Abstract:
A system and method for percutaneous heart valve replacement includes implanting a heart valve replacement prosthetic into tissue and driving anchors into the heart valve replacement to affix the prosthetic to the tissue.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of, and incorporates by reference thereto in its entirety, U.S. Provisional Patent Application Ser. No. 62/010,680, filed on Jun. 11, 2014. 
         [0002]    Further, each of the following is hereby incorporated by reference thereto in its entirety: U.S. patent application Ser. No. 14/321,476, filed Jul. 1, 2014, U.S. patent application Ser. No. 14/301,106, filed Jun. 10, 2014, U.S. patent application Ser. No. 13/843,930, filed Mar. 15, 2013, PCT Application No. PCT/US14/30868, filed Mar. 17, 2014, U.S. patent application Ser. No. 13/010,769, filed Jan. 20, 2011, U.S. Provisional Patent Application Ser. No. 61/296,868, filed on Jan. 20, 2010, U.S. patent application Ser. No. 13/010,766, filed on Jan. 20, 2011, U.S. patent application Ser. No. 13/010,777, filed on Jan. 20, 2011, and U.S. patent application Ser. No. 13/010,774, filed on Jan. 20, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0003]    The present invention relates to a system and method of percutaneous heart valve replacement, including anchoring the heart valve replacement into tissue. 
       BACKGROUND INFORMATION 
       [0004]    Heart valve replacements have been developed to counter heart valve failure, either from heart valve regurgitation (i.e., the failure of the heart valve to properly close), or from heart valve stenosis (i.e., the failure of the heart valve to properly open). Though early efforts at heart valve repair and replacement included open surgery, more recent developments have included percutaneous surgical applications. 
         [0005]    Percutaneous heart valve repair, however, has shown certain disadvantages. For example, percutaneous repair involves modified surgical techniques, which can limit the benefits of the procedure. Annular rings may lack effectiveness, and include risks of erosion, perforation, and coronary artery thrombosis. Edge-to-edge repair can be technically demanding, and may lack long term durability. Depending upon the particular valve failure, combinations of different repair techniques may be necessary, further complicating the procedure and limiting its effectiveness. 
         [0006]    In contrast, heart valve replacement has provided certain advantages, limiting the risks associated with heart valve repair, and applying to a broader scope of patients. Open surgery solutions for heart valve replacement, however, carry significant risks to the patient. Therefore, a less invasive, percutaneous heart valve replacement is needed. 
         [0007]    Existing percutaneous solutions include U.S. Pat. No. 7,621,948, describing a percutaneously inserted heart valve prosthesis, which can be folded inside a catheter for delivery to the implant location. Another percutaneous solution is available from CardiAQ Valve Technologies, Inc., described in U.S. Patent Application Publication No. 2013/0144378. Other percutaneous prosthetic valves include Neovasc Tiara, Valtech Cardiovalve, ValveXchange, Lutter Valve, and valves from Medtronic, Inc. and Edwards Lifesciences Corporation. 
         [0008]    In providing a percutaneous heart valve replacement, challenges include providing an implant that may be folded into a catheter for delivery, and can emerge from the catheter to fit properly into the implant site and serve its function as a valve. The implant valve must therefore be small enough to be folded into the catheter, but must be large enough, upon implantation, to provide the functions of the valve, without being so large as to obstruct ventricular flow. 
         [0009]    Moreover, fixing the heart valve implant to the implant site may be challenging, as the implant site may form an irregular shape, may lack calcium to secure the valve, or may cause difficulty in fixing the implant valve with the proper orientation. 
         [0010]    There is a need for a percutaneous heart valve solution to sufficiently and effectively address these challenges. 
       SUMMARY 
       [0011]    In accordance with example embodiments of the present invention, a device for delivering, implanting, and fixing to tissue a heart valve replacement prosthetic is provided. The device may include a ring, which may be pliable enough to be folded into a small space, such as the cavity of a catheter. The ring may be elastic, so as to automatically expand upon its release from its folded position in a catheter. Where an implant site is irregularly shaped, the elasticity of the ring permits the ring to form to the shape of the implant site. The device may further include one or more leaflets connected to the ring, effective to block fluid flow in a first fluid flow direction and to permit fluid flow in a second fluid flow direction. 
