Abstract:
An engaging element for engaging tissue that includes a first member and a second member. The first member includes at least one tissue engaging portion at a first free end. The first tissue engaging member is movable between an open position and a closed position and has a second free end. The first tissue engaging member is restrained in movement at an intermediate position between the first free end and the second free end. A lock portion is operatively associated with the first member with the lock portion maintaining a spacing between the first member and the second member and inhibiting movement of the first member to the open position. The lock portion is operatively associated with a portion of the first tissue engaging member proximal the intermediate position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/122,603, filed May 16, 2008, entitled “Apparatus and Methods for Engaging Tissue”, the entirety which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to medical devices, and more particularly to apparatus and methods for engaging tissue. 
       BACKGROUND OF THE INVENTION 
       [0003]    Catheterization and interventional procedures, such as angioplasty or stenting, generally are performed by inserting a hollow needle through a patient&#39;s skin and tissue into the vascular system. A guidewire may be advanced through the needle and into the patient&#39;s blood vessel accessed by the needle. The needle is then removed, enabling an introducer sheath to be advanced over the guidewire into the vessel, e.g., in conjunction with or subsequent to a dilator. 
         [0004]    A catheter or other device may then be advanced through a lumen of the introducer sheath and over the guidewire into a position for performing a medical procedure. Thus, the introducer sheath may facilitate introducing various devices into the vessel, while minimizing trauma to the vessel wall and/or minimizing blood loss during a procedure. 
         [0005]    Upon completing the procedure, the devices and introducer sheath are removed, leaving a puncture site in the vessel wall. Traditionally, external pressure had often been applied to the puncture site until clotting and wound sealing would occur; however, the patient must remain bedridden for a substantial period of time after clotting to ensure closure of the wound. This procedure, however, may be time consuming and expensive, requiring as much as an hour of a physician&#39;s or nurse&#39;s time. It is also uncomfortable for the patient and requires that the patient remain immobilized in the operating room, catheter lab, or holding area. In addition, a risk of hematoma exists from bleeding before hemostasis occurs. 
         [0006]    Various apparatus have been suggested for percutaneously sealing a vascular puncture by occluding the puncture site. For example, U.S. Pat. Nos. 5,192,302 and 5,222,974, issued to Kensey et al., describe the use of a biodegradable plug that may be delivered through an introducer sheath into a puncture site. Another technique has been suggested that involves percutaneously suturing the puncture site, such as that disclosed in U.S. Pat. No. 5,304,184, issued to Hathaway et al. 
         [0007]    To facilitate positioning devices that are percutaneously inserted into a blood vessel, “bleed back” indicators have been suggested. For instance, U.S. Pat. No. 5,676,689, issued to Kensey et al., discloses a bleed back lumen intended to facilitate positioning of a biodegradable plug within a puncture site. This device, however, requires that an anchor of the plug be positioned within the vessel, and therefore, may increase the risk of over-advancement of the plug itself into the vessel. 
         [0008]    Alternatively, U.S. Pat. No. 5,674,231, issued to Green et al., discloses a deployable loop that may be advanced through a sheath into a vessel. The loop is intended to resiliently expand in order to engage the inner wall of the vessel, thereby facilitating holding the sheath in a desired location with respect to the vessel. 
         [0009]    Accordingly, additional apparatus and methods for engaging tissue would be useful. 
       BRIEF SUMMARY 
       [0010]    An embodiment of an engaging element for engaging tissue is described. The engaging element includes a first member having at least one tissue engaging portion. The engaging element includes a second member having at least one tissue engaging portion and being pivotally connected to the first member. The engaging element includes a locking mechanism that is operatively associated with the first and second member. The locking mechanism is configured to inhibit the relative motion of the first and second member. 
         [0011]    An embodiment of an engaging system for engaging tissue is described. The engaging system includes an engaging element for engaging tissue. The engaging element includes a first member having at least one tissue engaging portion. The engaging element also includes a second member including at least one tissue engaging portion. The second member is pivotally connected to the first member. The engaging element further includes a locking mechanism operatively associated with the first and second member. The locking mechanism is configured to inhibit the relative motion of the first and second member. The engaging system also includes an engaging element delivery device. The engaging element delivery device includes a transitioning member. The transitioning member is configured to transition the engaging element from an open configuration toward a closed configuration. 
