OCCLUSION DEVICES

Abstract: Occlusion devices (10) that include anchors (20) having variable shapes and occluders, such as coils (30), that are attached to the anchors. The occlusion devices are retrievable by virtue of the shapes and by virtue, in some cases, of filaments (18) that can be manipulated to alter the variable shapes of the anchors.

Description: OCCLUSION DEVICES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to the field of passageway occlusion within living beings. More particularly, it concerns repositionable and, in some cases, retrievable devices useful for achieving vascular occlusion. 2. Description of Related Art The most widely-used permanent vascular occluding (i.e., clotting) device has long been the Gianturco stainless steel coil (Cook Inc., Bloomington, IN), which, since its introduction in the mid-1970s, has undergone several modifications regarding its thrombogenicity (i.e., its effectiveness in causing blood clotting) and delivery system (1-3). These devices, also known as macrocoils (0.035" - 0.038"), have been widely used for vessel occlusions throughout the body. For neurologic embolizations, several types of microcoils (0.010" - 0.018'") (Cook Inc, Bloomington, IN; Medi-Tech, a division of Boston Scientific Co., Natick, MA) have been developed. One disadvantage of these embolic coils is that they tend to migrate if they are used in veins or in non-tapered vascular structures. Additionally, high-flow vascular lesions including arterio-venous malformations (ANMs) and fistulas increase the possibility of coil dislodgment even further (4-6). There have been several attempts to offset this disadvantage of coil migration after placement, otherwise known as coil emboli. The "coil in coil technique" uses a smaller coil released into the lumen of a larger coil to decrease the length of the occluded vessel segment and also prevent coil migration (7). Coils have also been equipped with a single barb to anchor the coil when placed on the venous side (8). The separately-deployed Amplatz spider was designed to prevent coil dislodgment both in the arterial (9) and the venous side (10). It could be delivered downstream of the delivered coils, and was designed to capture them should they migrate. Some authors have recently proposed the use of a nitinol snare to improve transcatheter delivery of macrocoils in occlusion of patent ductus arteriosus (PDA) (11, 12). Additionally, detachable coils have been designed to prevent migration by allowing optimal positioning of the coil before its release. For neurologic interventions, several microcoil systems equipped with a controlled delivery mechanism have been developed. The most widely used system is the Guglielmi electrically detachable microcoil (Medi-Tech) (13-15). Mechanically detachable microcoils (e.g., interlocking detachable coil systems) are also available (Medi-Tech) (16, 17). Further, the use of controlled-release macrocoils (Cook detachable coil; William Cook Europe, Bjeverskov, Denmark) with a spiral releasing mechanism is increasing (18-20). The inventors of the present invention have published their first experimental results with a new anchoring coil system (37). Even more recently, a similar anchoring coil system has been presented in Japan (38). Although early experiences with the above-mentioned systems are favorable (37,38), problems still remain. Foremost among them occurs when the anchors for the systems are misplaced: the misplaced anchors cannot be retrieved or repositioned. As a result of this shortcoming, the functionality and reliability of these systems is compromised in many clinical situations, narrowing the acceptable scope of their use. The problems pointed out with the foregoing occlusion devices are not intended to be exhaustive but rather are among many that tend to impair the effectiveness of previously known occlusion devices. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that previous techniques appearing in the art have not been altogether satisfactory, particularly in providing an occlusion device that offers reliable, correctable functionality. SUMMARY OF THE INVENTION In an attempt to overcome the foregoing disadvantages, the inventors created the present occlusion devices and devised the following deployment system and methods for their deployment. The design of these occlusion devices simultaneously allow for their repositionability and retrievability while making it easy for the operator/surgeon to create the most appropriate arrangement of the occluder and anchor together. In one respect, the present invention is an occlusion device. The occlusion device includes an anchor having a variable shape. An occluder is attached to the anchor at a first location, and a filament is attached to the anchor at a second location. Manipulation of the filament alters the variable shape of the anchor. In other respects, the anchor may include a wire. The wire may be stainless steel. The wire may be a nickel titanium alloy. The anchor may include a wire having multiple acute bends. The anchor may include a wire having two ends, both of which contact the interior of a body passageway when the occlusion device is deployed. The anchor may also include a wire having two ends, neither of which contacts the interior of a body passageway when the occlusion device is deployed. The occluder may fit at least partially within the anchor after the occlusion device is deployed within a body passageway. The occluder may trail the anchor after the occlusion device is deployed within a body passageway. The filament may be polypropylene. The occluder may include a coil. In another respect, the present invention is a device useful in blocking flow through a passageway in a living being. The device includes an anchor having a variable shape. The device also includes a coil attached to the anchor at a first location. The coil has a passageway. The device also includes a filament attached to the anchor at a second location. The filament extends away from the second location through at least a portion of the passageway to a location from which the filament can be manipulated. Manipulation of the filament alters the variable shape of the anchor. In other respects, the anchor may include a wire having two ends, each of which is covered by a coil tip. The wire may be stainless steel. The wire may be a nickel titanium alloy. The anchor may include multiple acute bends. The anchor may include two ends, both of which contact the interior of a body passageway when the device is deployed. The coil may fit at least partially within the anchor after the device is deployed within a body passageway. The coil may trail the anchor after the occlusion device is deployed within a body passageway. The filament may interconnect multiple acute bends of the anchor. In another respect, the present invention is a retrievable device useful in blocking flow through a vessel. The device includes a wire forming at least part of an anchor that has a variable shape. The device includes a coil attached to the anchor at a first location. The coil has a passageway that houses at least a portion of the wire. The device includes a filament attached to the anchor at a second location. The filament extends away from the second location through at least a portion of the passageway to a location from which the filament can be manipulated. Manipulation of the filament alters the variable shape of the anchor. In another respect, the present invention is an occlusion device that includes a loop and an occluder attached to the loop. After deployment, the loop contacts the interior of a body passageway in order to prevent the occlusion device from migrating. In other respects, the loop may be curved. The occluder may include a coil, and, after deployment, the curved loop defines a space occupied at least in part by the coil. The occluder may include a coil that trails the loop after the occlusion device is deployed within a body passageway. The loop may be characterized by a bend that facilitates loading the occlusion device into a catheter for delivery. The occluder may include a coil. The coil may include a coil passageway and the loop may include a wire extending at least partially into the coil passageway. The wire may be a nickel titanium alloy. The occluder may include a coil to which one or more threads of polyester are attached. The device may include a second loop operably coupled to the loop. Both the loop and second loop may be curved. The occluder may include a coil. The coil may include a coil passageway and the loop may include a wire extending at least partially into the coil passageway. The wire may be a nickel titanium alloy. The occluder may include a coil to which one or more threads of polyester are attached. The occluder may include a coil that trails the loop and the second loop after the occlusion device is deployed within a body passageway. Both loops may be characterized by bends that facilitate loading the occlusion device into a catheter for delivery. In another respect, the