US20070066994A1 - Closure devices, related delivery methods, and related methods of use - Google Patents

Abstract

A device for sealing a patent foramen ovale (PFO) in the heart is provided. The device includes a left atrial anchor adapted to be placed in a left atrium of the heart, a right atrial anchor adapted to be placed in a right atrium of the heart, and an elongate member adapted to extend through the passageway and connect the left and right atrial anchors. The right atrial anchor preferably includes a plurality of arms and a cover attached to the arms. The left atrial anchor preferably also includes a plurality of arms and preferably does not include a cover. Preferably, the elongate member has a first end fixedly connected to the left atrial anchor and a portion, proximal to the first end, passing through the right atrial anchor. Preferably, the elongate member is flexible.

Description

FIELD OF THE INVENTION
• This invention relates to devices for closing a passageway in a body, for example a patent foramen ovale in a heart, related methods and devices for delivering such closure devices, and related methods of using such closure devices for sealing the passageway.
BACKGROUND OF THE INVENTION
• FIG. 1 shows a portion of a heart in longitudinal section, with the right |atrium (RA), left atrium (LA), right ventricle (RV) and left ventricle (LV) shown.FIG. 1 also shows the septum primum (SP), a flap-like structure, which normally covers the foramen ovale, an opening in the septum secundum (SS) of the heart. In utero, the foramen ovale serves as a physiologic conduit for right-to-left shunting of blood in the fetal heart. After birth, with the establishment of pulmonary circulation, the increased left atrial blood flow and pressure presses the septum primum (SP) against the walls of the septum secundum (SS), covering the foramen ovale and resulting in functional closure of the foramen ovale. This closure is usually followed by anatomical closure of the foramen ovale due to fusion of the septum primum (SP) to the septum secundum (SS).
• Where anatomical closure of the foramen ovale does not occur, a patent foramen ovale (PFO) is created. A patent foramen ovale is a persistent, usually flap-like opening between the atrial septum primum (SP) and septum secundum (SS) of a heart. A patent foramen ovale results when either partial or no fusion of the septum primum (SP) to the septum secundum (SS) occurs. In the case of partial fusion, a persistent passageway exists between the superior portion of the septum primum (SP) and septum secundum (SS). It is also possible that more than one passageway may exist between the septum primum (SP) and the septum secundum (SS).
• Studies have shown that a relatively large percentage of adults have a patent foramen ovale (PFO). It is believed that embolism via a PFO may be a cause of a significant number of ischemic strokes, particularly in relatively young patients. It has been estimated that in 50% of cryptogenic strokes, a PFO is present. Patients suffering a cryptogenic stroke or a transient ischemic attack (TIA) in the presence of a PFO often are considered for medical therapy to reduce the risk of a recurrent embolic event.
• Pharmacological therapy often includes oral anticoagulants or antiplatelet agents. These therapies may lead to certain side effects, including hemorrhaging. If pharmacologic therapy is unsuitable, open heart surgery may be employed to close a PFO with stitches, for example. Like other open surgical treatments, this surgery is highly invasive, risky, requires general anesthesia, and may result in lengthy recuperation.
• Nonsurgical closure of PFOs is possible with umbrella-like devices developed for percutaneous closure of atrial septal defects (ASD) (a condition where there is not a septum primum (SP)). Many of these conventional devices used for ASDs, however, are technically complex, bulky, and difficult to deploy in a precise location. In addition, such devices may be difficult or impossible to retrieve and/or reposition should initial positioning not be satisfactory. Moreover, these devices are specially designed for ASDs and therefore may not be suitable to close and seal a PFO, particularly because the septum primum (SP) overlaps the septum secundum (SS).
SUMMARY OF THE INVENTION
• In accordance with the invention, methods, tools, and devices for closing a passageway in a body, and more specifically closing a patent foramen ovale (PFO), are provided.
• According to one aspect of the invention, a device for sealing a passageway in a human body is provided. The device comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each first loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, and an elongate member adapted to extend through the passageway and connect the first and second anchors, the elongate member having a first end fixedly connected to one of the first and second anchors.
• According to another aspect of the invention, a device for sealing a passageway in a human body comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each first loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, and a flexible elongate member adapted to extend through the passageway and connect the first and second anchors, the elongate member capable of moving through the second anchor to vary a length of the elongate member between the first and second anchors.
• According to a further aspect of the invention, the device for sealing a passageway in a human body comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each first loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, the second anchor including a plurality of second loop structures, and a flexible elongate member adapted to extend through the passageway and connect the first and second anchors, the elongate member capable of moving through the second anchor to vary a length of the elongate member between the first and second anchors.
• According to yet another aspect of the invention, a device for sealing a passageway in a human body comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each first loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, and a flexible elongate member adapted to extend through the passageway and connect the first and second anchors, wherein the first anchor pivots relative to the elongate member and the second anchor pivots relative to the elongate member.
• According to another aspect of the present invention, a device for sealing a passageway in a human body comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each first loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, and a flexible elongate member adapted to extend through the passageway and connect the first and second anchors, wherein each of the first and second anchors is collapsible from a deployed state to a collapsed delivery state.
• According to a further aspect of the present invention, a device for sealing a passageway in a human body comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each loop structure including an outer loop portion and a member connecting portions of outer loop portion, a second anchor adapted to be placed proximate a second end of the passageway, and an elongate member adapted to extend through the passageway and connect the first and second anchors, the elongate member having a first end fixedly connected to the first anchor.
• According to yet another aspect of the invention, an assembly for sealing a passageway in a heart is provided. The assembly comprises a guide catheter capable of extending to the passageway, and a closure device capable of sealing the passageway, the closure device including a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each first loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, and a flexible elongate member adapted to extend through the passageway and connect the first and second anchors, wherein the closure device is positionable within the guide catheter in a first collapsed state and extendable from the guide catheter in a second deployed state.
