Patent Publication Number: US-2005125032-A1

Title: Patent foramen ovale (PFO) closure devices, delivery apparatus and related methods and systems

Description:
RELATED APPLICATIONS  
      This utility patent application claims the benefit of Provisional Application Ser. No. 60/530,866 filed on Dec. 17, 2003 and titled COUPLED PATENT FORAMEN OVALE (PFO) CLOSURE APPARATUS AND RELATED METHODS AND SYSTEMS, Provisional Application Ser. No. 60/510,263 filed on Oct. 10, 2003 and titled INTEGRAL PATENT FORAMEN OVALE (PFO) CLOSURE DEVICES AND RELATED METHODS AND SYSTEMS, and Application Ser. No. 60/510,203 filed on Oct. 10, 2003 and titled COUPLEABLE PATENT FORAMEN OVALE (PFO) CLOSURE APPARATUS AND RELATED METHODS AND SYSTEMS. These applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD  
      The present invention relates generally to a patent foramen ovale (“PFO”) in a mammalian heart. More specifically, the present invention relates to apparatus, methods, and systems for closure of a septal defect between the right and left atriums of a patient&#39;s heart. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Understanding that 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 specificity and detail through the use of the accompanying drawings. The drawings are listed below.  
       FIG. 1A  is a cross-sectional view of a heart.  
       FIG. 1B  is an enlarged cross-section view of septum primum and the septum secundum and a PFO tunnel between the septum primum and the septum secundum.  
       FIG. 1C  is a perspective view of the septum secundum with the tunnel and the septum primum shown in phantom.  
       FIG. 2  is a plan view of an embodiment of a PFO closure device  100 .  
       FIG. 3A  is an exploded perspective view of PFO closure device  100  and components of a delivery apparatus  200 .  
       FIG. 3B  is an assembled side view of PFO closure device  100  and components of delivery apparatus  200  shown in  FIG. 3A .  
       FIG. 4A  is a perspective view of PFO closure device  100  while still attached via a threaded detachment tip  210  (not shown in  FIG. 4A ) to a stem  220 . Stem  220  and threaded detachment tip  210  comprises a left atrial anchor (LAA) advancer  230 .  
       FIG. 4B  is a cross-sectional view taken at cutting line  4 B- 4 B which shows retainers  140  within anchor connector  150  and threaded detachment tip  210  (not shown in  FIG. 4A ) while it is still within anchor connector  150  for delivery.  
       FIG. 4C  is a side view of right atrial anchor  170  attached to pivot collar  190  before pivot collar  190  has been pushed fully onto anchor connector  150  and off of stem  220 .  
       FIG. 4D  is a top view of right atrial anchor  170  attached to pivot collar  190  before pivot collar  190  has been pushed fully onto anchor connector  150  and off of stem  220 .  
       FIG. 4E  is a cross-sectional view of right atrial anchor  170  attached to pivot collar  190  taken on cutting line  4 E- 4 E.  FIG. 4E  also provides a perspective view of stem  220  as pivot collar  190  is positioned around stem  220  in a configuration which permits pivot collar  190  to be glided on stem  220 .  
       FIG. 4F  is an enlarged perspective view of pivot collar  190 .  
       FIG. 4G  is a bottom view of pivot collar  190  taken from line  4 G- 4 G.  
       FIG. 5A  is a perspective view of catheter  250  and a cross-sectional view of PFO  50  which depicts an initial step in the method of delivering PFO closure device  100 .  FIGS. 5B-5P  depict subsequent steps.  
       FIG. 5B  is a cross-sectional view of delivery apparatus  200  positioned at PFO  50  to deploy left atrial anchor  130  of closure device  100 .  
       FIG. 5C  is perspective view of left atrial anchor  130  as it is being deployed out of catheter  250 .  
       FIG. 5D  is a cross-sectional view of left atrial anchor  130  of closure device  100  deployed into left atrium  40 .  
       FIG. 5E  is perspective view from within left atrium  40  of left atrial anchor  130  of closure device  100  after it has been deployed into left atrium  40 .  
       FIG. 5F  is a cross-sectional view of left atrial anchor  130  of closure device  100  being pulled against septum primum  52  and septum secundum  54  in the left atrium  40 .  
       FIG. 5G  is perspective view from within left atrium  140  of left atrial anchor  130  of closure device  100  being pulled against septum primum  52  and septum secundum  54  in the left atrium  40 .  
       FIG. 5H  is a cross-sectional view of right atrial anchor  170  of closure device  100  being deployed in right atrium  30 .  
       FIG. 5I  is perspective view from within right atrium  30  of right atrial anchor  170  after deployment and ready for clockwise rotation by right atrial anchor (RAA) advancer  270 .  
       FIG. 5J  is a cross-sectional view of right atrial anchor  170  of closure device  100  being deployed in right atrium  30 .  
       FIG. 5K  is perspective view from within right atrium  30  of right atrial anchor  170  positioned under the overhang of septum secundum  54 .  
       FIG. 5L  is a cross-sectional view of right atrial anchor  170  being advanced on anchor connector  150  toward left atrial anchor  130 .  
       FIG. 5M  is perspective view from within right atrium  30  of right atrial anchor  170  as positioned on anchor connector  150  by right atrial anchor (RAA) advancer  270 .  
       FIG. 5N  is a cross-sectional view of closure device  100  and delivery apparatus  200  after removal of left atrial anchor (LAA) advancer  230 .  
       FIG. 5O  is perspective view from within right atrium  30  of closure device  100  and right atrial anchor (RAA) advancer  270  of delivery apparatus  200  after removal of left atrial anchor (LAA) advancer  230 .  
       FIG. 5N  is a cross-sectional view of closure device  100  and delivery apparatus  200  after removal of right atrial anchor (LAA) advancer  270  and catheter  250 .  
       FIG. 5P  is perspective view from within right atrium  30  of closure device  100  positioned in PFO  50  after removal of delivery apparatus  200 .  
       FIG. 6A  is a plan view of an embodiment of a PFO closure device  100 ′.  
       FIG. 6B  is an assembled side view of PFO closure device  100 ′ and components of delivery apparatus  200 ′.  
       FIG. 6C  is an exploded perspective view of right atrial anchor  170 ′ and right atrial anchor (RAA) retainer  190 ′, also referred to herein as a pivot collar  190 ′.  
       FIGS. 6D  is a cross-sectional view taken along cutting line  6 D- 6 D which depicts pivot collar  190 ′ as positioned in right atrial anchor  170 ′.  
       FIG. 6E  is a perspective view of closure device  100 ′ (with right atrial anchor  170 ′ shown in a cross-sectional view) and components of delivery apparatus  200  including coupler  290 ′.  
       FIG. 6F  is a perspective view of closure device  100 ′ (with right atrial anchor  170 ′ shown in a cross-sectional view) and coupler  290 ′ engaging pivot members  190 ′ of pivot collar  190 ′.  