present invention is a device useful for occluding a passageway in a body. The device includes a wire having two ends. The wire forms a closed structure. The device also includes an occluder attached to the wire proximate at least one of the ends. The closed structure is elongated so as to facilitate delivery of the device into a body passageway, and, after deployment, the closed structure contacts the interior of the body passageway in order to prevent the device from migrating. The occluder may include a coil, and, after deployment, the closed structure may define a space occupied at least in part by the coil. The occluder may include a coil that trails the closed structure after the device is deployed within a body passageway. The closed structure may be characterized by a bend that facilitates loading the device into a catheter for delivery. The occluder may include a coil. The coil may include a coil passageway and the wire may extend at least partially into the coil passageway. The wire may be a nickel titanium alloy. The occluder may include a coil to which one or more threads of polyester are attached. The device may also include a second closed structure operably coupled to the closed structure. The occluder may include a coil. The coil may include a coil passageway and the wire may extend at least partially into the coil passageway. The wire may be a nickel titanium alloy. The occluder may include a coil to which one or more threads of polyester are attached. The occluder may include a coil that trails the closed structure and the second closed structure after the device is deployed within a body passageway. Both closed structures may be characterized by bends that facilitate loading the device into a catheter for delivery. BRIEF DESCRIPTION OF THE DRAWINGS The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present occlusion devices. The present occlusion devices may be better understood by reference to one or more of these drawings in combination with the description of illustrative embodiments presented herein. FIG. 1 is a front view of one of the present occlusion devices and a deployment system. FIG. 2 is a front view of the occlusion device depicted in FIG. 1 loaded into a delivery catheter. FIG. 3 depicts the interaction between a catheter, a pusher wire, and a coil used an occluder. FIGS. 4a-d depict various stages of compression of an anchor having multiple bends. FIG. 5 is a front view of the anchor depicted in FIGS. 4a-d and an occluder attached thereto partially-deployed in a body passageway. FIG. 6 is a front view of an embodiment of the occlusion device depicted in FIG. 5 that has a wire acting as a core within the passageway of the coil. FIG. 7 is a front view of another embodiment of the occlusion device depicted in FIG. 5 that has a fibrous braid surrounding a bare wire for use an the occluder. FIG. 8 is a front view of an occlusion device deployed in a body passageway. FIGS. 9a-b illustrate the variable nature of the shape of an anchor of an occlusion device. FIG. 10 is a front view of part of an occlusion device in which the anchor has symmetrical bends. FIG. 11 is a slightly perspective view of a partially-deployed occlusion device. FIGS. 12-14 depict various stages in the deployment of a bent loop anchor. FIG. 15 is a top view of the anchor depicted in FIGS. 12-14. FIG. 16 depicts a deployed bent loop occlusion device in which the space defined by the anchor is at least partially occupied by the coil acting as an occluder. FIG. 17 depicts an interdigitating connection between the proximal end of a coil and the distal end of a pusher wire. FIG. 18 is a side view of a bent loop anchor having multiple curves. FIG. 19 is a top view of the bent loop anchor depicted in FIG. 18. FIG. 20 is a side view another bent loop anchor having multiple curves with different radii. FIG. 21 depicts a partial view of a deployed double bent loop anchor in a body passageway. FIGS. 22 and 23 are front and top views, respectively, of another embodiment of a bent loop anchor . FIG. 24 is a front view of a generally round-shaped flat anchor. FIG. 25 is a front view of a generally round-shaped flat anchor having a small loop. FIG. 26 is a front view of a generally round-shaped flat anchor having a waist. FIG. 27 is a front view of a generally oval-shaped flat anchor. FIG. 28 is a front view of a C-shaped anchor within a body passageway. FIG. 29 is a front view of an S-shaped anchor within a body passageway. FIG. 30 is a front view of a corkscrew-shaped anchor within a body passageway. FIG. 31 is a front view of an anchor having two crossed wires within a body passageway. FIG. 32 is a slightly perspective view of an anchor having three wires with three, free wire ends. FIG. 33 is a perspective view of an occlusion device having two uncrossed, curved wires forming an anchor that is attached to a brush occluder. DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS The design of the present occlusion devices facilitates the surgeon's task of deploying the devices at locations within body passageways (e.g., blood vessels) from which the devices are unlikely to migrate. The present devices include anchors that may be configured in a variety of shapes, each of which are suited to securely contacting the interior of the body passageway in which the device is deployed. Occluders, such as coils, are attached to the anchors, including attachment through integral formation, to facilitate the occlusion of a chosen site within a body passageway. To further the occlusion process, strands of material such as polyester may be attached to the disclosed occluders. As a result of their unique shapes, the present occlusion devices are well-suited to creating occlusions in body passageways that are not tapered and in which the potential for migration is consequently very high, such as arteriovenous (a-v) fistulas, a-v malformations, aneurysms and pseudoaneurysms, patent ductus arteriosus, systemic-to- pulmonary collateral vessels and shunts, and varicocele. FIG. 1 depicts one embodiment of an occlusion device 10 that includes an anchor 20. Anchor 20 includes two wires 12 that each have two acute bends. The exposed ends of the wires are covered with atraumatic tips 14. Tips 14 may possess any shape suited to decreasing the potential that the covered wire ends will penetrate the wall of the passageway in which device 10 is deployed. For example, tips 14 may therefore be made from small pieces of coil. The materials from which tips 14 may be formed include those discussed below from which wires 12 may be formed. Wires 12 are attached to each other at location 16 so as to facilitate the ability of anchor 20 to retain its variable shape after it is manipulated and eventually deployed. This attachment may be made using solder or welding, by crimping a third piece of material around the wires, or through the use of any other suitable means. Wires 12 are also shown attached to occluder 30, which, as depicted, is a coil that has been substantially straightened in order to facilitate the deployment of occlusion device 10. Such attacliment may be made along any suitable length of wires 12 and any corresponding length of coil 30 using any of the foregoing types of attachment. Thus, as used herein, the term "first location" (or second location, etc.) in the phrase "at a first location," which phrase describes where the attacliment of an anchor (e.g., anchor 20) to an occluder (e.g., coil 30) is made, means any length and not simply an immeasurably small point. Filaments 18 are attached to both wires 12 of anchor 20 at one of the two acute bends in wires 12 as shown in FIG. 1. FIG. 1 further shows that filaments 18 may then extend away from their attachment locations through gaps in coil 30 to the coil passageway, or lumen, within coil 30. Filaments 18 may extend through at least a portion of this passageway to a location or locations (not shown) from which either or both may be manipulated. Filaments 18 may be made, for example, of polypropylene (e.g., PROLENE) or NYLON (available from Ethilon). In another embodiment of occlusion device 10, anchor 20 may be formed from a single wire having five acute bends, instead of two wires having two acute bends each. As a result, each time some aspect of wires 12 are discussed, it is to be understood that the discussion applies also to the foregoing single- wire embodiment of anchor 20. Wires 12 of anchor 20 depicted in FIG. 1 may be formed of virtually any material compatible with the tissue of the body passageway in which the occlusion device will be placed. The material may be suitably rigid and elastic, such as stainless steel. The material may also be suitably rigid and elastic and capable of being programmed with either superelasticity or thermal shape memory. Accordingly, the material may, for example, be a nickel titanium alloy such as nitinol. In one embodiment, for example, nitinol possessing about 55 to 56 % Nickel, and 45 to 44 % Titanium, may be used for the wire or wires of anchor 20. (Such nitinol wires