Patent Document

FIELD OF THE INVENTION 
     The invention generally relates to a method and apparatus for treating a heart valve. 
     BACKGROUND 
     Referring to  FIG. 1 , the heart  2  includes a mitral valve  6  that has a valve annulus  4 . As a result of age, congenital defect or disease, the mitral valve  6  may fail to close completely when it should during a heartbeat. The normal mitral valve  6  opens when the left ventricle  8  relaxes (diastole), allowing blood from the left atrium  10  to fill the decompressed left ventricle  8 . When the left ventricle  8  contracts (systole), the increase in pressure within the left ventricle  8  causes the mitral valve  6  to close, preventing blood from leaking into the left atrium  10  and assuring that all of the blood leaving the left ventricle  8  (the stroke volume) is ejected through the mitral valve  6  into the aorta  12  and then to the body. 
     Referring to  FIG. 2 , the mitral valve  6  has two leaflets. The anterior leaflet  14  has a semicircular shape and attached to approximately two-fifths of the perimeter of the valve annulus  4 . The free edge  15  of the anterior leaflet  14  is typically continuous, without indentations. The posterior leaflet  16  of the mitral valve  6  is attached to approximately three-fifths of the perimeter of the valve annulus  4 . Typically, the posterior leaflet  16  has three segments: the anterior scallop  18 , the middle scallop  20 , and the posterior scallop  22 . The anterior scallop  18  is divided from the middle scallop  20  by a first indentation  24 , and the middle scallop  20  is divided from the posterior scallop  22  by a second indentation  26 . The indentations  24 ,  26  aid in posterior leaflet  16  opening during diastole. The free edge  24  of the posterior leaflet  16  contacts the free edge  15  of the anterior leaflet  14  when the mitral valve  6  is closed. The height of the posterior leaflet  16  is typically less than the height of the anterior leaflet  14 ; however, both leaflets  14 ,  16  typically have generally similar surface areas. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-section view of a human heart. 
         FIG. 2  is a top view of a mitral valve of the human heart of  FIG. 1 . 
         FIG. 3  is a perspective view of a guide catheter. 
         FIG. 4  is an end view of the distal end of a first example of the guide catheter of  FIG. 3 . 
         FIG. 5  is an end view of the distal end of a second example of the guide catheter of  FIG. 3 . 
         FIG. 6  is a perspective view of an exemplary sling. 
         FIG. 7  is a perspective view of an exemplary hook. 
         FIG. 8  is a perspective view of an exemplary clip applier. 
         FIG. 9  is a perspective view of an exemplary clip. 
         FIG. 10  is a perspective view of a step of a method of treating the mitral valve. 
         FIG. 11  is a perspective view of another step of a method of treating the mitral valve. 
         FIG. 12  is a perspective view of another step of a method of treating the mitral valve. 
         FIG. 13  is a perspective view of another step of a method of treating the mitral valve. 
         FIG. 14  is a perspective view of another step of a method of treating the mitral valve. 
         FIG. 15  is a perspective view of a treated mitral valve with a clip holding the leaflets thereof. 
     
    
    
     The use of the same reference symbols in different figures indicates similar or identical items. 
     DETAILED DESCRIPTION 
     Structure 
     Referring to  FIGS. 3-4 , an exemplary guide catheter  30  is shown. The guide catheter  30  may be generally cylindrical in shape, and is flexible enough to be advanced through the vasculature of a patient. The surface of the guide catheter  30  is atraumatic, in order to prevent injury to the vasculature of a patient. The guide catheter  30  may be fabricated from any suitable material or combination of materials. The guide catheter  30  may have five channels within. A clip channel  32  may be the largest channel in the guide catheter  30 , and may be substantially concentric within the guide catheter  30 . The clip channel  32  may be generally cylindrical, with a substantially circular cross-section. However, the clip channel  32  may be shaped differently and/or offset from the longitudinal centerline of the guide catheter  30 . Two sling channels  34  may be positioned radially outward from the clip channel  32 , on opposed sides of the clip channel  32 . Two hook channels  36  may be positioned radially outward from the clip channel  32 , on opposed sides of the clip channel  32 . The hook channels  36  may be arranged substantially ninety arcuate degrees away from the sling channels  34 , such that the channels  34 ,  36  are substantially evenly spaced around the clip channel  32 . However, the channels  34 ,  36  may be positioned at any other suitable angular positions relative to one another; and the channels  32 ,  34 ,  36  as a group may be arranged in any other suitable manner. 