• According to another aspect of the invention, a method of sealing a passageway in a human body is provided. The method comprises placing a first anchor proximate a first end of the passageway, the first anchor including a plurality of first loop structures, placing a second anchor proximate a second end of the passageway, and moving the second anchor relative to the first anchor along a flexible elongate member disposed between the first and second anchors within the passageway.
• According to a further aspect of the invention, a method of placing a closure device to seal a passageway in a human body is provided. The method comprises advancing a catheter into a first end of the passageway and out a second end of the passageway, advancing a first anchor of a closure device out of a distal end of the catheter, withdrawing the catheter through the passageway, positioning the first anchor adjacent the second end of the passageway, advancing a second anchor of the closure device out of the distal end of the catheter, positioning the second anchor of the closure device adjacent the first end of the passageway, and advancing a lock to a position adjacent the second anchor.
• According to yet another aspect of the invention, a closure device for sealing a passageway in a heart is provided. The closure device comprises a left atrial anchor configured to close a first end of the passageway, a right atrial anchor configured to close a second end of the passageway, at least one of the left atrial anchor and the right atrial anchor including a plurality of loop structures, a flexible elongate member connecting the left and right atrial anchors, wherein the elongate member has a first end fixedly connected to the left atrial anchor and wherein the right atrial anchor is movable with respect to the elongate member, and a lock configured to prevent proximal movement of the right atrial anchor relative to the flexible elongate member.
• According to another aspect of the invention, a system for sealing a passage in a heart is provided. The system comprises a delivery catheter capable of extending to a position near the passage, a closure device capable of sealing the passage, the device including a first anchor adapted to be placed proximate a first end of the passage, a second anchor adapted to be placed proximate a second end of the passage, and a flexible elongate member adapted to extend through the passage and connect the first and second anchors, and a cutting tool capable of extending over the flexible elongate member to a position near the second anchor.
• According to yet another aspect of the invention, a device for sealing a passageway in a human body is provided. The device comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor including a plurality of first loop structures, each loop structure having a first end connected to the first anchor and a second free end, a second anchor adapted to be placed proximate a second end of the passageway, the second anchor including an element configured to engage a snare, and a flexible elongate member connecting the first and second anchors.
• According to another aspect of the invention, a device for closing a passageway in a heart comprises a left atrial anchor adapted to be placed in a left atrium of the heart and including a plurality of uncovered arms, a right atrial anchor adapted to be placed in a right atrium of the heart and including a plurality of arms, a cover attached to the plurality of arms, and an element configured to engage a snare, and a flexible elongate member adapted to extend through the passageway and connect the left and right atrial anchors, the elongate member having a first end fixedly connected to the left atrial anchor and a second end releasably connected to the right atrial anchor.
• According to yet another aspect of the invention, a device for closing a passageway in a heart comprises a left atrial anchor adapted to be placed in a left atrium of the heart and including a plurality of uncovered arms, a right atrial anchor adapted to be placed in a right atrium of the heart and including a plurality of arms and a cover attached to the plurality of arms, a flexible elongate member adapted to extend through the passageway and connect the left and right atrial anchors, the elongate member having a first end fixedly connected to the left atrial anchor, and a lock for preventing proximal movement of the right atrial anchor relative to the flexible elongate member.
• According to another aspect of the invention, a device for closing a passageway in a heart comprises a left atrial anchor adapted to be placed in a left atrium of the heart and including a plurality of uncovered arms and at least one, member connecting each arm to the left atrial anchor, a right atrial anchor adapted to be placed in a right atrium of the heart and including a plurality of arms and a cover attached to the plurality of arms, and a flexible elongate member adapted to extend through the passageway and connect the left and right atrial anchors, the elongate member having a first end fixedly connected to the left atrial anchor and a second end releasably connected to the right atrial anchor.
• According to a further aspect of the invention, a method for retrieving a device for sealing a passageway in a heart is provided. The method comprises advancing a snare catheter through a guide catheter toward the passageway covered by a second anchor of the device, engaging a portion of the second anchor with the snare, and drawing the second anchor into the guide catheter with the snare.
• According to yet another aspect of the invention, a cutting tool for severing a flexible elongate member is provided. The cutting tool comprises a cutting tool body having a distal end and a proximal end, the cutting tool body capable of extending through a guide catheter, a guide member for guiding the flexible elongate member, the guide member including a distal opening through which the flexible elongate member enters the cutting tool and a lateral opening through which the flexible elongate member exits the cutting tool, and a cutting element surrounding the guide member, wherein the cutting element is movable relative to the guide member to cut the flexible elongate member as it exits the guide member through the lateral opening of the guide member.
• Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
• The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
• The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
• FIG. 1 is a longitudinal section of a portion of a heart having a PFO;
• FIG. 2 is a closure device positioned in a heart to close a PFO, according to an embodiment of the present invention;
• FIG. 3 is a guide catheter inserted through a PFO and into the left atrium, according to an embodiment of the present invention;
• FIG. 4 is a left atrial anchor of the closure device ofFIG. 2 being advanced out of the guide catheter, according to an embodiment of the present invention;
• FIG. 5 is the left atrial anchor of the closure device ofFIG. 4 advanced out of the guide catheter, according to an embodiment of the present invention;
• FIG. 6 is the left atrial anchor ofFIG. 5 being pulled towards the PFO, according to an embodiment of the present invention;
• FIG. 7 is the guide catheter pulled proximally into the right atrium and the left atrial anchor seated against a septal wall, according to an embodiment of the present invention;