         [0012]    A method for engaging tissue is described. The method includes positioning an engaging element relative to an engaging element delivery device. The engaging element includes a first member having at least one tissue engaging portion. The engaging element also includes a second member having at least one tissue engaging portion. The second member is pivotally connected to the first member. The engaging element further includes a locking mechanism operatively associated with the first and second member. The locking mechanism is configured to inhibit the relative motion of the first and second member. The engaging element delivery device includes a retaining member. The retaining member includes a retaining mechanism and a transitioning member. The engaging element is positioned relative to a portion of tissue. A portion of the tissue is engaged with at least one tissue engaging portion. The engaging element is transitioned from an open configuration toward a closed configuration using the transitioning member. A locking mechanism is activated using the transitioning member to inhibit the relative motion of the first member and the second member. 
         [0013]    In some embodiments of an engaging member, the first and second member include a proximal end. In further embodiments of an engaging member, the proximal ends of the first member and second member are separated by a first transitioning dimension in an open configuration and a second transitioning dimension in a closed configuration. 
         [0014]    The first transitioning dimension, in some embodiments of an engaging member, is larger than said second transitioning dimension. In other embodiments of an engaging member, the first transitioning dimension is smaller than said second transitioning dimension. In further embodiments of an engaging member, the locking mechanism includes a first locking portion and a second locking portion, such that movement of the at least one tissue engaging portions of the first and second members is inhibited by the operative association between the first and second locking portions. 
         [0015]    In some embodiments of an engaging member, the first locking portion includes at least one tooth associated with the first member and the second locking portion includes a locking member associated with the second member. In other embodiments of an engaging member, the locking member is biased toward the at least one tooth. 
         [0016]    The locking member and the at least one tooth, in some embodiments of an engaging member, inhibit the at least one tissue engaging portions of the first and second members from moving toward the open configuration. In further embodiments of an engaging member, the first locking portion includes a latch associated with the first member and the second locking portion includes a latching portion associated with the second member. In still further embodiments of an engaging member, the latch and the latching portion inhibit the at least one tissue engaging portion of the first and second members from moving toward the open configuration. 
         [0017]    In some embodiments of an engaging member, at least one tissue engaging portion of the first member and the at least one tissue engaging portion of the second member are separated by a first distal dimension in an open configuration and are separated by a second distal dimension in a closed configuration. The first distal dimension is larger than the second distal dimension, in some embodiments of an engaging member. 
         [0018]    The engaging element, in some embodiments, includes a pivoting mechanism operatively associated with the first and the second members. In further embodiments of an engaging member, the pivoting mechanism includes a pivoting opening associated with one of the first member and the second member and a pivoting member associated with the other of the first member and the second member. 
         [0019]    In some embodiments of an engaging member, the engaging element further comprises a retaining portion configured to be operatively associated with a retaining mechanism. In further embodiments of an engaging member, the engaging element includes bioabsorbable, biodegradable, and/or bioerodible material. In still further embodiments, the engaging element includes collagen, polycaprolactone (PCL), poly-D,L-lactic acid, Poly-L-lactic acid, poly (lactide-co-glycolide), poly(hydroxybutyrate), polyanhydrides, and/or poly(glycolic acid). 
         [0020]    The engaging element, in some embodiments of an engaging system, includes a pivoting mechanism operatively associated with said first and said second member. Further embodiments of an engaging system include a retaining member that has a retaining mechanism configured to selectably inhibit the relative motion of said engaging element and said retaining member. 
         [0021]    In some embodiments of an engaging system, a pivoting mechanism includes a pivoting opening associated with one of the first and second member and a pivoting member associated with the other of the first and second member. In further embodiments of an engaging system, the retaining mechanism is operatively associated with the pivoting opening to selectably inhibit the relative motion of the engaging element and the retaining member. In still further embodiments of an engaging system, the retaining mechanism includes a retaining detent that engages the pivoting opening to selectably inhibit the relative motion of the engaging element and the retaining member. 
