Closure devices, related delivery methods and tools, and related methods of use

DESCRIPTION OF THE INVENTION

00011. Field of the Invention

0002This 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.

00032. Background of the Invention

0004<figref idref="DRAWINGS">FIG. 20</figref> 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. <figref idref="DRAWINGS">FIG. 20</figref> 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).

0005Where 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).

0006Studies 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.

0007Pharmacological 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.

0008Nonsurgical 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

0009In 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.

0010According 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, 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 and a second end that releasably connects to the second anchor.

0011According 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, 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.

0012According to another aspect of the invention, a device for sealing a passageway in a heart is provided. The device comprises a first anchor adapted to be placed proximate a first end of the passageway, 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.

0013According to yet another aspect of the invention, a device for sealing a passageway in a heart comprises a first anchor adapted to be placed proximate a first end of the passageway, 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.

0014According to a further aspect of the invention, a device for sealing a patent foramen ovale in a heart is provided. The device includes a first anchor including a first plurality of arms adapted to be placed proximate a first end of the patent foramen ovale, a second anchor including a second plurality of arms adapted to be placed proximate a second end of the patent foramen ovale, and a flexible elongate member adapted to extend through the patent foramen ovale and connect the first and second anchors, the elongate member having a first end fixedly connected to the first anchor and a second end that releasably connects to the second anchor, and wherein each of the first and second plurality of arms are collapsible from a deployed state to a delivery state.

0015According to another aspect of the invention, an assembly for sealing a passageway in a heart is provided. The assembly comprises a positioning 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, 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 positioning catheter in a first collapsed state and extendable from the positioning catheter in a second deployed state.

0016According to yet another aspect of the invention, an assembly for sealing a patent foramen ovale in a heart is provided. The assembly comprises a guide catheter capable of extending to the patent foramen ovale, a positioning catheter capable of extending through the guide catheter to a position near the patent foramen ovale, and a closure device capable of sealing the patent foramen ovale, the closure device including a first anchor having a first plurality of arms adapted to be placed proximate a first end of the patent foramen ovale, a second anchor having a second plurality of arms adapted to be placed proximate a second end of the patent foramen ovale, a flexible elongate member adapted to extend through the patent foramen ovale and connect the first and second anchors, and a releasable fixation mechanism that selectively engages a distal portion of the positioning catheter to releasably connect the second end of the elongate member to the second anchor, wherein the closure device is positionable within the positioning catheter in a first state wherein each of the first and second plurality of arms are collapsed and extendable from the positioning catheter in a second deployed state wherein each of the first and second plurality of arms are extended.

0017According to another aspect of the invention, a method of sealing a passageway in a heart is provided. The method comprises placing a first anchor proximate a first end of the passageway, 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.

0018According to another aspect of the invention, a method of placing a closure device to seal a passageway in a heart 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, and positioning the second anchor of the closure device adjacent the first end of the passageway.

0019According to a further aspect of the invention, a method of delivering a closure device to a patent foramen ovale in a heart is provided. The method includes advancing a catheter into the right atrium of the heart, advancing the catheter through the patent foramen ovale into the left atrium of the heart, deploying a first anchor of the closure device in the left atrium, withdrawing the catheter into the right atrium of the heart, and deploying a second anchor of the closure device in the right atrium.

0020According to another aspect of the invention, a closure device for sealing a passageway in a heart 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, and 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 is configured to releasably attach to the elongate member at any one of a plurality of points along a length of the elongate member.

0021According to another aspect of the invention, an assembly for sealing a passageway in a heart includes a guide catheter configured to extend from a point of entry into a body 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, a second anchor adapted to be placed proximate a second end of the passageway, and a flexible elongate member connecting the first and second anchors, wherein a first end of the elongate member is connected to the first anchor and wherein the elongate member extends through the second anchor and through the catheter to the point of entry into the body.

0022According 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, 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 tension of the elongate member.

0023According to another aspect of the invention, a device for closing a passageway in a human body comprises a first anchor adapted to be placed proximate a first end of the passageway, 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 having a first end releasably connected to the first anchor and a second end releasably connected to the second anchor.

0024According 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 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.

0025According to another aspect of the invention, a device for sealing a passageway in a heart comprises a first anchor adapted to be placed proximate a first end of the passageway, the first anchor comprising a plurality of uncovered arms, a second anchor adapted to be placed proximate a second end of the passageway, the second anchor comprising a plurality of uncovered arms, and a flexible 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 and a second end that releasably connects to the second anchor.

0026Additional 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.

0027The 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

0028The 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.

0029<figref idref="DRAWINGS">FIG. 1</figref> is a closure device positioned in a heart to close a PFO, according to an embodiment of the present invention.

0030<figref idref="DRAWINGS">FIG. 2</figref> is a delivery system guide catheter inserted through a PFO and into the left atrium, according to an embodiment of the present invention.

0031<figref idref="DRAWINGS">FIG. 3</figref> is a left atrial anchor of closure device of <figref idref="DRAWINGS">FIG. 1</figref> being advanced out of the delivery guide catheter, according to an embodiment of the present invention.

0032<figref idref="DRAWINGS">FIG. 4</figref> is a left atrial anchor of the closure device of <figref idref="DRAWINGS">FIG. 1</figref> advanced out of the delivery guide catheter, according to an embodiment of the present invention.

0033<figref idref="DRAWINGS">FIG. 5</figref> is the left atrial anchor of <figref idref="DRAWINGS">FIG. 4</figref> being pulled towards the PFO, according to an embodiment of the present invention.

0034<figref idref="DRAWINGS">FIG. 6</figref> is the delivery 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.

0035<figref idref="DRAWINGS">FIG. 7</figref> is a right atrial anchor of the closure device of <figref idref="DRAWINGS">FIG. 1</figref> being extended from the delivery guide catheter, according to an embodiment of the present invention.