         [0012]    The system of the present invention may include an applicator, including an applicator shaft passing through the ring, and terminating at its distal end in one or more spring arms. The spring arms may connect the distal end of the applicator shaft to the ring, such that the spring arms exert a spring force against the ring, pushing the ring radially outward. Each spring arm is separately connected to the ring, so that, in the case of a plurality of spring arms, each spring arm may each respond individually to an irregularly shaped implant site, allowing the ring to form to the shape of the implant site, and provide a better seat for the prosthetic heart valve. 
         [0013]    The prosthetic may be delivered to the implant site percutaneously, for example, by a catheter, into which the prosthetic may be folded. Once delivered to the implant site, the prosthetic may be pushed through a distal end of the catheter, such that the ring is allowed to expand. The prosthetic may then be implanted in the implant site, with the elasticity of the ring and the independent spring arms permitting the prosthetic to form to any irregular shape of the implant site. 
         [0014]    Once implanted, in an example embodiment of the present invention, a driver may be used to drive anchors through the ring, and into the tissue of the implant site, fixing the prosthetic to the tissue of the implant site. The driver may be configured to drive one or more anchors into one or more positions about the ring, and may index the driving of anchors in line with each spring arm. Once the prosthetic has been fixed to the implant site, the applicator may be withdrawn, leaving the prosthetic fixed in place. The prosthetic may have a smaller width or diameter than the width or diameter of the implant site, such that, once the anchors have been driven into the surrounding tissue of the implant site, the tissue of the implant site may be drawn toward the smaller prosthetic, to meet the exterior shape of the prosthetic. 
         [0015]    In this manner, the prosthetic valve may be securely fixed to the implant site, to more sufficiently and effectively improve valve function. The prosthetic may take a variety of shapes. The shape of the prosthetic to be used for a particular application may be selected based on the particular geometric needs of the particular application. 
         [0016]    In accordance with example embodiments of the present invention, a surgical device includes an applicator having an applicator shaft passing through the ring and terminating at a distal end having one or more spring arms connecting the distal end of the applicator shaft to the ring, such that a proximal force applied to the applicator shaft is transferred to the one or more spring arms and to the pliable ring, and a driver having a guide situated annularly about the applicator shaft, and at least one firing arm including at least one anchor outlet, the driver configured to slide between a proximal position and a distal position along the applicator shaft, wherein the at least one firing arm is in hinged communication with the driver, such that in the proximal position of the driver the at least one anchor outlet is situated in parallel with the applicator shaft, and in the distal position of the driver the at least one anchor outlet is directed toward the pliable ring, and the driver is configured to exert a driving force on at least one anchor to drive the anchor into the pliable ring. 
         [0017]    The prosthetic valve may be delivered to an implant site by a catheter, the pliable ring being folded for insertion into the catheter and expandable once pushed from a distal end of the catheter. The prosthetic valve may be implanted at an implant site, and the driver may be configured to drive the anchor at least partially through the ring and into tissue surrounding the implant site. 
         [0018]    The anchor may include a distal end tapered to a distal tip configured to pierce tissue, at least one barb extending proximally and radially outwardly from the distal end to a free end including a radially exterior surface and a radially interior surface, and a flexible stem extending proximally from the distal end, flexible with respect to the at least one barb and distal tip. The flexible stem may be configured to flex in cooperation with a force exerted on the anchor. The at least one anchor may be configured to engage with the tissue and resist proximal movement. 
         [0019]    The driver may be configured to rotate about the applicator shaft, and further may be configured to index the driving of anchors in line with each spring arm. 
         [0020]    The applicator may be removable from the prosthetic valve by exertion of a distal force on the applicator shaft to release the spring arms from engagement with the pliable ring, and exertion of a proximal force on the applicator shaft to draw the applicator proximally through the prosthetic valve. 