• FIG. 8 is a right atrial anchor of the closure device ofFIG. 2 being extended from the guide catheter, according to an embodiment of the present invention;
• FIG. 9 is the right atrial anchor deployed from the guide catheter, according to an embodiment of the present invention;
• FIG. 10 is the right atrial anchor advanced to contact the septal wall, according to an embodiment of the present invention
• FIG. 11 is the right atrial anchor fixed to a tether of the closure device ofFIG. 2, according to an embodiment of the present invention;
• FIG. 12 is an isometric view of a closure device extending from a delivery catheter, according to one aspect of the invention;
• FIG. 13 is an isometric view of the closure device ofFIG. 12, with a delivery catheter, and a guide catheter, according to an embodiment of the present invention;
• FIG. 14 is a cross sectional side view of a closure device and a delivery catheter positioned in a loading tube prior to introduction into a guide catheter, according to an embodiment of the present invention;
• FIG. 15 is a cross-sectional side view of the closure device ofFIG. 12 with a lock, according to an embodiment of the present invention;
• FIG. 16 is an isometric view of the lock used with the closure device inFIG. 14, according to an embodiment of the present invention;
• FIG. 17 is a side view of an outer tube of the delivery catheter, according to an embodiment of the present invention;
• FIG. 18 is a side view of an inner tube of the delivery catheter, according to an embodiment of the present invention;
• FIG. 19 is an isometric view of another embodiment of a closure device, according to the present invention;
• FIG. 20 is an isometric view of another alternative embodiment of a closure device, according to the present invention;
• FIG. 21 is a side view of the closure device ofFIG. 20; and
• FIG. 22 is a cross-sectional side view of a portion of a cutting tool, according to one aspect of the present invention.
DESCRIPTION OF THE EMBODIMENTS
• Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
• The various Figures show embodiments of patent foramen ovale (PFO) closure devices, devices and methods for delivery of the PFO closure devices, and methods of using the device to close a PFO. The devices and related methods are described herein in connection with use in sealing a PFO. These devices, however, also are suitable for closing other openings or passageways, including other such openings in the heart, for example atrial septal defects, ventricular septal defects, and patent ductus arterioses, and openings or passageways in other portions of a body such as an arteriovenous fistula. The invention therefore is not limited to use of the inventive closure devices to close PFOs.
• FIGS. 2, 12, and15 show aPFO closure device10 according to an embodiment of the present invention. InFIG. 2,device10 is shown positioned on either side of a PFO track (referenced as PFO in the Figures) with a portion of thedevice10 passing through the PFO track, after deliver from a delivery system. The PFO track can be seen more clearly inFIG. 3, which shows a catheter disposed in the PFO track between the septum primum (SP) and septum secundum (SS). As shown inFIG. 2,closure device10 includes a leftatrial anchor12 positioned in the LA, a rightatrial anchor14 positioned in the RA, and atether16 connecting the anchor structures.
• As embodied herein and shown inFIGS. 2, 12, and15, aPFO closure device10 includes a leftatrial anchor12, a rightatrial anchor14, atether16, and alock20.FIG. 12 shows leftatrial anchor12 and rightatrial anchor14 schematically in a deployed condition. As show inFIGS. 12 and 15, leftatrial anchor12 is permanently secured to thedistal end16aof thetether16 via ahub18.Hub18 is preferably tubular in shape such thattether16 extends throughhub18 to rightatrial anchor14. Rightatrial anchor14 is slidably disposed about thetether16 via a secondtubular hub19.Lock20 is advanceable along thetether16, in a distal direction only, to secure the rightatrial anchor14 in position against the atrial tissue defining the PFO track.Tether16 will be severed adjacent to lock20; and leftatrial anchor12, rightatrial anchor14 connected to leftatrial anchor12 viatether16, and lock20 will remain in the heart to seal the PFO.
• As shown inFIG. 13, thetether16 extends through the rightatrial anchor14, through a delivery catheter32 (that passes through a lumen of a guide catheter30), and emerges from the proximal end of thedelivery catheter32. Anadjustable tether clip34 provides for temporary securement of thetether16 relative to thedelivery catheter32. Thetether clip34 may be, for example, a spring-loaded clamp similar to those used to secure laces and drawstrings on backpacks or camping and other equipment.
• Thetether16 is preferably a high strength flexible polymeric material, such as a braid of polyester yarn. Preferably, such a braided yarn is approximately 0.010 to 0.025 inch in diameter, and most preferably is about 0.0175 inch. Suitable materials include, but are not limited to, multifilament yarns of ultra-high molecular weight polyethylene (UHMWPE) such as SPECTRA™ or DYNEEMA™. Other suitable materials include liquid crystal polymer (LCP) such as VECTRANT™, polyester, or other high strength fibers. Alternatively, thetether16 could be formed of a high strength polymeric monofilament. The distal end of thetether16 may be frayed and encapsulated with an adhesive to form a ball shape, which mechanically engages thehub18, permanently connecting the distal end of thetether16 to the leftatrial anchor12. Alternatively, the distal end of thetether16 could be knotted and trimmed to yield a ball shape for engagement withhub18 of leftatrial anchor12.FIGS. 12 and 15 illustrate an embodiment of leftatrial anchor12 and its connection totether16.
• As embodied herein and shown inFIGS. 12 and 15, leftatrial anchor12 includes one ormore arms40, which extend radially outward fromhub18. As shown, a leftatrial anchor12 preferably includes fourarms40, although fewer or more arms may be provided.Arms40 preferably form a unitary arm structure, such that the arms are connected to each other aroundhub18. Eacharm40 is preferably ovoid in shape to prevent tissue trauma. The primary structural element of thearm40 is aloop42, which extends from near the center of the unitary arm structure andhub18, towards the periphery of the leftatrial anchor12, and loops back towards thehub18. The outer portion of theloop42 defines an atraumatic curve. As shown inFIGS. 12 and 15, eacharm40 includes a first end connected to thehub18 and/orother arms40 and a second free end formed by the outer portion of theloop42. At least the portion of eacharm40 that is unconnected to theother arms40 of the unitary arm structure is freely movable, i.e., it is movable independently from theother arms40.
• The unitary arm structure, including thearms40, is preferably formed from a rolled sheet of binary nickel titanium alloy (also known as nitinol). The alloy is known in the art to have superior elastic properties. The geometry of the unitary arm structure may be formed either by laser cutting or chemical etching. A smooth and passive surface is created by electropolishing. Thermal processing is used to impart a parent shape, as is known in the art. A preferred parent shape is shown inFIG. 15. This curved shape (shown in side view) for the leftatrial anchor12 presents a concave surface to the left atrial wall.