0036<figref idref="DRAWINGS">FIG. 8</figref> is the right atrial anchor deployed from the delivery guide catheter, according to an embodiment of the present invention.

0037<figref idref="DRAWINGS">FIG. 9</figref> is the right atrial anchor advanced to contact the septal wall, according to an embodiment of the present invention.

0038<figref idref="DRAWINGS">FIG. 10</figref> is the right atrial anchor fixed to a tether of the closure device of <figref idref="DRAWINGS">FIG. 1</figref>, according to an embodiment of the present invention.

0039<figref idref="DRAWINGS">FIG. 11</figref> is a cross-sectional side view of a closure device, including a sectional view of a fixation mechanism, according to an embodiment of the present invention.

0040<figref idref="DRAWINGS">FIG. 11A</figref> is a partial plan view of a left atrial anchor of the closure device of <figref idref="DRAWINGS">FIG. 11</figref> taken along line A-A, according to an embodiment of the present invention.

0041<figref idref="DRAWINGS">FIG. 11B</figref> is a partial plan view of a right atrial anchor of the closure device of <figref idref="DRAWINGS">FIG. 11</figref> taken along line B-B, shown without a covering, according to an embodiment of the present invention.

0042<figref idref="DRAWINGS">FIG. 11C</figref> is a partial plan view of the right atrial anchor of <figref idref="DRAWINGS">FIG. 11B</figref> shown with a covering, according to an embodiment of the present invention.

0043<figref idref="DRAWINGS">FIG. 12</figref> is a cross-sectional side view of the closure device of <figref idref="DRAWINGS">FIG. 11</figref> with a positioning catheter (shown in cross section) engaging a fixation mechanism (also shown in cross section), according to an embodiment of the present invention.

0044<figref idref="DRAWINGS">FIG. 13</figref> is a cross sectional side view of the positioning catheter of <figref idref="DRAWINGS">FIG. 12</figref> engaging another embodiment of a fixation mechanism according to the present invention.

0045<figref idref="DRAWINGS">FIG. 14</figref> is a cross sectional side view of a delivery system, including a guide catheter and a positioning catheter, according to an embodiment of the present invention.

0046<figref idref="DRAWINGS">FIG. 15</figref> is a cross sectional side view of a closure device and a positioning catheter positioned in a guide or delivery catheter prior to deployment in a heart, according to an embodiment of the present invention.

0047<figref idref="DRAWINGS">FIG. 16</figref> is a partial cross sectional view of another embodiment of a fixation mechanism engaging a right atrial anchor, according to the present invention.

0048<figref idref="DRAWINGS">FIG. 17</figref> is a cross sectional side view of the closure device, the positioning catheter, and the guide or delivery catheter of <figref idref="DRAWINGS">FIG. 15</figref>, with the closure device in a recaptured position within the guide catheter, according to an embodiment of the present invention.

0049<figref idref="DRAWINGS">FIG. 18</figref> is the closure device of <figref idref="DRAWINGS">FIG. 1</figref> in a position covering a PFO where there is relatively short overlap between the septum primum and the septum secundum, according to an embodiment of the present invention.

0050<figref idref="DRAWINGS">FIG. 19</figref> is the closure device of <figref idref="DRAWINGS">FIG. 1</figref> in a position covering a PFO after an access channel has been made into the left atrium, according to an embodiment of the present invention.

0051<figref idref="DRAWINGS">FIG. 20</figref> is a longitudinal section of a portion of a heart having a PFO.

0052<figref idref="DRAWINGS">FIG. 21</figref> is a longitudinal cross-section of a delivery system including a delivery sheath containing a closure device according to the present invention.

DESCRIPTION OF THE EMBODIMENTS

0053Reference 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.

0054The various Figures show embodiments of patent foramen ovale (PFO) closure devices, tools, 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.

0055<figref idref="DRAWINGS">FIGS. 1 and 11</figref> show a PFO closure device <b>10</b> according to an embodiment of the present invention. In <figref idref="DRAWINGS">FIG. 1</figref>, device <b>10</b> is shown positioned on either side of a PFO track (referenced as PFO in the Figures) with a portion of the device <b>10</b> passing through the PFO track, after delivery from a delivery system. The PFO track can be seen more clearly in <figref idref="DRAWINGS">FIG. 2</figref>, which shows a catheter disposed in the PFO track between the septum primum (SP) and septum secundum (SS). As shown in <figref idref="DRAWINGS">FIG. 1</figref>, closure device <b>10</b> includes a left atrial anchor <b>12</b> positioned in the LA, a right atrial anchor <b>14</b> positioned in the RA, and a tether <b>16</b> connecting the anchor structures.

0056As embodied herein and shown in <figref idref="DRAWINGS">FIGS. 1 and 11</figref>, closure device <b>10</b> includes left atrial anchor <b>12</b> connected to tether <b>16</b>. <figref idref="DRAWINGS">FIG. 11</figref> shows tether <b>16</b> extending through and connecting to right atrial anchor <b>14</b> via a releasable fixation mechanism <b>30</b> (which is fixed to right atrial anchor <b>14</b>). When releasable fixation mechanism <b>30</b> is not fixed, right atrial anchor <b>14</b> is moveable along tether <b>16</b>. As shown in <figref idref="DRAWINGS">FIG. 11</figref>, releasable fixation member <b>30</b> engages tether <b>16</b>, which extends through right atrial anchor <b>14</b> on a side of right anchor <b>14</b> which does not face left anchor <b>12</b>. Although it is preferable that left atrial anchor <b>12</b> is permanently attached to tether <b>16</b>, it is possible that left atrial anchor <b>12</b> may also be attached to tether <b>16</b> by a device similar to releasable fixation mechanism <b>30</b>.

0057In one embodiment, tether <b>16</b> is formed of a multifilar braided polymeric material. 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 VECTRAN, polyester, or other high strength fibers. Other suitable materials of sufficient strength and flexibility may be used for tether <b>16</b>.