         [0022]    The retaining member and the transitioning member, in some embodiments of an engaging system, are axially aligned. In further embodiments of an engagement system, the retaining member is configured to slidably receive the transitioning member. 
         [0023]    In some embodiments of an engaging system, the first and second member of the engaging element include a transitioning portion. The transitioning member, in further embodiments, includes a transitioning surface that is shaped to engage with the transitioning portion of at least one of the first and second member of the engaging element. In some embodiments, the transitioning surface has a convex shape. In other embodiments, the transitioning surface has a concave shape. 
         [0024]    Some embodiments of a method for engaging tissue include selectably retaining the engaging element using a retaining mechanism to inhibit the relative motion of the engaging element and the retaining member. Further embodiments of a method for engaging tissue include disengaging the locking mechanism. 
         [0025]    Other aspects and features of the present invention will become apparent from consideration of the following description in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings. 
           [0027]      FIG. 1A  is a perspective partial cutaway view of an embodiment of a system for engaging tissue with an engaging element in an open configuration, according to an embodiment of the present invention. 
           [0028]      FIG. 1B  is a perspective partial cutaway view of the embodiment of a system for engaging tissue of  FIG. 1A  with an engaging element in a closed configuration, according to the present invention. 
           [0029]      FIG. 1C  is a top cutaway view of the embodiment of the system for engaging tissue of  FIG. 1A , according to the present invention. 
           [0030]      FIG. 2A  is a perspective view of another embodiment of an engaging element in an open configuration, according to the present invention. 
           [0031]      FIG. 2B  is a perspective view of the embodiment of the engaging element of  FIG. 2A  in a closed configuration, according to the present invention. 
           [0032]      FIG. 2C  is a perspective view of an embodiment of a system for engaging tissue with the embodiment of the engaging element of  FIG. 2A  in an open configuration, according to the present invention. 
           [0033]      FIG. 2D  is a perspective partial cutaway view of the embodiment of a system for engaging tissue of  FIG. 2C  with the embodiment of the engaging element of  FIG. 2A  in a closed configuration, according to the present invention. 
           [0034]      FIG. 2E  is a right cutaway view of the embodiment of the system for engaging tissue of  FIG. 2C  with the embodiment of the engaging element of  FIG. 2A  in an open configuration, according to the present invention. 
           [0035]      FIG. 2F  is a right cutaway view of the embodiment of the system for engaging tissue of  FIG. 2C  with the embodiment of the engaging element of  FIG. 2A  in a closed configuration, according to the present invention. 
           [0036]      FIGS. 3A-3K  illustrate various steps in the deployment of an embodiment of an engaging element to engage tissue according to one example. 
       
    
    
       [0037]    It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like-reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of embodiments of the present invention. 
       DETAILED DESCRIPTION 
       [0038]    Embodiments described herein extend to methods, systems, and apparatus for engaging tissue. Some embodiments may be used to close and/or seal openings in a blood vessel or other body lumen formed during a diagnostic, therapeutic, and/or other procedure. The engaging elements of the present invention may be configured to be delivered through tissue and into an opening formed in and/or adjacent to a wall of a blood vessel or other body lumen. The engaging elements provided herein may reliably engage. 
         [0039]    Moreover, the engaging elements may be made of any suitable material, including a bioabsorbable material, such as collagen. Other biodegradable materials may include polycaprolactone (PCL), poly-D,L-lactic acid, Poly-L-lactic acid, poly (lactide-co-glycolide), poly(hydroxybutyrate), polyanhydrides, poly(glycolic acid, and/or other biodegradable materials. 
         [0040]    Referring generally to  FIGS. 1A-1C , the system  100  may include an engaging element  110  and an engaging element delivery device  160 . The engaging element  110  may include a first member  112  and a second member  114 . The first member  112  and the second member  114  may include tissue engaging portions  116  (three tissue engaging portions  116  on each of the first member  112  and the second member  114 , in the present embodiment). The tissue engaging portions  116  may include a sharpened tip, as shown, and/or may include other tips, such as barbed tips. The tissue engaging portions  116  may be configured to engage tissue. 
