Abstract:
A surgical tool may include a self-expanding combination anchor, comprising a first segment connected to a second segment, wherein said first segment is distal to said second segment.

Description:
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/365,729, filed on Jul. 19, 2010, which is herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a system for closing a patent foramen ovale in heart tissue. 
     BACKGROUND 
     Referring to  FIG. 1 , a patent foramen ovale (PFO)  2  is a flap-like opening in the wall  4  between the left atrium  6  and the right atrium  8  of the heart  10 . That opening typically closes at or shortly after birth. However, in an estimated 20-25% of people, the PFO  2  remains open into adulthood. The PFO  2  allows blood clots in the bloodstream to bypass the natural filtering mechanism of the lungs, which can lead to stroke. A person with a PFO  2  is generally asymptomatic, and generally does not know he or she has a PFO  2  until after a stroke. In addition, research suggests a correlation between PFO  2  and migraine, the mechanism of which is still unknown. 
     Currently, patients having a known PFO  2  are treated in one of two ways. The patient may be prescribed blood thinners such as coumadin, to reduce the risk of clot formation. However, this course of treatment requires lifelong dependence on that medication, which does nothing to close the opening between the atria. Alternately, a device may be placed through the PFO  2  and then unfurled like a tent on each side of the PFO  2 . Such a device may include a material such as polyester stretched over a wire frame, or stuffed inside a wire mesh. However, such devices can expose a significant amount of metal to the bloodstream, which is considered undesirable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-section view of a heart. 
         FIG. 2  is a perspective view of the distal end of a PFO closure tool. 
         FIG. 3  is an end view of the distal end of a PFO closure tool. 
         FIG. 4  is a side view of a combination anchor of the PFO closure tool of  FIGS. 2-3  in a deployed state. 
         FIG. 5  is a side view of the combination anchor of the PFO closure tool of  FIGS. 2-3  in an undeployed state. 
         FIG. 6  is a side view of a first step in deployment of the combination anchor. 
         FIG. 7  is a side view of another step in deployment of the combination anchor. 
         FIG. 8  is a side view of another step in deployment of the combination anchor. 
         FIG. 9  is a side view of another step in deployment of the combination anchor. 
         FIG. 10  is a side view of another step in deployment of the combination anchor. 
         FIG. 11  is a side view of a step in the deployment of a staple. 
         FIG. 12  is a side view of another step in the deployment of a staple. 
         FIG. 13  is a side view of a completed staple deployment. 
         FIG. 14  is a side view of a first step in deployment of another embodiment of an anchor. 
         FIG. 15  is a side view of another step in deployment of the anchor of  FIG. 15 . 
         FIG. 16  is a side view of another step in deployment of the anchor of  FIG. 15 . 
         FIG. 17  is a side view of another step in deployment of the anchor of  FIG. 15 . 
         FIG. 18  is a side view of another step in deployment of the anchor of  FIG. 15 . 
         FIG. 19  is a side view of another step in deployment of the anchor of  FIG. 15 . 
         FIG. 20  is a side view of a completed staple deployment. 
     
    
    
     The use of the same reference symbols in different figures indicates similar or identical items. 
     DETAILED DESCRIPTION 
     Commonly-assigned U.S. Patent Publication No. 2009/0093826 (Ser. No. 11/868,431) filed on Oct. 5, 2007 and published on Apr. 9, 2009 (the “PFO Document”) is hereby incorporated by reference herein in its entirety. 
     Combination Anchor 
     Referring also to  FIGS. 2-4 , a combination anchor  20  is shown in a deployed state. The combination anchor  20  is a unitary structure that includes a first segment  22  and a second segment  24 . The first segment  22  is distal to and connected to the second segment  24 . As described in greater detail below, the first segment  22  is configured for introduction into the left atrium  6  of the heart  10  and the second segment  24  is configured for introduction into the right atrium  8  of the heart  10 . The combination anchor  20  also includes two or more fingers  26 . The first segment  22  is defined as the distal segments of the fingers  26  collectively, and the second segment  24  is defined as the proximal segments of the fingers  26  collectively. The distal end of each finger  26  may be blunt. Referring to  FIG. 4 , in a deployed state, the free end of each finger  26  is located radially outward from the longitudinal centerline  28  of the combination anchor  20 . The finger  26  may then extend inward toward the longitudinal centerline  28  of the combination anchor  20  and distal to the free end of the finger  26 . Continuing to move along the finger  26  away from its free end, the finger  26  may curve such that an inflection point of the finger  26  is tangent to a line parallel to the longitudinal centerline  28  of the combination anchor  20 . Substantially at that inflection point is the division  30  between the first segment  22  and the second segment  24 . The finger  26  continues to curve outward, then extends proximally from and radially outward from the inflection point. The finger  26  may curve inward, then extend proximally and radially inward to a proximal end  32 . The proximal end of the finger  26  may be fixed to a base  34  that may be generally cylindrical or that may have any other suitable shape. The base  34  in turn may be received within the lumen of a guide catheter  36  or other flexible tube. The base  34  may be the proximal end of the combination anchor  20 . 
