Abstract:
A device closes septal openings, such as a patent foramen ovale (PFO). The device includes two anchors and a flexible connector. Tension applied to one or more strings attached to the device causes the device to collapse into a reduced profile form for withdrawal into a delivery catheter, thereby facilitating retrieval of the device after insertion into a septal opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional application of U.S. application Ser. No. 13/651,643 filed Oct. 15, 2012, now pending; which is a continuation application of U.S. application Ser. No. 11/110,975 filed Apr. 20, 2005, now issued as U.S. Pat. No. 8,308,760; which claims the benefit under 35 USC §119(e) to U.S. application Ser. No. 60/568,527 filed May 6, 2004, now expired. The disclosure of each of the prior applications is considered part of and is incorporated by reference in the disclosure of this application. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to devices and methods that are used to close septal openings, such as a patent foramen ovale (PFO). A PFO is a persistent, one-way, usually flap-like opening in the wall between the right atrium (RA) and left atrium (LA) of the heart. Because left atrial pressure is normally higher than right atrial pressure, the flap usually stays closed. Under certain conditions, however, right atrial pressure can exceed left atrial pressure, which creates the possibility that blood could pass from the right atrium to the left atrium and allow blood clots to enter the systemic circulation. It is desirable to avoid this situation. 
       SUMMARY OF THE INVENTION 
       [0003]    Embodiments of the present invention are directed to devices for closing septal defects such as PFOs, and for delivering and recovering closure devices. The closure devices in these embodiments generally include a proximal anchor, a distal anchor, and a flexible anchor connector for connecting the two anchors. The connector is preferably a flexible elastomeric layer, which can also be used to promote tissue ingrowth or for drug delivery. The flexible material can also be covered with a biocompatible glue to promote adherence to tissue or growth factors to accelerate tissue ingrowth. 
         [0004]    In accordance with some embodiments of the invention, options are provided for multiple delivery/recovery of the same device without withdrawing the device from the delivery sheath or otherwise replacing it. Other embodiments include the use of a single use delivery/recovery string that reduces the complexity of the delivery/recovery system and the procedure itself. 
         [0005]    These and other features will become apparent from the following detailed description and drawings. The inventions are capable of other and different embodiments and its several details may be capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not in a restrictive or limiting sense. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a closure device according to a first embodiment. 
           [0007]      FIGS. 2-7  are partial side and partial cross-sectional views showing the delivery and recovery of a closure device of the type shown in  FIG. 1 . 
           [0008]      FIGS. 8-11  are partial side and partial cross-sectional views of the removal of a closure device according to a second embodiment of the present invention. 
           [0009]      FIG. 12  is a perspective view of a device according to a third embodiment of the present invention. 
           [0010]      FIGS. 13-17  are partial side and partial cross-sectional views of a device and steps for delivering and removing the device of  FIG. 12 . 
           [0011]      FIG. 18  is a perspective view of a device according to a fourth embodiment of the present invention. 
           [0012]      FIGS. 19-22  are partial side and partial cross-sectional views of a device and steps for delivering and recovering the device of  FIG. 18 . 
           [0013]      FIG. 23  is a perspective view of a device according to a fifth embodiment of the present invention. 
           [0014]      FIGS. 24-28  are partial side and partial cross-sectional views of the device of  FIG. 23  and steps for recovering it. 
           [0015]      FIGS. 29-34  are a perspective view of a sixth embodiment and partial side and cross-sectional views of the device of  FIG. 29  and its delivery and recovery. 
           [0016]      FIGS. 35-37  are perspective views of further embodiments of devices according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    This invention relates to structures of the type shown in application Ser. No. 10/326,535, filed Dec. 19, 2002, published application no. 2003/0191495, which is expressly incorporated herein by reference. This invention includes further embodiments of the device, and methods to allow a physician or other practitioner to deliver and deploy the device in a defect, then recover and remove it if desired from a defect after deployment. Some embodiments allow for multiple deployments and removals of the same occluder. Other embodiments have a single delivery/recovery mechanism requiring a simpler delivery/recovery system. While described for use with a patent foramen ovale (PFO), these systems and methods could be used for occluding or holding together other defects. 