0058Releasable fixation mechanism <b>30</b> is preferably spring-loaded and is shown in <figref idref="DRAWINGS">FIG. 11</figref> in a fixed condition on tether <b>16</b>, i.e., fixation mechanism <b>30</b> has fixed tether <b>16</b> to anchor <b>14</b>. Releasable fixation mechanism <b>30</b> includes two oppositely directed piercing pins <b>32</b>, which are adapted to penetrate and pierce tether <b>16</b>. Each piercing pin <b>32</b> includes a spring portion <b>32</b><i>a </i>which connects to a housing <b>31</b> and the corresponding piercing pin <b>32</b>. In the embodiment shown, housing <b>31</b> connects to an anchor attachment hub <b>36</b>, which in turn connects to anchor <b>14</b>, as will be described below.

0059Piercing pin <b>32</b> has a sharpened end and is oriented generally orthogonal to tether <b>16</b>. Spring portion <b>32</b><i>a </i>is connected to housing <b>31</b> such that the natural, unbiased position of spring portion <b>32</b><i>a </i>forces piercing pin <b>32</b> through tether <b>16</b>. Piercing pins <b>32</b> are illustrated as passing completely through tether <b>16</b>, but it is contemplated that pins <b>32</b> may pass only partially into tether <b>16</b>.

0060Piercing pins <b>32</b> cooperate with a piercing collar <b>34</b> that is attached to housing <b>31</b>. Collar <b>34</b> has an internal passage which is somewhat larger than tether <b>16</b>. In the embodiment shown, collar <b>34</b> also has two passageways, one for each piercing pin <b>32</b>, through which piercing pins <b>32</b> pass. Once piercing pins <b>32</b> have passed into (and potentially through) tether <b>16</b>, piercing pins <b>32</b> securely lock tether <b>16</b> relative to fixation mechanism <b>30</b> and thus to right atrial anchor <b>14</b>. Piercing collar <b>34</b> also holds tether <b>16</b> in place if piercing pins <b>32</b> are desired to be extracted from tether <b>16</b>, as will be described later.

0061Piercing pins <b>32</b> are preferably formed of an elastic metal with spring characteristics. Suitable materials include but are not limited to stainless steel, nickel-titanium, ELGILOY, or MP35N. Housing <b>31</b> is preferably a thin walled tube formed of a biocompatible metal or polymer. The releasable fixation mechanism <b>30</b> illustrated in <figref idref="DRAWINGS">FIG. 11</figref> is exemplary only, and other embodiments of a releasable fixation mechanism suitable to fix tether <b>16</b> to anchor <b>14</b> are contemplated, some of which will be described below.

0062<figref idref="DRAWINGS">FIG. 12</figref> illustrates the operation of releasable fixation mechanism <b>30</b> shown in <figref idref="DRAWINGS">FIG. 11</figref>. In <figref idref="DRAWINGS">FIG. 12</figref>, a right atrial anchor positioning catheter (RPC) <b>22</b> is engaged with right atrial anchor <b>14</b>, such that right atrial anchor <b>14</b> is not yet secured to tether <b>16</b>. RPC <b>22</b>, as embodied herein and shown in <figref idref="DRAWINGS">FIG. 12</figref>, includes an inflatable balloon <b>24</b> which, when inflated, engages releasable fixation mechanism <b>30</b>, allowing right atrial anchor <b>14</b> to be moved relative to tether <b>16</b>. RPC <b>22</b> includes a lumen <b>26</b> which allows for inflation and deflation of balloon <b>24</b>. A proximal end <b>24</b><i>a </i>of balloon <b>24</b> is attached to a distal end of an outer tube <b>22</b><i>b </i>of RPC <b>22</b>, whereas a distal end <b>24</b><i>b </i>of balloon <b>24</b> is attached to the distal end of an inner tube <b>22</b><i>a </i>of RPC <b>22</b>. The inner and outer tubes <b>22</b><i>a</i>, <b>22</b><i>b </i>of RPC <b>22</b> define lumen <b>26</b>.

0063Balloon <b>24</b> is shown in <figref idref="DRAWINGS">FIG. 12</figref> in its inflated condition. Balloon <b>24</b> may be formed in the dumbbell shape, as shown, to facilitate engagement with releasable fixation mechanism <b>30</b>. As shown, when balloon <b>24</b> is inflated, a distal portion of dumbbell shaped balloon <b>24</b> presses against spring portions <b>32</b><i>a</i>, a proximal portion of balloon <b>24</b> expands without contacting any surface, and a middle waist portion of balloon <b>24</b> presses against housing <b>31</b>, limiting expansion of that waist portion. The distal portion of balloon <b>24</b> forces piercing pins <b>32</b> outward from tether <b>16</b>. This is done by balloon <b>24</b> pressing outward against spring portions <b>32</b><i>a </i>of piercing pins <b>32</b>. Once a desired position for right atrial anchor <b>14</b> with respect to left atrial anchor <b>12</b> and tether <b>16</b> is established, balloon <b>24</b> is deflated, which allows piercing pins <b>32</b> to penetrate tether <b>16</b>, fixing anchor <b>14</b> with respect to tether <b>16</b>. If it is desired to re-position right atrial anchor <b>14</b> after fixing, RPC <b>22</b> is advanced along tether <b>16</b> to re-engage releasable fixation mechanism <b>30</b>. Balloon <b>24</b> is re-inflated, extracting pins <b>32</b> from tether <b>16</b>, and allowing for re-positioning of right atrial anchor <b>14</b> relative to tether <b>16</b>.

0064RPC <b>22</b> described and illustrated with respect to <figref idref="DRAWINGS">FIG. 12</figref> is only exemplary, and other catheter structures which may interact with a releasable fixation mechanism are contemplated. For example, catheter devices with alternative mechanical expansion structures for releasably engaging the fixation mechanism may be used.