         [0021]    The firing arm may be hinged to the driver at a proximal end of the firing arm, or may be hinged to the driver at a distal end of the firing arm. 
         [0022]    In accordance with example embodiments of the present invention, a surgical device includes a driver having a distal end, at least one firing arm in hinged communication with the distal end of the driver, each including at least one anchor outlet, having a refracted position parallel to the driver, and a firing position in which the firing arm is directed proximally and radially outward, a guide situated within the driver, and a firing mechanism connected to the guide and configured to transfer force from the guide in the proximal and radially outward direction of the firing arm in the firing position. 
         [0023]    In accordance with example embodiments of the present invention, a surgical device includes a pliable ring collapsible for insertion into a catheter and expandable upon ejection from the catheter, an applicator having one or more spring arms configured to exert a force on the ring to ring the ring into apposition with tissue, and a driver having at least one firing arm configured to drive at least one anchor into the ring and the tissue to affix the ring to the tissue. The spring arms may further be configured to conform the ring to the contours of the surrounding tissue. The spring arm may exert the force on the ring while the driver drives the at least one anchor into the ring and the tissue to affix the ring to the tissue. 
         [0024]    The surgical device may include an applicator shaft passing through the ring and terminating in the one or more spring arms connecting the distal end of the applicator shaft to the ring, such that a proximal force applied to the applicator shaft is transferred to the one or more spring arms and to the pliable ring, and the firing arm may be in hinged communication with the driver, having a retracted position in which the firing arm is in parallel with the applicator shaft, and a firing position in which the firing arm is directed toward the ring. 
         [0025]    The driver may include a plurality of firing arms, and the plurality of firing arms may fire a plurality of anchors simultaneously. 
         [0026]    The firing position may be perpendicular to the applicator shaft. The firing position may also be less than 90 degrees from the retracted position. 
         [0027]    The firing arm may be hinged to the driver at a proximal end of the firing arm, or may be hinged to the driver at a distal end of the firing arm. 
         [0028]    Further features and aspects of example embodiments of the present invention are described in more detail below with reference to the appended Figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0030]      FIG. 2  is an illustration of the heart valve replacement prosthetic, the applicator shaft, and the spring arms, in accordance with an example embodiment of the present invention. 
           [0031]      FIG. 3  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0032]      FIG. 4  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0033]      FIG. 5  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0034]      FIG. 6  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0035]      FIG. 7  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0036]      FIG. 8  is an illustration of the heart valve replacement prosthetic, the applicator shaft, the spring arms, and the driver, in accordance with an example embodiment of the present invention. 
           [0037]      FIG. 9  is an illustration of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0038]      FIG. 10  is an illustration of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0039]      FIG. 11  is an illustration of an anchor in accordance with an exemplary embodiment of the present invention. 
           [0040]      FIG. 12  is an illustration of an anchor in accordance with an exemplary embodiment of the present invention. 
           [0041]      FIG. 13  is an illustration of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0042]      FIG. 14  is an illustration of a cross-sectional view of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0043]      FIG. 15  is an illustration of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0044]      FIG. 16  is an illustration of a cross-sectional view of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0045]      FIG. 17  is an illustration of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0046]      FIG. 18  is an illustration of a cross-sectional view of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0047]      FIG. 19  is an illustration of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
           [0048]      FIG. 20  is an illustration of a cross-sectional view of the driver of the heart valve replacement prosthetic in accordance with an example embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0049]    As set forth in greater detail below, example embodiments of the present invention allow for the reliable and effective delivery, implantation, and fixation of a heart valve replacement prosthetic, such that the prosthetic can effectively address heart valve failure. 
