Patent Abstract:
A device for occluding an atrial appendage includes a catheter-deliverable epicardial implant that is detachably secured to a delivery device. The implant includes an inflatable cuff that is positionable about the atrial appendage to an extent that, when adjustably inflated, the cuff physiologically occludes the atrial appendage. Such occlusion addresses health risks associated with atrial fibrillation and cardiac rhythm disorder.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/168,009, filed on Jun. 24, 2011 and entitled “System for Occlusion of Left Atrial Appendage”, which itself claims priority to U.S. provisional Patent Application Ser. No. 61/358,127, filed on Jun. 24, 2010 and entitled “System for Occlusion of Left Atrial Appendage”, the contents of which being incorporated herein in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to devices and methods for occluding lumens in internal soft body tissue, and more particularly to devices and methods for physiologically occluding the left atrial appendage (“LAA”). The present invention involves a permanent or semi-permanent implant which epicardially occludes the LAA, and is adjustable so as to occlude the LAA from its base. 
     BACKGROUND OF THE INVENTION 
     Atrial fibrillation (“AF”) is a common cardiac rhythm disorder (“cardiac arrhythmia”) and is characterized by a rapid chaotic heartbeat in which the upper chambers of the heart known as the atria quiver rapidly instead of beating in a steady rhythm. This rapid quivering reduces the heart&#39;s ability to properly function as a pump. 
     Atrial fibrillation typically increases the risks of thrombo-embolic stroke and congestive heart failure. Quality of life is also impaired by common AF symptoms such as palpitations, chest pain, fatigue, and dizziness. The irregular heartbeat associated with AF causes blood to pool in the left atrial appendage, allowing clots to accumulate over time. From time to time, clots may dislodge from the left atrial appendage, and may enter various circulation tracks causing strokes, myocardial infarction, limb ischemia, and other vascular problems. 
     A number of approaches have been implemented to address the health risks associated with AF. Among such techniques, surgical procedures for closing (occluding) the left atrial appendage (LAA) have been proposed. Some of such procedures involve open chest wall midsternotomy procedures while others may access the pericardial space through a thoracotomy or from a sub-xiphoid access point. In such approaches, a physical device is typically employed to cinch or compress the LAA. 
     Conventional LAA closure devices, however, are difficult to precisely position at the LAA, and therefore result in incomplete occlusion of the LAA, as the surgical closure point is oftentimes spaced from the base of the LAA. Moreover, conventional closure devices lack simple repositioning and adjustment capabilities, such that attempts to physiologically completely occlude the LAA frequently fail. 
     It is therefore an object of the invention to provide a tissue occlusion device which facilitates placement and ultimate closure of the left atrial appendage at its base. 
     It is another object of the present invention to provide an atrial appendage closure device having adjustment capabilities to facilitate re-positioning of the device at the atrial appendage, and complete occlusion of the appendage at its base. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an atrial appendage occlusion device of the present invention; 
         FIG. 2  is an isolation view of a portion of the atrial appendage occlusion device illustrated in  FIG. 1 ; 
         FIG. 2A  is a top schematic view of a portion of the atrial appendage occlusion device illustrated in  FIGS. 1 and 2  in an open condition; 
         FIG. 2B  is a top schematic view of a portion of the atrial appendage occlusion device illustrated in  FIGS. 1 and 2  in a closed condition; 
         FIG. 3  is a schematic diagram of an atrial appendage occlusion device of the present invention engaged with a left atrial appendage; 
         FIG. 3A  is a schematic view of an atrial appendage occlusion device engaged with a left atrial appendage in an open condition; 
         FIG. 3B  is a schematic view of an atrial appendage occlusion device engaged with a left atrial appendage in a closed condition; 
         FIG. 4A  is an isolation view of a portion of the atrial appendage occlusion device illustrated in  FIGS. 1 and 2  in an open condition; 
         FIG. 4B  is an isolation view of a portion of the atrial appendage occlusion device illustrated in  FIGS. 1 and 2  in a closed condition; 
         FIG. 5A  is an isolation elevational view of a portion of the atrial appendage occlusion device illustrated in  FIGS. 1 and 2 ; 
         FIG. 5B  is a schematic view of an atrial appendage occlusion device in engagement with a left atrial appendage; 
         FIG. 5C  is a schematic view of an atrial appendage occlusion device in engagement with a left atrial appendage; 
         FIG. 5D  is a schematic view of an atrial appendage occlusion device in engagement with a left atrial appendage in a closed condition; 
         FIG. 5E  is a schematic view of an atrial appendage occlusion device in occlusive engagement with a left atrial appendage; and 
         FIG. 5F  is a schematic view of an atrial appendage occlusion device with an implant portion separated from a delivery device. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     The objects and advantages enumerated above together with other objects, features, and advances represented by the present invention will now be presented in terms of detailed embodiments described with reference to the attached drawing figures which are intended to be representative of various embodiments of the invention. Other embodiments and aspects of the invention are recognized as being within the grasp of those having ordinary skill in the art. 
