Patent Publication Number: US-2021169496-A1

Title: System for and method of treating aneurysms

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/984,644, filed on May 21, 2018, which is a continuation of U.S. patent application Ser. No. 15/675,255, filed on Aug. 11, 2017, which is a continuation of International Application No. PCT/US2016/019135, filed on Feb. 23, 2016, which claims priority to and the benefit of U.S. Application No. 62/120,456, filed on Feb. 25, 2015, each of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Aneurysms are abnormal bulging or weakening of a blood vessel, often an artery, and can have many complications. A bulging of the blood vessel can disrupt or put pressure on surrounding tissues. In the brain, this can result in a variety of side effects, such as impaired vision, impaired speech, impaired balance, etc. Further, the aneurysm creates a volume that is not along the main flow path of the blood through the blood vessel. It therefore can serve as a location for blood to become stagnant and, due to swirling eddy currents, can contribute to the formation of a thromboembolism. If the aneurysm ruptures, they can cause severe internal bleeding. 
     Aneurysms can be treated externally with open surgery. Such procedures typically involve closing off the entrance or “neck” of the aneurysm with a device such as vascular clamp or a ligature. However, such open surgical procedures can be highly invasive and may lead to trauma to the adjacent tissue and other side effects. 
     Aneurysms can also be treated through endovascular procedures. In one procedure, detachable lengths of wires (e.g., coils) are inserted into the interior volume of the aneurysm using a catheter. The coils are intended to fill the volume of the aneurysm to decrease the flow of blood into the aneurysm, inducing stagnation of flow and stimulate clotting within the aneurysm. In settings of large cerebral aneurysms, filling of the aneurysm with multiple coils can lead to mass effect that may induce brain swelling and be an independent cause for new symptoms. In another procedure, for aneurysms with a relatively large neck, the adjunctive use of stents assists with the retention of the coils within the aneurysm. This approach has a contraindication to being used when treating ruptured aneurysm, due to the need for additional anti-thrombotic medications. In another procedure, the coils are held in the volume of the aneurysm with a temporary balloon that is inflated in the blood vessel. The balloon is deflated and removed once the mass of coils is secured. In still another procedure, a stent device is placed in the artery to promote flow of blood past the aneurysm. This leads to stagnation of the blood within the aneurysm and thrombosis inside the aneurysm volume. However, a side branch of a main artery in which the stent device is placed may become trapped or “jailed”, which impedes access to the side branch. In other instances, the side branch can become clotted off, possibly causing a stroke. Additionally, such a procedure generally requires the use additional anti-thrombotic medications, which limits the use of such devices in the setting of treatment of ruptured aneurysms. The stent device is generally formed with a relatively tight weave. While the tight weave increases the effectiveness of the stent device in diverting the blood flow, it also impedes or prevents access to the volume of the aneurysm or the jailed artery. In the event that the aneurysm fails to clot, the obstruction of the aneurysm by the stent device prevents the possibility of placing embolic devices inside the aneurysm. Additional procedures such as the placement of additional stents or open surgery may then be required to treat the residual. 
     All procedures that involve packing the volume of the aneurysm suffer from several common shortcomings. First, it can take many coils of wire to fill the volume of the aneurysm, which is time consuming and increases the time it takes to complete the procedure. Further, the coils may be compacted over time to occupy a smaller percentage of the total volume of the aneurysm. A great enough compaction of the coils can be considered a recurrence of the aneurysm and may require further treatment. 
     It would be advantageous to provide an improved system and method of treating an aneurysm. 
     SUMMARY 
     One embodiment relates to a catheter for treating an aneurysm in a blood vessel. The catheter includes a tube, a wire disposed within the tube; and an occlusion element. The occlusion element is disposed on the wire. The occlusion element is configured to fit within the tube and slide out of an opening at distal end of the tube in response to movement of the wire within the tube. The occlusion element is configured to expand to have a radius greater than a radius of the tube and cover a neck portion of the aneurysm. 