         [0018]    As shown in  FIG. 1 , a closure device  10  has a distal anchor  12  for placement on the left atrial side of a PFO, a proximal anchor  14  for placement in the right atrial side of a PFO, a proximal attachment point  16  spaced from anchor  14  for attachment and release from a wire through a catheter on an anchor connector  22  for connecting anchors  12  and  14 , and frangible attachment points  18 ,  20  on anchor  14 . A bore  24  is provided along the lengthwise direction in proximal anchor  14 . A string  26  extends from attachment point  18  on anchor  14  attachment point  16  to attachment point  20  on anchor  14 . The string then runs through bore  24  to the end of anchor  14 , and across to a permanent attachment point  28  on anchor  12 . Within bore  24 , the string can move relative to anchor  14 . 
         [0019]    In this embodiment and others, the distal anchor, the proximal anchor, and the connectors between the anchor members can each be made of a bioresorbable material. These components can be fabricated from a single piece of a bioresorbable polymer or by a laminated composite of two or more materials to provide a mix of properties; for example, anchors can have stiff centers and flexible edges, and blood contacting surfaces can have controlled porosity or surface texture to promote fast and thorough endothelialization, while minimizing thrombosis. In addition, the tissue contacting surface of the anchors can be designed to provide added stability, such as being roughened. Other components, such as connection balls and strings, can also be made of bioresorbable materials; e.g., the string can be made of bioresorbable fibers that are braided or otherwise combined for strength. 
         [0020]    The anchors are elongated supports, preferably generally cylindrical with rod-like bodies with ends that are atraumatic, and preferably rounded. In size, the distal anchor component could be about 15-30 mm long and 2 mm in diameter with a circular cross-section. The proximal anchor can have similar dimensions and shape, although it can be shorter in overall length. Other distal and proximal anchor structures are also possible. For example, sides of the anchors can be flattened, especially the side which will contact the atrial septum. The generally cylindrical shape for the anchors means that they have at least some portions with generally round cross-sections, but could have one or more flattened sides, cut-outs, or other variations from an “ideal” cylinder. 
         [0021]    The anchor connector can be elastomeric and resilient and made from a material, such as polyester, biological tissue, bioresorbable polymer, small diameter springs (e.g., Nitinol), or spongy polymeric material, and can include thrombogenic or inflammatory materials. Alternatively, the anchor connector can be made of multiple strands of material such as polymer fibers. The anchor connector can be textured or porous. These kinds of surfaces can also produce inflammatory responses, and therefore can promote faster tissue ingrowth and faster defect closure. 
         [0022]      FIGS. 2-4  show the delivery of device  10  to a PFO. Device  10  is shown inside a delivery sheath  30 , and represented as delivered in phantom with anchors  12 ′ and  14 ′ and anchor connector  22 ′. While in the delivery sheath, the string between the anchors has some slack in it. The delivery sheath is introduced so that anchor  12  is positioned in the left atrium  32 . This positioning is typically done by providing delivery sheath  30  in or at the edge of left atrium  32  through PFO tunnel  34 , and retracting sheath  30  so that anchor  12  is deployed in left atrium  32  against septum primum  38  and septum secundum  39 . Sheath  30  is retracted until anchor  14  is deployed in right atrium  36  as indicated in  FIG. 2  in phantom.  FIGS. 3 and 4  show a side view and a top view of device  10  in PFO tunnel  34 . A catheter  40  is maintained in contact with attachment point  16 . 
         [0023]      FIGS. 5-7  show how device  10  can be retrieved as described, such as if the practitioner determines that it is not sitting properly. As shown in  FIG. 5 , delivery sheath  30  is placed up close to anchor  14  while catheter  40  connected to attachment point  16  is pulled. As also shown in  FIG. 6 , the portion  42  of string  26  connected to attachment point  18  breaks, leaving a loose strand of string. The string also pulls attachment point  20  from anchor  14 , but continues to extend through bore  24  of anchor  14  and be rigidly attached to anchor  12 . Continued pulling on catheter  40  continues to pull string  26  and causes anchor  12  to rotate as shown to move from a position where it is generally perpendicular to the lengthwise direction of delivery sheath  30  to a sufficient angle where it can be drawn within sheath  30 . This pulling action also reduces the length of string between anchors  14  and  12  until they are close to each other or in actual contact. This causes anchor  12  to rotate as shown in a direction opposite to that of anchor  14 . Anchor  12  and anchor connector  22  are pulled through the PFO tunnel and back into sheath  30 . 