     With reference now to the drawings, and first to  FIG. 1 , an atrial appendage occlusion device  10  includes a multiple lumen delivery device  12 , such as a steerable catheter, as is well known in the art. In one embodiment, delivery device  12  includes first and second lumens  14 ,  16  for simultaneously delivering a plurality of devices to, for example, the left atrial appendage (LAA)  20  of a left atrium  22  of a human heart. In the illustrated embodiment, a grasping device  18  may be delivered through first lumen  14 , while an implant  24  may be delivered through second lumen  16  of delivery device  12 . 
     One aspect of the present invention provides for laparoscopic/percutaneous transport of delivery device  12  to LAA  20 . In some embodiments, delivery device  12  is a distally steerable catheter for minimally invasive introduction to the pericardial space through the pleural or sub-xiphoid spaces using a seldinger technique. In such a manner, implant  24  of the present invention may be delivered to the LAA without the need for midsternotomy. It is to be understood, however, that the device  10  of the present invention may be useful for direct access to the LAA in cases where the patient is undergoing a midsternotomy for other surgical procedures. In either scenario, device  10  is arranged for an epicardial treatment of the LAA. 
     Once device  10  has been introduced into the patient, advancement and positioning may be performed through conventional imaging techniques, such as thoracoscopic or fluoroscopic imaging. In some embodiments, delivery device  12  may be compatible with imaging scopes which may be introduced through a selected lumen  14 ,  16  thereof. 
     As described above, the device of the present invention is arranged to occlude, for example, LAA  20  by pinching, cinching, crimping, clamping, compressing, or otherwise closing base  26  of LAA  20 . In one embodiment, closing or “occluding” LAA  20  at base  26  is accomplished by securing an inner surface  28  of LAA  20  to itself substantially at base  26 . Such securement effectively fluidly seals off an interior of LAA  20  from left atrium  22 , and prevents blood clots from embolizing from within LAA  20  to left atrium  22 . In some embodiments, the occlusion is of a character to cut off nutrient-providing blood supply to the tissue of LAA  20 , thereby eventually resulting in necrosis and/or obliteration of LAA  20 . In the illustrated embodiment, a means for effectuating occlusion of LAA  20  is implant  24 , which may be detachably secured to delivery device  12  to remain indefinitely after delivery device  12  is removed from the patient. 
     In the embodiment illustrated in  FIG. 1 , a grasping device  18  may be employed to grasp and releasably hold LAA  20  to facilitate positioning and engagement of implant  24  at LAA  20 . Grasping device  18  may typically comprise a conventional grasping tool, such as a suction tube which establishes negative pressure at a distal end  19  thereof, the negative pressure being suitable to releasably retain tissue, such as LAA  20  at distal end  19 . Alternative grasping tools include thoracoscopic forceps and the like. 
     An enlarged view of implant  24  is illustrated in  FIG. 2 , wherein implant  24  includes a clamp  32  and an inflatable cuff  34  attached to clamp  32 . In some embodiments, clamp  32  is selectively adjustable between an open, unclamped condition  36  (as illustrated in  FIG. 2 ), and a closed, clamped position  38 . Applicant contemplates a variety of mechanisms for selectively adjusting clamp  22  between the open and closed conditions  36 ,  38 . For example, implant  24  may utilize a control arm  40 , which incorporates the dual purpose of physically manipulating the spatial position of clamp  32 , as well as selectively adjusting clamp  32  between open and closed conditions  36 ,  38 . An example mechanism for effectuating such selective adjustment is illustrated in  FIGS. 2A and 2B . In the illustrated embodiment, control arm  40  includes actuators  42 ,  44 , which are detachably secured to clamp  32  at securement points  46 . First and second actuators  42 ,  44  may be proximally controlled to move relative to one another generally along directions  48 ,  50  so as to adjust clamp  32  between open and closed conditions  36 ,  38 . First and second actuators  42 ,  44  are also capable of rotating clamp  32  about an axis  52 , and for turning clamp  32  into alignment with LAA  20 . Such alignment enables first and second prongs  60 ,  62  to be placed at least partially about LAA  20 . 
