the suture. 
     An aspect of the present disclosure involves a tissue anchor having an anchor portion comprising a helical thread configured to be implanted into bodily tissue by rotation in a first direction about a longitudinal axis of the tissue anchor. One or more barbs are configured to permit rotation of the tissue anchor in the first direction and inhibit rotation of the tissue anchor in a second direction opposite the first direction. The tissue anchor also comprises a drive portion that is rotatably fixed with respect to the anchor portion. The drive portion is configured to removably engage with a drive member of a catheter such that rotation of the drive member rotates the drive portion and the anchor portion of the tissue anchor. The tissue anchor also comprises a suture mount portion configured to connect to a suture at a suture mount location. 
     In an embodiment, the suture mount portion is rotatable relative to the anchor portion and the drive portion. 
     In an embodiment, the suture mount portion is configured to rotate to align the suture mount location with a direction of force of the suture. 
     In an embodiment, the suture mount portion is located between the drive portion and the anchor portion along the longitudinal axis. 
     In an embodiment, the one or more barbs comprises a plurality of barbs spaced from one another along a length of the helical thread. 
     In an embodiment, each of the one or more barbs comprises an angled end having a tip that is located radially outward on the barb. 
     In an embodiment, the angled end has an angle between 30-60 degrees. 
     In an embodiment, each of the one or more barbs is or comprises a tubular element secured to the helical thread. 
     In an embodiment, the tubular element is straight. 
     In an embodiment, the tubular element defines an interior passage having a diameter that is larger than a diameter of the helical thread to allow the tubular element to be advanced along the helical thread during manufacture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Throughout the drawings, reference numbers can be reused to indicate general correspondence between reference elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the disclosure. 
         FIG. 1  is a perspective view of a mitral valve remodeling system implanted in a mitral valve of a patient. 
         FIG. 2  is a perspective view of a tissue anchor of the system of  FIG. 1 . 
         FIG. 2A  is a side elevation view of the tissue anchor of  FIG. 2 . 
         FIG. 2B  is a top plan view of a suture mount portion of the tissue anchor of  FIG. 2 . 
         FIG. 3  is perspective view of a suture lock of the system of  FIG. 1 . 
         FIG. 4  is a sectional view of the suture lock of  FIG. 3 . 
         FIG. 5  is a view of a guide catheter and delivery catheter for use in implanting the system of  FIG. 1 . 
         FIG. 6  is a perspective view of the delivery catheter of  FIG. 5 . 
         FIG. 7  is a perspective view of a first tissue anchor being implanted at a first location in the mitral valve of a patient. 
         FIG. 8  is a perspective view of a second tissue anchor being implanted at a second location in the mitral valve of the patient. 
         FIG. 8A  is a partial sectional view of a tip of a delivery catheter for delivering the tissue anchors. 
         FIG. 9  is a perspective view of a suture lock being placed at the second location in the mitral valve of the patient. 
         FIG. 9A  is a sectional view of a tip of a delivery catheter for delivering the suture lock. 
         FIG. 10  is a perspective view of an excess portion of the suture being trimmed. 
         FIG. 11  is a process flow of a method for implanting and, optionally, adjusting a mitral valve remodeling system. 
         FIG. 12A  is a perspective view of a portion of an alternative delivery catheter having a distal tip cover in which the tissue anchor is stowed. 
         FIG. 12B  illustrates the tissue anchor deployed from the distal tip cover with the suture extending through a slot in the distal tip. 
         FIG. 12C  illustrates the suture passing through a slit in the distal tip cover. 
         FIG. 13  illustrates an alternative tissue anchor having a plurality of barbs on the anchor portion. 
         FIG. 14  illustrates a tissue anchor and suture lock configured to be secured to the tissue anchor separately from the suture. 
         FIG. 15  illustrates a remodeling system having a blocking element that is configured to retain a portion of the suture and the suture lock relative to the associated tissue anchor. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of systems, components and methods of assembly and manufacture will now be described with reference to the accompanying figures, wherein like numerals refer to like or similar elements throughout. Although several embodiments, examples and illustrations are disclosed below, it will be understood by those of ordinary skill in the art that the inventions described herein extends beyond the specifically disclosed embodiments, examples and illustrations, and can include other uses of the inventions and obvious modifications and equivalents thereof. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner simply because it is being used in conjunction with a detailed description of certain specific embodiments of the inventions. In addition, embodiments of the inventions can comprise several novel features and no single feature is solely responsible for its desirable attributes or is essential to practicing the inventions herein described. 
     Certain terminology may be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “above” and “below” refer to directions in the drawings to which reference is made. Terms such as “front,” “back,” “left,” “right,” “rear,” and “side” describe the orientation and/or location of portions of the components or elements within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the components or elements under discussion. Moreover, terms such as “first,” “second,” “third,” and so on may be used to describe separate components. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. 
     The percutaneous technology described in this application is designed to treat valve regurgitation by structurally changing the heart to increase leaflet coaptation. The technology may be applied to either atrio-ventricular valve of the heart (mitral and tricuspid valve). The concept of repair is an annular approach of valve repair. 
     There are several advantages of one or more embodiments of the technology described within this application compared to currently either commercially available or currently developed, experimental technology. Those advantages include one or more of the following:
         1. In one or more embodiments, the disclosed technology allows individualization of regurgitation reduction, depending on the underlying pathology and valve size (specifically, where anchors are placed and how much the chord is tethered). From a practical point of view, the disclosed technology eliminates the need for hospitals to acquire a large range of devices of different sizes. Substantially the only equipment necessary is delivery catheters, anchors, and chord.   2. The disclosed technology conceptually may be particularly helpful in so far unstudied patient populations, such as those with secondary mitral regurgitation due to atrial pathologies or patients with tricuspid regurgitation due to pacemaker or defibrillator leads. Nevertheless, one or more embodiments of the disclosed technology may also prove effective in secondary mitral regurgitation due to ventricular disease, or even in select cases of primary mitral regurgitation.   3. In one or more embodiments, the disclosed technology may be used as an adjunct to existing technology (edge to edge repair) in cases where suboptimal results are present or anticipated.   4. Further advantages of one or more embodiments of the disclosed technology is its ability to permit other, future catheter-based valve repair or replacement strategies due to the ability to cut the repair chord.   5. As with most percutaneous repair strategies, one or more embodiments of the disclosed technology is anticipated to have a much shorter recovery time and better safety profile compared to open surgical repair or replacement.   6. Comparing the disclosed technology to other currently available or tested repair devices, the simplicity is striking. Procedure time and learning curve likely are favorable due to its simple design.   7. Finally, the smaller access of the delivery system of one or more embodiments of the disclosed technology likely will eliminate concerns about residual iatrogenic atrial septal defects following percutaneous, transseptal access for mitral valve repair and allows easy access via the right internal jugular vein for repair of the tricuspid valve.       

     The figures illustrate systems and methods for stabilizing or remodeling tissue. Preferably, the systems and methods disclosed are configured for remodeling soft tissue, such as heart tissue, for example. The illustrated systems and related methods are configured for remodeling the mitral valve. However, the system, components thereof and/or related methods could be used for other purposes or could be modified for use in other applications. For example, the disclosed systems, components or methods could be modified for use in stabilizing or remodeling other soft (e.g., muscle or connective tissue) or hard (e.g., bone) bodily tissues. 
     The illustrated systems are configured for percutaneous transvascular delivery using one or more catheters or other suitable conduits. However, in alternative arrangements or applications, the systems or components thereof as disclosed or as modified by one skilled in the art could be delivered to or installed at the desired bodily location by other means, such as by using a direct approach. 