     As one example, referring to  FIG. 4 , one or more of the channels  32 ,  34 ,  36  may be lumens defined within a solid or partially solid guide catheter  30 . If so, any such channel may be fabricated within the guide catheter  30  in any suitable manner, such as by drilling, boring, or laser-cutting, or the guide catheter  30  may be fabricated in such a manner that any such channel is devoid of material within throughout the fabrication process. As another example, referring to  FIG. 5 , one or more of the channels  32 ,  34 ,  36  may be individual tubes positioned within the guide catheter  30 . If so, the channels  34 ,  36  may be positioned between the outer surface  38  of the clip channel  32  and the inner surface  42  of an outer sheath  40 . In this way, the channels  34 ,  36  also may support the clip channel  32  within the lumen  44  of the outer sheath  44 . The channels  32 ,  34 ,  36  may be connected to the outer sheath  40  in any suitable manner. As another example, the guide catheter  30  may be fabricated in any other suitable manner that results in a suitable number of channels defined therethrough. 
     Referring to  FIG. 6 , at least one sling  50  may be utilized in conjunction with the guide catheter  30 . Each sling  50  may include a broad section  52  and an extension  54  extending proximal to the broad section  52 . The broad section  52  may be substantially D-shaped, as shown in  FIG. 6 , or may have any other suitable shape. The broad section  52  may be a closed loop, or may be open at least in party. The broad section  52  may lie in substantially a single plane, but need not do so. The sling  50  may be fabricated from one or more pieces of superelastic wire, such as wire composed of nickel-titanium alloy. However, the sling  50  may be fabricated from spring steel or other metal that is not superelastic, or may be fabricated from any suitable nonmetallic material. The extension  54  is configured to extend through a corresponding sling channel  34  in the guide catheter  30 . The sling  50  is collapsible, such that the sling  50  in its entirety can be held partially or completely within a corresponding sling channel  34  in an initial position, as described in greater detail below. 
     Referring to  FIG. 7 , at least one hook  60  may be utilized in conjunction with the guide catheter  30 . Each hook  60  may be curved or angled at the distal end thereof, such that the free end of the hook  60  is oriented at least partially in the proximal direction. The hook  60  may be J-shaped, or may be shaped in any other suitable manner. The hook  60  may be fabricated from one or more pieces of superelastic wire, such as wire composed of nickel-titanium alloy. However, the hook  60  may be fabricated from spring steel or other metal that is not superelastic, or may be fabricated from any suitable nonmetallic material. The proximal end of the hook  60  is configured to extend through a corresponding hook channel  36  in the guide catheter  30 . The hook  60  is collapsible, such that the hook  60  can be held partially or completely within a corresponding hook channel  36  in an initial position, as described in greater detail below. One or more hooks  60  may include a closing or locking feature at the distal end thereof that can be automatically or remotely actuated to open and close as needed. 
     A clip applier may be utilized in conjunction with the clip channel  32 . As one example, the clip applier may be substantially as set forth in U.S. Pat. App. Pub. No. 2009/0093826 of Warder-Gabaldon et. al., filed on Oct. 5, 2007 (the “Clip Publication”), which is hereby incorporated by reference in its entirety. Referring to  FIG. 8 , the clip applier  70  may be configured to splay and then deploy a clip  72 , as set forth in the Clip Publication. Referring to  FIG. 9 , the clip  72  may have four tines  74  arranged in an X configuration. However, the clip  72  may have tines  74  arranged in any other suitable configuration, and/or may include a different number of tines  74 . The clip applier  70  is configured to be held partially or completely with the corresponding clip channel  32  of the guide catheter  30  in an initial position, as described in greater detail below. 
     Operation 
     Referring to  FIG. 10 , the distal end  31  of the guide catheter  30  is advanced through the left atrium  10  into the left ventricle  8 , through the mitral valve  6 . The guide catheter  30  may be introduced into the left atrium  10  through a transseptal puncture, through the patient&#39;s vasculature, or in any other suitable manner that provides access to the left atrium  10  for the guide catheter  30 . The heart  2  advantageously continues to beat during and after introduction of the guide catheter  30  thereinto; however, the heart  2  may be stopped and the patient placed on a heart-lung machine at the discretion of the user. 