     In addition to, or in place of, the detachable securement of first and second actuators  42 ,  44  at securemented points  46 , control arm  40  may include a detachable link  54  which may be severed, opened, or otherwise released so as to disengage clamp  32  from control arm  40 . Applicant contemplates a variety of mechanisms for detachably securing clamp  32  to control arm  40 , with some of such mechanisms being conventionally understood by those of ordinary skill in the art. 
     As indicated above, implant  24  may be positioned at LAA  20  through thoracoscopic or fluoroscopic guidance.  FIG. 3  illustrates an engagement of implant  24  with LAA  20 . Implant  24  may be manipulated by, for example, first and second actuators  42 ,  44 , so that first and second prongs  60 ,  62  of clamp  32  are positioned at substantially opposed sides  68 ,  70  of LAA  20 , and about at least a portion of LAA  20 . 
     As illustrated in the schematic views of  FIGS. 3A and 3B , LAA  20  includes a lumen  21  defined by inner surface  28 . Implant  24  is engaged with LAA  20  initially while in an open condition  36 , with first and second prongs  60 ,  62  of clamp  32  being positioned at substantially opposed sides  68 ,  70  of LAA  20 . When clamp  32  is manipulated as described above from open condition  36  to closed condition  38 , as illustrated in  FIG. 3B , lumen  21  of LAA  20  may be substantially closed through the pressing together of opposed sides  68 ,  70  of LAA  20  to an extent that inner surface  28  is in contact with itself. The placement of clamp  32  in closed condition  38  may occlude LAA  20  by completely closing lumen  21 . However, as described in greater detail hereinbelow, clamp  32  primarily serves as an anchoring element for inflatable cuff  34 , such that inflatable cuff  34  is positioned and oriented to physiologically occlude LAA  20  at base  26 . 
     In one aspect of the present invention, clamp  32  may be selectively adjusted between open and closed positions  36 ,  38  to not only anchor implant  24  at LAA  20 , but to also facilitate the repositioning of implant  24  at LAA  20 . For example, imaging techniques such as fluoroscopy and echocardiography may be utilized to assess whether inflatable cuff  34  is properly positioned to physiologically occlude LAA  20  at base  26 . In the event that it is determined that the initial placement of implant  24  is incorrect for a preferred occlusion of LAA  20 , an adjustment mechanism, such as first and second actuators  42 ,  44  of control arm  40  may reopen clamp  32  from closed condition  38  to open condition  36 , and thereafter reposition clamp  32  at LAA  20 . Once the position of clamp  32  (and implant  24 ) has been adjusted, clamp  32  may again be modified from open condition  36  to closed condition  38  to securely anchor implant  24  at LAA  20 . Such adjustability of clamp  32 , and correspondingly implant  24 , is facilitated through the detachable connection of control arm  40  to clamp  32 . The detachable connection, as described above, enables proximal control to repeatedly adjust clamp  32  between open and closed conditions  36 ,  38 , including from open condition  36  to closed condition  38 , and from closed condition  38  to open condition  36 . Such adjustment of clamp  32  may be repeated several times if necessary to appropriately position and orient implant  24  at LAA  20 . 
     Clamp  32  may be fabricated from a variety of biocompatible materials, such as stainless steel, titanium, and other metallic, alloy, and non-metallic materials. In some embodiments, clamp  32  may be formed of a resilient material, thereby continuing to apply direct pressure to LAA  20  enclosed within clamp  32  in closed condition  28 . Because clamp  32  primarily serves as an anchoring device, clamp  32  need not be of specific structural capacity, and may therefore exhibit a relatively low profile for ease of delivery and placement at LAA  20 . 