     The combination anchor  20  may include four fingers  26  arranged in an X-shape, where the fingers  26  are substantially evenly angularly arranged and radially symmetrically arranged about the longitudinal centerline  28  of the combination anchor  20 , as seen in  FIG. 3 . However, more or less than four fingers  26  may be utilized. Further, the fingers  26  need not be evenly angularly arranged about the longitudinal centerline  28  of the combination anchor  20 , nor radially symmetrically arranged about the longitudinal centerline of the combination anchor  20 . 
     Advantageously, the combination anchor  20  is fabricated from nickel-titanium alloy. However, the combination anchor  20  may be constructed from any biocompatible superelastic alloy or material. Alternately, the combination anchor  20  may be fabricated from any material that is capable of self-expansion after removal of a constraining force. 
     A staple  38  may be held by the base  34 . The staple  38 , its retention by the base  34 , and its deployment may be substantially as described in the PFO Document. The staple  38  may be substantially X-shaped as viewed on end. Advantageously, the tines  40  of the staple  38  are angularly spaced apart from the fingers  26  of the combination anchor  20  to prevent interference between the staple  38  and the combination anchor  20 . 
     The operation of the combination anchor  20  will now be described. Referring to  FIG. 5 , in an initial configuration, the base  34  is retracted far enough into the guide catheter  36  such that the guide catheter  36  constrains the fingers  26  of the combination anchor  20  radially, and such that the diameter of the base  34  and fingers  26  is substantially not greater than the diameter of the guide catheter  36 . In this initial configuration, the base  34  may be partially or completely withdrawn into the lumen of the guide catheter  36 . 
     As set forth in the PFO Document, the femoral artery, radial artery or other artery or vein in the vasculature remote from the PFO  2  may be punctured, and a standard introducer sheath may be placed into the puncture. A guidewire of the user&#39;s choosing may be inserted through the introducer sheath. Optionally, the guidewire may include a standard radiopaque feature at or near its distal end, to aid positioning of the distal end of the guide catheter  36  relative to the PFO  2 . The guidewire may be advanced through the vasculature to the PFO  2 , then completely through the PFO  2  into the left atrium  6 . The guide catheter  36  then may be inserted through the introducer sheath over the guidewire and advanced through the vasculature to the PFO  2 . The distal end of the guide catheter  36  then may be advanced completely through the PFO  2  into the left atrium  6 . Alternately, the guide catheter  36  and the guidewire may be inserted substantially simultaneously, in which case the guidewire may be located completely within a lumen of the guide catheter  36 , or may extend distally from the end of the guide catheter  36 , during this advancement. Advancement of the guide catheter  36  and at least one guidewire advantageously may be performed with the assistance of a fluoroscope or other imaging device that indicates the position of the guide catheter  36  and/or at least one guidewire in the patient. The use of such an imaging device in conjunction with a guide catheter  36  and/or at least one guidewire is standard in the art. The guidewire may then be removed from the guide catheter  36 . Alternately, the guide catheter  36  may be advanced to the PFO  2 , then through the PFO  2  into the left atrium, without the use of a guidewire. 
     Referring to  FIG. 6 , the base  34  then may be pushed distally relative to the end of the guide catheter  36 . As the base  34  moves distally, the combination anchor  20  that is attached to the base  34  moves distally also. Continued motion of the base  34  causes the first segment  22  of the combination anchor  20  to move distal to the guide catheter  36 , such that the guide catheter  36  no longer restrains the first segment  22 . As a result, the distal ends of the fingers  26  self-expand radially outward to form the deployed first segment  22 . Referring to  FIG. 7 , the guide catheter  36  and base  34  then may be retracted into the right atrium  8 . Consequently, the first segment  22 , which is positioned within the left atrium  6 , is moved into contact with the wall of the left atrium  6  in proximity to the PFO  2 . The expanded first segment  22  is too large to fit through the PFO  2  and thus holds the combination anchor  20  in place relative to the left atrium  6 . 