are commercially available from Shape Memory Applications in Santa Clara, CA.) Such alloys can be heat treated to have either superelastic or thermal shape memory properties, depending on the type of heat treatment, as is well known by those of skill in the art. A wire that is superelastic may generally be bent into virtually any conceivable shape through the application of a force and will return to substantially, if not identically, its original shape when that force is removed. A wire that has thermal memory will generally be malleable below a certain temperature, but will take on a preprogrammed shape at some higher temperature. After taking on its preprogrammed shape, the wire having thermal memory will then generally act like a wire with superelasticity. Other alloys that may be used include FePt, FePd, and FeNiCoTi. These alloys may be heat treated to exliibit thermoelastic martensitic transformation, and, therefore, good thermal shape memory. Other alloys such as FeNiC, FeMnSi, and FeMnSiCrNi do not possess long-range order and undergo nonthermoelastic transformation, and, thus, may also be used. Additionally, some β-Ti alloys and iron-based alloys may also be used. These materials may be used for all of the present anchors. Like wires 12, coil 30 may be made from virtually any material compatible with the tissue of the body passageway in which the occlusion device will be placed. As a result, the materials described above that are suitable for forming wires 12 may also be used to form coil 30. In addition, materials such as tantalum or platinum may also be used for coil 30. Any suitable coil mentioned in the Background may be used in conjunction with anchor 20, including the microcoils marketed by Medi-Tech or the Gianturco coils marketed by Cook, Inc. Coil 30 may be coated with thrombogenic material such as an electro-positive substance. Platinum is an example of an electro-positive substance that may be used either as the coil material or as a coil coating. Depending on the material used, coil 30 may be spring-biased or provided with superelasticity or thermal memory so as to assume any desired shape, including a helical shape, a rosette shape, or an irregular tangle, when unrestrained. The size of wires 12 of anchor 20 will vary depending on the size of the body passageway into which the occlusion device will be deployed. Wires having diameters ranging from 0.003 inches to 0.012 inches in diameter may be used for most applications. In addition, when the occluder attached to the anchor is a coil, as in FIG. 1, a coil ranging in diameter from 0.03 to 0.05 inches may be used for most applications. Turning to one manner of deploying the present occlusion devices, FIG. 2 depicts occlusion device 10 loaded into delivery catheter 32. A catheter is a medical term used to describe a hollow, flexible tube that may be inserted into a living being. Catheter 32 may be any adequate size. For some applications, a 5-French (F) outer diameter catheter having an internal diameter of 0.05 inches may be used for catheter 32. Also depicted in FIG. 2 is catheter 34, which abuts the proximal end of coil 30. "Proximal" refers to the end of the coil (or any other thing in question) that is closest (with respect to the other end of the coil) to the operator/surgeon. The term "distal" refers to the coil end that is the farthest from the operator. As depicted in both FIGS. 1 and 3, catheter 34 may possess an internal diameter that decreases in size slightly as one moves away from the distal end of the catheter. As a result, the proximal end of the coil will not slide beyond that narrowed portion when an operator abuts the coil with the distal end of catheter 34. Being able to stabilize coil 30, or prevent it from moving, is useful because it may become desirable to retract, or pull back on, filaments 30, as discussed below. During deployment, the operator/surgeon may lock catheter 34 to delivery catheter 32 together using locking mechanisms, such as Luer locks, which are well known in the art. Within the lumen, or passageway, of catheter 34 is pusher wire 36 depicted in FIGS. 1 and 3. Pusher wire 36 may be equipped with a cutting edge 37, as depicted in FIG. 3, in order to sever filaments 18 at the appropriate time. Pusher wire 36 and catheter 34 make up one embodiment of pusher system 31. Pusher system 31 may include catheter 34, catheter 34 and pusher wire 36, or any device capable of preventing coil 30 from moving when resistance is applied to filaments 18 (i.e., when the operator/surgeon pulls back, or withdraws, filaments 18). As with delivery catheter 32 and catheter 34, pusher wire 36 may be locked to catheter 34 during deployment using any suitable locking mechanism. Similarly, filaments 18 may be locked to pusher wire 36 (or catheter 34 if only the same is used without pusher wire 36 as described above). By locking two devices together, one device cannot be moved relative to the other; they will move together. Anchor 20, like all of the present anchors, possesses a variable shape. This means that while anchor 20 possesses a relatively stable, unconstrained shape, that shape can be altered by applying some kind of force to the anchor in order to facilitate deployment of the occlusion device. For example, the acute bends in wires 12 of anchor 20 make it easy to reduce the size of anchor 20 by squeezing together, or compressing, wires 12. Similarly, as described below, the proximal end of coil 30 may be held steady by pusher system 31 within delivery catheter 32 while filaments 18 are pulled back thereby forcing wires 12 to compress and reduce the size, or profile, of anchor 20. In other words, manipulation of filaments 18 alters the variable shape of anchor 20. After occlusion device 10 is loaded into delivery catheter 32, the operator/surgeon may utilize a guiding catheter (not shown) to facilitate guiding delivery catheter 32 to the target site within the body passageway. More specifically, if there is not enough room within delivery catheter 32 to insert a guidewire that can facilitate guiding the delivery catheter to the target location, a guiding catheter may be used for this purpose. That is, a guiding catheter may be introduced over a guidewire that has negotiated the body to the appropriate location within the body passageway, the guidewire may be removed, and the delivery catheter may be inserted into the guiding catheter and advanced to the target location. The guiding catheter may be removed after the delivery catheter is in place if the operator/surgeon so chooses. After delivery catheter 32 is satisfactorily positioned, occlusion device 10 is deployed. The distal portions of anchor 20 may be released by pushing, or advancing, the occlusion device with pusher system 31. As a result, anchor 20 will contact the interior of the body passageway at multiple sites, thereby stabilizing the occlusion device and reducing the chance of migration. Pusher system 31 may then be held steady while delivery catheter 32 is gently pulled back, or withdrawn, thereby exposing the proximal portions of anchor 20. Using this technique, anchor 20 can be precisely deployed. Coil 30 may be deployed, and thus occlusion device 10 may be deployed, by using a combination of pushing the coil using pusher system 31 and retracting delivery catheter 32, as well as by rotating delivery catheter 32. Using these or similar maneuvers, the operator/surgeon may achieve the most compact arrangement of the occlusion device possible. If deployment of occlusion device 10 is satisfactory, any locking mechanism used to couple catheter 34 to pusher wire 36, if both are used, may be released. Pusher wire 36 may then be rotated such that cutting edge 37 severs any suitable length off of filaments 18. Any suitable manner of severing filaments 18 may be used in the alternative to cutting edge 37 of pusher wire 36. Pusher wire 36 may then be advanced, or moved distally, to push the proximal end of coil 30 from the lumen of catheter 34 to free the occlusion device from the deployment system. If deployment of occlusion device 10 is not satisfactory, the operator/surgeon should maintain control of filaments 18, and any portion of the device may be withdrawn into delivery catheter 32, and the process started again. The operator/surgeon may position pusher system 31 against, or close to, the proximal end of coil 30 as delivery catheter 32 is advanced over the malpositioned portion of the occlusion device. If anchor 20 is misplaced, once coil 30 has been pulled back into delivery catheter 32, any mechanism that is locking filaments 18 to any other aspect of the deployment system may be released. Then, while pusher system 31 is held steady, filaments 18 are pulled back to cause anchor 20 to contract such that it can be re-housed by delivery catheter 32. Filaments 18 may then be re-locked to the appropriate device. Filaments 18 and pusher system 31 may then be held steady while delivery catheter 32 is advanced (i.e., pushed or moved forward) to enclose anchor 20. The deployment process may then