         [0041]    The engaging element delivery device  160  may include a retaining member  164 , a transitioning member  168 , a carrier member  172 , a locator  176 , and/or other components. The transitioning member  168  may include a lumen. The lumen may receive the carrier member  172 , the locator  176 , and/or other components. The carrier member  172  may be configured to receive a locator  176  and/or other components. 
         [0042]    The engaging element  110 , locator  176 , carrier member  172 , transitioning member  168 , and/or retaining member  164  may be axially aligned. The carrier member  172  and/or locator  176  may be configured to fit within a channel of the engaging element  110  in the open configuration. 
         [0043]    The first member  112  and second member  114  may be pivotally connected. The first member  112  and second member  114  may be pivotally connected by a pivoting mechanism  120 . The pivoting mechanism  120  may include a pivoting opening  122  and a pivoting member  124 . The pivoting member  124  may be located on the first member  112  and the pivoting opening  122  may be located on the second member  114 . Alternatively, the pivoting member  124  and pivoting opening  122  may be located on either the first member  112  or the second member  114 . Other pivoting mechanisms  120  may also be used. The pivoting member  124  of the present embodiment may include a detent configured to engage the pivoting opening  122 . 
         [0044]    The engaging element  110  may include a transitioning portion  130  with a first transitioning dimension  132   a , in the open configuration shown in  FIG. 1A , and a second transitioning dimension  132   b  in the closed configuration shown in  FIG. 1B . Transitioning dimensions  132   a ,  132   b  may indicate distances between the first member  112  and the second member  114  in various configurations. The first transitioning dimension  132   a  may be smaller than the second transitioning dimension  132   b.    
         [0045]    The engaging element  110  may include a first distal dimension  134   a  in the open configuration and a second distal dimension  134   b  in the closed configuration. Distal dimensions  134   a ,  134   b  may indicate distances between the first member  112  and the second member  114  in various configurations. The first distal dimension  134   a  may be larger than the second transitioning dimension  132   b.    
         [0046]    The transitioning portion  130  may be configured to receive a distal end of the transitioning member  168 . The transitioning member  168  may include a transitioning surface  170  located near the distal end. The transitioning member  168  may be elongate and/or convex. The transitioning surface  170  may be operatively associated with the transitioning portion  130  of the engaging element  110  to transition the engaging element  110  from the open configuration toward the closed configuration. 
         [0047]    Referring to  FIGS. 1A and 1B , transitioning the engaging element  110  from the open configuration toward the closed configuration may include expanding the first transitioning dimension  132   a  toward the second transitioning dimension  132   b . As the transitioning surface  170  of the transitioning member  168  engages the transitioning portion  130  of the engaging element  110 , the proximal ends of the first member  112  and second member  114  may expand away from each other. As the proximal ends expand away from each other (from the open configuration), the tissue engaging portions  116  of the first member  112  and the second member  114  may move toward each other (toward the closed configuration). 
         [0048]    The engaging element  110  may include a locking mechanism  140  that may be configured to generally inhibit movement from the closed configuration towards the open configuration. For example, as the proximal ends expand away from each other, the locking mechanism  140  may inhibit movement back toward the open configuration. 
         [0049]    The locking mechanism  140  may include a first locking portion  142  and a second locking portion  144 . The first locking portion  142  and the second locking portion  144  may be operatively associated. The first locking portion  142  and/or the second locking portion  144  may be located near the proximal ends of the first member  112  and/or the second member  114 , respectively. The first locking portion  142  may include at least one tooth. The at least one tooth may be configured to receive the second locking portion  144  which may include a locking member such as a follower. The locking member may be biased toward the at least one tooth. The use of multiple teeth may incrementally inhibit movement toward the open configuration. 