     System Overview 
     The illustrated system  100  for remodeling a mitral valve includes a first tissue anchor  102 , a second tissue anchor  104 , a suture  106  and a suture lock  110 . The suture  106  extends between the first tissue anchor  102  and the second tissue anchor  104 . The suture  106  can be secured relative to the first tissue anchor  102  and the second tissue anchor  104  to fix a distance between the tissue anchors  102 ,  104 . The distance between the anchors  102 ,  104  can be adjusted to achieve a desired level of performance of the mitral valve. The suture lock  110  secures the suture  106  relative to the second tissue anchor  104  to maintain the desired distance between the anchors  102 ,  104 . 
     The first tissue anchor  102  is implanted at a first location  112  in the heart tissue of a patient, which can be at or near the mitral valve  114 . The second tissue anchor  104  is implanted at a second location  116 , which can be at or near the mitral valve  114 . Preferably, the first tissue anchor  102  and the second tissue anchor  104  are each implanted at or near the annulus  120  of the mitral valve  114 . Preferably, each of the tissue anchors  102 ,  104  are located close enough to the annulus  120  so that the tissue has sufficient strength to support the tissue anchors  102 ,  104  without tearing or otherwise being compromised under normal or expected conditions. 
     In the illustrated arrangement, the first tissue anchor  102  and the second tissue anchor  104 , or the first location  112  and the second location  116 , are located on opposite sides of the mitral valve  114 . In particular, the first tissue anchor  102  is located on the posterior leaflet  122  and the second tissue anchor  104  is located on the anterior leaflet  124 . However, these positions could also be reversed. The first tissue anchor  102  can be located within a central region or at or near a midpoint of the posterior leaflet  122  in a direction along the sealing edge  126  of the mitral valve  114 . The second tissue anchor  104  can be located within a central region or at or near a midpoint of the anterior/posterior leaflet  124  in a direction along the sealing edge  126  of the mitral valve  114 . 
     The suture  106  has a first end  130  that is secured to the first tissue anchor  102 . As used herein, the term suture can refer to any suitable line capable of connecting the tissue anchors  102 ,  104  and maintaining the tissue anchors  102 ,  104  at the adjusted separation distance (e.g., not stretching) under the expected conditions and for the expected life of the system  100 , unless otherwise indicated. The suture  106  extends from the first tissue anchor  102  to the second tissue anchor  104 . The suture  106  engages the second tissue anchor  104  such that the relative movement is permitted between the suture  106  and the second tissue anchor  104 . In the illustrated configuration, the suture  106  slides within or relative to the second tissue anchor  104 . A length of the suture  106  located between the tissue anchors  102 ,  104  can be adjusted to achieve a desired distance between the tissue anchors  102 ,  104 . The distance between the tissue anchors  102 ,  104  can be adjusted to achieve a desired level of remodeling of the mitral valve  114  or a desired performance of the mitral valve  114 . 
     The suture lock  110  can be secured at a desired location along a length of a portion of the suture  106  that is not located between the tissue anchors  102 ,  104 . The suture lock  110  can contact the second tissue anchor  104  to limit a length of the suture  106  located between the tissue anchors  102 ,  104 . When the suture  106  is used to remodel the mitral valve  114  by moving the first location  112  closer to the second location  116 , the resiliency of the tissue of the mitral valve  114  will exert a force in a direction tending to move the anchors  102 ,  104  apart thereby tensioning the portion of the suture  106  located between the first tissue anchor  102  and the second tissue anchor  104 . Accordingly, this portion of the suture  106  can be referred to herein as the tensioned length  132 . Thus, in some configurations, the suture lock  110  is held against the second tissue anchor  104  by the tension of the tensioned length  132  of the suture  106 . The suture lock  110  only fixes the maximum separation distance of the first tissue anchor  102  and the second tissue anchor  104 , but permits the tissue anchors  102 ,  104  to move closer to one another. 
     In some configurations, as described further below, the suture lock  110  is reversible. That is, the suture lock  110  can be secured at a location along the length of the suture  106  to define a desired tensioned length  132 . The performance of the mitral valve  114  can then be observed and, if desired, the suture lock  110  can be unsecured from the suture  106 , moved to another location and once again secured to the suture  106  to define a different tensioned length  132 . This process can be repeated until a desired level of remodeling or performance of the mitral valve  114  is obtained. 
     Tissue Anchor 
     In some configurations, the tissue anchors  102 ,  104  are identical or substantially identical to one another. Accordingly, the first tissue anchor  102  is described. The second tissue anchor  104  can be identical or substantially identical, or can be of another suitable arrangement. 
     The illustrated tissue anchor  102  includes an anchor portion  140 , a drive portion  142  and a suture mount portion  144  arranged along a longitudinal axis  148  of the tissue anchor  102 . In some configurations, the suture mount portion  144  is located adjacent the anchor portion  140 . In the illustrated configuration, the suture mount portion  144  is located between the anchor portion  140  and the drive portion  142  along the longitudinal axis  148 . 
     The anchor portion  140  is configured to be implanted into tissue. Preferably, the anchor portion  140  is configured to be implanted into soft tissue, such as heart tissue. In some configurations, the anchor portion  140  is a threaded member that is implanted by rotation about the longitudinal axis  148 . The illustrated anchor portion  140  comprises a helical member  150 . The helical member  150  comprises an elongate member having a circular cross-section, which is wound about the longitudinal axis  148  to define an elongate hollow space  152  extending along the longitudinal axis  148 . The anchor portion  140  defines a length  151  that is sufficient for the anchor portion  140  to be secured in the desired tissue. 
     The drive portion  142  is configured to be engaged by a catheter or other implantation tool to allow for implantation of the tissue anchor  102 . The drive portion  142  is fixed for rotation with the anchor portion  140  such that rotation of the drive portion  142  results in rotation of the anchor portion  140 . 
     The drive portion  142  includes a drive surface  154  configured to engage with a drive member of a catheter. In the illustrated arrangement, the drive surface  154  is non-circular in shape. In the illustrated arrangement, the drive surface  154  is defined by an outward-facing surface of the drive portion  142 . The drive surface  154  is configured to be engaged by an inward-facing surface of a drive member of a catheter. The illustrated drive surface  154  has a square shape in a plane that is perpendicular to the longitudinal axis  148 . However, other shapes can also be used. Moreover, although the illustrated drive surface  154  is an outward-facing surface, the drive surface  154  could be defined by an inward-facing surface of, for example, a tool cavity. 
     The drive portion  142  defines a length  156  that is sufficient to permit the drive portion  142  to be engaged by a tool, such as a drive member of a catheter. In some configurations, a length of the drive surface  154  is equal to the length  156  of the drive portion  142 . 
     The suture mount portion  144  is movable relative to one or both of the anchor portion  140  and the drive portion  142 . In some configurations, the suture mount portion  144  is movable relative to both the anchor portion  140  and the drive portion  142 . In the illustrated arrangement, the suture mount portion  144  is rotatable relative to one or both of the anchor portion  140  and the drive portion  142 . Preferably, the suture mount portion  144  is rotatable about the longitudinal axis  148  of the tissue anchor  102 . 
     In some configurations, the suture mount portion  144  comprises a cylindrical body portion  158  having a relatively small length  160  or dimension extending along the longitudinal axis  148 . In some configurations, the length  160  is smaller than a diameter  162  or a maximum dimension in a direction perpendicular to the longitudinal axis  148 . The body portion  158  includes a cylindrical sidewall  164  that defines a peripheral surface of the body portion. The cylindrical sidewall  164  surrounds and, preferably, extends in a direction parallel to the longitudinal axis  148 . The cylindrical sidewall  164  defines a center point or axis  168 . Preferably, the center point or axis  168  is offset from the longitudinal axis  148  of the tissue anchor  102 . 