• Thearms40, as shown inFIG. 12, may incorporate anoptional web44. Theweb44 includes one or more radial struts46, intersected by cross struts47. Theweb44 is preferably thinner in dimension than theloop42. As such, theweb44 adds relatively little to the stiffness of the arm, but adds redundancy to the arm in the event of a fracture in theloop42. Since theweb44 is thinner, any oscillating motion (primarily perpendicular to the surface of the arm) imparted to thearms40 due to the beating of the heart will cause an oscillatory strain on theloop42. Such a strain will be greatest near thehub18. However, the strain imparted to theweb44 will be significantly less than that imparted to theloop42, due to the thinness of theweb44. Thus, in the event of a fracture in theloop42, theweb44 will maintain a connection between thearm40 and the remainder of the unitary arm structure forming the leftatrial anchor12.
• The diameter (span) of the leftatrial anchor12 is primarily determined by the size of the unitary arm structure. In a PFO closure application, the span of the unitary arm structure is preferably from about 10 mm to about 40 mm, and is most preferably from about 15 mm to about 25 mm. The preferred span width of theentire loop42 at its widest point is preferably from about 0.050 inch to about 0.150 inch, and is most preferably about 0.100 inch. The rolled sheet that forms theloop42 is preferably between about 0.003 inch and about 0.006 inch uniform thickness, and is most preferably about 0.045 inch, with a width of theloop42 between about 0.002 inch and about 0.015 inch. Theloop42 is preferably wider near thehub18, and narrower further away. Thestruts46,47 of theweb44 are thinner than the material forming theloop42, preferably between about 0.001 inch and about 0.004 inch in width and thickness. The only structure within the left atrium is the relatively small struts of thearms40, which are preferably well apposed to the wall tissue by virtue of their imparted parent shape. These small struts will readily be incorporated into the tissue of the left atrium, resulting in an endothelialized non-thrombogenic surface.
• At the center of the unitary arm structure forming the leftatrial anchor12 is a hole, through which thehub18 is secured. Thehub18 is preferably a tube formed of radiopaque material such as platinum alloy, and is swaged in place, forming a mechanical interlock with the unitary arm structure that forms leftatrial anchor12. Thehub18 serves to engage thedistal bulb16aof thetether16, as previously described.
• To facilitate visualization during and following implantation of thePFO closure device10,markers48 are provided on thearms40. Holes near the free ends of thearms40 are formed into the geometry of the unitary arm structure.Markers48 may include, for example, rivets formed from a radiopaque material such as platinum alloy. Themarkers48 are positioned into the holes and swaged in place.
• FIGS. 12 and 15 also illustrate an embodiment of rightatrial anchor14. As embodied herein and shown inFIGS. 12 and 15, rightatrial anchor14 includesarms50, which extend radially outward fromhub19. The structure of eacharm50 is essentially identical to that described for leftatrial anchor12. As shown in FIGS.12 and15, eacharm50 includes a first end connected to thehub19 and/orother arms50 and a second free end formed by the outer portion of theloop52. At least the portion of eacharm50 that is unconnected to theother arms50 of the unitary arm structure is freely movable, i.e., it is movable independently from theother arms50. Eacharm50 is formed by aloop52 and may include aweb54 having at least oneradial strut56 and several cross struts57. The free end of eacharm50 may include a hole containing amarker58.
• With regard to the shape of eacharm50, thermal processing is used to impart a parent shape, as is known in the art. A preferred parent shape is shown inFIG. 15. This curved shape (shown in side view) for the rightatrial anchor14 presents a concave shape to the right atrial wall. This parent shape helps insure that the entire right atrial anchor will be apposed to atrial tissue once implanted. This apposition serves to minimize the chance for excessive thrombus formation and subsequent embolism, and also facilitates rapid incorporation of the anchor by adjacent atrial tissue.
• Thearms50 form a unitary arm structure that is centered about ahub19.Hub19 is tubular, and is preferably formed of a radiopaque material such as platinum alloy. The inner diameter of thehub19 is slightly larger than the diameter of thetether16, to allow for the rightatrial anchor14 to slide relative to thetether16. Thehub19 is secured to the unitary arm structure that forms the rightatrial anchor14 by swaging. A shoulder at the distal end ofhub19 is inserted inside the rightatrial anchor14, and flared by swaging, thus interlocking thehub19 to the unitary arm structure, as shown inFIG. 15. Thehub19 is preferably about 0.090 inch to about 0.110 inch in length, with anenlarged ring19aat the proximal end. Thisring19afacilitates removal or repositioning of the rightatrial anchor14 by a snare, as will be described later.
• As embodied herein and shown inFIGS. 12 and 15, the rightatrial anchor14 may include acovering60. Covering60 provides assurance of complete closure of the PFO track, and facilitates tissue ingrowth into the rightatrial anchor14. The covering60 preferably includes two layers,60a,60b, one on each side of the unitary arm structure that forms rightatrial anchor14. Alternatively, covering60 may be a single layer attached on one side of the unitary arm structure. Preferably, the covering60 is formed of a knitted or woven fabric of polyester, but may be formed from any suitable polymeric material such as expanded polytetrafluoroethylene. The covering60 is secured to the unitary arm structure by suitable means, such as ultrasonically securing the two layers offabric60a,60b, at their peripheries, and/or at locations between thearms50 or within theloops52. The covering60 may be generally circular, as shown inFIG. 12, or any other suitable shape. The ends ofarms50 may also include small loops to receive sutures, for example, for suturing to the covering60 of the unitary arm structure.
• Positioned proximally to rightatrial anchor14 ontether16 is alock20. As embodied herein and shown inFIG. 16, thelock20 is disposed about thetether16. Thelock20 is tubular in shape and may be fabricated from a metallic material, such as a tube of nickel-titanium alloy. The inner diameter of thelock20 is somewhat larger that the diameter of thetether16, preferably about 0.010 inch to about 0.015 inch larger, and most preferably about 0.0125 inch larger. Thelock20 may have a wall thickness of between about 0.002 inch and about 0.005 inch, and most preferably about 0.003 inch.Lock20 includes one ormore tabs22 formed in the tube. Preferably, lock20 includes sixtabs22, three towards the distal end of thelock20, and three towards the proximal end of thelock20. The tabs towards the distal end are preferably circumferentially offset from the tabs towards the proximal end, better ensuring engagement oflock20 with thetether16. Thetabs22 may be formed by laser cutting. Eachtab22 includes abase24, which connects to the main body of thelock20, and apoint26, which serves to mechanically engage thetether16. Thetabs22 are thermally shape set (as is known in the art) to have a parent shape with thetabs22 deflected inward, such that thepoints26 are forced to engage thetether16. Thepoints26 engage thetether16, by extending into thetether16, when thelock20 is moved relative to thetether16 in one direction only. This allows thelock20 to be advanced distally along thetether16, while preventing proximal movement of thelock20 alongtether16.