0065<figref idref="DRAWINGS">FIG. 11A</figref> illustrates an embodiment of left atrial anchor <b>12</b> and its connection to tether <b>16</b>. As embodied herein and shown in <figref idref="DRAWINGS">FIG. 11A</figref>, anchor <b>12</b> includes one or more arms <b>40</b>, which preferably extend across an anchor attachment hub <b>42</b>. Attachment hub <b>42</b> is tubular, preferably made of a biocompatible metallic or polymeric material, and includes radially oriented passageways through which arms <b>40</b> extend. <figref idref="DRAWINGS">FIG. 12</figref> shows one such radial passageway through which an arm <b>40</b> extends. Arms <b>40</b> may be further secured to attachment hub <b>42</b> by suitable means such as welding, brazing, adhesive bonding, or any other suitable method of securing arms <b>40</b> to hub <b>42</b>. Anchor attachment hub <b>42</b> also defines a longitudinal lumen <b>48</b> through which tether <b>16</b> extends, as shown in <figref idref="DRAWINGS">FIG. 11</figref>. Each arm <b>40</b> extends generally orthogonally through the tether <b>16</b>, passing through the braid structure of tether <b>16</b> and fixing the left atrial anchor to tether <b>16</b>. <figref idref="DRAWINGS">FIG. 11A</figref> illustrates anchor <b>12</b> having four arms, however any number of arms may be used, preferably from one to six. While not shown in <figref idref="DRAWINGS">FIG. 11</figref>, arms <b>40</b> of this embodiment would be spaced longitudinally relative to one another along the length of tether <b>16</b>, at least in the region of the anchor attachment hub, i.e., no two arms would be located at exactly the same point on the tether <b>16</b>.

0066Although arms <b>40</b> preferably pass through hub <b>42</b>, in an alternative arrangement arms <b>40</b> may not actually pass though hub <b>42</b>, i.e., they may extend radially from hub <b>42</b>. Additionally, it is possible that instead of arms <b>40</b>, the anchors <b>12</b>, <b>14</b> may comprise spiral structures, flat braided structures, or webs. Any structure of sufficient size and shape to hold the septum primum (SP) in contact with the septum secondum (SS) to close the PFO may be used.

0067Arms <b>40</b> are preferably fabricated of metallic wire, such as stainless steel, nickel-titanium, ELGILOY, or MP35N. In the case of nickel-titanium, the wires may be used in either a super-elastic mode, whereby the wires deploy due to the super-elastic properties of this alloy, or they may be used in a thermal-transforming mode. In the thermal-transforming mode, the wires may be chilled prior to deployment, for example by the introduction of chilled saline in the delivery assembly, and subsequently warmed by exposure to the blood, once guide catheter <b>20</b> (or a delivery sheath) is withdrawn.

0068As shown in <figref idref="DRAWINGS">FIG. 11A</figref>, arms <b>40</b> may be straight. Alternatively, arms <b>40</b> may be formed to present a concave-shaped anchor to the atrial wall. The anchor <b>12</b> and its arms <b>40</b> then will conform to lay flat and apposed to the surface of the atrial wall once tensioned by tether <b>16</b>. It is preferable for arms <b>40</b> to lie on or close to the atrial wall surface once fully positioned, as this will facilitate tissue growth over arms <b>40</b>, and minimize thrombus formation and subsequent embolization of thrombi. To further assist in arms <b>40</b> becoming rapidly endothelialized and grown into the atrial wall, arms <b>40</b> may be individually coated with a material to accelerate this ingrowth, such as expanded PTFE or a woven polyester. Arms <b>40</b>, together with any desired coating, may further be coated with a non-thrombogenic material such as heparin. All exposed surfaces of the closure device, including the full length of tether <b>16</b>, may include such coatings.

0069To minimize frictional forces between a guide catheter <b>20</b> (or delivery sheath) and the undeployed anchors, as well as minimizing tissue trauma during deployment, the ends of arms <b>40</b> are preferably rounded (as shown by the right-hand arm in <figref idref="DRAWINGS">FIG. 11A</figref>). The ends of arms <b>40</b> also may include small loops to receive sutures, for example, for suturing to a covering of the anchor <b>12</b>. The overall length of the arms (which will correspond to the diameter of the anchor) will depend on the particular anatomy to be treated, but will preferably range from about 3-50 mm for septal closure applications including PFO closure. Arms <b>40</b> need not extend an equal distance from the attachment hub. Depending on the location of the PFO relative to remainder of the left atrium, it may be desirable to have some of arms <b>40</b> extend asymmetrically from the attachment hub <b>42</b>, for example, longer towards the inferior direction. Also, while left atrial anchor <b>12</b> is shown in <figref idref="DRAWINGS">FIG. 11A</figref> without a fabric covering spanning the arms, it is anticipated that in some instances it may be beneficial to incorporate such a covering, similar to that described below in connection with right atrial anchor <b>14</b> shown in <figref idref="DRAWINGS">FIG. 11C</figref>.