be repeated as necessary to achieve a satisfactory deployment of occlusion device 10. The present occlusion devices are advantageous because any displacement of the present occlusion device (including of the anchor) can be corrected during any phase of deployment. As a result, deployment becomes completely controlled. Further, the relationship between the coil and the pusher system makes it possible to achieve the most compact arrangement of the coil possible, thereby furthering the effectiveness of the occluder and of the occlusion device generally. Throughout this disclosure, like reference numerals indicate like features. The anchors of the present occlusion devices may possess a variety of shapes. FIGS. 4a- d illustrate the various states of deployed anchor 20 (illustrated in FIG. 5) as anchor 20 is being folded from its unconstrained state (FIG. 4a) to its constrained state (FIG. 4d). In this embodiment of anchor 20, it is worth noting that the unconstraint shape of anchor 20 (FIG. 4a) differs from the deployed shape of anchor 20 depicted in FIG. 5. Anchor 20 depicted in FIGS. 4a-5 may include one or two wires 12 like anchor 20 depicted in FIG. 1. These two wires, or the segments of one wire bent at a very acute angle, may be attached to each other at location 16 as described above. FIG. 5 illustrates occlusion device 10 having only one filament 18 as it is being deployed within a body passageway. As depicted, pusher system 31 along with deliver catheter 32 may be used to facilitate deployment. In any embodiment of the present occlusion devices, including those depicted in FIGS. 1 and 5, a wire 12 of anchor 20 may extend partially or completely along the length of the passageway, or lumen, within coil 30, sometimes referred to herein as the coil passageway. In such an embodiment, anchor 20 will usually consist of two wires 12, one of which may be attached to coil 30 near the same portion of coil 30 to which the shorter wire of anchor 20 is attached. Alternatively, the longer wire extending into the coil passageway may be attached at any suitable location along the coil passageway, including at multiple, spaced-apart locations. Such an embodiment of an occlusion device 10 is depicted in FIG. 6. The portion of the wire extending into the coil passageway may be referred to as occluder core 13. When wire 12, and hence occluder core 13, is made from a nickel titanium alloy such a nitinol, core 13 may be preprogrammed to take on any given shape. The preprogramming may impart either superelastic or thermal memory properties to core 13, which properties are discussed above. This feature allows coil 30 to take on shapes that can better fill a target location within a body passageway so as to result in quicker occlusion. In addition, any portion of the occluder (e.g., coil) passageway may be occupied by core 13. Leaving a portion of the coil empty near its proximal end may facilitate the operator/surgeon's task of compactly arranging coil 30 within the space defined by deployed anchor 20. Core 13 may be tapered along any portion of its length to facilitate this task as well. In other words, core 13 may be continuously tapered from the proximal end of anchor 20 (where it meets anchor 20) to its own proximal end, or it may be both uniform in width from the proximal end of anchor 20 to a location proximal thereof and tapered from the latter location to its own proximal end. Another embodiment of occlusion device 10 is depicted in FIG. 7. In this embodiment, anchor 20 may include the same arrangement of wires 12 that is depicted in FIG. 6. With this embodiment, as with the embodiment of occlusion device 10 depicted in FIG. 6, wires 12 may be connected to each other for stability at or near the proximal end of the shorter wire. The difference between the embodiment of occlusion device 10 and of the occlusion device shown in FIG. 6 is that a coil is not used for occluder 30. Instead, and as shown in FIG. 7, the longer of the two wires may be covered, partially or completely, with a fibrous material, such as braided polyester, braided DACRON, braided silk, or the like. Fibrous material 39 may be secured to the longer of the two wires 12 using any suitable means, such as glue, resin, etc. Another embodiment of occlusion device 10 is depicted in FIG. 8. As shown, anchor 20 of occlusion device 10 includes a single wire 12 having two acute bends. Prior to loading this embodiment of occlusion device 10 into a delivery catheter, the unconstrained shape of anchor 20 similar to that of a triangle, where atraumatic tip 14 is located near the distal end of coil 30. Additional embodiments of anchor 20 appear in FIGS. 9a-10. These embodiments of anchor 20 include one wire that is bent at least three times at acute angles and does not include any exposed wire ends. It is to be understood that the lengths of coil 30 depicted in FIGS. 9a-10 are truncated (i.e., shorter than normal) for ease of illustration, as is the case throughout the present figures. As illustrated in FIG. 9a, anchor 20 includes wire 12, which is bent at locations 40, 41, and 42. As shown, bend 41 has the appearance of a beak. The ends of wire 12 (not shown) may be secured to each other and attached to coil 30 as described above. FIG. 9b illustrates occlusion device 10 depicted in FIG. 9a in its constrained form, ready for insertion into a delivery catheter. In additions to bends 40, 41, and 42, wire 12 forming anchor 20 may be bent at any other suitable angles to better ensure that anchor 20 will serve to prevent the migration of occlusion device 10. For example, as shown in FIG. 10, wire 12 may be bent at locations 43 and 44 to cause anchor to contact the interior of a body passageway in additional locations. Additionally, the lengths of the segments of wire between the bends in wire 12 may also be varied as desired. As shown in FIG. 10, for example, the various lengths of wire between bends 41 and 42, in between bends 41 and 40, are virtually identical, as are the lengths of wire between, for example, bends 40 and 43 and between bends 42 and 44. As a result, anchor 20 is symmetrically shaped. In yet another embodiment of the anchor that may be used for present occlusion devices, FIG. 11 depicts a zigzag-shaped anchor 20 that includes a single wire 12 having multiple bends and small loops 50 (see FIG. 12 for an enlarged view of small loop 50). Like the other single wire embodiments of the present anchors, the ends of wire 12 may be secured to each other and to coil 30 at or near the distal end of coil 30. While three bends 52 characterize the distal portion of anchor 20 in FIG. 11, it is to be understood that fewer or greater than three bends 52 may be used. However, three bends 52 are well-suited to evenly distributing the expansile force of anchor 20 against the interior of body passageway in which it is deployed. Specifically, the expansile force of this configuration may be evenly distributed along the circumference of the effected body passageway. As shown, filament 18 may be threaded through small loops 50 and into the coil passageway of coil 30. It should be noted that as with all of the present occlusion devices, filament(s) 18 may enter the coil passageway beginning at the distal end of coil 30 or at any point along coil 30 through an appropriately situated gap. It is also to be understood that, although it is not shown, upon deployment, coil 30 may fill all or at least a part of the space defined by anchor 20. Alternatively, coil 30 may trail (i.e., be located proximately of) anchor 20 after occlusion device 10 is deployed. Alternative embodiments of the present occlusion devices may not include filament 18. FIGS. 12-14 illustrate different stages of the delivery of occlusion device 10 having anchor 20 in the shape of a bent loop. The ends of the wire that may be used to form anchor 20 may be secured to each other and occluder 30 in the manner described above. Further, the wire ends may be attached to each other in a manner that results in the creation of a short segment near the proximal end of the anchor and the distal end of the occluder that is unbent. Further, the wire portions may be arranged in parallel with each other along such a short segment. This short segment, which may be used with any of the anchors disclosed herein, may add stability to the shape of the particular anchor and may facilitate the attachment of the particular occluder. The bent loops that may be used for anchor 20 may have any suitable shape for securely contacting the interior of a given body passageway, including circular (or substantially circular) and elliptical (or substantially elliptical) shapes. FIG. 15 is a top view of only anchor 20 of the embodiment of occlusion device 10 shown in FIG. 14 as it would appear after deployment. As shown, anchor 20 may be provided with a bend 60 that facilitates loading occlusion device 10 into a delivery catheter. In other words, bend 60 makes it easier to compress anchor 20 so as to reduce its size, or profile, and slip it into a delivery catheter for deployment. Many