       FIGS. 6G  is a cross-sectional view taken along cutting line  6 G- 6 G which depicts coupler  290 ′ engaging pivot members  194 ′ of pivot collar  190 ′.  
       FIG. 7A  is a perspective view depicting another embodiment of a right atrial anchor at  170   a.    
       FIG. 7B  is a perspective view depicting another embodiment of a right atrial anchor at  170   b.    
       FIG. 7C  is a perspective view depicting another embodiment of a right atrial anchor at  170   c.    
       FIG. 7D  is a plan view depicting another embodiment of a right atrial anchor at  170   d.    
       FIG. 7E  is a side view of the embodiment of right atrial anchor  170   d  shown in  FIG. 7E .  
       FIG. 8A  is perspective view from within right atrium  30  of closure device  100  positioned in PFO  50  with both ends of right atrial anchor  170  positioned within pockets  59   a  and  59   p.    
       FIG. 8B  is perspective view from within right atrium  30  of closure device  100  positioned in PFO  50  with one end of right atrial anchor  170  positioned within pocket  59   p.    
       FIG. 8C  is perspective view from within right atrium  30  of closure device  100  positioned in PFO  50  with both ends  171  of right atrial anchor  170   a  positioned within pockets  59   a  and  59   p.    
       FIG. 8D  is perspective view from within right atrium  30  of closure device  100  positioned in PFO  50  with one end  171  of right atrial anchor  170   a  positioned within pocket  59   p.    
       FIG. 9  is plan and cross-sectional view of another embodiment of a left atrial anchor as identified at  130 ′.  
       FIG. 10  is perspective view of another embodiment of a left atrial anchor as identified at  130 ″.  
       FIG. 11  is cross-sectional view of another embodiment of a left atrial anchor as identified at  130 ′″.  
       FIG. 12A  is a cross-sectional view of another embodiment of a closure device  100 i a having a left atrial anchor  130   a  and another embodiment of a delivery apparatus  200 ″ having a left atrial anchor (LAA) advancer  230 ″.  
       FIG. 12B  provides a perspective view of left atrial anchor  130   a  as depicted in  FIG. 12A  during deployment and a cross-section view of catheter  250 ″ to show right atrial anchor (LM) advancer  270 ″.  
       FIG. 12C  provides a perspective view of left atrial anchor  130   a  as compressed in a left atrium and right atrial anchor  170 ″ as positioned in the right atrium by right atrial anchor (LAA) advancer  270 ″.  
       FIG. 13A  is a plan view of left atrial anchor  130   a  shown in  FIGS. 12A-12C .  
       FIG. 13B  is a plan view of another embodiment of a left atrial anchor as identified at  130   b.    
       FIG. 13C  is a plan view of another embodiment of a left atrial anchor as identified at  130   c.    
       FIG. 13D  is a plan view of another embodiment of a left atrial anchor as identified at  130   d.    
       FIG. 13E  is a plan view of another embodiment of a left atrial anchor as identified at  130   e.    
       FIG. 13F  is a plan view of another embodiment of a left atrial anchor as identified at  130   f  as combined with links  122   f.    
       FIG. 14A  is an enlarged cross-sectional view of the joint identified at  135   a.    
       FIG. 14B  is an enlarged cross-sectional view of the joint identified at  135   b.    
       FIG. 14C  is an enlarged cross-sectional view of the joint identified at  135   c.    
       FIG. 14D  is a side view of left atrial anchor  130   d.    
       FIG. 15A  is a plan view of web  122  for combination with left atrial anchor members of left atrial anchor  130   e.    
       FIG. 15B  is a plan view of web  122 ′ for combination with left atrial anchor members of left atrial anchor  130   e.    
       FIG. 15C  is a side view of left atrial anchor  130   f  and anchor connector  150   f.   
    
    
     INDEX OF ELEMENTS IDENTIFIED IN THE DRAWINGS  
      Elements of the heart  10  are shown in  FIGS. 1A-1C . Some of these elements are also shown in one or more of or are discussed with reference  FIGS. 5A-5Q ,  8 A- 8 D, and  11 . These elements include: 
           15  superior vena cava      25  inferior vena cava      30  right atrium      35  tricuspid valve      40  left atrium      45  bicuspid valve      50  PFO      52  septum primum      53  superior aspect      54  septum secundum      56   a  anterior merger point      56   p  posterior merger point      57   a  anterior portion      57   p  posterior portion      58  tunnel      59   a  anterior pocket      59   p  posterior pocket      60  right ventricle      70  interventricular septum      75  pulmonary veins      80  left ventricle      85  aorta      99  delivery path        

      The elements listed below are components of patent foramen ovale (PFO) closure device  100  or other embodiments including  100 ′,  100 ″,  100 ′″ and  100   a . Note that all features or subcomponents of components even those which relate only to a particular embodiment are listed below without reference to the particular embodiment. For example, left atrial anchors  130   a - f  and right atrial anchors  170 ′ and  170   a - d  include certain features and subcomponents which are unique to the particular embodiment, however, they are generically included in this list and are not individually listed. The following elements are shown in one or more of or are discussed with reference to FIGS.  2 ,  3 A- 3 B,  4 A- 4 G,  5 B- 5 Q,  6 A- 6 G,  7 A- 7 C,  8 A- 8 D,  9 ,  10 ,  11 ,  12 A- 12 C,  13 A- 13 F,  5 A- 15 C. These elements include: 
           120  mesh      122  web      123  arm link      124  perimeter link      125  inset link      130  left atrial anchor      132  anchor member      133  flex point      134  tips      135  joints (referenced to LAA  130   a - c )      138  first center feature (referenced to LM  130   a  and LAA  130   d )      139  second center feature (referenced to LAA  130   a  and LAA  130   d )      140  left atrial anchor retainer      150  anchor connector      151  threads      152  stop      153  end (referenced to anchor connector  150   a )      155  retention holes      157  right atrial anchor (RAA) end of anchor connector  150       158  coating      162  non-resorbable components (referenced to RAA  170   b - c )      164  resorbable components (referenced to RAA  170   b - c )      166  notches (referenced to RAA  170   b - c )      168  torque groove      170  right atrial anchor      171   a  anterior end of right atrial anchor  170       171   p  posterior end of right atrial anchor  170       172   a  stem groove of anterior end  171   a        172   p  stem groove of posterior end  171   p        173   a  stem chamber of anterior end  171   a        173   p  stem chamber of posterior end  171   p        174  hole      175  top surface or contact surface      176   a  flat portion      176   p  rounded portion      177  concave portion      178  pivot groove      179  pivot chamber      180  loop or flex point or region      184  opening in right atrial anchor      190  right atrial anchor (RAA) retainer, pivot collar or locking arm      191  groove      192  band (referenced with pivot collar  190 ′)      194  pivot members      195  ferrule (referenced with pivot collar  190 ′)      196  body portion      199  retention pawls        

      The elements listed below are components of delivery apparatus  200 ,  200 ′,  200 ″ or other embodiments. The following elements are shown in one or more of or discussed with reference to  FIGS. 3A-3B ,  4 A,  4 E,  5 A- 50 ,  6 B,  6 E- 6 G, and  12 A including: 
           210  threaded detachment tip      212  threads      220  stem      230  left atrial anchor (LM) advancer      250  catheter      270  right atrial anchor (RAA) advancer      280  stem      290  coupler      294  torque feature        

     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       FIGS. 1A-1C  depict various views of a heart. Heart  10  is shown in a cross-section view in  FIG. 1A . In a normal heart, the right atrium  30  receives systemic venous blood from the superior vena cava  15  and the inferior vena cava  25  and then delivers the blood via the tricuspid valve  35  to the right ventricle  60 . However, in heart  10 , there is a septal defect between right atrium  30  and left atrium  40  of a patient&#39;s heart which is referred to as a patent foramen ovale (“PFO”). The PFO, which is an open flap on the septum between the heart&#39;s right and left atria, is generally identified at  50 . In a normal heart, left atrium  40  receives oxygenated blood from the lungs  40  via pulmonary veins  75  and then delivers the blood to the left ventricle  80  via the bicuspid valve  45 . However, in heart  10  some systemic venous blood also passes from right atrium  30  through PFO  50 , mixes with the oxygenated blood in left atrium  40  and then is routed to the body from left ventricle  80  via aorta  85 .  