         [0050]    The pivoting opening  122  may include a retaining portion. The pivoting opening  122  may be configured to receive at least a portion of a retaining mechanism  166  on the retaining member  164  and the pivoting member  124  of the engaging element  110 . The pivoting opening  122  and retaining mechanism  166  may be operatively associated to limit movement of the engaging element  110  in at least one direction. For instance, the pivoting opening  122  and retaining mechanism  166  may limit motion of the engaging element  110  both longitudinally (i.e. through the retaining member  164 ) and radially (i.e. about an axis within the retaining member  164 ). The engaging element  110  may be inserted through the retaining member  164  until the retaining mechanism  166  and the pivoting opening  122  are retained. Alternatively, the retaining portion may be located on the retaining member  164  while the retaining mechanism  166  is located on the engaging element  110 . Other retaining portion and/or retaining mechanism combinations, such as a detent and retaining groove combination, may be used. 
         [0051]    In order to align the pivoting opening  122  of the engaging element  110  with the retaining mechanism  166  of the retaining member  164 , the engaging element  110  may include an aligning portion  150 , as shown in  FIGS. 1A and 1B , which may be operatively associated with an aligning mechanism  167  of the retaining member  164 . The aligning portion  150  of the engaging element  110  may include a ridge configured to be inserted into the aligning mechanism  167  (i.e. a corresponding slot or groove) of the retaining member  164 . In another embodiment, the aligning portion  150  of the engaging element  110  may be a slot or groove configured to receive the aligning mechanism  167 , i.e. ridge, tab, etc., of the retaining member  164 . In further embodiments, the aligning portion  150  and/or the aligning mechanism  167  may take other forms to align the engaging element  110  with the retaining member  164  and/or transitioning member  168 . 
         [0052]    Referring to  FIGS. 2A-2F , the system  200  and engaging element  210  of this embodiment may be at least partially functionally similar to that of the system  100  and engaging element  210  previously described above and shown in  FIG. 1  in most respects, wherein certain features will not be described in relation to this embodiment wherein those components may function in the manner as described above and are hereby incorporated into this alternative embodiment described below. Like structures and/or components are given like reference numerals. 
         [0053]    The engaging element  210  may include a first member  212  and a second member  214 . The first member  212  and the second member  214  may be configured to engage tissue. The tissue engaging portions  216  may include tissue engaging portions  216  that may include a sharpened tip, barb, and/or other tip. 
         [0054]    The first member  212  and second member  214  may be pivotally connected by a pivoting mechanism  220 . The pivoting mechanism  220  may include a pivoting opening  222  and a pivoting member  224 . The pivoting opening  222  may be located on the first member  212  and the pivoting member  224  may be located on the second member  214 . 
         [0055]    The engaging element  210  may include a transitioning portion  230  with a first transitioning dimension  232   a , in the open configuration shown in  FIG. 2A , and a second transitioning dimension  232   b  in the closed configuration shown in  FIG. 2B . The first transitioning dimension  232   a  may be larger than the second transitioning dimension  232   b.    
         [0056]    The engaging element  210  may include a first distal dimension  234   a  in the open configuration and a second distal dimension  234   b  in the closed configuration. The first distal dimension  134   a  may be larger than the second transitioning dimension  232   b.    
         [0057]    Referring to the system  200  shown in  FIGS. 2C-2D , the engaging element delivery device  260  may include a transitioning member  268 , a retaining member  264 , a carrier member  272 , a locator  276 , and/or other components. The transitioning portion  230  of the engaging element  210  may be configured to receive a distal end of the transitioning member  268 . The transitioning member  268  may include a transitioning surface  270  located near the distal end that may be concave. The transitioning surface  270  may be operatively associated with the transitioning portion  230  of the engaging element  210  to transition the engaging element  210  from the open configuration toward the closed configuration. 
         [0058]    Referring to  FIGS. 2C-2F , transitioning the engaging element  210  from the open configuration toward the closed configuration may include moving the first transitioning dimension  232   a  toward the second transitioning dimension  232   b . As the transitioning surface  270  of the transitioning member  268  engages the transitioning portion  230  of the engaging element  210 , the proximal ends of the first member  212  and second member  214  may move toward each other. As the proximal ends move toward each other (from the open configuration), the tissue engaging portions  216  of the first member  212  and the second member  214  may also move toward each other (toward the closed configuration). 