     The suture mount portion  144  comprises a suture mount location  170  configured to connect to, engage or otherwise support a suture, line or other tension member. The suture mount location  170  allows the suture  106  to extend from the tissue anchor  102  in a generally perpendicular direction relative to the longitudinal axis  148 . As used herein, the suture  106  extending in a generally perpendicular direction means that the suture  106  is oriented closer to the perpendicular direction than a parallel direction. 
     In some configurations, the suture mount location  170  is configured to allow the suture mount portion  144  and the tissue anchor  102  to slide on the suture  106 . In the illustrated arrangement, the suture mount location  170  comprises a passage  172  that extends through the body portion  158  of the suture mount portion  144  from a first surface  174  to a second surface  176 . The first surface  174  is nearer the drive portion  142  and the second surface  176  is nearer the anchor portion  140 . In some configurations, the passage  172  extends in a direction generally parallel to the longitudinal axis  148 . The passage  172  of the first tissue anchor  102  allows the suture  106  to be tied or otherwise fixedly secured to the first tissue anchor  102 . The passage  172  of the second tissue anchor  104  allows the second tissue anchor  104  to slide along the suture  106  so that the tensioned length  132  can be adjusted. As used herein, the term connect when used to describe the interaction between the suture  106  and the suture mount portion  144  can cover both of these situations unless indicated otherwise. 
     Preferably, the passage  172  is located on an opposite side of the center point or axis  168  from the longitudinal axis  148 . Accordingly, a portion of the body portion  158  that includes the passage  172  is oriented in the direction of force acting on the suture  106 . The body portion  158  protrudes from the longitudinal axis  148  a greater distance on the side of the passage  172  in comparison to the side opposite the passage  172 . In the illustrated arrangement, the suture  106  extends from an end of the passage  172  closest to the anchor portion  140 . Such an arrangement advantageously positions the suture  106  close to the tissue surface to inhibit or reduce leaning of the tissue anchor  102  when the suture  106  is tensioned. 
     In some configurations, the length  151  of the anchor portion  140  is greater than one or both of the length  156  of the drive portion  142  and the length  160  of the suture mount portion  144 . In the illustrated arrangement, the length  151  of the anchor portion  140  is greater than both the length  156  of the drive portion  142  and the length  160  of the suture mount portion  144 . In some configurations, the length  156  of the drive portion  142  is greater than the length  160  of the suture mount portion  144 . 
     Suture Lock 
     The suture lock  110  includes a first portion or base  180 . A second portion or cap  182  of the suture lock  110  is movable relative to the base  180  along a longitudinal axis  184  of the suture lock  110 . The base  180  and the cap  182  are rotationally fixed relative to one another. A threaded fastener  186  passes through an opening  190  in the cap  182  and engages a threaded cavity  192  of the base  180 . Rotation of the threaded fastener  186  in a first direction moves the cap  182  toward the base  180  and rotation of the threaded fastener  186  in a second, opposite direction moves the cap  182  away from the base  180 . Accordingly, the suture lock  110  can clamp a lock portion  188  of the suture  106  between the base  180  and the cap  182 , release the suture  106  to allow for adjustment of the position of the suture lock  110  relative to the suture  106 , and then re-clamp the suture  106 . 
     The base  180  and the cap  182  include cooperating structures that inhibit or prevent relative rotation. The cooperating structures can be one or more flat surfaces or non-circular surfaces relative to the longitudinal axis  184 . 
     In the illustrated arrangement, the base  180  is generally cylindrical in shape. The base  180  includes a protruding portion in the form of a central hub  200  that defines at least one non-circular surface (e.g., a flat surface  202 ). In the illustrated arrangement, the hub  200  defines a pair of flat surfaces  202  that are spaced from one another on opposite sides of the longitudinal axis  184 . The illustrated base  180  is symmetrical about the longitudinal axis  184 . Accordingly, the flat surfaces  202  as shown are equidistant from the longitudinal axis  184 . As used herein with respect to a structure that inhibits or prevents rotation, a non-circular surface is one in which the surface can cooperate with another surface to inhibit or prevent rotation about the longitudinal  184 . Such surfaces can include, for example, flat surfaces or curved surfaces that have a curvature about a center that is not located on the longitudinal axis  184 . 
     The flat surfaces  202  each have at least a component that extends in a direction parallel to the longitudinal axis  184 . In the illustrated arrangement, the flat surfaces  202  each are oriented parallel to the longitudinal axis  184 . Accordingly, the flat surfaces  202  permit axial movement of the cap  182  relative to the base  180  but inhibit or prevent rotational movement of the cap  182  relative to the base  180 . 
     Each of the flat surfaces  202  is created by a cutout section of a cylindrical work piece that extends only partially through the work piece in a longitudinal direction such that the base  180  also includes at least one flange portion or a base flange  204 . In the illustrated arrangement, the base  180  includes a pair of flange portions, which are referred to for convenience hereinafter as flanges  204 . Each flange  204  defines a shoulder surface or shoulder  206  adjacent the flat surfaces  202 . The shoulders  206  provide a stop surface to limit axial movement of the cap  182  along the longitudinal axis  184 . The shoulders  206  also provide a surface against which the suture  106  can be clamped, as is described further below. 
     The cap  182  is generally cylindrical in shape with a central cut-out defining a space  210  that receives a portion of the base  180 . In particular, the space  210  receives the hub  200  of the base  180 . The illustrated cap  182  defines an end wall portion  212  and a pair of (e.g., a first and a second) depending side wall portions  214  that cooperate to define the space  210 . The end wall portion  212  defines the opening  190  through which the threaded fastener  186  passes. The first and second side wall portions  214  each define a surface  216  that cooperates with one of the flat surfaces  202  to inhibit or prevent relative rotation between the base  180  and the cap  182 . The surfaces  216  can be non-circular. In the illustrated arrangement, the surfaces  216  of the side wall portions  214  are flat. Thus, in the illustrated arrangement, both the surfaces  202  of the base  180  and the surfaces  216  are flat. However, other arrangements are possible in which only one of the surfaces  202 ,  216  are flat or in which neither of the surfaces  202 ,  216  are flat, but are otherwise configured to cooperate with one another to inhibit or prevent rotation between the base  180  and the cap  182 . The illustrated flat surfaces  216  of the cap  182  are in sliding contact with the flat surfaces  202  of the base  180  to permit axial movement and inhibit or prevent rotational movement of the cap  182  relative to the base  180 . 
     The ends of the side wall portions  214  opposite the end wall portion  212  terminate in outwardly or radially-extending flanges  220 . The portions of the side wall portions  214  adjacent the flanges  220  define flat surfaces  222 . The flat surfaces  222  are parallel to one another in the illustrated arrangement but could be non-parallel in other configurations. The flat surfaces  222  are located radially inward from an outermost extent of the flanges  220  to define a stop surface or shoulder  224 . The flat surfaces  222  can be utilized so that a tool (e.g., a catheter) can hold the cap  182  against rotation while the threaded fastener  186  is rotated to move the base  180  and the cap  182  toward or away from one another along the longitudinal axis  184 . 