      During fetal development of the heart, the interventricular septum  70  divides right ventricle  60  and left ventricle  80 . In contrast, the atrium is only partially partitioned into right and left chambers during normal fetal development as there is a foramen ovale. When the septum primum  52  incompletely fuses with the septum secundum  54  of the atrial wall, the result is a PFO, such as the PFO  50  shown in  FIGS. 1A-1C , or an atrial septal defect referred to as an ASD.  
       FIG. 1C  provides a view of the crescent-shaped, overhanging configuration of the typical septum secundum  54  from within right atrium  30 . Septum secundum  54  is defined by its inferior aspect  55 , corresponding with the solid line in  FIG. 1C , and its superior aspect  53 , which is its attachment location to septum primum  52  as represented by the phantom line. Septum secundum  54  and septum primum  52  blend together at the ends of septum secundum  54 ; these anterior and posterior ends are referred to herein as “merger points” and are respectively identified at  56   a  and  56   p . The length of the overhang of septum secundum  54 , the distance between superior aspect  53  and inferior aspect  55 , increases towards the center portion of the septum secundum as shown. A tunnel  58  is defined by portions of septum primum  52  and septum secundum  54  between the merger points  56   a  and  56   p  which have failed to fuse. The tunnel is often at the apex of the septum secundum as shown. When viewed within right atrium  30 , the portion of septum secundum  54  to the left of tunnel  58 , which is referred to herein as the posterior portion  57   p  of the septum secundum, is longer than the portion of the septum secundum  54  to the right of tunnel  58 , which is referred to herein as the anterior portion  57   a  of the septum secundum. In addition to being typically longer, the left portion also typically has a more gradual taper than the right portion, as shown. The area defined by the overhang of the anterior portion  57   a  of septum secundum  54  and the septum primum  52  and extending from the anterior merger point  56   a  toward tunnel  58  is an anterior pocket  59   a . Similarly, the area defined by the overhang of the posterior portion  57   p  of septum secundum  54  and the septum primum  52  and extending from the posterior merger point  56   p  toward tunnel  58  is a posterior pocket  59   p.    
      The invention described hereinafter relates to a closure device, a delivery apparatus, methods, and systems for closure of a PFO.  FIG. 2  depicts one embodiment of a closure device at  100 .  FIGS. 3A-3B  depict closure device  100  and an embodiment of a delivery apparatus  200 .  
      Closure device  100  comprises a left atrial anchor  130  and a right atrial anchor  170 . In the embodiment of the closure device shown in  FIG. 2 , left atrial anchor  130  and right atrial anchor  170  are coupled together via an anchor connector  150 . Left atrial anchor  130  is secured to anchor connector  150  via two left atrial anchor (LAA) retainers  140 . While the components described above are separate, several of these components may alternatively be integral. For example, in another embodiment, left atrial anchor  130 , retainer  140  and/or anchor coupler  150  may be integral. Right atrial anchor  170  is secured to anchor connector  150  by a right atrial anchor (RAA) retainer. The embodiment of right atrial anchor (RAA) retainer identified at  190  is referred to herein as a pivot collar.  
      Anchor connector may alternatively be coated with a coating  158  as may left atrial anchor  130 , right atrial anchor  170  and any other component of closure device  100  to facilitate closure of PFO  50 . Such coatings may be applied to promote occlusion of tunnel  58  and endothelial growth while minimizing thrombosis and embolization. For example, a coating of bioresorbable polymers may be applied which facilitates closure of tunnel  58 . Examples of suitable bioresorbable polymers include polycaprolactones, polyorthoesters, polylactide, polyglycolide and copolymers of these polymers. An example of a suitable copolymer is polylactide and polyglycolide. In addition to polymers, drug eluting compositions, proteins and growth factors may also be applied as coatings. Examples of suitable proteins and growth factors include elastin, fibronectin, collagen, laminin, basic fibroblast growth factor, platelet-derived growth factor. The coating may be cellular or foamed or may be more dense as needed. The material used for the coating may depend on the particular component of closure device  100  being coated. For example, elastin is useful for coating left atrial anchor  130  and right atrial anchors as it is not aggressive for tissue growth. Anchor connector  150  may be wrapped with a foam material, fuzzy bioresorbable thread or any other material which assists in facilitating the closure of tunnel  58 .  
      By coating components of closure device  100  such as left atrial anchor  130 , anchor connector  150  and right atrial connector  170 , tissue growth can be promoted at the points of contact of each of these three components in three regions or planes. Note that the components of the closure device may also be formed entirely from the materials listed above for coatings.  
       FIG. 3A  provides an exploded perspective view of closure device  100  and some components of delivery apparatus  200 .  FIG. 3B  provides a cross-sectional view of the same components. Components of delivery apparatus  200  shown in  FIGS. 3A-3B  include a left atrial anchor (LAA) advancer  230  for advancing left atrial anchor  130 , a right atrial anchor (RAA) advancer  270  for advancing right atrial anchor  170  and catheter  250 . Left atrial anchor (LAA) advancer  230  comprises a stem  220  which is fixedly or integrally coupled to a threaded detachment tip  210 . Right atrial anchor (RAA) advancer  270  comprises a stem  280  and a coupler  290 . Left atrial anchor (LAA) advancer  230  pass through right atrial anchor (RAA) advancer  270 .  
       FIGS. 4A-4G  show additional features of closure device  100  particularly, right atrial anchor  170 . The functions of these features are best understood with reference to  FIGS. 5A-5P .  