         [0024]    In this embodiment, because some of the attachment points have been broken, the device can be retrieved once, but would typically not be redeployed in this form. This embodiment does provide the ability to deliver and retrieve the device using one string and one wire. 
         [0025]      FIGS. 8-11  illustrate another embodiment with a device  80  including distal anchor  82  and proximal anchor  84 . A string  86  extends from a rigid attachment point  88  on anchor  84  located at about a midpoint along the lengthwise direction of anchor  84 , and extends through a loop (or hook)  90  in a delivery catheter  92  within a sheath  94  from this loop, the string extends to an end of anchor  84 , through a lengthwise bore  96  and across a PFO tunnel to a rigid attachment point  98  at anchor  82 . Loop  90  is movable from a locked position in which the string is held rigidly, to an unlocked position in which the string can move freely. Control for the loop is provided to the operator, e.g., by pulling one end of the loop until the looping wire is fully withdrawn. In this embodiment, with the loop in the locked position, the delivery process is substantially the same as that shown in the embodiment in connection with  FIGS. 2-4 . 
         [0026]    To retrieve device  80 , loop  90  is unlocked from its locked delivery position, and delivery catheter  92  is withdrawn. This motion pulls on string  86  and hence anchor  84 . Because the distance to attachment point  88  is shorter than the distance to the end of anchor  84 , this pulling causes the string lengths to equalize and anchor  84  to rotate. The length of string between anchors  84  and  82  is reduced until anchor  82  rotates in a direction opposite to that of anchor  84  so that the anchors are end to end and can be withdrawn into sheath  94 . 
         [0027]    This embodiment is useful for recovering the device and can be redelivered. Only one connection to the device is needed. 
         [0028]      FIGS. 12-17  show yet another embodiment with a device  120 . Referring particularly to  FIGS. 12  and.  13 , distal anchor  122  is similar to that in the prior embodiments and has a rigid attachment point  126  at one end. Proximal anchor  124  for the right atrium is also elongated and generally cylindrical, but it has a cut out to form a flat axial face  128  over a portion of the length at one end, and a flat radial face  130 . The cutout provides a smaller profile than without the cutout. 
         [0029]    A passage  132  extends along a diameter of anchor  124  with a first ball  134  and a second ball  136  at either end of passage  132  and connected with a string. Ball  136  is slightly larger in diameter than passage  132 , but is small enough that ball  134  can be pulled through passage  132  when sufficient force is exerted on it. The ball may deform in the process. An attachment ball  138  is coupled to ball  136  to provide an attachment point for the operator. 
         [0030]    These balls can provide distinct functions, such as ball  138  serving as a coupling, and ball  134  serving as a stop. While the contact points and stops are described in this embodiment and in other embodiments as balls and while they are preferably spherical in some embodiments, they can have any shape suitable to form a coupling to a wire in conjunction with a holder that can push or pull them, or a stop, or some other connector. These couplings can be formed differently within one device when there are several couplings; for example, a spherical ball that can be gripped with a grappling hook could be used in one case for a coupling, and a hemispheric piece could be used as a stop. 
         [0031]    Referring to  FIGS. 14-17 , the device is shown in a deployed position ( FIG. 14 ) from which it can be retrieved. A wire  140  in a delivery sheath  142  is connected to ball  138  for attachment. As shown in  FIG. 15 , the pulling force represented by arrow  144  pulls ball  134  through passage  132 . After ball  134  is clear of passage  132 , sheath  142  is drawn back. Further pulling force causes anchor  124  to rotate and anchor  122  to rotate in a direction opposite to that of anchor  124 . As shown in  FIG. 17 , device  120  can be pulled back fully into sheath  142 . 