     As described above, the suture  106  can be captured or clamped between the base  180  and the cap  182 . The suture  106  can be captured or clamped between the flange  204  of the base  180  and the corresponding flange  220  of the cap  182 . In some configurations, one or both of the base  180  and the cap  182  include a suture retention feature configured to retain the suture  106  to the base  180  and/or cap  182  or at least inhibit or prevent complete separation of the suture  106  from the base  180  and/or cap  182 . In the illustrated arrangement, at least one of the flanges  204  of the base  180  includes a suture passage  226  configured to accommodate the suture  106 . However, in other arrangements, at least one of the flanges  220  of the cap  182 , or both the flange(s)  204  of the base  180  and the flange(s)  220  of the cap  182 , can include a suture passage  226 . 
     In the illustrated arrangement, the suture passage  226  extends through the flange  204  from an end surface  230  to the shoulder surface  206 . In some configurations, the passage  226  extends in a direction generally parallel to the longitudinal axis  184 . As used herein, generally parallel means that the passage  226  is oriented closer to the parallel direction than a perpendicular direction. The passage  226  allows the suture  106  to be retained to the base  180  of the suture lock  110 . The passage  226  allows the tissue anchor  110  to slide along the suture  106 . The passage  226  retains a portion of the suture  106  between the flange  204  of the base  180  and the flange  220  of the cap  182  so that the suture  106  can be selectively clamped by movement of the cap  182  toward the base  180 . 
     The threaded fastener  186  can be, or can be similar to, a socket head cap bolt. The threaded fastener  186  has a threaded shaft portion or shaft  232  and a head portion or head  234 . The head  234  has a larger diameter or cross-sectional size than the shaft  232 . The head  234  can define a surface or surfaces configured to engage a tool. In the illustrated arrangement, the head  234  defines a tool cavity  236 , such as a hexagon-shaped tool cavity. The shaft  232  passes through the opening  190  of the cap  182  and engages the threaded cavity  192  of the base  180 . The head  234  contacts the end wall portion  212  of the cap  182  to retain the cap  182  on the base  180 . As described previously, contact between the head  234  and the end wall portion  212  allows the threaded fastener  186  to selectively move the cap  182  toward the base  180  to clamp the suture  106  or to allow the cap  182  to move away from the base  180  to release the suture  106 . 
     Delivery Catheter(s) 
     As described previously, the system  100  utilizes one or more catheters to deliver and implant or install the components of the system  100  within the desired anatomy of the patient, such as the mitral valve  114  of the heart in the illustrated application. The catheters can be steerable catheters, as is known in the art. In some implementations, the system  100  includes an anchor delivery catheter  250  configured to deliver one or both of the tissue anchors  102 ,  104  from outside of the patient to within the heart of the patient. The delivery catheter  250  is configured to implant the tissue anchors  102 ,  104  within the desired tissue of the patient, such as the mitral valve  114 . 
     The delivery catheter  250  includes an elongate catheter body or tube  252 . A handle  254  can be connected to the external end of the tube  252  and can be configured to allow a user to control the delivery catheter  250 . A delivery end of the tube  252  that is inserted into the patient includes a tip  256  that is configured to engage the tissue anchors  102 ,  104 . The illustrated tip  256  has a first portion  260  and a second portion  262 . The first portion  260  is a stationary portion that is secured to the tube  252  in a rotationally fixed manner. The second portion  262  is a rotatable portion that is rotatable relative to the first portion  260  and, thus, to the tube  252 . 
     The delivery catheter  250  includes a drive element configured to selectively rotate the second portion  262  of the tip  256 . In the illustrated arrangement, the drive element is an elongate drive shaft  264  that extends through the tube  252  from the handle  254  to the second portion  262  of the tip  256 . The drive shaft  264  is coupled to the second portion  262  of the tip  256  in a manner such that torque can be transferred from the drive shaft  264  to the second portion  262  of the tip  256 . Accordingly, rotation of the drive shaft  264  causes rotation of the second portion  262  of the tip  256 . Rotation of the drive shaft  264  can be actuated from the handle  254 , such as via a dial or knob  266  or other suitable control member. The handle  254  in  FIG. 7  is not shown to scale. 
     The first portion  260  of the tip  256  can have a diameter or cross-sectional dimension that is larger than the diameter or cross-sectional dimension of the second portion  262  of the tip  256  and/or the tube  252 . Preferably, the diameter or cross-sectional dimension of the first portion  260  of the tip  256  is larger than the diameter or cross-sectional dimension of both the second portion  262  of the tip  256  and the tube  252 . The first portion  260  of the tip  256  can include a suture passage  270  configured to accommodate the suture  106 . The suture passage  270  can extend generally in an axial direction of the delivery catheter  250 . Preferably, the delivery catheter  250  is a “rapid exchange” type catheter in which the suture  106  passes through only a small portion of the catheter  250  and is otherwise external of the catheter  250 . In the illustrated configuration, the suture  106  passes only through the suture passage  270  of the tip  256  and is completely external of the tube  252 . 
     The second portion  262  of the tip  256  defines an engagement portion configured to engage the tissue anchor  102 ,  104  and to transfer torque from the second portion  262  of the tip  256  to the tissue anchor  102 ,  104 . In the illustrated arrangement, the second portion  262  of the tip  256  defines a tool cavity  272  configured to receive the drive portion  142  of the tissue anchor  102 ,  104 . The tool cavity  272  and the drive portion  142  each have non-circular cross-sectional shapes that are complementary to one another. In the illustrated arrangement, each of the tool cavity  272  and the drive portion  142  have a square cross-sectional shape. Thus, the drive portion  142  of the tissue anchor  102 ,  104  can slide into the tool cavity  272  of the second portion  262  of the tip  256 . Accordingly, the tissue anchor  102 ,  104  can be selectively engaged to and disengaged from the tip  256  of the delivery catheter  250 . In addition, rotation of the second portion  262  of the tip  256  causes rotation of the drive portion  142  of the tissue anchor  102 ,  104 . 
     The illustrated system  100  also includes a suture lock delivery catheter  280  configured to deliver and install the suture lock  110 . The delivery catheter  280  can be similar to the delivery catheter  250  that delivers the tissue anchors  102 ,  104 . The illustrated delivery catheter  280  includes an elongate catheter body or tube  282 . A handle  284  can be connected to the external end of the tube  282  and can be configured to allow a user to control the delivery catheter  280 . A delivery end of the tube  282  that is inserted into the patient includes a tip  286  that is configured to engage the suture lock  110 . The tip  286  is secured to the tube  282  in a rotationally fixed manner. 
     The tip  286  can have a diameter or cross-sectional dimension that is larger than the diameter or cross-sectional dimension of the tube  282 . The tip  286  can include a suture passage  290  configured to accommodate the suture  106 . The suture passage  290  can extend generally in an axial direction of the delivery catheter  280 . Preferably, the delivery catheter  280  is a “rapid exchange” type catheter in which the suture  106  passes through only a small portion of the catheter  280  and is otherwise external of the catheter  280 . In the illustrated configuration, the suture  106  passes only through the suture passage  290  of the tip  286  and is completely external of the tube  282 . 
     The tip  286  defines an engagement portion configured to engage the suture lock  110 . In particular, the tip  286  is configured to hold the cap  182  of the suture lock  110  and inhibit or prevent rotation of the cap  182  so the threaded fastener  186  can be rotated relative to the cap  182  to move the base  180  toward or away from the cap  182 . In the illustrated arrangement, the tip  286  defines a cavity  292  configured to receive the cap  182  of the suture lock  110 . The cavity  292  includes engagement surfaces  294  that engage the flat surfaces  222  of the cap  182  of the tissue anchor  110 . Thus, the cap  182  of the suture lock  110  can slide into the cavity  292  of the tip  286 . Accordingly, the cap  182  of the suture lock  110  can be selectively engaged to and disengaged from the tip  286  of the delivery catheter  280 . In addition, the tip  286  can hold the cap  182  of the suture lock  110  against rotation. 