       FIG. 4A  provides a perspective view of closure device  100  with anchor connector  150  still attached to stem  220  of left atrial anchor (LAA) advancer  230 . Right atrial anchor  170  has not yet been advanced into its final position on the right atrial anchor (RAA) end  157  of anchor connector  150 . Hole  155  in end  157  of anchor connector  150  are shown in  FIG. 4A  ready to receive retention pawls  199  of pivot collar  190 , which is more generally referred to as a right atrial anchor (RAA) retainer.  
       FIG. 4B  provides a cross-section view of anchor connector  150  taken at cutting line  4 B- 4 B.  FIG. 4B  shows retainers  140  within anchor connector  150  and a coating  158  on anchor connector  150 .  
       FIG. 4C  is a side view of right atrial anchor  170  attached to pivot collar  190  before pivot collar  190  has been pushed fully onto anchor connector  150  and off of stem  220 .  FIG. 4D  is a top view of right atrial anchor  170  attached to pivot collar  190 ; in the same position as is shown in  FIG. 4C .  FIG. 4E  provides a cross-sectional view of right atrial anchor  170  taken on cutting line  4 E- 4 E, right atrial anchor  170  is in the same position as  FIGS. 4C-4D  on stem  220  after being rotated.  FIG. 4E  also provides a perspective view of stem  220  as pivot collar  190  is positioned around stem  220  in a configuration which permits pivot collar  190  to be glided on stem  220 .  
      Right atrial anchor  170  has two opposing ends which are respectively adapted to be positioned in anterior pocket  59   a  and posterior pocket  59   p . The opposing end identified at  171   a  may be placed in anterior pocket  59   a  or adjacent to the anterior portion  57   a  of septum secundum  54 . Similarly, the opposing end of right atrial anchor  170  identified at  171   p  may be placed in posterior pocket  59   p  or adjacent to the posterior anterior portion  57   p . Right atrial anchor is relatively symmetrical so that end  171   p  or end  171   a  can be positioned in either posterior pocket  59   p  or anterior pocket  59   a . Accordingly, the use of the designations “a” and “p” to designate an eventual position with either an anterior or posterior orientation does not indicate that either end  171   a  or end  171   p  must be positioned to have respective anterior and posterior orientations.  
      To permit right atrial anchor  170  to be easily moved within a catheter, right atrial anchor  170  has three chambers which are adapted to fit around pivot collar  190 , anchor connector  150  and stem  220 . A stem groove is formed in the two opposing ends of right atrial anchor  170  as identified at  172   a  and  172   p  which each respectively defined a stem chamber  173   a  and  173   p . Pivot collar  190  has pivot members  194  which are received within holes  174  to permit right atrial anchor to pivot with respect to pivot collar  190 . Right atrial anchor  170  has a pivot groove  178  which defines a pivot chamber  179 . In this embodiment, the chambers described above allow relatively concentric movement of right atrial anchor  170  with respect to catheter  250  shown in  FIG. 5B , anchor connector  150  and stem  220 .  
      Right atrial anchor  170  has a top surface  175  which has a convex shape. The convex shape of top surface  175  permits optimal anatomical conformance with the shape of septum secundum  54 . Note that the shape of surface  175  on either side of pivot groove  178  is essentially the same to permit right atrial anchor to oriented with ends  171   a  and  171   p  respectively positioned adjacent to portions  57   p  and  57   a  or vice versa. Right atrial anchor has a flat portion  176   a  opposite a rounded portion  176   p  at its bottom surface. Flat portion  176   a  provides for an optimal fit within catheter  250 . The bottom surface includes a concave portion  177  between flat portion  176   a  and rounded portion  176   p . Concave portion  177  is shaped to minimize the size of right atrial anchor  170 .  
      Right atrial anchor  170  has a torque groove  168  which is adapted to fit in a mated with a complimentary torque feature  194 . The interaction of torque groove  168  and torque feature  194  to rotate and move right atrial anchor  170  is described below with reference to  FIGS. 5I-5O . Another embodiment of a torque feature for rotation and movement of a right atrial anchor is described below with reference to  FIGS. 6A-6G .  
      Details of pivot collar  190  can be easily seen in the enlarged cross-sectional view of  FIG. 4F  and the view of pivot collar provided by  FIG. 4G  which is taken along line  4 G- 4 G. Note that another embodiment of a right atrial anchor (RAA) retainer identified at  190 ′ is discussed below in relation to  FIG. 6C . As mentioned above, pivot collar  190  has pivot members  194  which are received within holes  174  to permit right atrial anchor to pivot with respect to pivot collar  190 . Pivot members  194  extend from body portion  196 . A plurality of arms  198  extend from body portion  196 . Each arm  198  has a retention pawl  199 . As mentioned above, retention pawls  199  enter retention hole  155  of anchor connector  150  to secure pivot collar  190  to anchor connector  150 .  
       FIGS. 5A-5P  depict one method for delivering closure device  100  to PFO  50  via delivery apparatus  200  and deploying closure device  100 . Steps involved in recapturing closure device  100  are shown in  FIGS. 6A-6G .  
      Catheter  250  is introduced to PFO  50  via delivery path  99  which is identified in  FIGS. 1A-1C . Catheter  250  is a long somewhat flexible catheter or sheath introduced into a vein such as the femoral vein and routed up to the right atrium of a patient&#39;s heart. The catheter may be tracked over a guide wire that has been advanced into the heart by a known methodology. After catheter  250  is introduced into the heart via inferior vena cava  25 , catheter  250  is positioned at right atrium  30  in front of the interatrial communication or PFO, and then through tunnel  58 . Once the distal end of  252  of catheter  250  is positioned at the end of tunnel  58  as shown in  FIGS. 5A-5B  or extends beyond tunnel  58 , left atrial anchor  130  is deployed as shown in  FIG. 5D .  
       FIG. 5B  provides a cross-sectional view of closure device  100  and delivery apparatus  200  just before left atrial anchor  130  is pushed out of catheter  250  and deployed into left atrium  40 . As indicated above, left atrial anchor (LAA) advancer  230 , more particularly stem  220  and threaded detachment tip  210 , move within right atrial anchor (RAA) advancer  270 , more particularly stem  280  and coupler  290 , to advance left atrial anchor  130  within catheter  250 .  
       FIG. 5C  depicts left atrial anchor  130  just before deployment and  FIG. 5D  depicts left atrial anchor  130  after deployment. As provided below, the left atrial anchor may have many different configurations which permit it to fit within the catheter, either by being rotatably or pivotally aligned with the axis of the catheter or by being sufficiently flexible to fit within the catheter in a compressed and/or flexed state. The state in which a left atrial anchor is within the catheter will be referred to herein as a delivery configuration. The state in which an anchor is outside of the catheter and has been pivoted, rotated, flexed, expanded, or otherwise put in position to be placed at the PFO site will be referred to herein as a deployed configuration.  