• FIG. 19 shows an alternative embodiment of aclosure device110. In at least some respects, theclosure device110 is similar todevice10 described with respect toFIGS. 12 and 15. Similar elements will be labeled with similar reference numerals in the Figure, and the differences between the embodiments will be explained. As embodied herein and shown inFIG. 19, the arms ofclosure device110 may not include a web structure.Closure device110 includes a leftatrial anchor112, a rightatrial anchor114, and atether116. Eachanchor112,114, includesarms140,150, respectively. As shown inFIG. 19, eacharm140,150, may be formed by aloop142,152, as previously described with respect todevice10.Arms140,150 may also includemarkers148,158, respectively, as previously described.
• Additionally, thecover160 for the rightatrial anchor114, as shown inFIG. 19, may be lobular in shape, instead of circular. Cover160 also preferably includes two layers to effectively sandwich thearms150. The two layers are preferably secured together at theirperipheries161 as shown, as well as atdiscrete locations162 within theloops152. The layers160a,160b, are secured by suitable means, such as by ultrasonic welding. Thecover160 could also be incorporated in any of the other embodiments of closure devices described in this application.
• FIGS. 20 and 21 show another alternative embodiment of a leftatrial anchor212 for aclosure device210. In at least some respects, leftatrial anchor212 is similar to leftatrial anchor112 described with respect toFIG. 19. Similar elements will be labeled with similar reference numerals in the Figures, and the differences between the embodiments will be explained. As embodied herein and shown inFIGS. 20 and 21, leftatrial anchor212 includes fourarms240. As previously discussed with respect toFIG. 19,arms240 do not include a web structure, and are formed byloops242. Eacharm240 may include a marker (not shown). Each leftatrial arm240 may further include a structure to prevent embolism of thatarm240, in the event of arm fracture. This structure performs a function similar to that theweb44, shown inFIG. 12, performs.
• As shown inFIGS. 20 and 21, one ormore safety lines264 extend parallel to thearms240 of the leftatrial anchor212. Twosafety lines264a,264bare shown inFIG. 20. Afirst safety line264asecures twoarms240aof theanchor212, and asecond safety line264bsecures the remainingarms240b. Eachsafety line264a,264bis preferably formed of a flexible but strong polymeric material, such as a braided filament bundle of polyester or ultra-high molecular weight polyethylene. Thesafety lines264 preferably pass through the ends of thearms240 throughholes266. Although not shown, additional holes may be provided near the ends of the arms to contain markers, as described above. The preferred path for eachsafety line264 is shown inFIG. 21. The two ends265a,265bof thesafety line264 lie next to the distal end of thetether216. Thesafety line264 extends through thehub218, then along and parallel to twoarms240, through theholes266, back along and parallel to the twoarms240, and then through the body of thetether216 itself at a very distal end.
• Alternatively, eacharm240 may include aseparate safety line264. For example, the end265 of theline264 could be adjacent the end of thetether216 as described above, extend through thehub218 and parallel to thearm240 to thehole266, and terminate in a knot or encapsulated fray at a hole (not shown) in the end of thetether216, as previously described in connection with the distal end of thetether216.
• FIG. 13 shows theclosure device10 positioned relative to an embodiment of adelivery catheter32. As embodied herein and shown inFIGS. 12, 13,17, and18, thedelivery catheter32 includes anouter tube36 and aninner tube38. Theouter tube36 may be formed from a polymer, preferably high density polyethylene. Thedistal portion36bof theouter tube36 preferably has an inner diameter of between about 0.040 inch and about 0.060 inch, and is most preferably about 0.048 inch, with a wall thickness of between about 0.005 and about 0.010 inch, and most preferably about 0.008 inch. As shown inFIG. 17, thedistal portion36bof theouter tube36 may taper along its length to the most distal end. Alternatively, thedistal portion36bof the outer tube may have a constant inner and outer diameter. The proximal portion of theouter tube36 preferably has an inner diameter of between about 0.050 inch and about 0.070 inch, and is most preferably about 0.060 inch, with a wall thickness of between about 0.005 inch and about 0.010 inch, and most preferably about 0.007 inch. The dimensions of theouter tube36 are such that it can engage and abut with thehub19 of the rightatrial anchor14 during the delivery of thedevice10. The proximal end of theouter tube36 includes arigid sleeve36a, formed of a hypotube which surrounds the polymeric tube. Therigid sleeve36aserves to prevent kinking of theouter tube36 during the delivery of the device. The length of the proximalrigid sleeve36ais preferably between about 10 cm and about 20 cm, and is most preferably about 14 cm. The length of theouter tube36, including therigid sleeve36a, is preferably between about 100 cm and about 130 cm, and is most preferably about 115 cm.
• Theinner tube38 ofdelivery catheter32 may be formed from a suitable polymer, such as PEBAX 6333™, and have a preferred inner diameter of between about 0.020 inch and about 0.040 inch, most preferably about 0.030 inch, with a wall thickness of between about 0.003 inch and about 0.010 inch, and most preferably about 0.006 inch. The preferred dimensions of theinner tube38 are such that it can engage and advance thelock20 along thetether16. Thedistal end38bof theinner tube38 preferably has a uniform inner and outer diameter. The proximal end of theinner tube38 also includes arigid sleeve38a, formed of a hypotube surrounding the polymeric tube. The length of therigid sleeve38ais preferably between about 15 cm and about 30 cm, and is most preferably about 23 cm. The length of theinner tube38, including therigid sleeve38a, is preferably between about 90 cm and about 110 cm, and is most preferably about 100 cm.
• InFIGS. 12 and 13, leftatrial anchor12 and rightatrial anchor14 are shown deployed fromdelivery catheter32. As shown inFIG. 13,delivery catheter32 may be used with aguide catheter30. Although not shown, guidecatheter30 may have a preformed curve near its distal end.Guide catheter30 can be any suitable, conventional guide catheter. A suitable, exemplary guide catheter is known as “Mullins” guide catheter, sold commercially by Cook. Connected to the proximal end ofguide catheter30 is ahemostasis valve31.
• Prior to deployment ofclosure device10,guide catheter30 would be delivered by conventional techniques to the site of the PFO. Such conventional techniques may include the temporary use of a guide wire (not shown).
• FIG. 14 illustrates theclosure device10 in a collapsed condition prior to delivery, within aloading tube70. As shown inFIG. 14,loading tube70 preferably has a flared proximal end to facilitate introduction of thedevice10 anddelivery catheter32 into theloading tube70. This is the state of theclosure device10 anddelivery catheter32 prior to introduction into the previously placedguide catheter30. As shown inFIG. 14, theouter tube36 of thedelivery catheter32 has a size that will abut thehub19 of rightatrial anchor14 astube36 moves alongtether16. The rightatrial anchor14 also may move alongtether16 to abut the leftatrial anchor12. This abutment allows the left and rightatrial anchors12,14 to move in response to movement of thedelivery catheter32 within theguide catheter30. The condition in which the structures abut one another may be created and maintained by having thetether clip34 positioned against the proximal end of thedelivery catheter32, after removing any initial slack in thetether16. As shown inFIG. 14, thearms40 of the leftatrial anchor12 are collapsed in the distal direction, while thearms50 of the rightatrial anchor14 are collapsed in a proximal direction.