         [0050]    An exemplary embodiment of the present invention is present in  FIG. 1 .  FIG. 1  illustrates heart valve replacement prosthetic  1  having ring  10 , which, in an exemplary embodiment, may be elastic.  FIG. 1  further illustrates applicator  20  having applicator shaft  21  and spring arms  22 . Spring arms  22  may be affixed to the distal end of the applicator shaft  21 , and may connect the distal end of the applicator shaft  21  to the ring  10  of the replacement prosthetic  1 .  FIG. 1  further illustrates driver  40 , as will be described in more detail below. 
         [0051]    As will be generally understood, as described by, for example, U.S. Pat. No. 7,621,948, the entirety of which is hereby incorporated by reference as if fully disclosed herein, the replacement prosthetic  1  of the present invention may be delivered to an implant site by first collapsing the replacement prosthetic  1  into a collapsed or folded position, such that the prosthetic fits within a cavity of a catheter. The catheter, including the collapsed or folded prosthetic, is advanced percutaneously to an implant site. Once the distal end of the catheter is adjacent to the implant site, the collapsed prosthetic may be pushed or forced through the distal end of the catheter. 
         [0052]    Heart valve replacement prosthetic  1  may be formed of compliant, elastic material such as deformable plastic or nitinol, such that once the collapsed prosthetic emerges from the distal end of the catheter, the ring  10  may elastically return to an uncollapsed, or expanded formation, as illustrated in  FIGS. 1 to 10 . The prosthetic  1 , including ring  10 , may be maneuvered in the implant site, where it may be pressed into position in the implant site. 
         [0053]    As further illustrated in  FIGS. 1 to 10 , ring  10  may, in an exemplary embodiment of the present invention, take on the shape of the implant site, which may be an irregular shape (e.g., non-circular). In the exemplary embodiments illustrated in  FIGS. 1 to 10 , the ring  10  is formed to a non-circular, irregular shape. In this manner, the heart valve replacement prosthetic of the present invention may be adapted to a wide variety of implant sites, to address a wide variety of heart valve failures. 
         [0054]    As illustrated in  FIG. 2 , heart valve replacement prosthetic  1  further includes leaflets  30 , which perform the valve function. Leaflets  30  are connected to ring  10 , and are further held in proper position by valve struts  31 . Leaflets  30  are configured to prevent the flow of fluid in a first fluid flow direction, and to permit the flow of fluid in a second fluid flow direction. 
         [0055]      FIGS. 2 through 8  illustrate an exemplary embodiment of the fixing of the replacement prosthetic  1  to the tissue of the implant site. 
         [0056]    As illustrated in  FIG. 2 , replacement prosthetic  1  is expanded from the catheter, with ring  10  in a nearly fully expanded formation. Applicator shaft  21  extends from the proximal direction through and to the distal side of the ring  10 . Spring arms  22  are connected to the distal end of the applicator shaft  21 , such that the distal end of the applicator shaft  21  forms the apex of a conical shape formed by the spring arms  22  about the axis of the applicator shaft  21 . Once delivered to the implant site, applicator shaft  21  may be used to press ring  10  into the tissue of the implant site, by pulling the applicator shaft  21  in a proximal direction, such that the force in the proximal direction is transferred to the spring arms  22 , which in turn exert a force in a proximal and radial direction against the ring  10 . Because the spring arms include spring elements  23 , such as springs or spring-like ribbons, each spring arm is flexible to absorb force independently of the other spring arms. In this manner, ring  10  is further able to achieve an irregular shape, to meet the shape of any implant tissue.  FIGS. 2 to 8  illustrate various spring arms  22  being extended or compressed to a different degree. 
         [0057]    As illustrated in  FIG. 3 , once the prosthetic  1  is in place at the implant site, driver  40  may be actuated to fasten the ring  10  to the tissue of the implant site. Driver  40  includes firing arm  41 , having anchor outlets  42 , and a guide  43 . Driver  40  may be operated to slide or otherwise move along the applicator shaft  21 . Guide  43  and firing arm  41  may be situated on opposite sides of the applicator shaft  21 , as illustrated in  FIG. 3 . 
         [0058]    As illustrated in  FIG. 4 , driver  40  is moved to the distal end of the applicator shaft  21 , where the applicator shaft  21  meets the spring arms  22 . 