     The delivery catheter  250  includes a drive element configured to selectively rotate the threaded fastener  186  of the suture lock  110 . In the illustrated arrangement, the drive element is an elongate drive shaft  296  that extends through the tube  282  from the handle  284  to the tip  286 . The drive shaft  296  carries a drive element, such as a drive tip or drive tool  298  that is configured to transfer torque from the drive shaft  296  to the threaded fastener  186 . In the illustrated arrangement, the drive tool  298  has a shape that is complementary to the tool cavity  236  of the threaded fastener  186 . Accordingly, rotation of the drive shaft  296  causes rotation of the threaded fastener  186 . Rotation of the drive shaft  296  can be actuated from the handle  284 , such as via a dial or knob  300  or other suitable control member. The handle  284  in  FIG. 9  is not shown to scale. 
     Suture Trimmer 
     The system  100  can also include a suture trimmer  350  configured to cut off or trim the excess portion of the suture  106 . In the illustrated arrangement, the suture trimmer  350  includes an elongate catheter body or tube  352 . A handle  354  can be connected to the external end of the tube  352  and can be configured to allow a user to control the suture trimmer  350 . A trimming end of the tube  352  that is inserted into the patient includes a tip  356  that is configured to trim the suture  106 . 
     The illustrated tip  356  has a first portion  360  and a second portion  362 . The second portion  362  is axially movable relative to the first portion  360 . The first portion  360  supports or houses a cutting blade  364 . The second portion  362  is configured to receive and retain the suture  106  for cutting by the cutting blade  354 . The second portion  362  defines a suture passage  366  configured to accommodate the suture  106 . The suture passage  366  extends in a radially or a generally radial direction of the tube  352 . That is, the suture passage  366  can extend in a radial direction or a direction that is oblique relative to a longitudinal axis of the tube  352 . 
     The illustrated second portion  362  of the tip  356  also includes a slot  370  configured to receive the cutting blade  364 when the second portion  362  is moved axially toward the first portion  360 . The slot  370  intersects the suture passage  366 . Accordingly, when the suture  106  is located within the suture passage  366 , the cutting blade  364  can be moved into the slot  370  to cut the suture  106  by movement of the second portion  362  of the tip  356  toward the first portion  360 . In the illustrated arrangement, the slot  370  extends through the end of the second portion  362  of the tip  356 . However, in other arrangements, the slot  370  could have a closed end. In other arrangements, the second portion  362  of the tip can be stationary and the blade  364  can be configured to move. 
     The suture trimmer  350  includes an actuator for moving the second portion  362  toward the first portion  360  for advancing the cutting blade  364  into the slot  370 . In the illustrated arrangement, the suture trimmer  350  includes an actuation wire or shaft  372 . The actuation wire  372  extends from the handle  354  to the second portion  362  of the tip  356 . A user control element, such as a button, knob, dial or lever  374 , can be located on the handle  374  and coupled to the actuation wire  372 . The control element  374  can apply a pulling force on the actuation wire  372  tending to move the second portion  362  of the tip  356  in an axial direction toward the first portion  360 . As a result, the cutting blade  364  is advanced through the slot  370  to cut the suture  106 . The handle  354  in  FIG. 10  is not shown to scale. 
     Advantageously, the illustrated arrangement allows the suture  106  to be trimmed at a location close to the suture lock  110 . As a result, a relatively short length of excess suture  106  remains within the patient. For example, the excess portion of the suture  106  can be equal to or less than a radius of the tip  356 , such as a second portion  362  of the tip  356 , if the slot  370  is located in a center of the tube  352  or the tip  356  and the suture passage  366  is oriented in a radial direction of the tube  352  or the tip  356 . Accordingly, the second portion  362  of the tip  356  can be configured to have a smaller diameter or cross-sectional dimension than one or both of the first portion  360  of the tip  356  and the tube  352 . 
     Method 
     The components of the system  100  can be delivered to the mitral valve  114  of the patient by any suitable method. In some configurations, the components of the system  100  are routed to the left atrium via a transeptal approach, wherein an incision is made in the atrial portion of the septum to allow access from the right atrium, such as via the inferior or superior vena cava. A guide catheter  310  can be routed to the left atrium by any suitable method, such as any transvascular approach as is known in the art. The guide catheter  310  can be configured to receive the delivery catheters  250 ,  280 . 
     In one method of implantation of the system  100 , the suture  106  is attached to the first tissue anchor  102  by any suitable arrangement or method, as indicated at block  400 . For example, the suture  106  can be passed through the passage  172  of the suture mount location  170  of the first tissue anchor  102  and tied to itself using a suitable knot. Preferably, the suture  106  extends from the second surface  176  of the anchor portion  140  so that the suture  106  is located adjacent to the tissue of the mitral valve  114 . 
     At block  402 , the first tissue anchor  102  can be loaded onto the delivery catheter  250 . For example, the suture  106  can be passed through the suture passage  270  of the first portion  260  of the tip  256  of the catheter  250 . The suture  106  can be passed through the passage  270  in a direction from the tip  256  toward the tube  252 . The drive portion  142  of the first tissue anchor  102  can be inserted into the tool cavity  272  of the tip  256  of the catheter  250 . 
     At block  404 , the delivery catheter  250  can be used to deliver the first tissue anchor  102  to the first location  112 . For example, the delivery catheter  250  can be passed through the guide catheter  310  to the first location  112 , using a suitable guidance technique. During delivery, the suture  106  can be tensioned to help maintain the first tissue anchor  102  in engagement with the tip  256 . 
     At block  406 , the first tissue anchor  102  is implanted at the first location  112 . For example, the knob  266  can be used to rotate the drive shaft  264 , which rotates the second portion  262  of the tip  256  of the catheter  250 . Rotation of the second portion  262 , in turn, rotates the drive portion  142  and anchor portion  140  of the first tissue anchor  102 . Rotation of the anchor portion  140  screws the first tissue anchor  102  into the tissue of the mitral valve  114  at the first location  112 . Tension can be kept on the suture  106  to inhibit or prevent rotation of the mount portion  144  of the first tissue anchor  102 , which can keep the suture  106  from wrapping around the delivery catheter  250 . 
     At block  408 , the delivery catheter  250  is withdrawn from the guide catheter  310  leaving the first tissue anchor  102  in place at the first location  112  of the mitral valve  114 . The suture  106  can be removed from the tip  256  of the delivery catheter  250 . 
     At block  410 , the second tissue anchor  104  can be loaded onto the delivery catheter  250 . For example, the suture  106  can be passed through the suture passage  172  of the second tissue anchor  104 . The suture  106  can be passed through the suture passage  172  in a direction from the second surface  176  to the first surface  174  so that the suture  106  is located adjacent to the tissue of the mitral valve  114 . The suture  106  can be passed through the suture passage  270  of the first portion  260  of the tip  256  of the catheter  250 . The suture  106  can be passed through the passage  270  in a direction from the tip  256  toward the tube  252 . The drive portion  142  of the second tissue anchor  104  can be inserted into the tool cavity  272  of the tip  256  of the catheter  250 . 
     At block  412 , the delivery catheter  250  can be used to deliver the second tissue anchor  104  to the second location  116 . For example, the delivery catheter  250  can be passed through the guide catheter  310  to the second location  116 , using a suitable guidance technique. During delivery, the suture  106  can be tensioned to help maintain the second tissue anchor  102  in engagement with the tip  256 . 