• FIGS. 3-11 show sequential steps for delivery ofclosure device10, according to one aspect of the invention. At the level of the longitudinal section shown inFIG. 3, the inferior vena cava (IVC) is not shown. In an embodiment, a delivery system is passed through the IVC to gain access to the RA and PFO. Other methods, of percutaneously, minimally invasively, or more directly obtaining access to the RA and PFO are within the scope of the invention. As embodied herein and shown inFIG. 3, aguide catheter30 is advanced to and through the PFO track and into the LA. Theguide catheter30 extends across the PFO track, as shown inFIG. 3. The proximal end of theguide catheter30 includes ahemostasis valve31. Theloading tube70, thecollapsed closure device10, anddelivery catheter32 are introduced into theguide catheter30 through thehemostasis valve31. When fully inserted into thehemostasis valve31, the distal end of theloading tube70 abuts the hub (not shown) of theguide catheter30, preventing theloading tube70 from continuing to advance down the lumen of theguide catheter30. Thecollapsed closure device10 is then advanced out theloading tube70 by advancement of thedelivery catheter32 into the lumen of theguide catheter30. Advancement of thedelivery catheter32 and collapsedclosure device10 continues until theclosure device10 is near the distal end of theguide catheter30. Theloading tube70 is then withdrawn out of thehemostasis valve31 and positioned on thedelivery catheter32 towards the proximal end. Thehemostasis valve31 is then closed to stop back bleeding.
• Thedelivery catheter32 is further advanced relative to theguide catheter30, deploying only the leftatrial anchor12, as shown inFIGS. 4 and 5.FIG. 5 shows the leftatrial anchor12 fully deployed from theguide catheter30 in the left atrium.Tether16 extends fromanchor12 intoguide catheter30 and throughdelivery catheter32. As discussed above, leftatrial anchor12 and rightatrial anchor14 are preferably self-expanding structures, expanding through a mechanical or thermal shape change, for example. Also at this point, rightatrial anchor14 remains within the delivery assembly in a collapsed state.
• Thedelivery catheter32 and guidecatheter30 are withdrawn, pulling the leftatrial anchor12 against the opening of the PFO track, as shown inFIG. 6. As thetether clip34 remains in the initial position abutting the proximal end of thedelivery catheter32, the leftatrial anchor12 is pulled against the opening of the PFO track. Next, thetether clip34 is re-positioned several centimeters proximally on thetether16.
• As shown inFIG. 7, a significant portion of the PFO track (specifically the portion of the track between the superior portion of the septum primum and septum secundum) runs along and roughly parallel with the septal wall. A feature ofclosure device10 according to this embodiment is that leftatrial anchor12 andtether16 are flexibly connected, andtether16 is itself preferably flexible, to allowtether16 to extend through the PFO track, while leftatrial anchor12 remains significantly apposed to the left atrial surface.Tether16 is able to extend from leftatrial anchor12 at an obtuse angle. In many instances, leftatrial anchor12, with tension applied fromtether16, may mechanically close and thereby seal the PFO by bringing the septum primum (SP) into sealing contact with the septum secundum (SS). The effectiveness of this seal can be tested at this time by conventional techniques, such as contrast visualization, or a Valsalva maneuver combined with injection of bubbles, visualized with transesophageal ultrasound or intracardiac ultrasound. If the seal is ineffective,closure device10 can be removed as described later, and exchanged for a different device. Alternatively, thedevice10 can be repositioned as will be described below.
• Theguide catheter30 anddelivery catheter32 are further withdrawn relative to the PFO track, until the distal end of theguide catheter30 is well within the right atrium, as shown inFIG. 7. The rightatrial anchor14, still collapsed within the lumen of theguide catheter30, moves together with theguide catheter30 anddelivery catheter32. With thetether clip34 previously positioned proximally, thecatheters30,32 and the collapsed rightatrial anchor14 can freely slide proximally relative to thetether16 and the leftatrial anchor12.
• Once leftatrial anchor12 is positioned, rightatrial anchor14 may be deployed. As shown inFIG. 7, initial deployment of rightatrial anchor14 is preferably performed with the delivery catheter and the collapsed rightatrial anchor14 withdrawn sufficiently away from leftatrial anchor12 and the right atrial septal wall, so that rightatrial anchor14 does not impinge on the wall when it initially expands. This also assures that rightatrial anchor14 will not inadvertently deploy in the PFO track or the left atrium. Because rightatrial anchor14 is not permanently attached to tether16,anchor14 is free to be positioned in such a location away from the right atrial septal wall.
• With theguide catheter30 positioned in the right atrium, the rightatrial anchor14 is deployed by advancing thedelivery catheter32 relative to theguide catheter30, as shown inFIGS. 8-10. This relative movement results in full deployment of rightatrial anchor14 within the right atrium RA, as shown inFIG. 9 At this stage of the delivery method, tether16 passes through rightatrial anchor14 and preferably extends continuously throughdelivery catheter32 and guidecatheter30 to the proximal end of thedelivery catheter32. Light tension is maintained on thetether16 from the proximal end to prevent slack on the portion of thetether16 between the left and rightatrial anchors12,14.
• In the next step of this embodiment of a closure device delivery method, rightatrial anchor14 is advanced into contact with the right atrial septal wall, as shown inFIG. 10. This is accomplished by advancing rightatrial anchor14 anddelivery catheter32 alongtether16 until rightatrial anchor14 is in a desired position relative to leftatrial anchor12, the septa wall, and the PFO, and has a desired amount of tension on leftatrial anchor12. It is preferred that leftatrial anchor12 have sufficient tension applied that the septum primum (SP) is brought into sealing apposition with the septum secundum (SS). This apposition, in many cases, may be enough to effectively close and seal the PFO. If desired, at this point in the delivery method, the effectiveness of the closure and seal can again be tested by conventional techniques, such as those described above. If the seal is ineffective,closure device10 can be removed as described later, and exchanged for a different device (e.g., one of a different size). Alternatively, thedevice10 can be repositioned as described later.
• The rightatrial anchor14 is advanced until it makes contact with the right atrial end of the PFO track, thus closing it off. Thetether clip34 is then repositioned back to abut the proximal end of thedelivery catheter32 to temporarily maintain the relative positions of the left and rightatrial anchors12,14. A test of the effectiveness of the closure of the PFO track can then be performed, as described earlier. Note that the distal end of thedelivery catheter32 is not fully connected to the rightatrial anchor14, but is merely abutting it. This arrangement allows for thedelivery catheter32 to pivot relative to the rightatrial anchor14 when abutting the rightatrial anchor14, as shown inFIG. 10. Therefore, the natural orientation that the rightatrial anchor14 takes as it conforms to the wall of the right atrium is not impacted by the orientation of the delivery catheter32 (or guide catheter30), enabling the position of thePFO closure device10 to accurately represent the final state of closure, once the tether is cut and all catheters removed.