shapes for the bent loop anchors are possible. For example, FIGS. 22 and 23 illustrate the front and top views of one such configuration. FIG. 16 depicts a deployed occlusion device 10 having a bent loop for anchor 20 and a coil for occluder 30. Note that while the loop forming anchor 20 is bent so as to contact the interior of the body passageway near bend 60, the loop may also be bent so as to contact the interior of the body passageway at a more proximal location along the bent loop, as shown, for example, in FIG. 14. Here, as in similar embodiments throughout this disclosure, "proximal" refers to the position along the bent loop as if it were stretched relatively straightly within a delivery catheter. Additionally, note that coil 30 may be arranged so as to contact the interior of the body passageway, thereby further anchoring the occlusion device within the body passageway. As illustrated in FIG. 17, to facilitate deployment of the occlusion devices that do not include filaments 18, the proximal end of the occluders may be provided with an interdigitated cap 70 (i.e., the proximal end may be "interdigitated"), which is also depicted in FIG. 16. As a result, deployment using pusher wire 36 having a corresponding interdigitated cap 72 is possible. Such an interdigitating mechanism allows for the firm yet separable connection of occluder 30 to pusher wire 36. Interdigitated cap 70 may be attached to occluder 30 using any suitable means, including welding, soldering, crimping, friction-fit, etc. Alternatively, any suitable mechanism for separably joining occluder 30 to pusher wire 36 may be used, including any suitable quick- release type or latching mechanism. FIGS. 18 and 19 depict aspects of bent-loop anchors 20 relevant to their sizing. For example, FIG. 18 depicts that anchor 20 may include dimension 64, which extends between bend 60 and the short vertical segment of the wires forming the bent loop anchor. Dimension 64 is also depicted in FIG. 19, as is dimension 62, which extends between the sides of anchor 20 and is perpendicular to dimension 64. FIG. 18 also depicts dimension 66, which extends between secondary curve 68 and bend 60. Primary curve 69 is also depicted in FIG. 18. Accordingly, it is to be understood that while anchor 20 is shaped like a bent loop, the term "bent" includes a single gentle curve, as well as multiple curves, such as 68 and 69. Turning to sizing, for most body passageways, dimensions 62 and 64 may be configured not to exceed 25-33% of the diameter of the body passageway to be occluded. When the targeted body passageway possesses a relatively thin and compliant wall, this range may be exceeded. Additionally, FIG. 20 illustrates -that primary curve 69 may have a greater radius, R69, than radius R68 of secondary curve 68. Such a bent-loop anchor 20 may be thought of as cobra-shaped. Radius R68 should be equal to or less than the diameter of the body passageway to be occluded in order for the portion of anchor 20 characterized by dimension 66 in FIG. 18 to turn proximally after leaving the tip of the delivery catheter, as shown, for example, in FIG. 12. Otherwise, anchor 20 may not be able to take on its preprogrammed shape, and could remain elongated within the body passageway. As discussed generally above, the thrombogenicity of the present occlusion devices may be improved by providing the occluders (e.g., coils) with strands of material such as polyester. See, for example, strands 80 attached intermittently along the proximal end of coil 30 in FIG. 17. The strands may be placed in bundles at every 1.5 to 2.0 centimeters along the occluder, for the entire length of the occluder. The strands may also be attached to the relevant occluder, particularly with respect to coils, without forming bundles and without leaving empty sections, or spaces, along the occluder. h another embodiment, fibrous material may be braided around a particular occluder, especially coils, forming an even layer on its surface. As shown in FIG. 21, anchor 20 may have two bent loops. The loops may be attached to each other in any suitable fashion, using any of the techniques described above. That is, the loops may be operably coupled to one another. For example, the wire ends of both bent loops may be attached to each other to form short proximal segments (as discussed above), and those short proximal segments may be attached to each other. The short segments for the double-loop anchor may be even shorter than that of a single loop anchor. Although occlusion device 10 having two bent loops for anchor 20 is depicted in FIG. 21 as being deployed in a relatively symmetrical arrangement within the body passageway, it is to be understood that varying dimension 80, which is two times dimension 64, may result in more asymmetrical arrangements of deployed occlusion devices within body passageways. For example, asymmetrical arrangements tend to result when dimension 80 exceeds about 135% of the diameter of the body passageway. Asymmetrical arrangements generally do not effect the ability of the present anchors to remain secured within a body passageway. Further, it has been the inventors' experience that if the diameter of the body passageway is equal to or exceeds half of dimension 80, the distal ends of the two loops will have enough space to turn back and not remain elongated within the body passageway. Deployment of the filament-free occlusion devices may be achieved in a manner that is generally similar to the one described above. The occlusion device may be loaded into an appropriately-sized delivery catheter by compressing the anchor (i.e., by reducing its profile, or size) and sliding it and the attached occluder into the delivery catheter. The occluder may be connected to a pusher wire at any suitable stage of loading. The delivery catheter may then be advanced to the target location as described above. Once in place, deployment of the occlusion device may begin by pushing the occluder distally while maintaining the position of the delivery catheter. Deployment may alternatively begin by holding the pusher wire steady while the delivery catheter is withdrawn, thereby exposing the anchor to the body passageway. Any combination of these techniques may also be utilized. After deploying the anchor, it will contact the interior of the body passageway at multiple locations, thereby stabilizing the anchor for deployment of the occluder. In the case of a coil used as an occluder, the coil may then be deployed using the same techniques described for deployment of the anchor. Additionally, and as described above with respect to the filament occlusion devices, rotation of the delivery catheter may further facilitate the precise deployment of the filament-free occlusion devices. If the occlusion device is malpositioned after deployment, or if the patient would benefit from repositioning the occlusion device during deployment, the pusher wire and delivery catheter may be manipulated so as to re-house the misplaced portion of the occlusion device, and the process may begin again. Examples of single bent loop and double bent loop deployments (acute animal experiments) In an acute study, six single bent loop occlusion devices and two double bent loop occlusion devices were tested in the IVC of four pigs. All the anchors for the devices were made of 0.012-inch nitinol wire. The coils used for the occluders were equipped with 8-10 mm long polyester fibers, which were contiguously arranged along the coils' total lengths. The pigs were heparinized (100 units/kg) at the beginning of the procedure. PIG 682 A 7-F Lumax guiding catheter (COOK Inc.) was advanced into the suprarenal segment of INC (a-p diameter was measured as 25 mm) from the left iliac vein. A double bent loop occlusion device was tested (Anterio-posterior diameter: 33 mm, lateral diameter (e.g., dimension 64) of the single bent loops was 18 and 19 mm, respectively; anchor's height (i.e., distance between top of unconstrained bent loops and location of attachment to coil) was 17 mm). A 32-cm-long, 0.038-inch, 10-mm-diameter stainless steel spring coil was attached to the anchor. The proximal end of the coil was equipped with a piece of tubing formed for use as an intedigitating connection. A 0.052-inch diameter delivery cable equipped with an interdigitating connection and a button release mechanism was used to push and withdraw the coil and anchor within the guiding catheter. The anchor was deployed and retrieved three times. There was no problem with moving the coil except that the longer than usual coil showed increased stretchablity. As a result, the anchor followed the pulling movements with some delay. The coil was then deployed and partially withdrawn 4 times. Eventually it was detached from the delivery cable A single bent loop occlusion device (A-P diameter: 19 mm, lateral diameter: 20 mm, height: 15 mm) with a 0.038-inch, 36-cm-long, 9 mm diameter coil was deployed infrarenally. The anchor was deployed and retrieved three times. The anchor readily took on its preprogrammed