     After the distal end  31  of the guide catheter  30  has been introduced into the left ventricle  8 , then one or more slings  50  are each advanced distally out of the corresponding sling channels  34  in the guide catheter  30 . Such advancement may be performed in any suitable manner, such as by pushing the extension  54  distally either by hand or by application of force through a handle (not shown). The broad section  52  of each sling  50  is initially compressed by and constrained by contact with the interior of the corresponding sling channel  34  such that each sling  50  can be held within the circumference of the guide catheter  30 . As each sling  50  advances distally, its broad section  52  advances out of the corresponding sling channel  34  such that the broad section  52  is no longer constrained by the corresponding sling channel  34 . At that time, the broad section  52  self-expands within the left ventricle  8 . Alternately, the guide catheter  30  actively expands each broad section  52  within the left ventricle  8 . Referring to  FIG. 11 , advantageously two slings  50  are deployed from the guide catheter  30  and expanded. The slings  50  expand from the left ventricle  8  through the mitral valve  6  and into the left atrium  10 . In this way, the slings  50  generally center the guide catheter  30  within the mitral valve  6 . The guide catheter  30  may then be retracted such that its distal end  31  is positioned in the left atrium  10 . During that refraction of the guide catheter  30 , the slings  50  substantially remain in position relative to the left ventricle  8 , mitral valve  6  and left atrium  10  due to the outward force exerted by the slings against the inner surfaces of the left ventricle  8  and the left atrium  10 , as well as the lateral ends  82  of the opening  80  of the mitral valve  6 . The guide catheter  30  slides along the extensions  54  of the slings  50  as the broad sections  52  of the slings  50  remain generally in place in the heart  2 . The guide catheter  30  may be retracted using ultrasound, fluoroscopy, or any other suitable imaging method to determine the location of the distal end  31  of the guide catheter  30 . 
     Next, one or more hooks  60  are each advanced distally out of the corresponding hook channels  34  in the guide catheter  30 . Such advancement may be performed in any suitable manner, such as by pushing each hook  60  distally either by hand or by application of force through a handle (not shown). The distal J-portion  64  of at least one hook  60  may be narrower than the corresponding hook channel  36  in the guide catheter  30 , such that the J-portion  64  of at least one hook  60  is not substantially compressed while that hook  60  is in its initial position within the hook channel  36  in the guide catheter  30 . Alternately, the J-shaped portion  64  of at least one hook  60  may be wider than the corresponding hook channel  36 , such that the J-shaped portion  64  is initially compressed by and constrained by contact with the interior of the corresponding hook channel  36  such that each J-shaped portion  64  can be held within the circumference of the guide catheter  30 . As each hook  60  advances distally, the J-shaped portion  64  of each hook  60  advances out of the corresponding hook channel  36  in the guide catheter  30 . The hook  64  may simply move out of the hook channel  36  without substantially changing its size or shape. Alternately, where the hook channel  36  initially constrained the J-shaped portion  64  of at least one hook  60 , motion of the J-shaped portion  64  of that hook or hooks  60  out of the corresponding hook channel  36  may allow the J-shaped portion  64  to self-expand, and/or frees the J-shaped portion  64  to allow the guide catheter  30  to actively expand it. As the hooks  60  are advanced, they pass through the mitral valve  6  and entire the left ventricle  8 . Because each hook  60  has a J-shaped portion  64  or similarly shaped portion at the distal end thereof, the distal end of each hook  60  is substantially blunt, and thereby passes through the mitral valve  6  without engaging or damaging the tissue of the mitral valve  6 . 
     Next, the physician retracts one of the hooks  60 , causing each retracted hook  60  to grab the edge of a corresponding leaflet  14 ,  16  of the mitral valve  6 . This may require multiple attempts, and may be controlled using ultrasound, fluoroscopy, or any other suitable imaging device or technique. Either leaflet  14 ,  16  may be engaged first. For purposes of describing the method, and not to limit the order of engagement, it is assumed in this document that the physician chooses to engage the anterior leaflet  14  first. Once that hook  60  has engaged the anterior leaflet  14 , the hook  60  is retracted toward the guide catheter  30 , moving the edge of the anterior leaflet  14  to its closed position—that is, the position the anterior leaflet  14  would assume during normal closure of the mitral valve  6 . Optionally, the hook  60  may include a locking feature (not shown) that allows the physician to manually lock the J-shaped portion  64  of the hook  60  after it engages the anterior leaflet  14 , or may include an automatic locking feature that automatically locks the J-shaped portion  64  of the hook  60  after it engages the anterior leaflet  14 . Such a locking feature would prevent the leaflet  14  from disengaging from the hook  60 . 
     Next, the posterior leaflet  16  may be engaged with a second hook  60  in substantially the same manner in which the anterior leaflet  14  was engaged, as described above. The hook  60  is retracted toward the guide catheter  30 , moving the edge of the posterior leaflet  16  to its closed position—that is, the position the posterior leaflet  16  would assume during normal closure of the mitral valve  6 . Alternately, the hooks  60  can be manipulated substantially simultaneously to engage leaflets  14 ,  16  at substantially the same time, rather than sequentially as described above. Referring also to  FIG. 12 , the hooks  60  thereby hold the leaflets  14 ,  16  in a closed position that mimics the position in which the leaflets  14 ,  16  would be held by a clip. The physician may utilize ultrasound, fluoroscopy, or any other suitable imaging technique, and/or a nonimaging technique such as flow measurement, to view and/or measure the mitral valve  6  and determine the impact of fixing the leaflets  14 ,  16  in substantially the position in which they are held by the hooks  60 . If the imaging and/or measurement does not indicate sufficient reduction of mitral insufficiency, the physician can release the leaflets  14 ,  16  from the hooks  60 , such as by moving the hooks  60  distally. The physician may then reorient the guide catheter  30  and capture the leaflets  14 ,  16  again, as described above, where the hooks  60  engage different portions of the leaflets  14 ,  16 . 