• Up to this point, the two primary components of thedelivery catheter32, theinner tube38 and theouter tube36, have been secured together by way of a touhy-borstfitting33 in a y-adaptor35 at the proximal end of theouter tube36, as shown inFIG. 13. The touhy-borstfitting33 is initially tightened to prevent relative movement between theinner tube38 and theouter tube36. Theinner tube38 initially extends several cm proximally of the touhy-borstfitting33.
• Thelock20, which is initially positioned on thetether16, several cm proximal of the distal end of thetether16, is now advanced distally to permanently secure the position of the rightatrial anchor14 relative to thetether16. To advance thelock20, the touhy-borstfitting33 securing theinner tube38 and theouter tube36 is loosened. Then, theinner tube38 is advanced while maintaining the position of theouter tube36 against the rightatrial anchor14. To prevent creating slack on thetether16, light tension is applied at its proximal end.
• Thelock20 is advanced along thetether16 under fluoroscopic visualization until it abuts thehub19 of the rightatrial anchor14. At this point, thedelivery catheter32 is withdrawn several cm, and the PFO closure is re-assessed as discussed previously. In some instances, the right and leftatrial anchors12,14 may need to be further tightened relative to each other. This can be done by re-advancing theinner tube38 to thelock20. Thelock20 is then incrementally advanced along thetether16, shortening the length of thetether16 between the left and rightatrial anchors12,14.
• At this point, the effectiveness of the closure and sealing of the PFO can be tested by conventional techniques, such as contrast visualization, or a Valsalva maneuver combined with injection of bubbles, visualized with (TEE) or intracardiac ultrasound.
• Once a satisfactory closure of the PFO track is confirmed, thetether16 may be cut at a position near the rightatrial anchor14. A cuttingtool80 is used to perform this step. An embodiment of acutting tool80 is illustrated inFIG. 22. The cuttingtool80 includes atubular cutting element90, preferably formed of stainless steel, with a sharpeneddistal edge92. The cuttingelement90 is connected to anouter tube96 via a linkingportion94.Outer tube96 extends to the proximal end of thecutting tool80. Theouter tube96 is preferably incorporates a wire braid (not shown) to impart a relatively high torsional stiffness.
• Thecuttings element90 surrounds atether guide86, preferably formed from metallic hypotubing, with an outer diameter close to the inner diameter of the cuttingelement90. Thetether guide86 incorporates adistal opening82. Alateral opening84 is a short distance, preferably about 1 mm to about 5 mm proximal of thedistal opening82. Thetether guide86 is secured about the distal end of acentral wire98. Thecentral wire98, preferably made of stainless steel, extends proximally through theouter tube96 to the proximal end of thecutting tool80. The distal portion of thecentral wire98 is enlarged to fill the inside diameter of thetether guide86. The distal end of thecentral wire98 further incorporates abevel88.Central wire98 moves axially and rotationally relative toouter tube96. At the proximal end of the cutting tool (not shown) is a handle mechanism, which facilitates controlled relative rotation and longitudinal movement between thecentral wire98 and theeouter tube96.
• The initial position of the cuttingelement90 is just proximal to thelateral opening84 in thetether guide86, as shown inFIG. 22. The handle mechanism when activated causes theouter tube96 and cuttingelement90 to rotate relative to thecentral wire98 and thetether guide86. A screw or other suitable mechanism in the handle mechanism further causes theouter tube96 and cullingelement90 to advance distally along thetether guide86, until the cuttingelement90 is just distal of thelateral opening84 thereby severingtether16.
• In use, the cuttingtool80 is loaded over the proximal end of thetether16, as Shown inFIG. 22, thetether16 being inserted in thedistal opening82 of thetether guide86. Thebevel88 causes thetether16 to emerge out thelateral opening84. The cuttingtool80 is advanced along thetether16 until the distal end of thecutting tool80 abuts thelock20. At this point, the handle mechanism is activated, which causes the cuttingelement90 to advance and slice thetether16. ThePFO closure device10 is now fully implanted.
• There are several points during the delivery ofclosure device10 wheredevice10 can be completely removed from the patient. This may be necessary if, for example,device10 is not creating a complete seal due to any of a number of causes, including, for example, the selected device being too small.
• For example, after deployment of the leftatrial arm12, but before deployment of the right atrial arm14 (the position shown inFIG. 7), the deployed leftatrial arm12 can be captured by advancement of theguide catheter30 relative to thetether16 and leftatrial anchor12, which are fixed relative to the PFO track. Theguide catheter30 is advanced through the PFO track until it meets the leftatrial anchor12. Theguide catheter30 continues to advance, causing the leftatrial anchor12 to essentially resume the position it was in prior to initial deployment. Light tension is applied to thetether16 during the advancement.
• Alternatively, thedevice10 may be retrieved after deployment of the rightatrial anchor14, but before advancement of the lock20 (the position shown inFIG. 10). The deployed rightatrial anchor14 can be captured by use of a snare catheter (not shown). A preferred snare catheter is commercially available by Microvena (ev3), and sold under the trade name Amplatz Gooseneck Snare. Theouter tube36 ofdelivery catheter32 is left in place abutting the rightatrial anchor14. Thetether clip34, y-adaptor, and theinner tube38 ofdelivery catheter32 are all removed from the tether in a proximal direction, leaving theouter tube36 ofdelivery catheter32 in place. The snare is advanced over the proximal end of theouter tube36 ofdelivery catheter32 and along the annular space between theguide catheter30 and theouter tube36 ofdelivery catheter32. The share is activated to engage theenlarged ring19aon thehub19 of the rightatrial anchor14. Then the snare, together with theouter tube36 ofdelivery catheter32, is withdrawn relative to theguide catheter30 andtether16. Continued proximal movement of the snare causes the rightatrial anchor14 to collapse into theguide catheter30. Once the collapsed right atrial anchor is near thehemostasis valve31 of theguide catheter30, theloading tube70 is re-advanced through thehemostasis valve31. The collapsed rightatrial anchor14 is drawn into theloading tube70, allowing the rightatrial anchor14,outer tube36 ofdelivery catheter32, and snare to be removed from theguide catheter30. The leftatrial anchor12 then may be removed by advancing theguide catheter30 through the PFO track, while maintaining tension on thetether16. Once theguide catheter30 contacts the leftatrial anchor12, continued advancement of theguide catheter30 relative to the leftatrial anchor12 will cause it to collapse, into theguide catheter30, allowing subsequent removal.
• The various described embodiments of closure devices and methods and tools for their delivery are suitable for closure of a wide variety of PFOs. For example, PFOs with a relatively long overlap between the septum primum (SP) and septum secundum (SS) may be suitably closed, as shown inFIG. 2.
• Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The specification and examples are exemplary, with a true scope and spirit of the invention being indicated by the following claims.