      Depending on the particular embodiment of left atrial anchor, in deploying the left atrial anchor from the catheter, it will be expanded, pivoted, or rotated to extend once out of the catheter. The embodiment of the left atrial anchor depicted in  FIG. 5D  expands and pivots from the delivery configuration to a deployed configuration. Left atrial anchor  130  may be formed from any suitable material such as coiled metal, coiled polymer or a solid core of metal or plastic wrapped with metal or polymer coil. For example, left atrial anchor may be formed from super elastic nickel/titanium or nitinol. It may have a single strand core or a core with multiple strands. The core may be wrapped with metal wire formed from a dense biocompatible metal such as platinum, platinum/tungsten alloy, platinum/iridium alloy, or platinum/iridium/rhodium alloy to increase the radio-opacity of the left atrial anchor. Utilizing a multiple strand core permits the left atrial anchor to have lower bending stiffness and better memory compared with a left atrial anchor formed with a single strand having approximately the same cross-sectional area as the multiple strands.  
       FIG. 5E  shows the appearance of left atrial anchor  130  from within left atrium  40  once left atrial anchor  130  has been deployed. Catheter  250  is shown extending beyond tunnel  58 .  
       FIGS. 5F-5G  show left atrial anchor being pulled proximally and positioned proximate to the PFO. For embodiments such as left atrial anchor  130 , the left atrial anchor pivots at or near its center. This pivoting motion permits the left atrial anchor to conform to the surfaces of the septum secundum and the septum primum. Once left atrial anchor  130  is pivoted at an angle with respect to the axis of the anchor connector  150 , left atrial anchor  130  is pulled flush against septum secundum  54  and septum primum  52 . As explained above, each anchor member  132  is angled. More particularly, each anchor member  132  is bowed such that there is a flex point  133  along its length. Pulling left atrial anchor  130  flush against septum secundum  54  and septum primum  52  flattens anchor members  132  of left atrial anchor  130  and enables left atrial anchor  130  to push against septum secundum  54  and septum primum  52  when closure device  100  is finally positioned. Note that tips  134  of each anchor member  132  remain angled slightly away from septum secundum  54  and septum primum  52  even after anchor members  132  are flattened to minimize trauma to septum secundum  54  and septum primum  52 .  
       FIG. 5G  depicts left atrial anchor  130  with two anchor members  132  of the left atrial anchor positioned against the septum primum of the heart and the other two anchor members  132  positioned against the septum secundum of the heart. In addition to a left atrial anchor with four anchor members, other configurations permit at least one anchor member  132  to be positioned against the septum primum of the heart while at least one other anchor member is positioned against the septum secundum of the heart such that the left atrial anchor remains positioned in the left atrium. For example, the left atrial anchor may have two or three anchor members or more than four anchor members. Examples of other shapes are described below in reference to  FIGS. 9-11 ,  12 A- 12 C,  13 A- 13 I and  14 A- 14 D.  
      Right atrial anchor  170  can be seen in its delivery configuration rotated within catheter  250  in  FIG. 5F . Right atrial anchor  170  is deployed by advancing it with respect to catheter  250  by urging right atrial anchor (RAA) advancer  270  against right atrial anchor  170 . Once outside of catheter  250  as shown in  FIG. 5H , right atrial anchor  170  pivots into a deployed configuration such that it extends perpendicular to, or at least at an angle with respect to catheter  250 . Note that at least one anchor member  132  is in a different plane relative to another anchor member  132 .  
       FIG. 5I  shows right atrial anchor  170  being rotated clockwise. Rotation of right atrial anchor  170  is achieved by rotating stem  280  of right atrial anchor (LAA) advancer  270 . Left atrial anchor  130  and right atrial anchor  170  are not brought into a locked configuration until after right atrial anchor  170  is positioned. As right atrial anchor  170  is rotated, posterior end  171   p  tucks under the overhang of posterior portion  57   p  of septum secundum  54  and in posterior pocket  59   p . The posterior end of a typical septum secundum has a deeper pocket than the anterior portion of a typical septum secundum. The deeper pocket of the typical posterior end makes it easier to position an end of the right atrial anchor than under the anterior portion. Note that while  FIGS. 5J-5Q  depict or are described in reference to placement of the ends of right atrial anchor  170  into pocket  59   a  and pocket  59   p  at the anterior and posterior portions, closure device  100  also effectively closes a PFO when only one end of right atrial anchor  170  is positioned within pocket  59   p  and the other end is positioned on top of anterior portion  57   a  instead of in pocket  59   a  as discussed below with reference to  FIG. 8B  and  FIG. 8D .  
       FIG. 5J  depicts right atrial anchor positioned with its top surface  175  directed toward tunnel  58 .  FIG. 5K  shows right atrial anchor  170  with its posterior end  171   p  partially under the overhanging posterior portion  57   p  of septum secundum in posterior pocket  59   p  and its anterior end  171   a  partially under the overhanging anterior portion  57   a  of septum secundum  54  in anterior pocket  59   a.    
      In  FIG. 5L , right atrial anchor  170  is shown after being driven toward left atrial anchor  130  on anchor connector  150  by right atrial anchor (RAA) advancer  270 . Advancement of right atrial anchor  170  on anchor connector  150  enables retention pawls  199  of right atrial anchor (RAA) retainer  190  to enter retention hole  155  of anchor connector  150  so that right atrial anchor (RAA) retainer  190  is secured to anchor connector  150 . Once retainer  190  locks with connector  150 , right atrial anchor  170  becomes positioned further under septum secundum  54 , as shown in  FIG. 5M . More particularly,  FIG. 5M  shows right atrial anchor  170  with its posterior end  171   p  fully under the overhanging posterior portion  171   p  of septum secundum  54  in posterior pocket  59   p and its anterior end  171  a fully under the overhanging anterior portion  57   a  of septum secundum  54  in anterior pocket  59   a . With reference to  FIG. 3A  and  FIG. 4A , note that there may be only one hole  155  while there is a plurality of retention pawls  199 . This ratio and the relative widths of the hole  155  and retention pawls  199  ensures that at least one pawl  199  will be engaged in hole  155 .  
      The sequence of steps described above with reference to  FIGS. 5H-5M , indicates that the right atrial anchor  170  is first rotated clockwise into position and then right atrial anchor  170  is advanced toward left atrial anchor  130 . However, these steps may also be achieved in manner which involves simultaneous clockwise rotation and advancement of right atrial anchor  170 . Simultaneous rotation and advancement may involve a transition from a combination of rotation and advancement to just advancement.  
       FIGS. 5N-5O  shows catheter  250  after removal of left atrial anchor (LAA) advancer  230 . Left atrial anchor (LAA) advancer  230  can be removed after right atrial anchor  170  has been driven forward and locked with anchor connector  150  as described with reference to  FIG. 5H-5M . Removal of left atrial anchor (LAA) advancer  230  is achieved by rotating stem  220  counterclockwise while maintaining tension on stem  220  and holding stem  280  secure so that threads  212  of tip  210  are no longer engaged by threads  151  of anchor connector  150 . Once right atrial anchor  170  and left atrial anchor  130  have been deployed and properly positioned in the heart against the septum primum and septum secundum, as discussed above, the deployed anchors may then be detached from the remainder of the device. More particularly, after left atrial anchor (LAA) advancer  230  has been removed, then right atrial anchor advancer  270  is removed from catheter  250 .  