shape. The coil was then deployed. It was completely deployed and released 4 times. Eventually it was released from the delivery cable. In the caudad portion of the INC, another single bent loop occlusion device (A-P diameter 20 mm, lateral diameter: 15 mm; height: 13 mm) with a 0.038-inch, 23-cm-long, 7-mm, diameter coil was used. First, the anchor was deployed and retrieved 4 times, then the coil was deployed. Both the coil and the anchor were retrieved completely twice. Then the coil was released and detached from the delivery cable. A medium sized single bent loop occlusion device (A-P diameter: 15.5 mm, lateral diameter: 13 mm, height: 12 mm) with a 0.038-inch, 16 cm-long, 6 mm diameter coil was deployed in the left iliac vein. Both the coil and the anchor were completely deployed and retrieved eight times. The coil was deployed and partially or completely retrieved and redeployed another 6 times. Eventually the coil was released. All the coils deployed in pig 682 showed compact configurations. Plain films (a-p) and lateral were taken to document the coils' position within the vessel. At necropsy, the cava was removed in toto. The coils formed compact plugs within the INC. They were firmly anchored to the vessel wall. The double bent loop anchor wire caused shallow but definite indentations on the intimal layer. There were soft red clots attached to the coil plugs. Between the coil plugs contiguous clot filled the lumen. There was no sign of any injury to the vessel wall. Pig 685 A single bent loop anchor (A-P diameter 18 mm., lateral diameter. 16 mm, height: 15 mm.) with a 0.038-inch, 25-cm-long, 8.5-mm-diameter coil was advanced through a 7-F Lumax guiding catheter. The anchor was deployed and retrieved 5 times. Eventually, it was deployed in the very caudad INC (just above the iliac junction) where the a-p diameter of the INC was measured as 13 mm. The anchor always readily assumed its preprogrammed shape. At the level of deployment, the anchor was stable: even forceful cephalad movement of the catheter could not dislodge it. The coil was then deployed. At the first attempt, a very tight conglomerate was formed. In 12 minutes after deployment, complete occlusion of the INC was seen and documented by angio. At necropsy, the occluded segment of the INC was also taken out. At the level of the anchor, a 1 x 2 cm soft red clot was found attached to the coil plug. The anchor could not be dislodged by using pushing/pulling forces. The anchor wire was clearly seen through the thin vessel wall. There was no damage to the vessel wall related to the deployment of the occlusion device. Pig 688 A double bent loop occlusion device was introduced via a 7-F Lumax guiding catheter. The anchor tested (Anterio-posterior diameter: 33 mm, lateral diameter of the single loops was 18 and 19 mm, respectively; anchor's height was 17 mm) was attached to a 0.038-inch, 43-cm- long, 8-mm diameter coil. The anchor was deployed and retrieved 3 times. Eventually, it was deployed in the suprarenal INC where the a-p diameter of the INC was measured as 21 mm. The anchor readily assumed its pre-programmed shape. At the level of deployment, the anchor was stable: even forceful cephalad (i.e., toward the head) movement of the catheter could not dislodge it. The coil was deployed then but was not retrieved because of its length and prominent stretchability within the catheter. The coil plug formed a very tight conglomerate at the first attempt. Then the coil was deployed. Another single bent loop occlusion device (A-p diameter: 19 mm, lateral diameter: 20 mm, height: 15 mm) with a 0-038-inch, 23-cm-long, 8-mm-diameter coil was then deployed in the infrarenal portion of the INC where the lumen was 14 mm (a-p). The anchor was deployed and retrieved 3 times, and then the coil was deployed and retrieved 5 times. There was no problem with the retrievability of the anchor and the coil. Eventually a compact plug was achieved. 12 minutes after the single bent loop occlusion device was deployed, complete occlusion of the IVC was seen; a pair of ascending lumbar veins were readily activated as functioning collaterals. At necropsy, the occluded segment of the INC was taken out. At the level of the double bent loop occlusion device, a 1 x 3 cm soft red clot was attached from above to the coil plug. The single bent loop anchor could not be dislodged by using pushing/pulling forces. The anchor wire was clearly seen through the thin vessel wall. A 2 x 1 cm soft red clot was attached to the coil plug from below. Between the two coils, a tough, contiguous red clot was formed that completely filled the lumen of the IVC. There was no damage to the vessel wall related to the deployment of any of the occlusion devices. Pig 686 A single bent loop occlusion device (a-p diameter: 17.5 mm, lateral diameter: 17 mm, height: 13 mm) was attached to a 0.038-inch, 26 cm-long, 10.5 mm diameter coil. It was deployed at the renal level of the IN. First, the anchor was deployed from the catheter. It was retrieved and re-deployed 7 times without difficulty. The anchor was able to assume its shape readily within the IN lumen. The coil was then deployed. It was retrieved and re-deployed 9 times. Eventually the coil was detached from the delivery pusher (button release). A compact plug was surrounded by contrast flow and seen. Within 1 hour, partial occlusion occurred. With Beuthanasia the pig was sacrificed. In the IN, the anchor leaned against the wall at several sites ensuring good fixation of the plug. There was a compact plug with soft red clot that could not completely fill the lumen because of the junctions of renal veins. There was no sign of any damage to the vessel wall related to coil deployment. *** Straight loop anchors As an alternative to the bent loop anchors described above, it is also feasible to create a suitable anchor from a straight loop that is basically a two-, rather than a three-, dimensional structure. FIG. 24 illustrates such an anchor 20. In one embodiment of such an anchor, a nitinol wire having a diameter of 0.007 to 0.010 inches, including, for example, 0.009 inches, may be used to form a generally annular-, or round-, shaped loop. Two to four millimeters proximate the ends of the wire may be united and placed in the lumen of a stainless steel spring coil. Silver solder may be used to make a firm connection between the wire ends and between the wire ends and the coil. The loop may be formed from any suitable shape, including a generally elliptical shape or an oval shape. The inventors' preliminary bench top and animal experiences have shown that a loop made from a 0.009-inch nitinol wire and having a diameter of 9-mm has been effective at anchoring itself in a vessel with a diameter of 5-6 mm. A 7-F guiding catheter may be used to deploy such an anchor (to which a coil is, of course, attached). Furthermore, the compression needed for placement, travel and/or withdrawal of the anchor within the lumen of the guiding catheter does not cause permanent deformation to the nitinol wire loop. In other words, the roundness of the loop is not compromised and it regains its preprogrammed shape once unconstrained. Like the foregoing bent loop anchors, a bend (i.e., like bend 60 above) may be made at the attachment site created between the free ends of the loop wire and the coil. This bend facilitates the loop's small profile inside the lumen of a catheter, and does not compromise the expansile force of the loop. This is advantageous when a wire larger than 0.009-inch should be used to form a larger and stronger loop in a body passageway with a diameter greater than 5-6- mm. The radial force of a loop without such a bend may prevent the loop's withdrawal or advancement into the lumen of an appropriately-sized (e.g., 7-F) guiding catheter, and it may be caught by the rim of the tip of the catheter. By creating a waist 82 the proximal end of the anchor, as shown in FIG. 26, the retrievability of the anchor may be facilitated without any loss of expansile force. Waist 82 may be used in conjunction with a bend (such as bend 60 above) or without such a bend. In place of a bend like bend 60 above, a small loop similar to small loop 50 above may be utilized. Like bend 60 above, this small loop facilitates the compressibility of the loop forming the anchor. This configuration can offer adequate expansile force provided that if straight segments are utilized, they are kept reasonably short. While a generally oval or elliptical loop like the one depicted in FIG. 27 may be used in place of a generally round loop for anchor 20, one should take into account that the radial force of such a design will be less than that of a generally round loop provided that both are made from the same size nitinol wire. The inventors' bench top tests have shown that the diameter of a round loop anchor should exceed the diameter of the body passageway by 30-40% to most effectively anchor the coil. If an oval loop with a front-end bend (e.g., bend 60) is used, however, the transversal diameter of the loop should be