     At block  414 , the second tissue anchor  104  is implanted at the second location  116 . For example, the knob  266  can be used to rotate the drive shaft  264 , which rotates the second portion  262  of the tip  256  of the catheter  250 . Rotation of the second portion  262 , in turn, rotates the drive portion  142  and anchor portion  140  of the second tissue anchor  104 . Rotation of the anchor portion  140  screws the second tissue anchor  104  into the tissue of the mitral valve  114  at the second location  116 . Tension can be kept on the suture  106  to inhibit or prevent rotation of the mount portion  144  of the second tissue anchor  104 , which can keep the suture  106  from wrapping around the delivery catheter  250 . 
     At block  416 , the delivery catheter  250  is withdrawn from the guide catheter  310  leaving the second tissue anchor  104  in place at the second location  116  of the mitral valve  114 . The suture  106  can be removed from the tip  256  of the delivery catheter  250 . 
     At block  418 , the suture lock  110  can be loaded onto the delivery catheter  280 . For example, the suture  106  can be passed through the suture passage  226  of the base  180  of the suture lock  110 . The suture  106  can be passed through the suture passage  226  in a direction from the end surface  230  to the shoulder surface  206 . The suture  106  can be passed through the suture passage  290  of the tip  286  of the delivery catheter  280 . The drive tool  298  can be inserted into the tool cavity  236  of the threaded fastener  186 . The cap  182  can be inserted into the cavity  292  of the tip  286  of the delivery catheter  280 . 
     At block  420 , the suture lock  110  can be delivered to the second location  116  using the delivery catheter  280 . For example, the delivery catheter  280  can be passed through the guide catheter  310  to the second location  116 , using a suitable guidance technique. During delivery, the suture  106  can be tensioned to help maintain the suture lock  110  in engagement with the tip  286 . 
     At block  422 , the tension length  132  of the suture  106  can be adjusted. For example, the end surface  230  of the suture lock  110  can be positioned against the first surface  174  of the suture mount portion  144  of the second tissue anchor  104 . The suture  106  can be pulled and the column strength of the delivery catheter  280  can hold the second tissue anchor  104  and suture lock  110  in place. Thus, the suture  106  can be pulled through the respective suture passages  172 ,  226 ,  290  of the second tissue anchor  104 , the suture lock  110  and the tip  286  of the catheter  280 . As a result, the first tissue anchor  102  is pulled toward the second tissue anchor  104  and the tension length  132  is reduced. The suture  106  can also be released and the inherent resiliency of the tissue of the mitral valve  114  can increase the tension length  132 . 
     At block  424 , once a desired tension length  132  has been achieved, the suture lock  100  can be locked to secure the fix the suture  106  relative to the suture lock  110 . For example, the knob  300  can be used to rotate the drive shaft  296 . Rotation of the drive shaft  296  rotates the drive tool  298 , which rotates the threaded fastener  186  of the suture lock  110 . Rotation of the threaded fastener  186  causes the base  180  and cap  182  of the suture lock  110  to move toward one another thereby clamping the suture  106  between the shoulder surface  206  of the base  180  and the flange  220  of the cap  182 . 
     At block  430 , once the suture lock  110  has been locked, but before the delivery catheter  280  has been removed from the suture lock  100 , the performance or operation of the mitral valve  114  can be monitored by any suitable imaging process. 
     At block  426 , the delivery catheter  280  can be withdrawn leaving the suture lock  110  in place. For example, the catheter tip  286  and the drive tool  298  can be removed from the cap  182  and the threaded fastener  186 , respectively, and the delivery catheter  280  can be withdrawn from the guide catheter  310 . 
     At block  428 , the excess portion of the suture  106  can be trimmed. For example, the suture  106  can be passed through the suture passage  366  of the suture trimmer  350 . The end of the suture trimmer  350  comprising the tip  356  can be inserted into the guide catheter  310  and advanced to the second location  116 . The tip  356  slides along the suture  106  such that an end of the suture  106  remains outside of the patient. The suture  106  can guide the tip  356  of the suture trimmer  350  to the suture lock  110 . Once the tip  356  of the suture trimmer  350  is located adjacent the suture lock  110 , the control element  374  can be actuated to advance the cutting blade  364  within the slot  370  and cut the suture  106 . The external end of the suture  106  can be held to maintain tension in the excess portion of the suture  106  to allow for easier cutting. 
     As described above, the system  100  is configured such that the tension length  132  can be set, the operation of the mitral valve  114  monitored and, if desired, the tension length  132  changed. This process can be repeated until a desired result is achieved. 
     Optionally, returning to block  430 , once the suture lock  110  has been locked, but before the delivery catheter  280  has been removed from the suture lock  100 , the performance or operation of the mitral valve  114  can be monitored by any suitable imaging process. 
     Optionally, at block  432 , if an adjustment is desired, the suture lock  110  can release the suture  106  to allow for adjustment of the tension length  132 . For example, the knob  300  can be used to rotate the drive shaft  296  and drive tool  298  in a counter-clockwise direction (or opposite the direction used to clamp the suture  106 ). Rotation of the drive tool  298  rotates the threaded fastener  186 , which allows the cap  182  to move away from the base  180 . As a result, the suture  106  is no longer clamped between the cap  182  and the base  180  and is permitted to move relative to the suture lock  110  and second tissue anchor  104 . 
     The tension length  132  can be adjusted as described above with respect to block  422 . Once a desired tension length  132  is obtained, the suture  106  can be locked as described with respect to block  424 . The method can then return to block  430  to permit further monitoring and, if desired, further adjustment. If the desired operation or performance of the mitral valve  114  has been achieved, the method can move to block  426  and block  428  to release the suture lock  110  and trim the suture  106 , as described above. 
     Tissue Anchor Cover 
       FIGS. 12A-12C  illustrate an alternative delivery catheter  250  having a distal tip cover  500  located at the distal end or delivery end of the catheter tube  252 . The cover  500  can be configured to accommodate (e.g., cover) the tissue anchor  102 ,  104  to inhibit or prevent the tissue anchor  102 ,  104  from damaging tissue (e.g., vasculature or heart tissue) prior to deployment. The cover  500  can be connected, such as bonded or otherwise secured, to or around the tip  256  of the catheter tube  252  at a connection  501 . The cover  500  can be generally tubular in form and can define an interior space that receives the tissue anchor  102 ,  104 . The cover  500  can have an open distal end through which the tissue anchor  102 ,  104  can be deployed. 
     The cover  500  includes a through hole in the form of a slot  502  that passes in a radial direction through a sidewall of the cover  500 . The slot  502  accommodates the suture  106  such that the suture  106  can pass from external of the cover  500  to internal of the cover  500 . As described above, the suture  106  engages the tissue anchor  102 ,  104  that is initially located within the cover  500  prior to deployment. Thus, the suture  106  is located outside of the catheter tube  252  and passes through the slot  502  to engage the tissue anchor  102 ,  104 , as illustrated in  FIG. 12B . 
     The cover  500  also includes a slit  504  that extends lengthwise from the slot  502  to the distal or free end of the cover  500 . The slit  504  passes entirely through the sidewall of the cover  500 . As a result, the suture  106  can pass from the slot  502  through the slit  504  as the tissue anchor  102 ,  104  is deployed from the cover  500  thereby allowing the suture  106  can separate or disengage from the cover  500  and the catheter  250 .  FIG. 12C  illustrates the suture  106  passing through the slit  504 . 