     One embodiment relates to a method treating an aneurysm in a blood vessel. The method includes providing a distal portion of a tube to a neck region of the aneurysm, and sliding a wire attached to an occlusion element within the tube so that the occlusion element exits the tube at the neck region. The method also includes separating the occlusion element from the wire after the occlusion element exits the tube. 
     One embodiment relates to an occlusion system for treating an aneurysm in a blood vessel. The occlusion system includes a wire, and an occlusion element disposed on the wire. The occlusion element is configured to be compressed in a conical shape and expand in a disk or concave shape for covering a neck portion of the aneurysm. 
     The invention is capable of other embodiments and of being practiced or being carried out in various ways. Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
         FIG. 1  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to an exemplary embodiment. 
         FIG. 2  is schematic cross-sectional bottom view of the aneurysm occlusion device of  FIG. 1 . 
         FIGS. 3A-3E  are schematic side cross-section views of a catheter deploying the aneurysm occlusion device of  FIG. 1 , according to an exemplary embodiment. 
         FIG. 4  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 5  is a schematic cross-section view of the occlusion device of  FIG. 4  inside of a catheter, according to an exemplary embodiment. 
         FIG. 6  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 7  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 8  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 9  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 10  is a schematic cross-section view of the occlusion device of  FIG. 7  inside of a catheter, according to an exemplary embodiment. 
         FIG. 11  is a schematic cross-section side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 12  is a schematic cross-sectional bottom view of an aneurysm occlusion device, according to an exemplary embodiment. 
         FIG. 13  is a schematic cross-sectional bottom view of an aneurysm occlusion device, according to an exemplary embodiment. 
         FIG. 14  is a schematic cross-sectional bottom view of an aneurysm occlusion device, according to an exemplary embodiment. 
         FIG. 15  is a schematic cross-sectional side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 16  is a schematic cross-sectional side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
         FIG. 17  is a schematic bottom view of an outer anchoring member for an aneurysm occlusion device, according to an exemplary embodiment. 
         FIG. 18A  is a schematic top view of a cover for an aneurysm occlusion device, according to an exemplary embodiment. 
         FIG. 18B  is a schematic side view of the cover of  FIG. 18A  in a partially folded configuration. 
         FIG. 19  is a schematic side view of an endovascular device configured to occlude an aneurysm, according to another exemplary embodiment. 
         FIG. 20  is a schematic cross-sectional side view of an aneurysm with an endovascular device configured to occlude the aneurysm, according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring in general to  FIGS. 1-14 , an aneurysm occlusion device configured to treat an aneurysm  10  is shown according to several exemplary embodiments. The aneurysm  10  is an outwardly extending bulge in the wall  13  of a blood vessel  12  and has an internal volume  14  that is in fluid communication with the blood vessel  12  through an opening at a neck portion  16 . The aneurysm  10  may occur at a portion of the blood vessel  12  at which the wall  13  is weakened by disease or trauma. In one embodiment, the aneurysm  10  may be along an artery, such as a cranial artery (e.g., e.g., basilar artery, middle cerebral artery, etc.). The aneurysm  10 , as depicted in the figures is exemplary only and it should be appreciated that the occlusion devices as described herein may be utilized in the treatment of aneurysms of various sizes and locations. For example, the aneurysm  10  may be located between two branches of a blood vessel. 
     Referring to  FIGS. 1-3E , an occlusion device  20  is shown according to one exemplary embodiment disposed in the neck portion  16  of the aneurysm  10  to disrupt or halt the flow of blood flow between the vessel  12  and the internal volume  14  of the aneurysm, thereby reducing the likelihood that the aneurysm  10  will rupture. The occlusion device  20  is configured to be low profile device, minimizing disruptions to surrounding bodies, such as a side branch  18  of the blood vessel  12 . The occlusion device  20  may be configured to be biodegradable or bioabsorbable material and may be configured to promote endothelialization. 