         [0059]    As illustrated in  FIG. 5 , firing arm  41  is configured to rotate from a position aligned with the axis defined by the applicator shaft  21  to a position directed radially away from the applicator shaft  21 , so that the anchor outlets  42  of the firing arm are directed towards the ring  10 . 
         [0060]    As illustrated in  FIG. 6 , firing arm  41  may be configured to drive anchors  50  through anchor outlets  42 . Anchors  50  may be driven through ring  10 , and into surrounding tissue of the implant site, fixing or fastening the ring  10  to the tissue of the implant site. 
         [0061]    As illustrated in  FIG. 7 , once anchors  50  are driven into ring  10  and the surrounding tissue, firing arm  41  may be rotated back into alignment with the axis defined by the applicator shaft  21 , so that the driver  40  may be retracted from the distal end of the applicator  20 , as illustrated in  FIG. 8 . 
         [0062]    In an exemplary embodiment of the present invention, the driving of anchors  50  may be repeated by driver  40  and firing arm  41 , so as to drive anchors  50  around the ring  10 . A plurality of anchors  50  may be loaded into a cartridge or tray of anchors, such that additional anchors may be loaded into a position to be driven into ring  10  and the surrounding tissue. Driver  40  may index the driving of each anchor  50  to the position of each spring arm  22  about the periphery of the ring  10 . In the alternative, applicator shaft  21  may have grooves or other markings to which driver  40  may index the driving of each anchor  50 . 
         [0063]    As illustrated in  FIG. 9 , heart valve replacement prosthetic  1  is shown alone, absent applicator  20 , driver  40 , or anchors  50 . 
         [0064]      FIG. 10  illustrates the heart valve replacement prosthetic  1  after the driver  40  has completed driving a plurality of anchors  50  about the periphery of ring  10 , and further after the applicator  20 , including applicator shaft  21  and spring arms  22 , have been withdrawn. To withdraw the applicator  20 , the applicator shaft  21  may be moved in a distal direction, extending spring arms  22  further beyond the distal side of the ring  10 , and permitting the conical structure formed by the spring arms  22  to collapse. Once collapsed, the spring arms  22  may be permitted to pass through ring  10  with the withdrawal of the applicator shaft  21 , so that the entire applicator  20  may be withdrawn from the implant site. 
         [0065]    Anchors  50  may be any of the anchors described in U.S. Patent Provisional Application No. 61/296,868, filed Jan. 20, 2010, U.S. patent application Ser. No. 13/010,766, filed Jan. 20, 2011, U.S. patent application Ser. No. 13/828,256, filed Mar. 14, 2013, U.S. patent application Ser. No. 13/843,930, filed Mar. 15, 2013, and U.S. patent application Ser. No. 14/301,106, filed Jun. 10, 2014, each of which is incorporated by reference in their entirety as if fully disclosed herein. 
         [0066]    For example,  FIG. 11  shows an anchor or implant  200  which is configured to be driven into a tissue. The anchor  200  includes a corrugated body  201 . The body  201  includes grooves  203  that extend axially along the length of the body  201 . Thus, extending circumferentially around the body  201 , a plurality of grooves  203  alternate with a plurality of ridges  205 . Further, the anchor body  201  includes a pair of wings or split portions  207  and  208 . The split portions  207  and  208  are formed by respective splits or cuts  209  into the body  201 . In this regard, the splits  209  may be formed by making a cut radially into the body  201  and extending in an axial direction. Thus, the two split portions  207  and  208  are attached to the remainder of the body  201  at a distal position and extend proximally to free ends. The free ends include a plurality of sharp protrusions along a curved surface. These points are formed due to the corrugations. In particular, the ridges  205  form the sharp protrusions, as illustrated in the inset partial side view in  FIG. 11 , which are advantageous for gripping tissue and preventing distal sliding of the anchor  200 . Although each split portion  207  and  208  includes three such protrusions as illustrated, it should be understood that the anchor  200  may be designed such that one or more of the split portions has any other number of protrusions, including a single sharp protrusion. For example, if a larger number of sharp protrusions are desired, the body  201  could be more densely corrugated (i.e., a greater number of alternating grooves  203  and ridges  205  could be provided) and/or the angle of the cut or slice could be adjusted. Further, the length of proximal extension of the projections may be adjusted by varying the depth of the grooves  203  with respect to the ridges  205 . 