         [0059]    The engaging element  210  may include a locking mechanism  240  that may be configured to generally inhibit movement from the closed configuration towards the open configuration. For example, as the proximal ends move toward each other the locking mechanism  240  may inhibit movement toward the open configuration. 
         [0060]    The locking mechanism  240  may include a first locking portion  242  and a second locking portion  244 . The first locking portion  242  and the second locking portion  244  may be operatively associated. The first locking portion  242  and/or the second locking portion  244  may be located near the proximal ends of the first member  212  and/or the second member  214 , respectively. The first locking portion  242  may include a latch member. The latch member may be configured to engage the second locking portion  244  which may include a latching portion. The latch member may be biased to engage the latching portion. Although the latch member and latching portion may be located on the first member  212  and the second member  214 , respectively, other locations may also be used. Furthermore, although a locking member and tooth combination and a latch member and latching portion combination have been described, other locking mechanisms may be used. For instance, a set of interlocking teeth may be disposed on the first member  212  and the second member  214  similar to the locking mechanism used for locking forceps. 
         [0061]    The pivoting opening  222  may include a retaining portion that may be configured to receive a retaining mechanism  266  on the retaining member  264 . The pivoting opening  222  and retaining mechanism  266  may be operatively associated to limit movement of the engaging element  210  in at least one direction. 
         [0062]    The engaging element  210  of the present embodiment may include two types of aligning portions  250   a ,  250   b . The aligning portions  250   a  near the proximal end of the engaging element  210  may be grooves configured to receive an aligning mechanism  271  (i.e. a ridge) on the transitioning member  268 . The aligning portions  250   b  near the tissue engaging portions  216  may be ridges configured to be inserted into a first aligning mechanism  267 , i.e. a corresponding slot or groove, of the retaining member  264 . Other alignment portions  250   a ,  250   b , alignment mechanisms  267 ,  271 , and/or configurations of the same (i.e. alignment portions and/or alignment mechanisms on the engaging element  210 , retaining member  264 , transitioning member  268 , and/or other components) may be used to orient the engaging element  210  relative to the engaging element delivery device  260  such that the retaining member  264  may retain the engaging element  210 . 
         [0063]    The transitioning member  268  may include a lumen that may receive a carrier member  272 , a locator  276 , and/or other components. The carrier member  272  may be configured to receive a locator  276  and/or other components. 
         [0064]    The transitioning member  268  may abut the transitioning portion  230  of the engaging element  210 . The transitioning member  268  may include a transitioning surface  270  that is concave. As the transitioning member  268  is advanced through the retaining member  264 , the transitioning member  268  may transition the engaging member  210  toward a closed configuration. The concave transitioning surface  270  may generally cause the proximal ends of the first member  212  and the second member  214  to move toward each other. As the proximal ends of the first member  212  and the second member  214  move toward each other, the tissue engaging portions  216  on the first member  212  and the second member  214  may move toward each other. 
         [0065]      FIGS. 3A-3K  illustrate various steps in the deployment of an embodiment of an engaging element  310  to close a puncture according to one example. The systems  100 ,  200  and engaging elements  110 ,  210  discussed above in connection with  FIGS. 1A-1C and 2A-2F  will now be discussed in the context of a patient and with respect to a blood vessel  390 . The systems  100 ,  200  and engaging elements  110 ,  210  may also be used with body lumens other than blood vessels. 
         [0066]    The system  300  and engaging element  310  of this embodiment may be at least partially functionally similar to that of the systems  100 ,  200  and engaging elements  110 ,  210  previously described above and shown in  FIGS. 1 and 2  in most respects, wherein certain features will not be described in relation to this embodiment wherein those components may function in the manner as described above and are hereby incorporated into this alternative embodiment described below. Like structures and/or components are given like reference numerals. 