0070<figref idref="DRAWINGS">FIG. 11B</figref> illustrates an embodiment of right atrial anchor <b>14</b> and its connection to anchor attachment hub <b>36</b>. Tether <b>16</b> and the fabric that covers anchor <b>14</b> are not shown in <figref idref="DRAWINGS">FIG. 11B</figref>. As embodied herein and shown in <figref idref="DRAWINGS">FIG. 11B</figref>, right atrial anchor <b>14</b> includes one or more arms <b>50</b> which extend through anchor attachment hub <b>36</b>. Attachment hub <b>36</b> for right atrial anchor <b>14</b> is similar to that for left atrial anchor <b>12</b> and defines a longitudinal lumen <b>58</b> (see <figref idref="DRAWINGS">FIG. 11</figref>) through which tether <b>16</b> extends and radially oriented passages <b>51</b> in its wall through which arms <b>50</b> extend. Unlike left atrial anchor <b>12</b>, arms <b>50</b> do not extend through tether <b>16</b>. Instead, arms <b>50</b> are formed to curve around tether <b>16</b> and follow the inner surface of anchor attachment hub <b>36</b>, as shown in <figref idref="DRAWINGS">FIG. 11B</figref>. <figref idref="DRAWINGS">FIG. 11B</figref> also illustrates four arms, but a larger or smaller number of arms may be used, preferably from one to six arms. Arms <b>50</b> may be formed straight (away from hub <b>36</b>), or with a concave shape, as described in connection with left atrial anchor <b>12</b>. Preferred materials include those described for left atrial anchor arms <b>40</b>. The overall length of arms <b>50</b> (which will correspond to the diameter of anchor <b>14</b>) will depend on the particular anatomy to be treated, but will preferably range from about 3-50 mm for septal closure applications including PFO closure. In some instances, left atrial anchor arms <b>40</b> are the same length as right atrial anchor arms <b>50</b>, and in others they may be different, e.g. shorter than right atrial anchor arms <b>50</b>. This will depend on the anatomy of the heart.

0071Right atrial anchor <b>14</b> preferably includes a fabric or other membrane covering that span between arms <b>50</b>. This covering, represented in <figref idref="DRAWINGS">FIG. 11C</figref> as reference numeral <b>52</b>, serves to ensure a hemodynamic sealing of the PFO. The covering <b>52</b> is preferably formed of a single sheet, with a hole for surrounding anchor attachment hub <b>36</b>, and is preferably positioned on the arms <b>50</b> such that it faces the septum. Suitable materials for covering <b>52</b> include, but are not limited to, woven or knit polyester fabric, or ePTFE. Preferably, covering <b>52</b> has a porosity which will encourage rapid tissue ingrowth. Covering <b>52</b> may additionally include a coating, for example, a non-thrombogenic material such as heparin. Covering <b>52</b> may be attached to arms <b>50</b> of right atrial anchor <b>14</b> by suitable means, such as suturing. As shown in <figref idref="DRAWINGS">FIG. 11C</figref>, arm <b>50</b> may have a loop <b>54</b> formed at each of its ends, creating eyelets for a suture <b>56</b> to connect arm <b>50</b> to covering <b>52</b>. Additional sutures may be incorporated along the length of arms <b>50</b>. Although not preferred and not discussed with respect to left atrial anchor <b>12</b>, it is possible to include a covering attached to arms <b>40</b> of left atrial anchor <b>12</b>.

0072<figref idref="DRAWINGS">FIG. 13</figref> illustrates an alternative embodiment of a releasable fixation mechanism. A releasable fixation mechanism <b>60</b> operates in conjunction with right atrial positioning catheter RPC <b>22</b> in a manner similar to that described above. As in the prior described embodiment, anchor attachment hub <b>36</b> connects to a housing <b>61</b> of mechanism <b>60</b>. Housing <b>61</b> contains a gripping structure, preferably with two grips, a fixed grip <b>62</b><i>a </i>and a movable grip <b>62</b><i>b</i>. Fixed grip <b>62</b><i>a </i>is connected to housing <b>61</b> and has a rough surface with sharpened teeth-like projections. Movable grip <b>62</b><i>b </i>has a spring portion <b>62</b><i>c </i>connected to housing <b>61</b>. Grip <b>62</b><i>b </i>also includes sharpened teeth-like projections. When inflated, balloon <b>24</b> holds movable grip <b>62</b><i>b </i>away from tether <b>16</b>, but when balloon <b>24</b> is deflated, spring portion <b>62</b><i>c </i>forces movable grip <b>62</b><i>b </i>against tether <b>16</b>, and also forces tether <b>16</b> against fixed grip <b>62</b><i>a</i>. In this way, tether <b>16</b> fixedly connects to right atrial anchor <b>14</b>.

0073In another embodiment according to the present invention, the closure device <b>10</b> need not incorporate a releasable fixation mechanism such as those described above. Instead, other structures may be used to fix right anchor <b>14</b> to tether <b>16</b>. In such an embodiment, as illustrated in <figref idref="DRAWINGS">FIG. 16</figref>, anchor <b>14</b> is connected to anchor attachment hub <b>36</b>, as in the embodiments described above. Also as in the prior embodiments, once right atrial anchor <b>14</b> is deployed, it is not yet fixed to tether <b>16</b>. When right atrial anchor <b>14</b> is in its desired position, a locking element <b>70</b> is advanced along tether <b>16</b> towards anchor <b>14</b>. Element <b>70</b>, when it reaches hub <b>36</b>, will secure to both tether <b>16</b> and anchor attachment hub <b>36</b>. Locking element <b>70</b> is not necessarily releasable, and as such would be permanent. Locking element <b>70</b> may be moved distally by any suitable actuation mechanism known in the art that extends through a delivery assembly to its proximal end outside of the patient.

0074Locking element <b>70</b> is preferably tubular and includes a number of projecting grips <b>72</b>. These grips <b>72</b> may be oriented in a ratchet-like manner (not shown) such that locking element <b>70</b> can be advanced distally along tether <b>16</b>, but will resist proximal movement. Alternately, locking element <b>70</b> can be positioned in the desired location on tether <b>16</b>, and swaged down to bite into the surface of tether <b>16</b>. As a further alternative, locking element <b>70</b> may have an outer surface <b>74</b> which is tapered to engage with a tapered inner surface <b>36</b><i>a </i>of anchor attachment hub <b>36</b> in a wedge-like manner, as shown in <figref idref="DRAWINGS">FIG. 16</figref>. As locking element <b>70</b> is pushed into anchor attachment hub <b>36</b>, the gripping surface <b>72</b> is forced inward to bite into tether <b>16</b>.

0075While not shown, locking element <b>70</b> could also be used in conjunction with the embodiments above which utilize a releasable fixation mechanism. As such, locking element <b>70</b> would provide extra security in the fixation of right atrial anchor <b>14</b> to tether <b>16</b>.