         [0067]    The split portions  207  and  208  do not substantially impede distal insertion into tissue but resist proximal movement from an insertion location by engaging the tissue. It has been discovered that the combination of the pointed and/or sharp-edged proximal ends of the split portions  207  and  208  with the alternating ridges on the proximal end of the split portions creates improved performance. 
         [0068]    Further, the split portions or wings  207  and  208  are axially offset from each other. For example, split  207  is axially located at position along axis xx and split  208  is axially located at position b along axis xx. This allows for greater structural strength of the other portions of the body  201  as compared to a non-offset configuration. In particular, since the cuts progress continually radially inward as they progress distally, a non-offset portion would have a substantially smaller amount of material in cross-section at the distal end of the cut. This would lead to a mechanically weak point or region along the axis of the body and could lead to mechanical failure, especially in anchors of small dimensions. Although the anchors  200  utilize a pair of wings  207  and  208  to anchor the anchors  200  against proximal retraction from a tissue, it should be appreciated that any number of wings may be provided, and that as an alternative or in addition to the wings  207  and  208 , any other appropriate anchoring structure(s), e.g., anchoring filaments, may be provided. 
         [0069]    The distal tip of the anchor  200  is pyramidal, with a sharp point, and a plurality of surfaces separated by edges that converge at the sharp point. Although four planar surfaces are provided, it should be appreciated that any appropriate suitable number of surfaces may be provided and that one or more or all of the surfaces may be non-planar. 
         [0070]    The anchor  200  may include one or more shoulders, formed by the junction of a wing  207 ,  208 , with the body  201 , or otherwise defined by the area of the anchor  200  where the wing  207 ,  208 , extends proximally and radially outwardly from the distal end, or distal thereto. As illustrated in  FIG. 11 , wings  207 ,  208 , have a relaxed, uncompressed position, but may be compressed to a second, compressed position, in closer approximation with the body  201 . Further, the body  201  may be flexible, such that forces experienced in the proximal end may influence the position of the body or stem  201  with respect to the wings  207 ,  208 , and the distal end. 
         [0071]    The anchor  200  may be produced by first forming the body  201  with the corrugations, e.g., by injection molding or extrusion, and subsequently forming split portions  207  and  208 , e.g., by cutting radially into the side of the body  201 . As illustrated, the cut is curved, with an angle (at the proximal entry point), relative to the longitudinal axis xx of the body  201 , that gradually decreases from the proximal initial cutting location toward the distal end of the anchor  200  and eventually becoming linear. Although the split or cut of the illustrated example is made with a curved or varying angle with respect to the longitudinal axis xx of the body  201 , it should be understood that any appropriate cut, including a linear cut, may be made. 
         [0072]    Although the anchor  200  includes two wings or split portions spaced equally around the radial periphery of the body  201 , it should be appreciated that any number of split portions, including a single split portion may be provided and at any appropriate spacing around the radial periphery of the anchor  200 . 
         [0073]    Modern manufacturing processes allow for near nano technology applications. This allows the anchors to be manufactured in a size and complexity that may not have been possible in years past. The anchor  200  may be injection molded of either absorbable or non-absorbable polymers and then processed (e.g., by cutting) to add the features of the wings  207  and  208 . Although the anchors  200  are formed of polymer, it should be appreciated that any appropriate material may be used, e.g., metal or a composite material. The anchors  200  may have a diameter of, e.g., one millimeter, or approximately one millimeter, and a length that is in a range from, e.g., 5 millimeters to 10 millimeters. According to some example embodiments, the diameter is less than one millimeter. According to some example embodiments, the diameter is in a range from 0.8 millimeters to 1.2 millimeters. It should be understood, however, that other dimensions may be provided. 