       FIG. 5P-5Q  depict closure device  100  in a closure position relative to PFO  50  after delivery apparatus  200  has been removed. Following deployment and positioning of the anchors, the right and left atrial anchors are left to remain in the heart on opposite sides of the PFO. The tissue at the PFO is compressed between left atrial anchor  130  and right atrial anchor  170  via anchor connector. This configuration permits closure device  100  to remain in the heart in a stable configuration and facilitate closure of the PFO.  
       FIGS. 6A-6F  depict another embodiment of closure device which is identified as  100 ′ and another embodiment of delivery apparatus which is identified as  200 ′. The components of closure device  100 ′ which are different from closure device  100  include anchor connector  150 ′, right atrial anchor  170 , and right atrial anchor (RAA) retainer  190 ′. The component of delivery apparatus  200 ′ which is different from delivery apparatus  200  includes coupler  290 ′ of right atrial anchor (RAA) advancer  270 ′. As explained below, closure device  100 ′ and delivery apparatus  200 ′ permit adjustments based on the length of the particular PFO tunnel and also permit recapture of closure device  100 ′ by delivery apparatus  200 ′.  
       FIGS. 6A-6B  shows anchor connector  150 ′ having three retention holes which are identified at  155   a - c . A plurality of retention holes enables retention pawls  199  of right atrial anchor (RAA) retainer  190 ′ to enter holes  155   a - c  of anchor connector  150 ′ until right atrial anchor  170 ′ is set in a desired position. As the retention pawls  199 ′ are moved in succession in holes  155   a - c  to bring right atrial anchor  170 ′ closer to left atrial anchor  130 , the operator can identify the position of retention pawls  199 ′ with respect to each retention holes  155  by either feeling distinct clicks or by using instrumentation to view their position. The ability to variably set the length of the portion of anchor connector  150 ′ between left atrial anchor  130  and right atrial anchor  170 ′ is advantageous as tunnels  58  have different lengths.  
       FIG. 6C  provides a detailed depiction of pivot collar  190 ′ which is another example a right atrial anchor (RAA) retainer. Pivot collar  190 ′ has two bands  192 ′ which extend around body portion  196 ′. Bands  192 ′ each have a ring portion  193 ′ and opposing pivot members  194 ′ at opposite ends of the ring portion  193 ′. Each pivot member  194 ′ extends through hole  174 ′ and is held in hole  174 ′ by ferrule  195 ′.  
       FIGS. 6D-6G  and  FIG. 6B  show coupler  290 ′ and its torque feature  294 ′.  FIG. 6D  shows the portions of pivot members  194 ′ engaged by torque features  294 ′, the portion not in holes  174 ′ of right atrial anchor  170 ′. As can be seen in  FIG. 6G , the space between ring portions  193 ′ of pivot collars  190 ′ and right atrial anchor  170 ′ is filled by coupler  290 ′ when torque features  294 ′ engage pivot members  194 ′.  FIG. 6E  shows coupler  290 ′ approaching pivot collar  190 ′.  FIG. 6F  shows coupler  290 ′ and pivot collar  190 ′ locked together through the engagement of torque feature  294 ′ and pivot member  194 ′.  
      After the anchors have been deployed on either side of the PFO, the position of the anchors may be observed via fluoroscopic, ultrasonic, or any other type of imaging available to one of skill in the art. If the anchors are in an improper or otherwise undesirable position, they may be recaptured and withdrawn or recaptured and redeployed. In the embodiment depicted in  FIGS. 6A-6G , the location of the error in deployment or delivery determines where the recapture occurs. For example, if right atrial anchor  170  has been pushed through tunnel  58  and into left atrium  40  then catheter  250  is advanced distally through the PFO opening and into the left atrium so that the anchors may then be recaptured in catheter  250 . Tip  210  is rotated clockwise enough turns to push retention pawls  199  out of retention holes  155  of anchor connector  150 . The operator then pulls on stem  280 ′ of right atrial anchor (RAA) advancer  270 ′ while holding left atrial anchor (LAA) advancer  230 . This permits right atrial anchor  170  to be pulled into catheter  250  by utilizing split tip  252  of catheter  250  to pivot right atrial anchor  170  while pulling on stem  280 ′ of right atrial anchor (RAA) advancer  270 ′. Note that each of retention pawls  199 ′ and holes  155  are shaped to enable retention pawls  199 ′ to remain in place unless lifted by tip  210  for detachment during recapture. More particularly, retention pawls  199  each have a ramp-shaped inner surface and tip  210  lifts retention pawls up so that the ramp-shaped inner surfaces may ride up the edge of holes  155  when right atrial anchor (RAA) advancer  270  is pulled. Catheter  250  recaptures left atrial anchor  130  by pulling left atrial anchor  130  into catheter  250  while split tip  252  is in the left atrium.  
      In contrast to having a distinct stem groove  172   p  and pivot groove  178  like right atrial anchor  170 , right atrial anchor  170 ′ has a combined stem and pivot groove  178 ′. The combined groove  178 ′ is sized to permit easy access by pivot collar  190 . Also, once torque feature  294 ′ engages pivot members  194 ′ and the engagement is used to pull right atrial anchor  170 ′ into catheter  250 , space is needed within right atrial anchor  170  so that coupler  290 ′ can be received.  
       FIGS. 7A-7C  depict other embodiments of right atrial anchors respectively at  170   a - c . Like right atrial anchors  170  and  170 ′, right atrial anchor  170   c  has an arched shape. In contrast, right atrial anchors  170   a  and  170   b  are relatively straight. Right atrial anchors  170   b  and  170   c  have non-resorbable components  162   b  and  162   c  and resorbable components  164   b  and  164   c . Examples of resorbable components include components formed from bioresorbable polymers and drug-eluting compositions as described above. A bio-resorbable polymer may be used to give bulk to the anchor and further to promote the formation of fibrous tissue. In such embodiments, the non-resorbable components may be used as a backbone. Although not necessary, a metal wire backbone provides for radio-opacity needed for x-ray imaging. Of course, in some embodiments the anchors and other components of the closure device may entirely comprise bio-resorbable material such that no foreign material remains in the heart after a sufficient period of time for closure of the PFO to take place. Examples of non-resorbable components include stainless steel and a super-elastic material such as nitinol. These components, like the left atrial anchor, may have any suitable cross-sectional shape. For example, left atrial anchor and the non-resorbable components of the right atrial anchor may be formed from round or flattened wire that has been formed into an appropriate shape or may be wrought from bulk material as desired.  
      As shown in  FIG. 7A , right atrial anchor  170   a  has a top surface  175   a  and a bottom surface  177   a  which are both relatively straight and parallel to each other. Right atrial anchor  170   a  has a groove  178   a  which is open along its entire length except for its center.  