         [0067]    The blood vessel  390  has a vessel wall  392  with an outer portion  392   a  and an inner portion  392   b . The engaging element delivery device  360  may then be used to apply the engaging element  310 . In particular, a sheath  380  may be inserted or otherwise positioned through skin  394  and tissue  396  and within the blood vessel  390  or other body lumen via an opening  398 . The sheath  380  can include a substantially flexible or semi-rigid tubular member. Also, the sheath  380  can have a proximal end region  382   a  and a distal end region  382   b . The sheath  380  may further have a predetermined length and a predetermined cross-section, both of which can be of any suitable dimension. The sheath  380  also can form a lumen  384  that extends along a longitudinal axis of the sheath  380  and substantially between the proximal and distal end regions  382   a ,  382   b . The lumen  384  can have any suitable internal cross-section and is suitable for receiving one or more devices (not shown), such as a guidewire  388 , a catheter, and/or other devices. 
         [0068]    The sheath  380  may be advanced over a guidewire  388  and/or other rail that may have been positioned through the opening  398  and into the blood vessel  390  using conventional procedures. The blood vessel  390  can be a peripheral blood vessel, such as a femoral or carotid artery, although other body lumens may be accessed using the sheath  380 . The opening  398 , and consequently the sheath  380 , may be oriented with respect to the blood vessel  390  such as to facilitate the introduction of devices through the lumen  384  of the sheath  380  and into the blood vessel  390  with minimal risk of damage to the blood vessel  390 . One or more devices (not shown), such as a catheter, or the like, may be inserted through the sheath  380  and advanced to a preselected location within the patient&#39;s body. For example, the devices may be used to perform a therapeutic and/or diagnostic procedure, such as angioplasty, atherectomy, stent implantation, and the like, within the patient&#39;s vasculature. 
         [0069]    After the procedure is completed, the devices may be removed from the sheath  380 . The engaging element delivery device  360  may be prepared to be received by the lumen  384  of the sheath  380  as shown in  FIG. 3B . Alternatively, the sheath  380  may be removed and then the engaging element delivery device  360  may be positioned near the opening  398 . The engaging element delivery device  360  may include a retaining member  364 , a transitioning member  368 , a carrier member  372 , a locator  376 , and/or other components. The carrier member  372  may provide support for the engaging element  310 . The locator  376  may be inserted through a channel in the carrier member  372 . 
         [0070]    The locator  376  may include a tubular body  378  having a distal end region  379 . Being in the unexpanded state, the distal end region  379  of the tubular body  378  of the locator  376  can be slidably received by the lumen  384  and atraumatically advanced distally into the blood vessel  390  as illustrated in  FIGS. 3B-3C . Advancing the distal end region  379  into the lumen  384  begins the location of the locator  376  relative to the blood vessel  390 . 
         [0071]    Once the distal end region  379  of the tubular body  378  extends into the blood vessel  390 , the distal end region  379  may transition from the unexpanded state to the expanded state as shown in  FIG. 3D . A triggering system (not shown) of the locator  376  may be used to transition from the unexpanded state to the expanded state. Locators other than the expandable locator may also be used. For instance, a bleedback lumen and/or other locator may be used to locate the body lumen. Alternatively, no locator may be used. Rather, the engaging element delivery device  360  may be advanced until a technician determines that the distal end is near the opening. 
         [0072]    Turning to  FIG. 3E , the engaging element delivery device  360  and the sheath  380  may be retracted proximally until the distal end region  379  is substantially adjacent to an inner surface  392   b  of the blood vessel wall  392 . The distal end region  379  thereby may draw the blood vessel wall  392  taut and/or may maintain the proper position of the system  300  as the blood vessel  390  pulsates. Since the expanded cross-section of the distal end region  379  can be greater than or substantially equal to the cross-section of the opening  398  and/or the cross-section of the lumen  384 , the distal end region  379  may remain in the blood vessel  390  and may engage the inner surface  392   b  of the blood vessel wall  392 . The distal end region  379  may frictionally engage the inner surface  392   b  of the blood vessel wall  392 , thereby securing the system  300  to the blood vessel  390 . The sheath  380  can be retracted proximally such that the distal end region  382   b  of the sheath  380  may be substantially withdrawn from the blood vessel  390 , as shown in  FIG. 3E , permitting system  300  to access the blood vessel wall  392 . 