     Referring to  FIG. 8 , the guide catheter  36  may be withdrawn further distally. As a result, the proximal ends of the fingers  26  self-expand radially outward to form the deployed second segment  24 . The deployed second segment  24  is located in the right atrium  8 , on the opposite side of the PFO  2  from the first segment  22 . Referring to  FIG. 9 , the base  34  may then be advanced distally relative to the guide catheter  36 . As a result, the second segment  24  is compressed against the wall of the right atrium  8  relative to the first segment  22 , thereby compressing tissue adjacent to the PFO  2  between the first segment  22  and the second segment  24  of the combination anchor  20 . The second segment  24  may itself reduce in length longitudinally during this compression. 
     Referring also to  FIG. 10 , the tines  40  of the staple  38  then may be splayed, as set forth in the PFO Document. The base  34  then may be advanced, driving the tips of the tines  40  into tissue adjacent to the PFO  2 . The staple  38  may then be separated from the base  34 . Alternately, the tines  40  need not be driven into tissue at all at this time. Alternately, the staple  38  may be completely deployed into heart tissue adjacent to the PFO  2  at this time. Referring to  FIG. 11 , the base  34  then may be retracted proximally and/or the guide catheter  36  may be advanced distally, causing the second segment  24  to compress within the lumen of the guide catheter  36 . Further proximal motion of the base  34  and/or distal motion of the guide catheter  36  causes the first segment  22  to compress back into the lumen of the guide catheter  36  as well. 
     Referring also to  FIG. 12 , the staple  38  is then closed to close the PFO  2 . Closure of the staple  38  may be as set forth in the PFO Document, or may be performed in any other suitable manner. Referring to  FIG. 13 , the guide catheter  36  is then withdrawn from the heart  10  and from the insertion point into the patient, which itself is then closed in any suitable manner. The PFO  2  is closed and the procedure is complete. 
     One-Sided Anchor 
     As another example of an anchor  50 , the anchor  50  may be one-sided such that it expands only on a single side of the PFO  2 . Referring to  FIG. 14 , one or more guidewires  52  are inserted through the patient&#39;s vasculature as set forth above, through the PFO  2  and into the left atrium  6 . Referring to  FIG. 15 , the guide catheter  36  may be advanced over the guidewires  52  into the right atrium  8 . 
     Referring also to  FIG. 16 , the guide catheter  36  then may be withdrawn proximally. As set forth above, a base  34  may be provided, with fingers  26  attached thereto that form a second segment  24 . Withdrawal of the guide catheter  36  allows the second segment  24  to self-deform radially outward. The first segment  22  set forth above may be omitted, such that the anchor  50  only includes a second segment  24  configured to deploy in the right atrium  8 ; in other respects, the anchor  50  may be substantially as set forth above with regard to the combination anchor  20 . The term “second segment  24 ” is used for convenience in description here, to be consistent with the description of the combination anchor  20  above, even though the anchor  50  only includes a single segment. 
     Referring also to  FIG. 17 , the guide catheter  36  and base  34  are advanced distally to place the second segment  24  against tissue of the right atrium  8  adjacent to the PFO  2 . The second segment  24  is pushed against the tissue of the right atrium  8  to tension it and provide a suitable surface for staple deployment. Referring also to  FIG. 18 , the staple  38  is splayed, as set forth in the PFO Document. Referring also to  FIG. 19 , the staple  38  is advanced into tissue adjacent to the PFO  2 . The second segment  24  is then retracted proximally away from the PFO  2 , into the right atrium  8 . Referring also to  FIG. 20 , the staple  38  is then closed to close the PFO  2 . Closure of the staple  38  may be as set forth in the PFO Document, or may be performed in any other suitable manner. The guide catheter  36  and guidewires  52  are then withdrawn from the heart  10  and from the insertion point into the patient, which itself is then closed in any suitable manner. The PFO  2  is closed and the procedure is complete. 
     While the invention has been described in detail, it will be apparent to one skilled in the art that various changes and modifications can be made and equivalents employed, without departing from the present invention. It is to be understood that the invention is not limited to the details of construction, the arrangements of components, and/or the method set forth in the above description or illustrated in the drawings. Statements in the abstract of this document, and any summary statements in this document, are merely exemplary; they are not, and cannot be interpreted as, limiting the scope of the claims. Further, the figures are merely exemplary and not limiting. Topical headings and subheadings are for the convenience of the reader only. They should not and cannot be construed to have any substantive significance, meaning or interpretation, and should not and cannot be deemed to indicate that all of the information relating to any particular topic is to be found under or limited to any particular heading or subheading. Therefore, the invention is not to be restricted or limited except in accordance with the following claims and their legal equivalents.