         [0074]    In an exemplary embodiment of the present invention, the anchor  4200  illustrated in  FIG. 12  is described. Anchor  4200  includes a distal tip  4230 , and a stem  4201  extending proximally from the base of distal tip  4230 . Stem  4201  joins the base of distal tip  4230  at shoulder  4240 . Wings or barbs  4207 ,  4208  extend proximally, and, to some degree, radially, from the base of distal tip  4230 , and join the base of distal tip  4230  at shoulder  4240 . Barbs  4207 ,  4208  extend proximally and radially from the distal tip  4230  to free ends. The free ends may flare further radially outward, as illustrated in  FIG. 12 . Unlike the wings or split portions  207 ,  208  described above, wings or barbs  4207 ,  4208  are not formed from cuts or splits to the body of the anchor, so that the thickness of stem  4201  may be unaffected by the inclusion of barbs  4207 ,  4208 . Wings or barbs  4207 ,  4208  may have a relaxed, uncompressed position, illustrated in  FIG. 12 . In the uncompressed position, barbs  4207 ,  4208  are unbiased, having a barb opening W. Barbs  4207 ,  4208  may be compressed into closer approximation with stem  4201 . Varying amounts of compression may be applied to the barbs, such that the greater the compression, the closer approximation of the barbs to the stem. Barbs  4207 ,  4208  may include protrusions at the free ends of the barbs, to engage with tissue once the anchor has been deployed. While two barbs  4207 ,  4208  are illustrated, it should be appreciated that any number of barbs may be provided. Similarly, any number of protrusions at the free ends of the barbs may be provided, including one sharp protrusion. 
         [0075]    Stem  4201  may be flexible, able to be bent or flexed with respect to barbs  4207 ,  4208  and distal tip  4230 . Once deployed into tissue, a flexible stem provides for a different profile of forces acting on the anchor  4200 , as compared to an anchor having a rigid or stiff stem. A flexible shaft, able to flex in relation to the barbs and the distal tip, creates a living hinge between these elements of the anchor. Forces acting on the anchor from its proximal end may be at least partially absorbed by the flexible stem, so that the impact of these forces on the wings or barbs of the anchor may be reduced. In certain tissue environments, a flexible shaft may be more likely to prevent a levering action by the anchor, and may thereby prevent the anchor from partially or even completely pulling out of the tissue. 
         [0076]    Further, the anchors  50 ,  200 ,  4200  may include any of the features of the fasteners or other analogous implants disclosed in U.S. Provisional Patent Application Ser. No. 61/296,868, filed on Jan. 20, 2010, in U.S. patent application Ser. No. 13/010,766, filed on Jan. 20, 2011, and U.S. patent application Ser. No. 14/301,106, filed on Jun. 10, 2014, each of which is incorporated by reference in its entirety as if fully disclosed herein, and may be driven using any mechanism disclosed therein. 
         [0077]    To fire the anchors, a force delivery system may be situated at the proximal end of the driver. The force delivery system may use any mechanisms of nearly instantaneous force transfer, such as springs, gas, compressed fluid, or the like. Force is transferred through the shaft of the driver, which may be a rigid shaft or a flexible shaft, depending on the application. The force is used to displace a firing mechanism at the distal end of the shaft, which in turn exerts a driving force on the anchors to drive the anchors from the firing arms and into the prosthetic valve and the surrounding tissue. The driving force may result from a pushing force delivery system, which directs force in the distal direction of the driver, or a pulling force delivery system, which directs force in the proximal direction of the driver, depending on the application. 