     Optionally, the slings  50  may stretch the opening  80  of the mitral valve  6  by moving the ends  82  of the opening  80  away from one another. By stretching the mitral valve  6 , the leaflets  14 ,  16  may move closer to one another, rendering it easier to capture them with the hooks  60 . The broad sections  52  of the slings  50  may form substantially a single plane, where the sling channels  34  are oriented substantially along a line that includes the centerline of the guide catheter  30 . The hook channels  36  may be oriented along a line that includes the centerline of the guide catheter  30 , where that line is substantially perpendicular to the line formed by the sling channels  34  and the centerline of the guide catheter  30 . In this way, the hook channels  36  and sling channels  34  may be substantially evenly spaced along ninety-degree increments along the circumference of the guide catheter  30 . Further, in this way the hooks  60  may be oriented relative to the opening  80  in the mitral valve  6  in a manner that maximizes the ease of engagement between the hooks  60  and the leaflets  14 ,  16 . 
     Once the physician is satisfied with the alignment of the edges of the leaflets  14 ,  16 , the clip applier  70  is advanced distally along the clip channel  32  of the guide catheter  30 , at least partially out of the distal end  31  of the guide catheter  30 . The clip applier  70  is then actuated to splay the clip  72 , as described in the Clip Publication. The distal ends of the tines  74  of the clip  72  each move in a direction having a component of motion away from the longitudinal centerline of the clip  72 . This deformation of the clip  72  may be referred to as “splaying.” Advantageously, the clip  72  is plastically deformed during splaying, such that after splaying the tines  74  of the clip  72  remain in the splayed configuration on their own, without requiring the application of force from the clip applier  70  to maintain the tines  74  in the splayed configuration. Alternately, the clip  72  may be splayed in an elastic or superelastic manner. The splayed clip  72  is still held by the clip applier  70 , and the distal ends of the tines  74  extend radially outward beyond the outer perimeter of the clip applier  70  and of the guide catheter  30 . Next, referring also to  FIG. 13 , the leaflets  14 ,  16  and the splayed clip  72  are brought into contact with one another. This may be performed by moving the clip applier  70  distally, thereby penetrating the distal ends of at least two tines  74  into the leaflets  14 ,  16 . As another example, the hooks  60  may be retracted proximally, bringing the leaflets  14 ,  16  into contact with the tines  74  and causing the tines  74  to penetrate the leaflets  14 ,  16 . As another example, the clip applier  70  may be moved distally and the hooks  60  may be moved proximally in order to penetrate the tines  74  through the leaflets  14 ,  16 . Advantageously, all of the tines  74  penetrate the leaflets  14 ,  16 . However, because the clip  72  has multiple tines  74 , it is not necessary for all of the tines  74  to penetrate the leaflets  14 ,  16 ; rather, one or more tines  74  may enter the opening  80  in the mitral valve  6 . Alternately, the clip  72  may be configured to have two tines  74 , and the clip applier  70  may be actuated in a manner that ensures that one tine  74  penetrates each leaflet  14 ,  16 . 
     Next, the clip  72  is closed, substantially as described in the Clip Publication. As a result, the leaflets  14 ,  16  are firmly and permanently connected together by the clip  72 . Advantageously, the clip  72  engages the leaflets  14 ,  16  approximately at the center of the mitral valve  6 . However, the clip  72  may be placed at any location along the leaflets  14 ,  16 , at the discretion of the physician. Before the closed clip  72  is released from the clip applier, the physician can retract the clip applier  70  proximally a small amount, to ensure that the clip  72  has penetrated the leaflets  14 ,  16  and firmly attached them. Referring also to  FIG. 14 , after the physician is satisfied that the clip  72  has closed firmly into the tissue of the leaflets  14 ,  16 , the clip applier  70  releases the closed clip  72 , substantially as described in the Clip Publication. The clip applier  70  is then withdrawn proximally, partially or completely into the clip channel  32  in the guide catheter  30 . The hooks  60  are released from the leaflets  14 ,  16  in any suitable manner and withdrawn into the hook channels  36  in the guide catheter. Referring also to  FIG. 15 , the guide catheter  30  is then withdrawn, leaving the closed clip  72  in the mitral valve  6 . A double orifice mitral valve  6  has thus been created, which is suitable for treating mitral insufficiency. 
     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. For example, other heart valves or bodily valves than the mitral valve  6  may be treated with the apparatus and method described above. 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.

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