approximately twice the diameter of the body passageway to be occluded. Non-loop anchors in addition to those above In addition to those occlusion devices above having anchors with multiple acute bends and sometimes multiple wires, other embodiments of anchor 20 may be formed from wires having gentle curves. For example, FIGS. 28-30 illustrate a single wire 12 that has been preprogrammed to have a C-, S-, or corkscrew- (i.e., at least one full turn) shape, respectively. Tips 14 are attached to the ends of the wires 12. In another embodiment, two wires 12 may be joined together and arranged in a crossing fashion to a achieve a relatively symmetrically shape, as shown in FIG. 31. Alternatively, the curved wires may be arranged so as not to cross each other. In either embodiment, a single wire that is bent at the location where 2 wires would otherwise be joined, may alternatively be used. Three or more wires may also be used as shown in FIG. 32. Although not shown, the wires may be twisted together to improve their stability with respect to each other. An additional occluder useful with any of the anchors disclosed herein is the brush occluder 30 depicted in FIG. 33. The brush occluder is particularly well suited to use with the immediately foregoing multiple-wire anchors. The brush may be made from a cylindrical segment 86 (made from any biocompatible material such as stainless steel) having several filaments 88 attached to it. In one embodiment, these filaments may be attached to cylindrical segment 86 at an approximately right angle. The filaments may be made from any suitable material that is thrombogenic. The filaments may also possess shape memory qualities (like nitinol) to facilitate shaping them to take on an approximately right-angle arrangement to the cylindrical segment once they are unconstrained. As a result, occlusion device 10 will no tilt in the body passageway and the filaments may fill the space around the cylindrical segment. All of the present occlusion devices disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the techniques of this invention have been described in terms of specific embodiments, it will be apparent to those of skill in the art that variations may be applied to the present occlusion devices without departing from the concept, spirit and scope of the invention. REFERENCES The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference. 1. Gianturco C, Anderson JH, Wallace S. Mechanical device for arterial occlusion. A JR. 1975; 124.-428-435. 2. Chuang NP, Wallace S, Gianturco, C. A new improved coil for tapered-tip catheter for arterial occlusion. Radiology 1980; 135:507-509. 3. Hawkins J, Quisling RG, Mickle JP, Hawkins IF. Retrievable Gianturco-coil introducer. Radiology 1986; 158:262-264. 4. Remy-Jardin M, Wattinne L, Remy J. Transcatheter occlusion of pulmonary arterial circulation and collateral supply: failures, incidents, and complications. Radiology 1991; 180:699-705. 5. White R, Lynch-Νyhan A, Terry P et al. Pulmonary arteriovenous malformations: techniques and long-term outcome of embolotherapy. Radiology 1988; 169:663:669. 6. Keller FS, Rδsch J, Barker AF, Νath PH. Pulmonary arteriovenous fistulas occluded by percutaneous introduction of coil springs. Radiology 1984; 152:373:375. 7. Butto F, Hunter DW, Castaneda-Zuniga W, Amplatz K. Coil-in-coil technique for vascular embolization. Radiology 1986,161:554-555. 8. Castenada-Zuniga WR, Tadavarthy SM, Gonzalez R, Rysavy J, Amplatz K. Single barbed stainless steel coils for venous occlusion. A simple but useful modification. Invest Radiol 1982; 17:186-188. 9. Lund G, Cragg AH, Rysavy JA, Castaneda F, Castenada-Zuniga WR, Amplatz K Detachable stainless-steel spider. Radiology 1983; 148;567-568. 16. Castenada-Zuniga WR, Tadavarthy SM, Galliani CA, Laerum F, Schwarten DE, Amplatz K. Experimental venous occlusion with stainless-steel spiders. Radiology 1981; 141:238-242. 11. Ing FF, Bierman PZ. Percutaneous transcatheter coil occlusion of the patent ductus arteriosus aided by the nitinol snare: further observations. Cardiovasc Intervent Radiol 1995; 18:222-226. 12. Sommer RJ, Gutierrez A,. Lai WW, Pamess. Use of preformed nitinol snare to improve transcatheter coil delivery in occlusion of patent ductus arteriosus. Am j Cardiol; 1994, 74:836-839. 13. Zubillaga AF, Guglielimi G, Ninuela F, Duckwiler GR. Endovaesulur occlusion of intracranial aneurysams with electrically detachable coils: correlation of aneurysm neck size and treatment results. AJΝR 1994; 15:815-820. 14. Guglielimi G, Ninuela F, Duckwiler G, Dion J, Stocker A. High-flow, small-hole arteriovenous fistulas treatment with electrodetachable coils. AJΝR 1995; 16:325-328. 15. Ninuela F, Duckwiler G, Mewed IvL Guglielad detachable coil embolirAtion of acute intracramal aneurysm penoperative anatomical and clinical outcome in 403 patients. J Νeurosurg 1997,86.475482 16. Marks MP, Chee H, Liddel RP, Steinberg GK, Panahian Ν, Lane B. A mechanically detachable coil for the treatment of aneurysms and occlusion of blood vessel. AJΝR 1994;15:821-827. 17. Reidy JF, Qureshi SA. Interlocking detachable platinum coils, a controlled embolization device: early clinical experience. Cardiovasc intervent Radiol 1996; 19:85-90. 18. Uzun O, Hancock S, Parsons JM, Dickinson DF, Gibbs JL. Transcatheter occlusion of the arterial duct with Cook detachable coils: early experience. Heart 1996; 76:269-273. 19. Tometzki AJ, Arnold R, Peart I et al. Transcatheber occlusion of the patent ductus arteriosus with Cook detachable coils. Heart 1996, 76:531-535. 20. Dutton JAE, Jackson JE, Hughes JMB et al. Pulmonary arteriovenous malformations Results of treatment with coil embolization in 53 patients. AJR 1995; 165:1119-1125. 21. Hughes SR, Graves VB, Kesava PP, Rappe AH. The effect of flow arrest on distal embolic events during arterial occlusion with detachable coils: a canine study. AJTSfR 1996;17:685-691. 22. Chuang NP, Szwarc I. The coil baffle in the experimental occlusion of large vascular structures. Radiology 1982;143:25-28. 23. Levey DS, Teitelbaum GP, Finck EJ, Pentecost MJ. Safety and efficacy of transcatheter embolization of axfllary and shoulder arterial injuries. JNIR 1991; 2:99-104. 24. Celiker A. Qureshi SA, Bilgic A et al. Transcatheter closure of patent arterial ducts using controlled-relessed coils. Eur Heart J 1997;18:450-454. 25. Mauro MS. Jaques P. Transcatheter management of pseudoareurysms complicating pancreatitis. JNIR 1991; 2:527-532. 26. Yedlicka JW, Bjarnawn K Hunter DW, Castenada Zuniga WR, AmPlRtz K. Persistent pneurno thorax following embolization of a Pulmonary arteriovenOus malformation. JNIR 1994;5:887-889. 27. Krichenko A, Benson LΝ, Burows P, Moes CAF, McLaughlin P, Freedom RM. Angiographic classification of the isolated, persistently patent ductus arteriosus and impUcations for percutaneous catheter occlusion. Am J Cardiol 1989; 63:877-880. 28. Cambier PA, Kirby WC, Wortham DC, Moore JW. Percutaneous closure of the small (<2,5 mm) patent ductus arteriosus using coil embolization. Am J Cardiol 1992; 69:815-816. 29. Lloyd TF, Fedderly R, Mendelsohn AM, Sandhu SY, Beekman RH. Transcatheter occlusion of patent ductus arteriosus with Gianturco coils. Circulation 1993; 88:1412-1420. 30. Hijazi ZM, Geggel RL. Tramscatheter closure of large patent ductus arterimus (> or = 4 mm) with multiple Gianturco coilv Immediate and mid- results. Heart 1996; 76:536-540. 31. Dalvi B, Goyal N, Νarula D, Kulkarni H, Ramakantan R. New technique using temporary balloon occlusion for transcatheter closure of patent ductus arteriosus with Gianturco coils. Cathet Cardiovasc Diagn 1997; 41 :62-70. 32 Galalo de Moor M, Fadley F at al. Problems encountered during introduction of Gianturco coils for transcatheter occlusion of the patent arterial duct. Eur Heart J. 1997, 18:625-630. 33. Lois JF, Gomes AS, Smith DC, Laks H. Systemic-to-pulmonary collateral vessels and shunts: treatment with embolization. Radiology 1988; 169: 671 -676. 34. Perry SB, Rome J, Keane JF at al. Transcatheter. Closure of coronary artery fistulas. Am Coil Cardiol 1992; 20:205-209. 35. Chomyn JJ, Craven WM Groves BM, Durham JD. Percutaneous removal of a Gianturco coil from the pulmonary artery with use of flexible intravascular forceps. JIR 1991; 2:105-106. 36. Smith DC, Kohne RE, Taylor PC. Steel coil embolization supplementing filter placement in a patient with a duplicated inferior vena cave. JNIR 1992; 3 :577-580. 37. Kόnya A, Wright KC, Wallace S. Anchoring coil embolization in a high-flow arterial model: A pilot study. JNIR 1998; 9:249-254. 38. Maeda M, Okada A, Takamura M, Kawata S, Tomoda K, Tomiyama Ν, Curz MA, Johhoh T, Murakami T, Hamada S, Oi K Νakamura H. "Coil Anchor": A new device to improve coil embolization: Experimental and Initial Clinical Use. 7 th International Symposium on Interventional Radiology & New Vascular Imaging and 28 th Annual Meeting of the Japanese Society of Angiography & Interventional Radiology. Osaka, Japan, May 16-19,1999. Abstract No. 20 in Cardiovascular and Interventional Radiology 1999; 22(Suppl):S54.