         [0032]      FIG. 18  shows another embodiment of a device  180  with anchors  182  and  184 , and with a single ball  186  serving as a connector and a stop on the inner side of a radial passage  188 . A string  190  extends to one end of anchor  184 , through a lengthwise passage  192 , across to anchor  182  (through a PFO tunnel when deployed), through a lengthwise passage  194  in anchor  182 , and to a rigid connection with ball  186 . Two string ends extend away from the device and are used to control the device, but with ball  186 , the string forms an unbroken loop with two ends. 
         [0033]      FIG. 19  shows device  180  loaded in a sheath  198  and ready for delivery. A delivery catheter  200  within sheath  198  provides an inward force to one end of the anchor. The delivery sheath would typically be positioned in the left atrium and retracted to allow anchor  182  to be released within the left atrium. Then, sheath  198  would be withdrawn into the right atrium and further pulled back to release anchor  184  within the right atrium. The resulting deployed device  180  is shown in  FIG. 20 . After a successful deployment, the strings can be cut. 
         [0034]    Referring to  FIGS. 20-22 , to recover device  180 , a force is applied to lower end  202  of string  190  in order to rotate anchor  184 , causing anchor  182  to rotate in a direction opposite to that of anchor  184  and be returned into sheath  198 . 
         [0035]    In this embodiment, the device can be redeployed if desired. From  FIG. 22 , by pulling on upper string  204 , ball  186  is moved back against anchor  184  at passage  188  as shown by  186 ′. At that point.  FIG. 22  is substantially similar to  FIG. 19 , which shows device  180  ready to be deployed. 
         [0036]    Referring to  FIG. 23 , a device  230  has a right atrial anchor  234  with a portion cut out of a generally cylindrical side by making a radial cut part way into the anchor and an axial cut along part of the lengthwise direction, with the cuts at right angles to form a cutout section. The resulting faces are similar to those in the device of  FIG. 12 . In this case, a first ball  236  is connected with a string  238  to the flat axial face that is formed by the radial cut, while a second ball  240  is attached with a string  242  that extends through a lengthwise bore  244  in anchor  234 . That string further extends to anchor  232  where there is a rigid attachment at one end. At the other end of left atrial anchor  232  is an enlarged diameter portion  246 . 
         [0037]    Referring to  FIG. 24 , when device  230  is loaded in a delivery sheath  250  for delivery, increased diameter portion  246  of anchor  232  is larger than the opening of a delivery catheter  252  and is at the innermost distal end of catheter  252 . The string portion  254  between the anchors is shown with some slack, and upper and lower wires  256 , 258  are connected to respective attachment balls  236 , 240 . 
         [0038]    The device is delivered in a similar manner to those described above to a deployed position as shown in  FIG. 25 . The wires may provide enough stiffness to keep device  230  in place as catheter  252  is removed, or an additional mandrel or catheter (not shown) can be positioned against device  230  to prevent the device from moving toward the proximal end as the sheath is withdrawn toward the proximal end. 
         [0039]      FIGS. 26-28  show the retrieval process for device  230 . In this case, lower wire  258  is pulled to cause anchor  234  to rotate. In  FIG. 27 , the upper wire is pulled to reintroduce slack  254  ( FIG. 28 ). The upper wire is released to allow the device to assume the configuration of  FIG. 24 . Note that in this position, it can be redeployed into the PFO. 
         [0040]      FIG. 29  shows another device  290  which has similarities with the embodiment of  FIG. 23 , with one ball  296  attached to a face  298  formed by the partial radial cut, but with another ball  300  attached to an end of anchor  294 . In this embodiment, unlike a number of others, there is no lengthwise bore through either anchor. Anchors  292  and  294  are attached with permanent attachment points with a string  304  at the same end of each anchor, and therefore there is slack that would not be taken up by the operator. 
         [0041]    Referring to  FIG. 30 , device  290  is shown in a sheath  306  and ready for delivery. As indicated above, wires  308  and  310  against respective balls  296  and  300  may be able to provide sufficient resistance to keep the device from being withdrawn as sheath  306  is withdrawn around device  290 . If not, an additional device can be inserted to hold device  290  in place as sheath  306  is withdrawn. Device  290  is thus employed in a manner similar to that described above, with the sheath provided in the left atrium, or withdrawn to allow anchor  292  to be positioned, and then further withdrawn into the right atrium to allow anchor  294  to be positioned. 