      As mentioned above and as shown in  FIGS. 7B-7C , right atrial anchors  170   b  and  170   c , respectively have non-resorbable components  162   b  and  162   c  and resorbable components  164   b  and  164   c . In these embodiments, the resorbable component and the non-resorbable component are attached to each other. The resorbable components are segmented with notches respectively at  166   b  and  166   c  to provide enhanced flexibility. The notches facilitate flexing of the anchor into the arched configuration against the PFO.  
       FIGS. 7D-7E  depicts another embodiment of a right atrial anchor at  170   d . Right atrial anchor  170   d  has two opposing anchor members joined together by a loops  180  which act as flex points or regions for ends  171  to be flexed together inside a catheter when right atrial anchor  170   d  is in its delivery configuration. Loops  180  each define a hole  174   d . Holes  174   d  is adapted to engage pivot members  194  or  194 ′ of right atrial anchor (RAA) retainer  190 . An optional web  120  is shown extending within the area defined by the wire forming the opposing anchor members. Web  120  may also extend beyond the wire. A hole  184 d is provided in web  120  for an anchor connector (not shown in  FIGS. 7D-7E ) such as anchor connector  150  or  150   a.    
       FIGS. 8A-8D  depict two different embodiments of right atrial anchors which are each positioned adjacent to a septum secundum in anatomical conformance with the septum secundum. The right atrial anchor is preferably arched with an arch which is similar to that of the septum secundum. Right atrial anchor  170  has an arched top surface  175  which is similar in shape to superior aspect  53 , which is the attachment location of septum secundum  54  to septum primum  52 . Right atrial anchor also has a length which permits it to be tucked under the overhang of septum secundum  54 .  
      In addition to being rigid and having an arched configuration, the right atrial anchor can also have other shapes such as a straight configuration while being flexible so that it can conform to the arched shape of the superior aspect  53  of the septum secundum. For example, instead of right atrial anchor  170  being formed from a rigid material, it can also be formed from a more flexible material. Similarly, a flexible embodiment such as shown at  170   c  may be used.  
       FIG. 8B  shows right atrial anchor  170  positioned within pocket  59   p  and the other end positioned on top of anterior portion  57   a  instead of in pocket  59   a . As described above, relying on the anatomy of the posterior portion  57   p  of septum secundum  54  to position at least one end of right atrial anchor is an effective methodology for effectively closing a PFO. The ends of right atrial anchor are both short enough so that whichever end is positioned in pocket  59   p , it conforms with the anatomy of a portion of the septum secundum.  
      As shown in  FIGS. 8C-8D , a right atrial anchor which is rigid and straight, such as right atrial anchor  170   a  described above with reference to  FIG. 7A , may be used. Right atrial anchor  170   a  has a posterior end which is short enough to fit within pocket  59   p . Although, the rigidity and straight configuration of right atrial anchor  170   a  prevent it from curving like superior aspect  53 , top surface  175   a  is able to abut superior aspect  53  and septum secundum  54  does not block anchor connector  150  from full access into tunnel  58 . The embodiments of the right atrial anchor described above, facilitate closure of the PFO by allowing the right atrial anchor to be tucked under at least a portion of the septum secundum and against the septum primum such that the right atrial anchor can be drawn taughtly against both the septum primum and septum secundum. Healing is thereby facilitated along a greater portion of PFO tunnel  58 .  
      At the location of a PFO, the septum primum is joined with the septum secundum at two “merger points,” as discussed above. The right atrial anchor may be shorter than the distance between these merger points to enhance the ability of the right atrial anchor to be positioned with both of its ends within pockets  59   a  and  59   p . In other words, the right atrial anchor may extend from the point at which the septum primum is joined with the septum secundum on one end of the PFO “arch” to the point at which the septum primum is joined with the septum secundum on the other end of the PFO arch. Contact with these two merger points facilitates the right atrial anchor remaining in its proper position without being pulled through the PFO opening. Because a typical PFO has an arch that is 12-15 mm long, the right atrial anchor typically has a length of about 10 to about 30 mm although variations above and below this are contemplated in order to accommodate varying PFO anatomies. An example of a suitable right atrial anchor has a length within a range of about 15 mm to about 22 mm. An example of a suitable left atrial anchor has a length of about 15 mm to about 30 mm.  
       FIG. 9  depicts another embodiment of a left atrial anchor identified at  130 ′ which has three anchor members  132 ′. Left atrial anchor  130 ′ also has a web material or mesh  120  positioned on anchor members  132 ′ to further facilitate closure of PFO  50 . Left atrial anchor may have any suitable number of anchor members. For example, the left atrial anchor may have just two opposing anchor members like the right atrial anchor such that both anchor members are essentially rod-shaped. Similarly, the left atrial anchor may be rod-shaped while the right atrial anchor is banana-shaped. Anchors which are rod-shaped or banana-shaped are referred to herein as elongate-shaped anchors. When both anchors have just two opposing anchor members, the right and left atrial anchors are positioned perpendicular to one another at the point of their approximation such that when they are brought together they generally form a plus (+) shape at that point. With respect to such embodiments, the right atrial anchor is typically placed in an approximately horizontal, although arched, position in the right atrium against and with respect to the PFO and the left atrial anchor is typically placed in an approximately vertical position in the left atrium against the PFO. If not configured in perpendicular orientations with respect to one another, the right and left atrial anchors will typically at least be offset from one another. In other words, the right atrial anchor will typically be positioned such that it is at an angle with respect to—i.e., not parallel to—the left atrial anchor such that are positioned in intersecting planes with respect to one another. Also, one or both anchors may have an off-center pivot point.  
       FIG. 10  depicts another embodiment of a closure device at  100 ″. Closure device  100 ″ has a right atrial anchor  170 ″ comprising a single wire looped to have opposing anchor members. Right atrial anchor  170 ″ is connected to left atrial anchor  130 ″ via an anchor connector  150 ″ which is a ring with either an elliptical or round shape. From the view of  FIG. 10 , only two anchor members of left atrial anchor  130 ″ are depicted. However, as understood from the juncture of the anchor members, left atrial anchor  130 ″, in this embodiment, has four anchor members.  
       FIG. 11  depicts another closure device at  100 ′″. Closure device  100 ′″ is formed from an integral material. Closure device  100 ′″ has an anchor connector  150  which is integral at one end with a left atrial anchor with right atrial anchor  170 ′″. Anchor connector  150 ′″ is coated with a coating which facilitates closure of PFO  50 . Examples of suitable coatings include bioresorbable polymers and drug-eluting compositions. Closure device  100 ′″ is shaped to enable conformance with the anatomy of septum primum  52 , septum secundum  54  and tunnel  58 .  
       FIGS. 12A-12C  depict another embodiment of a closure device  100   a  comprising a left atrial anchor  130   a  and a right atrial anchor  170 ″ which are connected together by an anchor connector  150   a .  FIGS. 12A-12C  also depict  200 ″ another embodiment of delivery apparatus  200  having a left atrial anchor (LAA) advancer  230 ″ and a right atrial anchor (LAA) advancer  270 ″. Left atrial anchor  130   a  has a first set of anchor members  132   a  on top of a second set of anchor members  132   a . The two sets are identical. The tips  134   a  of anchor members  132   a  are joined together at joints  135   a .  FIG. 13A  provides a plan view of left atrial anchor  130   a  and  FIG. 14A  provides an enlarged cross-sectional view of joint  135   a.    