Claims (16)

1-90. (canceled)

91. A system for sealing a passage in a heart, the system comprising:

a delivery catheter capable of extending to a position near the passage;

a closure device capable of sealing the passage, the device including a first anchor adapted to be placed proximate a first end of the passage, a second anchor adapted to be placed proximate a second end of the passage, and a flexible elongate member adapted to extend through the passage and connect the first and second anchors; and

a cutting tool capable of extending over the flexible elongate member to a position near the second anchor.

92. The system ofclaim 91, wherein the cutting tool includes a guide member for guiding the flexible elongate member.

93. The system ofclaim 92, wherein the guide member includes a distal opening through which the flexible elongate member enters the cutting tool and a lateral opening through which the flexible elongate member exits the cutting tool.

94. The system ofclaim 92, wherein the cutting tool further includes a cutting element disposed around the guide member.

95. The system ofclaim 94, wherein the cutting element is movable relative to the guide member to cut the flexible elongate member as it exits the guide member through a lateral opening of the guide member.

96. The system ofclaim 91, further comprising a guide catheter capable of extending to a position near the passage.

97. The system ofclaim 91, further comprising a loading tube.

98. The system ofclaim 97, wherein the closure device is positionable within the loading tube in a collapsed state.

99. The system ofclaim 91, wherein the second anchor includes a plurality of second loop structures.

100-108. (canceled)

109. The system ofclaim 94, wherein the cutting element is formed of stainless steel.

110. The system ofclaim 94, wherein the cutting element includes a sharpened distal edge.

111. The system ofclaim 94, wherein the cutting tool includes a handle mechanism configured to move the cutting element relative to the guide member.

112. The system ofclaim 111, wherein the handle mechanism is configured to rotate the cutting element.

113. The system ofclaim 111, wherein the handle mechanism is configured to advance the cutting element distally.

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