Claims: CLAIMS 1. An occlusion device comprising: an anchor having a variable shape; an occluder attached to the anchor at a first location; and a filament attached to the anchor at a second location; wherein manipulation of the filament alters the variable shape of the anchor. 2. The occlusion device of claim 1 , wherein the anchor includes a wire. 3. The occlusion device of claim 2, wherein the wire is stainless steel. 4. The occlusion device of claim 2, wherein the wire is a nickel titanium alloy. 5. The occlusion device of claim 1, wherein the anchor includes a wire having multiple acute bends. 6. The occlusion device of claim 1, wherein the anchor includes a wire having two ends, both of which contact the interior of a body passageway when the occlusion device is deployed. 7. The occlusion device of claim 1, wherein the anchor includes a wire having two ends, neither of which contacts the interior of a body passageway when the occlusion device is deployed. 8. The occlusion device of claim 1, wherein the occluder fits at least partially within the anchor after the occlusion device is deployed within a body passageway. 9. The occlusion device of claim 1, wherein the occluder trails the anchor after the occlusion device is deployed within a body passageway. 10. The occlusion device of claim 1 , wherein the filament is polypropylene. 11. The occlusion device of claim 1 , wherein the occluder includes a coil. 12. A device useful in blocking flow through a passageway in a living being, the device comprising: an anchor having a variable shape; a coil attached to the anchor at a first location, the coil having a passageway; and a filament attached to the anchor at a second location; wherein the filament extends away from the second location through at least a portion of the passageway to a location from which the filament can be manipulated; and wherein manipulation of the filament alters the variable shape of the anchor. 13. The occlusion device of claim 12, wherein the anchor includes a wire having two ends, each of which is covered by a coil tip. 14. The occlusion device of claim 13, wherein the wire is stainless steel. 15. The occlusion device of claim 13 , wherein the wire is a nickel titanium alloy. 16. The occlusion device of claim 12, wherein the anchor includes multiple acute bends. 17. The occlusion device of claim 12, wherein the anchor includes two ends, both of which contact the interior of a body passageway when the device is deployed. 18. The occlusion device of claim 12, wherein the coil fits at least partially within the anchor after the device is deployed within a body passageway. 19. The occlusion device of claim 12, wherein the coil trails the anchor after the occlusion device is deployed within a body passageway. 20. The occlusion device of claim 12, wherein the filament interconnects multiple acute bends of the anchor. 21. A retrievable device useful in blocking flow through a vessel, the device comprising: a wire forming at least part of an anchor, the anchor having a variable shape; a coil attached to the anchor at a first location, the coil having a passageway that houses at least a portion of the wire; a filament attached to the anchor at a second location; wherein the filament extends away from the second location through at least a portion of the passageway to a location from which the filament can be manipulated; and wherein manipulation of the filament alters the variable shape of the anchor. 22. An occlusion device comprising: a loop; and an occluder attached to the loop; wherein, after deployment, the loop contacts the interior of a body passageway in order to prevent the occlusion device from migrating. 23. The occlusion device of claim 22, wherein the loop is curved. 24. The occlusion device of claim 23, wherein the occluder includes a coil, and, after deployment, the curved loop defines a space occupied at least in part by the coil. 25. The occlusion device of claim 23, wherein the occluder includes a coil that trails the loop after the occlusion device is deployed within a body passageway. 26. The occlusion device of claim 22, wherein the loop is characterized by a bend that facilitates loading the occlusion device into a catheter for delivery. 27. The occlusion device of claim 22, wherein the occluder includes a coil. 28. The occlusion device of claim 27, wherein the coil includes a coil passageway and the loop includes a wire extending at least partially into the coil passageway. 29. The occlusion device of claim 28, wherein the wire is a nickel titanium alloy. 30. The occlusion device of claim 22, wherein the occluder includes a coil to which one or more threads of polyester are attached. 31. The occlusion device of claim 22, further comprising a second loop operably coupled to the loop. 32. The occlusion device of claim 31, wherein both the loop and second loop are curved. 33. The occlusion device of claim 31 , wherein the occluder includes a coil. 34. The occlusion device of claim 33, wherein the coil includes a coil passageway and the loop includes a wire extending at least partially into the coil passageway. 35. The occlusion device of claim 34, wherein the wire is a nickel titanium alloy. 36. The occlusion device of claim 31, wherein the occluder includes a coil to which one or more threads of polyester are attached. 37. The occlusion device of claim 31, wherein the occluder includes a coil that trails the loop and the second loop after the occlusion device is deployed within a body passageway. 38. The occlusion device of claim 31, wherein both loops are characterized by bends that facilitate loading the occlusion device into a catheter for delivery. 39. A device useful for occluding a passageway in a body comprising: a wire having two ends, the wire forming a closed structure; and an occluder attached to the wire proximate at least one of the ends; wherein the closed structure may be elongated so as to facilitate delivery of the device into a body passageway; and wherein, after deployment, the closed structure contacts the interior of the body passageway in order to prevent the device from migrating. 40. The device of claim 39, wherein the occluder includes a coil, and, after deployment, the closed structure defines a space occupied at least in part by the coil. 41. The device of claim 39, wherein the occluder includes a coil that trails the closed structure after the device is deployed within a body passageway. 42. The device of claim 39, wherein the closed structure is characterized by a bend that facilitates loading the device into a catheter for delivery. 43. The device of claim 39, wherein the occluder includes a coil. 44. The device of claim 43, wherein the coil includes a coil passageway and the wire extends at least partially into the coil passageway. 45. The device of claim 44, wherein the wire is a nickel titanium alloy. 46. The device of claim 39, wherein the occluder includes a coil to which one or more threads of polyester are attached. 47. The device of claim 39, further comprising a second closed structure operably coupled to the closed structure. 48. The device of claim 47, wherein the occluder includes a coil. 49. The device of claim 48, wherein the coil includes a coil passageway and the wire extends at least partially into the coil passageway. 50. The device of claim 49, wherein the wire is a nickel titanium alloy. 51. The device of claim 47, wherein the occluder includes a coil to which one or more threads of polyester are attached. 52. The device of claim 47, wherein the occluder includes a coil that trails the closed structure and the second closed structure after the device is deployed within a body passageway. 53. The device of claim 47, wherein both closed structures are characterized by bends that facilitate loading the device into a catheter for delivery.

Inventors: KONYA ANDRAS, WRIGHT KENNETH C, KONYA, ANDRAS, WRIGHT, KENNETH, C.
Applicants: UNIV TEXAS, BOARD OF REGENTS, THE UNIVERSITY OF TEXAS SYSTEM
Application year: 2001
Main classification: A61B
IPC codes: A61B17