     As illustrated in  FIGS. 4A and 4B , clamp  32  includes first and second prongs  60 ,  62  emanating from central portion  61 . First and second prongs  60 ,  62  may be the same or different curvatures forming various shapes, including an opening with tapered ends, oval, ovoid, crescent, etc. Prong length “L” may be equal or different as between first and second prongs  60 ,  62 , and may be provided in various sizes as physiologically appropriate. For example, prong length “L” may be between about 1-5 cm, though other sizes are contemplated as being useful in the present invention. Moreover, prong thickness “T” may be even or uneven along first and second prongs  60 ,  62 , and may be between, for example, about 0.1-5 mm. 
     Clamp  32  may also include tissue engaging projections and fasteners, such as spikes, staples, rivets, sutures, and clips extending from one or both of first and second prongs  60 ,  62 . The tissue fasteners may be formed of a resilient, elastic, superelastic, metallic, alloy, or non-metallic material. The tissue fasteners may be integrally formed with clamp  32 , mounted within clamp  32 , or mounted within a device that may be attached to clamp  32 . 
     The repositionability of clamp  32  is advantageous for precisely positioning inflatable cuff  34  at LAA  20 , such that inflation of cuff  34  physiologically occludes LAA  20  at base  26 . For the purposes hereof, the term “physiologically occludes” is intended to mean the substantially complete closure or occlusion of lumen  21  of LAA  20  to an extent appropriate to prevent the formation of clot and the release of emboli from the appendage. Therefore, “physiological occlusion” may include any closure of LAA  20  which is effective in the prevention of clot formation and the release of emboli therefrom, and need not comprise the closure of the entirety of lumen  21  of LAA  20 . In some embodiments, “physiologically occludes” may refer to a closure of lumen  21  at or near base  26  with such closure constituting intimate contact of inner surface  28  at or near base  26  to an extent appropriate to prevent blood flow into and out from LAA  20 . 
     Inflatable cuff  34  includes one or more portions  70 A,  70 B that may be selectively inflated with a fluid, such as saline, to inwardly press upon LAA  20  to an extent appropriate to physiologically occlude LAA  20 . To selectively inflate inflatable cuff  34 , implant  24  includes a fluid supply tube  78  that is detachably secured to inflatable cuff  34 . Fluid supply tube  78  may be configured for selectively conveying pressurized fluid such as saline to inflatable cuff  34  through a one way valve  80  which permits fluid flow into, but not out from, inflatable cuff  34 . Fluid supply tube  78  is preferably deliverable along with implant  24  through a lumen  16  of delivery device  12 . 
     In some embodiments, inflatable cuff  34  defines one or more balloon structures defining respective portions  70 A,  70 B, with the balloon structures employing a resiliently elastic skin which may be resiliently expanded upon inflating fluid flow from fluid supply tube  78  into respective chambers thereof. As illustrated in  FIG. 5A , inflatable cuff  34  may include relatively rigid outer walls  35  with relatively elastic and non-rigid inner walls  37 . In such a manner, inflation of inflatable cuff  34  causes expansion of inflatable cuff  34  inwardly along direction arrows  39 . Such inward expansion of inflatable cuff  34  effectuates the occlusion of LAA  20 . 
     Inflatable cuff  34  may be fabricated from a variety of materials to provide the functionality described above. In particular, inflatable cuff  34  may include a skin layer  82  which is manufactured from one or more materials to provide zoned characteristics. As described above, a first material for skin layer  82  may be substantially rigid at outer surface  35 , while a different material may be provided at an inner surface  37 . In other embodiments, reinforcement materials or devices may be employed to promote inward expansion of cuff  34  upon inflation thereof. Such reinforcement materials or devices may be disposed at or adjacent to outer surface  35  of inflatable cuff  34  to limit outwardly-directed expansion. 
     Inflatable cuff  34  may be secured to clamp  32  at one or more points along clamp  32 . In some embodiments, inflatable cuff  34  is secured to the entire length of clamp  32 . In other embodiments, however, inflatable cuff  34  may extend only partially along clamp  32 , and may include discontinuous portions along clamp  32 . A variety of securement mechanisms are contemplated by the present invention to secure inflatable cuff  34  to clamp  32 . Example mechanisms include adhesives, fasteners, and other mechanisms, including conventional mechanisms for securing inflatable cuff  34  to clamp  32 . 
     Inflatable cuff  34  may include one or more distinct chambers that are sequentially or simultaneously filled with inflation fluid supplied through fluid supply tube  78 . In one embodiment, for example, inflatable cuff  34  may include a plurality of chambers which are filled through an “overflow” concept in which a secondary chamber is filled only after a primary chamber is completely filled with fluid. In some embodiments, each portion  70 A,  70 B of inflatable cuff  34  may be filled with between about 1-10 cc of fluid. 