     Such an arrangement advantageously provided protection to the tissue anchor  102 ,  104  and protects other tissues from the sharp end of the tissue anchor  102 ,  104  until deployment. The cover  500  also allows for simple disengagement of the suture  106  from the cover  500 . The cover  500  can be constructed from any suitable material or combination of materials. For example, the cover  500  can be constructed from a suitable medical grade polymer material or materials. The cover  500  can be implemented with the system  100  or components of the system  100  described with respect to  FIGS. 1-11 , such as the delivery catheter  250  of  FIGS. 1-11 . Alternatively, the catheter  250  of  FIGS. 12A-12C  can be utilized with the system  100  of  FIGS. 1-11 . 
     Tissue Anchor with Barbs 
       FIG. 13  illustrates an alternative tissue anchor  102  that provides for improved retention within tissue relative to the tissue anchors  102 ,  104  described above. The tissue anchor  102  of  FIG. 13  is similar to the prior tissue anchors  102 ,  104  and, therefore, the same reference numbers are used to refer to the same or corresponding components or features. The alternative tissue anchor  102  is described in the context of the differences relative to the previously described tissue anchors  102 ,  104 . Any components or features of the alternative tissue anchor  102  not described in detail can be assumed to be the same as or similar to the component or feature of the tissue anchors  102 ,  104 , or can be of another suitable arrangement. Moreover, the tissue anchor  102  of  FIG. 13  can replace either one or both of the tissue anchors  102 ,  104  in the systems and methods described above. 
     The illustrated tissue anchor  102  includes an anchor portion  140 , a drive portion  142  and a suture mount portion  144  arranged along a longitudinal axis  148  of the tissue anchor  102 . In the illustrated configuration, the suture mount portion  144  is located between the anchor portion  140  and the drive portion  142  along the longitudinal axis  148 . 
     The anchor portion  140  is configured to be implanted into soft tissue, such as heart tissue, as described above. The illustrated anchor portion  140  comprises a helical member  150  that is implanted by rotation (e.g., clockwise rotation) about the longitudinal axis  148 . The helical member  150  comprises an elongate member having a circular cross-section, which is wound about the longitudinal axis  148  to define an elongate hollow space  152  extending along the longitudinal axis  148 . 
     The anchor portion  140  of the tissue anchor  102  of  FIG. 13  includes at least one barb  600  or other similar projection that is configured to impede rotation of the anchor portion  140  in a direction tending to remove the tissue anchor  102  from tissue (e.g., counterclockwise rotation). Preferably, the anchor portion  140  includes a plurality of barbs  600  spaced from one another along a length of the helical member  150  and/or along the longitudinal axis  148 . In the illustrated arrangement, the anchor portion  140  includes three barbs  600 . However, other numbers of barbs  600  could also be used, such as one, two, four, five, six or more barbs  600 , for example and without limitation. The number of barbs  600  can be selected to provide a desired amount of resistance to removal of the tissue anchor  102  for the intended use. 
     Each barb  600  is configured to permit implantation of the tissue anchor  102  with a first level of resistance and to inhibit removal of the tissue anchor  102  with a second level of resistance that is greater than the first level of resistance. For example, each barb  600  can be configured to allow rotation in an implantation direction (e.g., clockwise rotation) to permit implantation of the tissue anchor  102  and to resist rotation in a removal direction (e.g., counterclockwise rotation). In some configurations, each barb  600  includes an end  602  configured to engage tissue to resist rotation of the anchor portion  140  of the tissue anchor  102  in the removal direction. In some configurations, the end  602  is an angled end that is oriented at an angle relative to the tangential direction of the location on the helical member  150  at which the barb  600  is provided. The angled end  602  is oriented with the tip  603  located radially outward on the barb  600 . With such an arrangement, the barb  600  permits rotation in the implantation direction (e.g., clockwise rotation) and resists rotation in the opposite removal direction (e.g., counterclockwise rotation). 
     In some configurations, each barb  600  is constructed of or comprises a tubular element or tube  604 . The tube  604  can define an interior passage that is equal to or somewhat larger in diameter and/or cross-sectional area than the diameter and/or cross-sectional area of the helical member  150 . The tube  604  can be formed separately from the helical member  150  an assembled thereto. Preferably, the tube  604  is configured to be movable along the helical member  150  so that the tube  604  can be assembled onto the helical member  150 . For example, the tube  604  can be pushed onto the terminal end of the helical member  150  and advanced along the helical member towards the drive portion  142  and suture mount portion  144  of the tissue anchor  102 . The tube  604  can be secured at a desired location along the helical member  150  by any suitable arrangement or method. For example, the tube  604  can have an interference fit with the helical member  150  and/or can be secured by soldering, welding or adhesives, for example and without limitation. 
     In some configurations, the tube  604  may be straight or linear. The angled end  602  can define an angle relative to a longitudinal axis  606  of the tube  604 . In some configurations, the tube  604  may be curved along its length. In such configurations, the angle of the angled end  602  can be measured relative to an axis that passes through the geometric center of the cross-section of the tube  604  and is oriented perpendicular to the cross-sectional plane. In some configurations the angle can be between 20-70 degrees, 30-60 degrees, 40-50 degrees, or about 45 degrees. 
     Although the illustrate barbs  600  are created by member that is formed separately from the helical member  150 , other suitable methods or structures for creating the barb(s)  600  can also be used. For example, the barb(s)  600  can be formed in a unitary manner along with the helical member  150 . In some configurations, the helical member  150  can be formed with the barb(s)  600  in place, such as by a forming or three-dimensional printing process. In other configurations, a workpiece used to create the helical member  150  could be notched or cut such that the barb(s)  600  are formed when the workpiece is wound to create the helical shape of the helical member  150 . Alternatively, the barb(s)  600  could be created by notching or cutting of the helical member  150  after it is provided in the helical form. Furthermore, although the illustrated barbs  600  are integral with and rotation along with the helical member  150 , in other configurations the barb(s)  600  or other anti-rotation features could be deployed and/or engaged separately once the tissue anchor  102  has been implanted by a suitable actuation arrangement (e.g., a push rod). 
     As in the tissue anchors  102 ,  104  described above, the drive portion  142  of the tissue anchor  102  of  FIG. 13  is configured to be engaged by a catheter or other implantation tool to allow for implantation of the tissue anchor  102 . The drive portion  142  is fixed for rotation with the anchor portion  140  such that rotation of the drive portion  142  results in rotation of the anchor portion  140 . 
     As in the tissue anchors  102 ,  104  described above, the suture mount portion  144  of the tissue anchor  102  of  FIG. 13  is rotatable relative to one or both of the anchor portion  140  and the drive portion  142 . Preferably, the suture mount portion  144  is rotatable about the longitudinal axis  148  of the tissue anchor  102 . The suture mount portion  144  comprises a suture mount location  170  configured to connect to, engage or otherwise support a suture, line or other tension member. The suture mount location  170  allows the suture  106  to extend from the tissue anchor  102  in a generally perpendicular direction relative to the longitudinal axis  148 . 
     In the illustrated arrangement, the suture mount location  170  comprises a passage  172  that extends through the body portion  158  of the suture mount portion  144  from a first surface  174  nearer the drive portion  142  to a second surface  176  nearer the anchor portion  140 . In some configurations, the passage  172  extends in a direction generally parallel to the longitudinal axis  148 . The passage  172  of the tissue anchor  102  allows the suture  106  to be tied or otherwise fixedly secured to the first tissue anchor  102  or allows the tissue anchor  102  to slide along the suture  106  so that the tensioned length  132  ( FIG. 1 ) can be adjusted, as described above. Accordingly, the tissue anchor  102  of  FIG. 13  can perform the function of either one of the previously described tissue anchors  102 ,  104 . 