0076<figref idref="DRAWINGS">FIG. 14</figref> shows the closure device <b>10</b> positioned relative to an embodiment of a delivery apparatus <b>18</b>. In <figref idref="DRAWINGS">FIG. 14</figref>, left atrial anchor <b>12</b> is shown deployed from delivery apparatus <b>18</b>, while right atrial anchor <b>14</b> is shown in a collapsed, undeployed state within delivery apparatus <b>18</b>. Delivery apparatus <b>18</b> may include a guide catheter <b>20</b> and right atrial positioning catheter (RPC) <b>22</b>. Although not shown, guide catheter <b>20</b> may have a pre-formed curve near its distal end. Guide catheter <b>20</b> 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 of guide catheter <b>20</b> is a conventional Y-adaptor <b>80</b>. A side arm <b>82</b> of Y-adaptor <b>80</b> allows fluid communication with the lumen of guide catheter <b>20</b>. Y-adaptor <b>80</b> also contains a touhy borst seal <b>84</b>, through which RPC <b>22</b> extends.

0077As described earlier, RPC <b>22</b> includes balloon <b>24</b> for engaging right atrial anchor <b>14</b>. Therefore RPC <b>22</b> is provided with a manifold <b>90</b> at a proximal end which includes a port <b>92</b> in fluid communication with balloon <b>24</b>. Manifold <b>90</b> may further include a touhy borst seal <b>94</b>, through which tether <b>16</b> extends.

0078As mentioned, <figref idref="DRAWINGS">FIG. 14</figref> depicts closure device <b>10</b> after left atrial anchor <b>12</b> has been deployed. However, prior to closure device <b>10</b> being in this state, guide catheter <b>20</b> 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). Closure device <b>10</b> then would be positioned within the lumen of guide catheter <b>20</b>, by suitable techniques, and advanced toward the distal end of guide catheter <b>20</b>, into a position depicted in <figref idref="DRAWINGS">FIG. 15</figref>. As shown in <figref idref="DRAWINGS">FIG. 15</figref>, right atrial anchor <b>14</b> is folded in a proximal direction, while left atrial anchor <b>12</b> is folded in a distal direction within guide catheter <b>20</b>. More specifically, arms <b>40</b> of left atrial anchor <b>12</b> are folded so as to extend in a distal direction, whereas arms <b>50</b> of right atrial anchor <b>14</b> are folded so as to extend in a proximal direction. This is a preferred position of the arms in a delivery position. Alternatively, it is possible that the arms of anchors <b>12</b> and <b>14</b> are folded to extended in the same direction, either distal or proximal, or the anchor may be disposed with arms <b>40</b> of left atrial anchor <b>12</b> folded to extend in a proximal direction and arms <b>50</b> of right atrial anchor <b>14</b> folded to extend in a distal direction.

0079When it is desired to deploy left atrial anchor <b>12</b>, right atrial positioning catheter <b>22</b> is advanced relative to guide catheter <b>20</b>, or guide catheter <b>20</b> is withdrawn relative to the RPC <b>22</b>, or both. Since RPC <b>22</b> is engaged with right atrial anchor <b>12</b>, the forces required for advancement of left atrial anchor <b>14</b> can be compressively transferred to abutting left atrial anchor <b>12</b>.

0080<figref idref="DRAWINGS">FIGS. 2-10</figref> show sequential steps for delivery of closure device <b>10</b>, according to one aspect of the invention. At the level of the longitudinal section shown in <figref idref="DRAWINGS">FIG. 1</figref>, 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 in <figref idref="DRAWINGS">FIG. 2</figref>, a delivery assembly <b>18</b> including a guide catheter <b>20</b> is advanced to and through the PFO track and into the LA. Delivery assembly <b>18</b> is shown in detail in <figref idref="DRAWINGS">FIG. 14</figref>. In addition to closure device <b>10</b>, additional delivery components, such as a delivery sheath or positioning catheter, may be included within the delivery assembly, as will be described below.

0081As embodied herein and shown in <figref idref="DRAWINGS">FIG. 2</figref>, in a method of delivery of closure device <b>10</b>, guide catheter <b>20</b> is positioned through the PFO track with the use of a conventional guide wire (not shown). After positioning of guide catheter <b>20</b> into the LA, the guide wire may be removed. Closure device <b>10</b>, in a collapsed state as shown in <figref idref="DRAWINGS">FIG. 15</figref> and as will be described below, and any delivery components are advanced within guide catheter <b>20</b> until closure device <b>10</b> is near a distal end of guide catheter <b>20</b>.

0082Then, as shown in <figref idref="DRAWINGS">FIG. 3</figref>, closure device <b>10</b> is advanced out of the distal end of guide catheter <b>20</b>. The advancement is accomplished by relative movement between guide catheter <b>20</b> and closure device <b>10</b> and its delivery components. Preferably, the advancement is accomplished by maintaining the position of guide catheter <b>20</b>, and pushing delivery components in a distal direction to push closure device <b>10</b> out of a distal end of guide catheter <b>20</b>.

0083While guide catheter <b>20</b> and delivery components are within the left atrium, only left atrial anchor <b>12</b> is deployed from guide catheter <b>20</b>. <figref idref="DRAWINGS">FIG. 4</figref> shows left atrial anchor <b>12</b> fully deployed from guide catheter <b>20</b> in the LA. <figref idref="DRAWINGS">FIG. 14</figref> also shows the delivery assembly with left atrial anchor <b>12</b> deployed. Tether <b>16</b> extends from anchor <b>12</b> into the delivery assembly. As discussed above, left atrial anchor <b>12</b> and right atrial anchor <b>14</b> are preferably self-expanding structures, expanding through a mechanical or thermal shape change, for example. Also at this point, right atrial anchor <b>14</b> remains within the delivery assembly in a collapsed state.