      Left atrial anchor (LAA) advancer  230 ″ pushes left atrial anchor  130   a  out of catheter  250  and into the left atrium.  FIG. 12B  provides a perspective view of left atrial anchor  130   a  during deployment. Anchor connector  150   a  of closure device  100   a  is a thread or filament. Anchor connector  150   a  is tied to first center feature  138   a  of left atrial anchor  130   a  at end  153   a . Anchor connector  150   a  has a stop  152   a  which is passed over by second center feature  139   a  of the second set of anchor members  132   a  as second center feature  139   a  is pushed towards first center feature  138   a . Anchor connector  150   a  can be used to selectively expand or collapse left atrial anchor  130   a.    
       FIG. 12C  provides a perspective view of left atrial anchor  130   a  as compressed in a left atrium and right atrial anchor  170 ″ as positioned in the right atrium by right atrial anchor (LAA) advancer  270 ″. Right atrial anchor  170 ″ has an opening  184  through which anchor connector  150   a  passes. Right atrial anchor  170 ″ also has a right atrial anchor (RAA) retainer  190 ″ also referred to as a locking arm. Locking arm  190 ″ permits right atrial anchor  170 ″ to advance on anchor connector  150   a  toward left atrial anchor  130   a . While other embodiments permit right atrial anchor  170 ″ to be retracted on anchor connector, locking arm  190 ″ does not permit right atrial anchor  170 ″ to be moved away from left atrial anchor  130   a . Note that coupler  290 ″ of right atrial anchor (LAA) advancer  270 ″ has a torque feature  294 ″ for engaging torque groove  168  of right atrial anchor  170 ″.  
      Other configurations of left atrial anchor  130   a  having two sets of linked anchor members are shown in  FIGS. 13B-13D  and are identified as  130   b - 130   d . FIGS.  14 B-C provide enlarged cross-sectional views of joints  135   b - c .  FIG. 14D  is a side view of left atrial anchor  130   d  being pulled slightly at its center.  
       FIGS. 13E-13F  depict additional embodiments of left atrial anchors as identified at  130   e - 130   f . Left atrial anchor  130   e  depicts an embodiment having six anchor members  132   e.    
       FIG. 15A  and  FIG. 15B  depict embodiments of webs respectively at  122  and  122 ′. Another embodiment of a web, web  122   f  is shown in  FIG. 13F  and  FIG. 15C  as used in combination with left atrial anchor  130   e  to provide left atrial anchor  130   f . Web  122   f  comprises arm links  123   f , a perimeter link  124   f  and an inset link  125   f . Perimeter link  124   f  comprises link components which are either integral or separate and are attached to each end or tip  134  of each anchor member  132   e . Arm links  123   f  and inset link  125   f  may also comprise link components which are either integral or separate. Web  122  shown in  FIG. 15A  differs from web  122   f  in that it does not have an inset link. Web  122 ′ shown in  FIG. 15B  differs from web  122   f  as web  122 ′ has a plurality of inset links. The inset links extending around a perimeter at certain lengths of each anchor member.  
       FIG. 15C  depicts a plan view of left atrial anchor  130   f  shown in  FIG. 13F  with anchor connector  150   f  in the center of anchor  130   f . The combination of webbed links on anchor members as shown in  FIG. 13F  permits left atrial anchors  130   f  to have a triangulated configuration as shown in  FIG. 15C . The links may be flexible and have some tensile strength but limited compressive strength much like a string. When flexible links are used in combination with arms which are relatively rigid, the combination permits compression within a catheter in a delivery configuration and a deployed configuration which resists collapsing and being pulled into tunnel  58 .  
      Triangulation anchors such as anchor  130   f  may have various configurations. For example, the links do not need to by symmetrical, integral or linked continuously on the anchor members. The webs may be formed from the same or different materials as the anchor members. For example, the anchor members may be formed from nitinol while the links are formed from resorbable polymers. Webs  122  and mesh  120  shown with reference to  FIG. 9  and  FIG. 7D  may be used with either a left atrial anchor or a right atrial anchor. Materials may also be used as a mesh or links which have a fuzzy appearance. Triangulation atrial anchors are not shown with a web material, however, it should be understood that such an embodiment acts much like an umbrella.  
      Since the embodiments disclosed herein have right and left atrial anchors that are coupled to one another—i.e., they are integral, attached, or otherwise connected with one another—once the anchors have each been deployed, they will remain in place on either side of the PFO opening.  
      Right atrial anchor and left atrial anchor can be coupled together by any available structure or in any available manner. For example, the respective anchors may be considered “coupled” if they are integral, attached, or otherwise connected with one another. The atrial anchor may be shaped to provide a torsion-spring-like flexural pivot that minimizes strain in the anchor material as it is deformed between the delivery configuration and the deployed configuration and vice versa. Note that while anchor connectors  150 ,  150 ′ and  150   a  are shown as the structure for coupling the right and left atrial anchors, some embodiments of the invention don&#39;t have a connector at all. For example, portions of the anchors may extend into or through tunnel  58  to join the anchors together. Also, the anchors could be welded, glued, or integrally connected. Moreover, a variety of other suitable structures or other arrangements could be used to connect the anchors, such as a cable, filament, chain, clip, clamp, band, or any other manner of connection available to those of skill in the art.  
      The left atrial anchors disclosed herein are examples of left atrial anchor means for anchoring a closure device in the left atrium of a heart. The right anchor disclosed herein are examples of right atrial anchor means for anchoring a closure device in the right atrium of a heart. Mesh disclosed herein is an example of means for increasing the surface area of the atrial anchor. Webs disclosed herein are means for preventing an atrial anchor from extending beyond the deployed configuration. The anchor connectors disclosed herein are examples of means for connecting the right atrial anchor means and the left atrial anchor means. Coatings and components of a closure device formed from a bioresorbable polymer, a drug eluting composition, a protein, a growth factor or a combination thereof.etc. are examples of means for enhancing mechanical closure of a PFO. Left atrial anchor retainers disclosed herein are examples of left atrial anchor retainer means for retaining the left atrial anchor on the anchor connector. Right atrial anchor retainers herein are examples of right atrial anchor retainer means for retaining the right atrial anchor on the anchor connector. Left atrial anchor (LM) advancers disclosed herein are examples of means for controlling the position of the left atrial anchor. Right atrial anchor (LAA) advancers disclosed herein are examples of means for controlling the position of the right atrial anchor. The catheters disclosed herein are examples of means for positioning the closure device. The closure devices disclosed herein are examples of means for closing a PFO.  
      All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.  
      The above description fully discloses the invention including preferred embodiments thereof. Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the invention to its fullest extent.  
      It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. Embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows. Note that elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. § 112 ¶6.