     The tissue anchor  102  of  FIG. 13  provides increased resistance to removal from tissue via one or both of straight pull out or backing out by rotation. Accordingly, under at least some conditions, it is preferably for one or both of the tissue anchors  102 ,  104  described previously to be replaced with the tissue anchor of  FIG. 13  in any of the systems or methods described herein to provide increased resistance to removal from the tissue into which the tissue anchor  102  is implanted. Therefore, any tissue anchor  102 ,  104  described herein can be replaced by the tissue anchor  102  of  FIG. 13  or otherwise modified to include similar barbs or other projections or features that increase retention. 
     Suture Lock Retention 
     In some situations, it may be desirable to retain the suture lock  110  relative to one of the tissue anchors  102 ,  104 . For example, in the event that the suture  106  is severed, it may be desirable to prevent the suture lock  110  from being unrestrained or free floating within the heart or other organ or anatomical location. In some cases, further interventions may be desirable in the place of the remodeling system  100 . Such interventions may include additional valve repair or valve replacement. The implementation of these further interventions may necessitate cutting of the suture to reduce or remove the influence of the remodeling system  100 . In the remodeling system  100  illustrated in  FIG. 1 , the suture lock  110  is not permanently coupled to the associated tissue anchor  104 , but is held in position against tissue anchor  104  by the tension of the suture  106 . Once the suture  106  is cut, the suture lock  110  is no longer held in place relative to the tissue anchor  104  and is capable of moving within the patient&#39;s anatomy. In order to avoid this situation, certain embodiments of the remodeling system  100  may be configured to retain the suture lock  110  relative to another component of the system  100 , which preferably is an implanted component (e.g., one of the tissue anchors  102 ,  104 ) that is secured within the patient&#39;s anatomy. The suture lock  110  may be coupled directly or indirectly relative to an associated component (e.g., tissue anchor  102 ,  104 ). 
     As illustrated in  FIG. 14 , a suture lock  110  may be configured to be secured to the tissue anchor  102 ,  104 . In particular, the suture lock  110  may be directly secured to the tissue anchor  102 ,  104 . In the illustrated arrangement, the suture lock  110  is configured to be directly secured to the suture mount portion  144  of the tissue anchor  102 ,  104 . For example, the suture lock  110  may be a clamp, such as a chuck or collet, that surrounds the suture  106  and is configured to apply a clamping force to the suture  106  when the suture lock  110  is secured to the tissue anchor  102 ,  104 . However, the clamping force and the coupling to the tissue anchor  102 ,  104  could also be accomplished separately. 
     In the illustrated arrangement, the suture lock  110  includes an outer threaded surface  700  that is configured to engage with an inner threaded surface (not shown) of the passage  172  of the tissue anchor  102 ,  104 . The outer threaded surface  700 , the inner threaded surface, or both may be tapered or include a tapered portion, or another suitable arrangement may be provided, such that the suture lock  110  clamps the suture  106  as the suture lock  110  is advanced into the passage  172  to both couple the suture  106  to the suture lock  110  and couple the suture lock  110  to the tissue anchor  102 ,  104 . Advantageously, with such an arrangement, if the suture  106  is severed, the suture lock  110  remains secured to the tissue anchor  102 ,  104 . Because the tissue anchor  102 ,  104  is securely implanted, the suture lock  110  also remains secured in place within the patient&#39;s anatomy. 
       FIG. 15  illustrated another retention arrangement to secure the suture lock  110 . In particular, the arrangement of  FIG. 15  is configured to retain the suture lock  110  in proximity to the associated tissue anchor  104  using a portion of the suture  106 . In the illustrated arrangement, a stop, block or blocking element  750 , such as a metal band or ferrule, is secured to the suture  106  between the tissue anchors  102 ,  104  or on an opposite side of the suture mount portion  144  of the associated tissue anchor  104  from the suture lock  110 . The blocking element  750  is configured to be unable to pass through the passage  172  (see,  FIGS. 2B and 14 ) of the tissue anchor  104 . As a result, once cut, a portion of the suture  106  that passes through the passage  172  is secured to the tissue anchor  104  by the blocking element  750  on one end and the suture lock  110  on the other end, each being unable to pass through the passage  172 . 
     The blocking element  750  can be any suitable structure that can be secured to the suture and unable to pass through the passage  172 . In the illustrated arrangement, the blocking element  750  is a metal band, which is placed onto the suture  106  and can be crimped or otherwise secured in place at a particular location on the suture  106 . Preferably, the metal band  750  is threaded onto the suture  106  before the second tissue anchor  104  and suture lock  110  are threaded onto the suture  106  in the delivery method described above. However, it may also be possible to attach the metal band  750  after delivery of both tissue anchors  102 ,  104 , including after delivery of the suture lock  110 . Preferably, the metal band  750  is crimped after it has been moved to the implantation site. The metal band  750  may be crimped after the second tissue anchor  104  is delivered or implanted. In some cases, the metal band  750  may be crimped after the entire remodeling system  100  is implanted and adjusted. 
     The position of the metal band  750  on the suture  106  can influence the degree of permitted movement of the suture lock  110 . That is, the length of the suture  106  between the suture lock  110  and the metal band  750  influences or defines the degree of permitted movement of the suture lock  110 . Thus, it may be desirable for the metal band  750  to be as close as possible or practical to the tissue anchor  104  associated with the suture lock  110 . 
     As indicated above, the blocking element  750  can be or comprise suitable structures other than a metal band. For example, the blocking element  750  can be any type of clamp having a body portion large enough to prevent the body portion from passing through the passage  172  of the tissue anchor. Other suitable blocking elements  750  can include a retention portion or function that allows the blocking element  750  to be secured in place on the suture  160  and a blocking portion or function that prevents the blocking element  750  from passing through the passage  172  of the tissue anchor  104 . 
     Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments. 
     The term “plurality” refers to two or more of an item. Recitations of quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics should be construed as if the term “about” or “approximately” precedes the quantity, dimension, size, formulation, parameter, shape or other characteristic. The terms “about” or “approximately” mean that quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics need not be exact, but may be approximated and/or larger or smaller, as desired, reflecting acceptable tolerances, conversion factors, rounding off, measurement error and the like and other factors known to those of skill in the art. Recitations of quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics should also be construed as if the term “substantially” precedes the quantity, dimension, size, formulation, parameter, shape or other characteristic. The term “substantially” means that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. 
     Numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also interpreted to include all of the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “1 to 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but should also be interpreted to also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3 and 4 and sub-ranges such as “1 to 3,” “2 to 4” and “3 to 5,” etc. This same principle applies to ranges reciting only one numerical value (e.g., “greater than 1”) and should apply regardless of the breadth of the range or the characteristics being described. 
     A plurality of items may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. Furthermore, where the terms “and” and “or” are used in conjunction with a list of items, they are to be interpreted broadly, in that any one or more of the listed items may be used alone or in combination with other listed items. The term “alternatively” refers to selection of one of two or more alternatives, and is not intended to limit the selection to only those listed alternatives or to only one of the listed alternatives at a time, unless the context clearly indicates otherwise. 
     The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features. 
     It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. For instance, various components may be repositioned as desired. It is therefore intended that such changes and modifications be included within the scope of the invention. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present invention. Accordingly, the scope of the present invention is intended to be defined only by the claims that follow.