0084In the next step of an embodiment of the delivery method, left atrial anchor <b>12</b> is pulled against the opening of the PFO, as shown in <figref idref="DRAWINGS">FIG. 5</figref>. This is done by the user pulling guide catheter <b>20</b> and other delivery components proximally. As guide catheter <b>20</b> is withdrawn proximally, left atrial anchor <b>12</b> will seat naturally against the septal wall, as shown in <figref idref="DRAWINGS">FIG. 6</figref>.

0085As shown in <figref idref="DRAWINGS">FIG. 6</figref>, 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 of closure device <b>10</b> according to this embodiment is that left atrial anchor <b>12</b> and tether <b>16</b> are flexibly connected, and tether <b>16</b> is itself preferably flexible, to allow tether <b>16</b> to extend through the PFO track, while left atrial anchor <b>12</b> remains significantly apposed to the left ventricular surface. Tether <b>16</b> is able to extend from left atrial anchor <b>12</b> at an obtuse angle. In many instances, left atrial anchor <b>12</b>, with tension applied from tether <b>16</b>, 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 device <b>10</b> can be removed as described later, and exchanged for a different device, for example, a device including a covering on arms <b>40</b> of left atrial anchor <b>12</b>. Alternatively, the device <b>10</b> can be repositioned as described below.

0086Once left atrial anchor <b>12</b> is positioned, right atrial anchor <b>14</b> may be deployed. As shown in <figref idref="DRAWINGS">FIG. 7</figref>, initial deployment of right atrial anchor <b>14</b> is preferably performed with the delivery assembly and the collapsed right atrial anchor <b>14</b> withdrawn sufficiently away from left atrial anchor <b>12</b> and the right atrial septal wall, so that right atrial anchor <b>14</b> does not impinge on the wall when it initially expands. Positioning right atrial anchor <b>14</b> in this position prior to deployment also assures that right atrial anchor <b>14</b> will not inadvertently deploy in the PFO track or the left atrium. Because right atrial anchor <b>14</b> is not permanently attached to tether <b>16</b>, anchor <b>14</b> is free to be positioned in such a location.

0087Right atrial anchor <b>14</b> is temporarily connected to a right atrial anchor positioning catheter (RPC) <b>22</b>, as shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref> and described in detail below. Deployment of right atrial anchor <b>14</b> is accomplished by relative movement of guide catheter <b>20</b> and RPC <b>22</b>, either by grasping a proximal end of RPC <b>22</b> and withdrawing guide catheter <b>20</b>, or by grasping guide catheter <b>20</b> and advancing RPC <b>22</b>. This relative movement results in full deployment of right atrial anchor <b>14</b> within the right atrium RA, as shown in <figref idref="DRAWINGS">FIG. 8</figref>. At this stage of the delivery method, tether <b>16</b> passes through right atrial anchor <b>14</b> and preferably extends continuously through guide catheter <b>20</b> to the proximal end of the delivery assembly <b>18</b>. Right atrial anchor <b>14</b> is not yet fixed to tether <b>16</b> and instead is connected to RPC <b>22</b>. Preferably, tether <b>16</b> also extends through RPC <b>22</b>.

0088In the next step of this embodiment of a closure device delivery method, right atrial anchor <b>14</b> is advanced into contact with the right atrial septal wall, as shown in <figref idref="DRAWINGS">FIG. 9</figref>. This is accomplished by advancing right atrial anchor <b>14</b> and RPC <b>22</b> along tether <b>16</b> until right atrial anchor <b>14</b> is in a desired position relative to left atrial anchor <b>12</b>, the septal wall, and the PFO, and has a desired amount of tension on left atrial anchor <b>12</b>. It is preferred that left atrial anchor <b>12</b> 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. It may be preferable to also include a fabric or other covering with right atrial anchor <b>14</b> to help provide a seal to the PFO, as described above. 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 device <b>10</b> can be removed as described later, and exchanged for a different device, for example, a device including a covering on arms <b>50</b> of right atrial anchor <b>14</b>. Alternatively, the device <b>10</b> can be repositioned as described below.

0089In the next step of an embodiment of the delivery method, right atrial anchor <b>14</b> is fixed to tether <b>16</b>. <figref idref="DRAWINGS">FIGS. 12 and 13</figref> show right atrial anchor <b>14</b> before it is fixed to tether <b>16</b>. <figref idref="DRAWINGS">FIGS. 10 and 11</figref> show right atrial anchor <b>14</b> after it is fixed to tether <b>16</b>. As shown in the Figures, RPC <b>22</b> has been disengaged from right atrial anchor <b>14</b>, which engages with a fixation mechanism <b>30</b> between right atrial anchor <b>14</b> and tether <b>16</b>. Embodiments of such fixation mechanisms and their related methods to fix anchor <b>14</b> to tether <b>16</b> were described above. These devices and methods may provide a releasable fixation mechanism that is associated with RPC <b>22</b> so that the fixing of anchor <b>14</b> to tether <b>16</b> can be reversed at any time prior to severing of tether <b>16</b>.

0090At this point, closure device <b>10</b> is in its final position, with the exception that flexible tether <b>16</b> extends between closure device <b>10</b> and guide catheter <b>20</b>. Closure device <b>10</b>, however, is essentially uninfluenced by guide catheter <b>20</b> or the extension of tether <b>16</b> to and through guide catheter <b>20</b>. 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.

0091Additionally, at this stage of delivery of closure device <b>10</b>, hemodynamic parameters such as oxygen saturation and pulmonary wedge pressure can be measured. In some rare instances, closure of a PFO may excessively increase pulmonary arterial pressure, in which case the closure device <b>10</b> can be removed, as described below. It may be necessary to leave the closure device in place for several hours or even days to fully assess the impact on hemodynamic parameters. If this is desired, the excess tether is simply left to extend from the closure device to the introduction site. At such time that the device is desired for permanent implanation, the excess tether is cut, or if the device is desired for removal, it is removed as described below.