     An occlusion sequence utilizing implant  24  is illustrated in  FIGS. 5B-5E , in which implant  24  is placed about LAA  20  in an open condition  36 . Positioning of implant  24  at LAA  20  may be verified through echocardiography and fluoroscopy.  FIG. 5B  illustrates an improper positioning of implant  24 , in that inflatable cuff  34  does not extend to base  26  of LAA  20 , where occlusion is desired. In one embodiment, clamp  32  may be adjusted to a closed condition  38  at the position illustrated in  FIG. 5B , followed by position verification through echocardiography and/or fluoroscopy. When it is determined that the position and/or orientation of implant  24  is incorrect, clamp  32  may be re-adjusted to an open condition  36  for re-positioning of implant  24 , as described above. 
     Implant  24  may be re-positioned, as illustrated in  FIG. 5C . Here, inflatable cuff  34  extends substantially to base  26  of LAA  20 . Confirmation of such appropriate position and orientation may be performed, for example, subsequent to adjustment of clamp  32  to a closed condition  38 , such as is illustrated in  FIG. 5D . 
     Once the appropriate position of implant  24  has been confirmed, fluid is directed through fluid supply tube  78 , and through one-way valve  80  into inflatable cuff  34  to thereby expand inflatable cuff  34  to an extent appropriate to physiologically occlude LAA  20  at base  26 .  FIG. 5E  illustrates such occlusion subsequent to inflation of inflatable cuff  34 . Sufficient occlusion of LAA  20  may be confirmed through echocardiography and/or fluoroscopy. If, for example, further closure of LAA  20  is required to accomplish physiological occlusion, additional fluid may be added to inflatable cuff  34  through fluid supply tube  78 . 
     Once appropriate occlusion has been confirmed, control arm  40  may be detached from clamp  32  as described above. Moreover, fluid supply tube  78  may be separated from inflatable cuff  34 , preferably upstream from one-way valve  80  so as to maintain fluid pressure within inflatable cuff  34 . An illustration of implant  24  at LAA  20  subsequent to separation from control arm  40  and fluid supply tube  78  is shown in  FIG. 5F . A variety of mechanisms are contemplated for separating fluid supply tube  78  from inflatable cuff  34 . In one embodiment, a thoracoscopic scissor may be guided through delivery device  12  to cut fluid supply tube  78  at a location proximal to one-way valve  80 . Subsequent to the separation, the thoracoscopic scissor, fluid supply tube  78 , and control arm  40  may be withdrawn through respective lumens  14 ,  16  of delivery device  12 , and the delivery device  12  may thereafter be withdrawn from the patient. Consequently, implant  24  may be left at LAA  20  indefinitely to ensure physiological occlusion thereof. 
     In one embodiment, inflatable cuff  34  is detachably secured to clamp  32 , such that subsequent to confirmation of physiological occlusion of LAA  20  by inflatable cuff  34 , clamp  32  may be detached from inflatable cuff  34 , and withdrawn from the procedure site through delivery device  12 . In such an embodiment, only inflatable cuff  34  is left at LAA  20  following the occlusion procedure. Therefore, it is to be understood that clamp  32  primarily acts as an anchoring mechanism, while inflatable cuff  34  performs the occlusion of LAA  20 . Inflatable cuff  34  may assume a variety of configurations, and in one embodiment may have a height “H” of about 0.2-2 cm. Other sizes, however, of inflatable cuff  34  may be employed in implant  24  of the present invention. 
     For the purposes hereof, the term “cuff” is not intended to be exclusive of the various inflatable or otherwise expandable bodies useful in the present application. To that end, other terms may be interchangeably utilized to describe inflatable cuff  34 . Example alternative terms include bladder, balloon, diaphragm, vessel, skirt, tube, and the like. Moreover, inflatable cuff  34  may be selectively and adjustably expandable through means other than inflation, including various mechanical expansion means to constrict the LAA  20  to an occlusive extent. 
     The invention has been described herein in considerable detail in order to comply with the patent statutes, and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the invention as required. However, it is to be understood that the invention can be carried out by different methods/devices, and that various modifications can be accomplished without departing from the scope of the invention itself.

Technology Classification (CPC): 0