         [0042]      FIGS. 31-34  show the device being retracted into a delivery sheath by pulling on the lowermost wire that is connected to the ball attached at the end of the right atrial anchor. In this embodiment, both anchors rotate in opposite directions until they are end-to-end and drawn into the delivery sheath. From the position in  FIG. 34 , the device could be redeployed. 
         [0043]      FIG. 35  shows another embodiment of a device  350 , similar to that shown in  FIG. 29 , except that the string connecting the anchors extends from one end of one anchor to an opposite end of the other anchor, thereby extending across the anchor connector. This string connection helps to pull anchor  352  so that it rotates in a direct opposite to the rotation of anchor  354 . 
         [0044]    Referring to  FIG. 36 , in another embodiment, a device  360  has distal anchor  362  and proximal anchor  364  connected together by strings  365  and  366 , both of which pass through a loop  367 . Anchor  364  also has balls  368  and  369  serving as connection points. In this case, retrieving the device includes providing a connection to ball  369  and pulling to rotate anchor  364 , with continued pulling causing rotation of anchor  362 . This device would thus be deployed and retrieved in a manner similar to those described above, and could be redeployed multiple times. 
         [0045]    Referring to  FIG. 37 , a device  370  has a distal anchor  372  and a proximal anchor  374 . It also has attachment balls that are similar to those shown in  FIG. 36 , namely one at one end and one in the middle of the anchor. Distal anchor  372  has strings  375  and  376  extending from each end. String  375  extends from one end of anchor  372 , through a loop. 
         [0046]      377  that is connected to anchor  374 , through a loop  378  connected with a string  376  to another end of anchor  372  and then to the opposite end of anchor  374 . String  375  can also have small strings attached to it, referred to here as whiskers  380 . These could be provided by being glued to the string, or if the string is in a braided form, the string can be intentionally frayed. The whiskers can help provide some inflammatory effect between tissues, such as between the tissue flaps of a PFO to encourage tissue ingrowth. The device can be delivered and redeployed in a manner similar to that described above. 
         [0047]    The closure devices described here can optionally be used along with suturing or stapling techniques deployed from the catheter or sheath. 
         [0048]    The devices can use radiopaque fillers or marker bands fabricated from noble metals such as platinum or gold to allow x-ray visualization. These markers can be attached using a variety of common methods, such as adhesive bonding, lamination between two layers of polymer, or vapor deposition where the anchors of the devices can be sewn or stapled to septum primum or secundum for better dislodgment resistance. Also, in some embodiments, an anchor connector can, if desired, be covered with biocompatible glue to adhere to the tissue or can be loaded or coated with drugs or growth factors to promote healing The glue and also certain drugs can be stored in any cavities in the anchors and released after deployment. 
         [0049]    The anchor connector can be mounted to allow the proximal anchor to slide relative to the connector. A biasing spring (not shown), which may be an expandable coil spring, can be formed at an outer end of the central connector to bias the proximal anchor toward the distal anchor when both are. 
         [0050]    The various closure devices described herein can include a number of advantageous features. The closure devices preferably have an atraumatic shape to reduce trauma during deployment or removal. In addition, the devices can be self-orienting for ease of deployment. Furthermore, because of the flexible anchor connector, the devices generally conform to the anatomy instead of the anatomy conforming to the devices, which is especially useful in long tunnel defects. The devices also generally have a relatively small profile within the heart after deployment. The flexible anchor connector of the devices can encourage faster tissue ingrowth, and thus faster defect closure. Furthermore, there are generally no exposed thrombogenic components on the left and right atrial sides. The devices can also advantageously include bioresorbable components, which can disappear over time. 
         [0051]    Other benefits of the devices can include possible use of a relatively small diameter delivery sheath, use of reduced or no metal mass in the device, ease of manufacturing, cost effectiveness, and overall design simplicity. 
         [0052]    Having described embodiments, it should be apparent that modifications can be made without departing from the scope of the invention. For example, while the anchors are shown generally as straight and elongated, they could be curved.