0092At this point in the delivery method, or at any other earlier point in the procedure, closure device <b>10</b> can be completely removed from the patient. This may be necessary if, for example, device <b>10</b> is not creating a complete seal due to any of a number of causes, including, for example, the selected device being too small. To remove closure device <b>10</b>, RPC <b>22</b> is re-engaged with right atrial anchor <b>14</b> to reverse the fixation mechanism that secures right atrial anchor <b>14</b> to tether <b>16</b>. This allows right atrial anchor <b>14</b> to slide relative to tether <b>16</b>. Right atrial anchor <b>14</b> may then be collapsed by retracting RPC <b>22</b> and right atrial anchor <b>14</b> within the delivery assembly <b>18</b>, and specifically into guide catheter <b>20</b>. Guide catheter <b>20</b> then may be re-advanced through the PFO track, while at the same time tension is maintained on tether <b>16</b>. Continued advancement of guide catheter <b>20</b> will advance catheter <b>20</b> over left atrial anchor <b>12</b> to collapse anchor <b>12</b> within catheter <b>20</b> as shown in <figref idref="DRAWINGS">FIG. 17</figref>. The entire delivery assembly, including catheter <b>20</b>, RPC <b>22</b>, and collapsed closure device <b>10</b>, may then be removed from the patient. In the alternative, closure device <b>10</b> may be redeployed and repositioned by repeating the delivery steps shown and described in connection with <figref idref="DRAWINGS">FIGS. 2 through 10</figref> to obtain an effective seal of the PFO track.

0093If closure device <b>10</b>, as shown in <figref idref="DRAWINGS">FIG. 10</figref>, results in satisfactory closure and sealing of the PFO, tether <b>16</b> is severed proximate right atrial anchor <b>14</b>. This may be facilitated by removal of RPC <b>22</b> from guide catheter <b>20</b> and off of tether <b>16</b>. A cutting device, such as, for example, a heated snare loop (not shown) or other suitable cutting device known in the art, may be positioned proximate right atrial anchor <b>14</b> to sever tether <b>16</b>. This results in closure device <b>10</b> deployed as shown in <figref idref="DRAWINGS">FIG. 1</figref>.

0094<figref idref="DRAWINGS">FIG. 21</figref> illustrates an alternative embodiment for a delivery apparatus. In this embodiment, rather than positioning closure device <b>10</b> directly inside guide catheter <b>20</b>, closure device <b>10</b> is pre-packaged inside a delivery sheath <b>21</b>. This entire assembly is then introduced into a conventional guide catheter <b>20</b>. The delivery sheath <b>21</b> of this embodiment essentially serves the restraining functions of guide catheter <b>20</b> of the embodiment described in connection with <figref idref="DRAWINGS">FIG. 14</figref>. However, the embodiment of <figref idref="DRAWINGS">FIG. 21</figref> does not require the separate step of loading closure device <b>10</b> just prior to introduction into the patient.

0095As mentioned above, closure device <b>10</b>, according to one aspect of the invention, can be re-captured at any time prior and up to the state of closure device <b>10</b> depicted in <figref idref="DRAWINGS">FIG. 10</figref>. This permits repositioning of closure device <b>10</b> should, for example, device <b>10</b> not provide sufficient closure and sealing of the PFO. To recapture closure device <b>10</b>, right atrial positioning catheter <b>22</b> is advanced along tether <b>16</b> and re-engaged with right atrial anchor <b>14</b>. This reengagement occurs by positioning balloon <b>24</b> of RPC <b>22</b> within releasable fixation mechanism <b>30</b> and inflating balloon <b>24</b> to press balloon <b>24</b> against spring portions <b>32</b><i>a</i>, forcing piercing pins <b>32</b> out of and away from tether <b>16</b>. Right atrial anchor <b>14</b> is then re-positioned in guide catheter <b>20</b> so that arms <b>50</b> extend in a distal direction. This is done by pulling RPC <b>22</b> and right atrial anchor <b>14</b> into guide catheter <b>20</b>, collapsing right atrial anchor <b>14</b> in a distal direction. Preferably, right atrial anchor <b>14</b> is positioned proximally enough within guide catheter <b>20</b> to leave space for left atrial anchor <b>12</b> within guide catheter <b>20</b>. Guide catheter <b>20</b> is then advanced towards left atrial anchor <b>12</b> to collapse left atrial anchor <b>12</b> so that arms <b>40</b> also face distally. Alternatively, guide catheter <b>20</b> is held stationary and left atrial anchor <b>12</b> is retracted into guide catheter <b>20</b>. The fully recaptured closure device is illustrated in <figref idref="DRAWINGS">FIG. 17</figref>.

0096The 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 in <figref idref="DRAWINGS">FIG. 1</figref>. Also, PFOs with a relatively short overlap between the septum primum and septum secundum may be suitably closed, as shown in <figref idref="DRAWINGS">FIG. 18</figref>.

0097<figref idref="DRAWINGS">FIG. 19</figref> illustrates an alternative method of delivery and use of closure device <b>10</b>. In certain circumstances, the PFO track may not be ideally suited for delivery as described above. For example, the PFO track may be unusually long or unusually tight or may comprise more than one passage. A variety of electrophysiological procedures, such as left atrial mapping and/or ablations utilize an access channel into the left atrium by puncturing a small hole in the wall of the atrial septum primum. A similar technique can be utilized for positioning a guide catheter <b>20</b> through the septum primum. By utilizing these techniques, once a small hole is created in the septal wall, similar procedures as described above can be followed, resulting in closure device <b>10</b> positioned as shown in <figref idref="DRAWINGS">FIG. 19</figref>. Although closure device <b>10</b> does not sit entirely within the PFO track, a fabric covering on one or both of anchors <b>12</b> or <b>14</b> will effectively close the PFO.

0098Other 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.