         [0073]    Once the distal end region  379  of the locator  376  contacts the inner surface  392   b  of the blood vessel wall  392 , the engaging element delivery device  360  may be advanced distally and may be received within the lumen  384  of the sheath  380  as illustrated in  FIG. 3F . The sheath  380  may radially expand and/or split in accordance with the predetermined pattern as the distal portion advances because the internal cross-section of the sheath  380  may be less than an outer portion of the retaining member  364 . 
         [0074]    Upon reaching the first predetermined position, the distal portion of the retaining member  364  can be disposed substantially adjacent to the outer surface  392   a  of the blood vessel wall  392  adjacent to the opening  398  such that the blood vessel wall  392  adjacent to the opening  398  may be disposed substantially between the expanded distal region  379  of the locator  376  and the distal portion of the retaining member  364 . The engaging element  310  and retaining member  364  may be configured such that as the retaining member  364  approaches the distal end  379  of the locator  376 , the tissue engaging portions  316  of the engaging member  310  may engage the outer portion  392   a  of the vessel wall  392 . 
         [0075]    As shown in  FIG. 3G , which is rotated ninety degrees to illustrate the interaction of the first member  312  and second member  314  of the engaging element  310  during deployment, the transitioning member  368  may advance distally to cause the tissue engaging portions  316  of the engaging member  310  to move toward the closed configuration (i.e. from the first distal dimension to the second distal dimension). The convex transitioning surface  370  may cause the transitioning portion  330  of the engaging element  310  to transition toward the closed configuration (i.e. the proximal ends of the first member  312  and the second member  314  may move away from each other while the tissue engaging portions  316  move toward each other). 
         [0076]    Alternatively, other transitioning members  368  and/or engaging elements  310  may be used. For example, the transitioning member  268  and engaging element  210  described in connection with  FIGS. 2A-2D  may be used, such that the concave transitioning surface  270  may cause the transitioning portion  230  of the engaging element  210  to transition toward the closed configuration (i.e. the proximal ends of the first member  212  and the second member  214  may move toward each other). 
         [0077]    As the tissue engaging portions  316  move toward each other, the distal end  379  of the locator  376  may move toward the unexpanded configuration and/or begin to move proximally to allow the tissue engaging portions  316  to fully engage the vessel wall  392 . Alternatively, the locator  376  may remain within the blood vessel  390  after the tissue engaging portions  316  have engaged the vessel wall  392  and/or may be later removed. 
         [0078]    As shown in  FIGS. 3H-3L , the engaging element  310  may be deployed. The engaging element  310  may engage the vessel wall  392  (as shown in  FIG. 3F ) in the open configuration. For instance, the tissue engaging portions  316  may frictionally, piercingly, and/or otherwise engage the vessel wall  392 . As shown in  FIG. 3I , the transitioning member  368  may continue to apply distal pressure to the engaging element  310  as the retaining member  364  begins to advance distally. The retaining member  364  may begin to disengage from the engaging element  310 . For example, the retaining mechanism  366  may begin to be removed from the pivoting opening  322  of the engaging element  310 , as shown in  FIG. 3I . The retaining member  364  may be fully removed while the transitioning member  368  maintains distal pressure on the engaging element  310 , as shown in  FIG. 3J . Then the remaining components of the system  300  may be removed through the skin  394 , as shown in  FIG. 3K . The engaging element  310  may remain between the outer surface  392   a  of the vessel wall  392  and the skin  394 , i.e. within the tissue  396 , while in the closed configuration. The opening  398  in the skin  394  may be closed with a bandage or other device. 
         [0079]    Access to the body lumen may be restablished by unlocking the locking mechanism ( 140  shown in  FIG. 1 ). For instance, a device (not shown) may be used to push the locking member and/or latch member out of engagement with the teeth and/or latching portion allowing the tissue engaging portions  316  to move away from each other toward the open configuration. 
         [0080]    The invention is susceptible to various modifications and alternative means, and specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular devices or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the claims.