     The occlusion device  20  includes an inner cover  22  (e.g., plate, membrane, etc.) disposed within the internal volume  14  of the aneurysm  10 . The inner cover  22  has an outer diameter that is greater than the diameter of the neck portion  16 . The inner cover  22  is a thin, flexible, concave body that can be distorted (e.g., collapsed) to be inserted through the neck portion  16  into the internal volume  14  of the aneurysm  10  (e.g., inserted by a catheter) and opened to at least partially occlude the neck portion  16 . Concave, as used herein, is meant to describe any body that is contoured to have a hollow or cavity along one side. As shown in  FIG. 1 , in one exemplary embodiment, the inner cover  22  may be generally dome-shaped. In another embodiment, the inner cover  22  may have another concave shape (e.g., conical) that is disposed in the neck portion  16  and opens into the internal volume  14 . In one embodiment, cover  22  can be disk shaped. 
     The inner cover  22  is formed from a flexible (e.g., soft) biocompatible material that can be collapsed into a microcatheter for endovascular delivery to the aneurysm  10 . The flexibility of the inner cover  22  allows it to conform to the shape of the interior surface  15  of the aneurysm  10  and more effectively impeded the flow of blood between the aneurysm  10  and the blood vessel  12 . Closely conforming to the shape of the interior surface  15  of the aneurysm  10  also facilitates the adhesion of the inner cover  22  to the tissue of the aneurysm  10  and the formation of new tissue to close off the neck portion  16 . 
     The inner cover  22  may be sized to fit a specific aneurysm  10 . As shown in  FIGS. 1-2 , the inner cover  22  has a diameter that is greater than the diameter of the neck portion  16  such that a peripheral portion  24  of the inner cover  22  contacts the interior surface  15  of the aneurysm  10 . The flexibility of the inner cover  22  allows the inner cover  22  to be oversized relative to the size of the neck portion  16  without damaging (e.g., rupturing) the aneurysm  10 . For example, an inner cover having a diameter of approximately 5 mm may be utilized to occlude an aneurysm having a neck portion with a diameter of up to 4 mm; an inner cover having a diameter of approximately 8 mm may be utilized to occlude an aneurysm having a neck portion with a diameter of 4-6 mm; and an inner cover having a diameter of approximately 12 mm may be utilized to occlude an aneurysm having a neck portion with a diameter of 6-10 mm. 
     In one embodiment, the inner cover  22  may be formed from a biocompatible metal or metal alloy, such as platinum, stainless steel, titanium, a titanium-nickel alloy (e.g., nitinol). For example, the inner cover  22  may be a concave disk formed from sheet-cut nitinol. The nitinol alloy may be configured to undergo a secondary heat setting to form the desired concave shape. According to an exemplary embodiment, the inner cover  22  may have a thickness of less than 100 microns, to achieve a desired flexibility. In another embodiment, the inner cover  22  may be formed as a relatively dense mesh such as 37 micron mesh formed by a plurality of wires or fibers that are coupled together (e.g., welded, soldered, woven, etc.). 
     In another embodiment, the inner cover  22  may be formed from a biocompatible polymer, such as polytetrafluoroethylene (PTFE), modified polyurethane, silicone or other suitable polymer. In still other exemplary embodiments, the inner cover  22  may be formed from a metal or alloy that is coated with a polymer (e.g., parylene, PTFE, PFE, etc.) to increase lubricity and biocompatibility and to reduce thrombogenicity. The inner cover  22  may be formed as a solid sheet or membrane or may be a relatively dense mesh. In some embodiments, the inner cover  22  may include laser drilled nylon sheeting to provide a matrix for endothelialization, while reducing the bulk of the segment. Another embodiment may involve two photon polymerization, or 3-D printing of a biocompatible material to form the inner cover  22  directly onto the delivery system, or to overlie a skeleton frame which is attached to the delivery system, allowing customization of the final shape of the inner cover  22  at the time of treatment. 