         [0078]    In an exemplary embodiment of the present invention, a plurality of firing arms may be provided around the applicator, as illustrated in  FIGS. 13 to 20 .  FIGS. 13 and 14  show driver  60  having, at its distal end, a plurality of firing arms  61  situated annularly around tubular guide  63 . Guide  63  may surround an applicator shaft, much like guide  43 . Firing arms  61  are in a refracted position against the driver and parallel to the axis of the driver.  FIG. 14  also shows anchors  4200  provided in the firing arms  61 . Windows  64  allow for the barbs  4207 ,  4208  to be stored in the firing arm  61  in their relaxed position before being driven from the anchor outlet and into the ring  10  and the surrounding tissue. 
         [0079]      FIGS. 15 and 16  illustrate the driver  60  in which the firing arms have been moved from the retracted position to a firing position. The movement of the firing arms from the retracted position of  FIGS. 13 and 14  to the firing position of  FIGS. 15 and 16  may be achieved by manual or electric actuation of a translating force, for example, by a screw or a sliding mechanism, or by any other mechanical operation. Firing arms  61  are hinged to driver  60  at the distal end of the driver, so that the firing arms  61  open radially outwardly from a position proximal to the hinges and the distal end of the driver  60 . The firing position of the firing arms may be at an angle of less than 90 degrees from the axis of driver  60 . An acute angle of firing arms  61  allows for an angled anchor delivery into ring  10  and the surrounding tissue, and therefore greater control of the placement of the anchors in the surrounding tissue. 
         [0080]    As illustrated in  FIG. 16 , firing arms  61  include firing mechanisms  65  and fingers  66 , for driving anchors  4200  through anchor outlets  62 . Guide  63  is connected to firing mechanisms  65  and fingers  66 , so that the application of a proximal or pull force to the guide will translate the force in a proximal direction to the firing mechanisms  65  and finger  66 . Fingers  66  abut shoulder  4240  of anchor  4200 , and may transfer the pull force from the guide  63  and firing mechanism  65  to anchor  4200 . 
         [0081]      FIGS. 17 ,  18 ,  19 , and  20  illustrate the firing of anchors  4200 . Anchors  4200  are fired by exertion of a proximal or pulling force, pulling guide  63  in a proximal direction with respect to driver  60 . As shown in  FIGS. 17 and 18 , guide  63  is drawn nearly level with the hinged ends of firing arms  61 , and, as shown in  FIGS. 19 and 20 , guide  63  is drawn to a recessed position with respect to the hinged ends of firing arms  61 . The proximal force drawing guide  63  is transferred to firing mechanisms  65 , and in turn to finger  66 , which then transfers the driving force to shoulder  4240  of anchor  4200 , driving anchor  4200  through anchor outlet  62 , into ring  10  and the surrounding tissue. In this manner, all of the firing arms  61  may fire anchors  4200  at the same time. 
         [0082]    Further, any of the implantable elements described herein, e.g., anchors  50 ,  200 ,  4200 , and ring  10 , leaflets  30 , valve struts  31 , or any other element of heart valve replacement prosthetic  1 , may be formed wholly or partly of a material absorbable into the patient&#39;s body, or of a non-absorbable material, depending on, e.g., the specific application. For example, these elements may be formed of polyglycolic acid (PGA), or a PGA copolymer. These elements may also, or alternatively, be formed of copolymers of polyester and/or nylon and/or other polymer(s). Moreover, these elements may contain one or more shape-memory alloys, e.g., nitinol, spring-loaded steel or other alloy or material with appropriate properties. 
         [0083]    Absorbable materials may be advantageous where there is a potential for misfiring or improper locating of the various implants. For example, in a situation where the driver drives an anchor  50 ,  200 ,  4200  at an unintended location, or where the tissue does not properly receive the anchor  50 ,  200 ,  4200 , the anchor  50 ,  200 ,  4200 , even where not needed, would be relatively harmless, as it would eventually absorb into the patient&#39;s body. 
         [0084]    Although particular example heart valve replacement prosthetic systems have been described above, the systems and devices described here are in no way limited to these examples. 
         [0085]    Although the present invention has been described with reference to particular examples and exemplary embodiments, it should be understood that the foregoing description is in no manner limiting. Moreover, the features described herein may be used in any combination.