     Referring now to  FIGS. 3A-3D , the inner cover  22  is showing being deployed with a catheter  30  according to an exemplary embodiment. Referring to  FIG. 3A , the catheter  30  including a push wire  32  is advanced through the blood vessel  12  to the location of the aneurysm  10 . A distal end  34  of the catheter is advanced through the neck portion  16  and into the internal volume  14  of the aneurysm  10  or to the portion of the blood vessel  12  proximate the neck portion  16 . The push wire  32  is positioned within a lumen formed in the catheter  30 . The catheter  30  may have a single lumen or the push wire  32  may be positioned within one of several lumens formed within the catheter  30 . The inner cover  22  is coupled to a distal end  36  of the push wire  32  and is housed, in a collapsed configuration, within the lumen. In the collapsed configuration, the peripheral portion  24  of the inner cover  22  is upstream (e.g., closer to the distal end  34 ) compared to a central portion  26  to which the push wire  36  is coupled. Referring to  FIG. 3B , the push wire  32  is moved within the lumen relative to the catheter  30  until the inner cover  22  begins to emerge from the end  34  of the catheter  30 . The inner cover  22  is configured to expand (e.g., due to the internal spring forces of the inner cover  22 ) into an expanded configuration within the internal volume  14  as it clears the end  34  of the catheter  30 . The push wire  32  may be moved relative to the catheter  30  by holding the catheter  30  stationary while the push wire  32  is advanced (e.g., pushing), by holding the push wire  32  stationary and retracting the catheter  30  (e.g., unsheathing), or by a combination of movements of the catheter  30  and the push wire  32 . The inner cover  22  may be partially deployed with the distal end  34  of the catheter  30  positioned within the blood vessel  12  or within the aneurysm  10 . 
     Referring to  FIG. 3C , the distal end  34  of the catheter  30  is advanced into the internal volume  14  of the aneurysm  10  before the inner cover  22  is fully deployed from the catheter  30 . Referring to  FIG. 3D , with the inner cover  22  deployed from the catheter  30 , the catheter  30  and/or the push wire  32  is retracted until the inner cover  22  is seated against the interior surface  15  of the aneurysm. Referring to  FIG. 3E , the distal end  36  of the push wire  32  is detached from the inner cover  22  such that the catheter  30  and the push wire  32  may be withdrawn from the blood vessel  12  while the inner cover  22  remains in the neck portion  16  of the aneurysm  10 . The push wire  32  may be detached from the inner cover  22  by any suitable electrical or mechanical cutting device. Alternatively, the inner cover  22  can be removed by pulling the wire  32  from cover  22  causing cover  22  to engage distal end of tube  30  and be slid off wire  32 . 
     In one embodiment, the inner cover  32  can be formed to be biased toward the open position. In another embodiment, the inner cover  32  can include a mesh supported by rib members or splines radiating outwardly form a center of inner cover  32 . The rib members or splines are biased toward an open position in one embodiment. In one embodiment, the rib members and splines operate in an upside down umbrella operation fashion and lock in the fully open position once the fully open position is reached. 
     Referring now to  FIG. 4-5 , an occlusion device  120  is shown according to an exemplary embodiment disposed in the neck portion  16  of the aneurysm  10  to disrupt or halt the flow of blood flow between the vessel  12  and the internal volume  14  of the aneurysm, thereby reducing the likelihood that the aneurysm  10  will rupture. The occlusion device  120  is configured to be low profile device, minimizing disruptions to surrounding bodies, such as a side branch  18  of the blood vessel  12 . The occlusion device  120  may be configured to be biodegradable or bioabsorbable material and may be configured to promote endothelialization. 
     The occlusion device  120  includes an inner cover  122  (e.g., plate, membrane, etc.) disposed within the internal volume  14  of the aneurysm  10  and similar to the inner cover  22  described above. The occlusion device  120  further includes an inner anchoring member  140  disposed within the aneurysm  10 . The inner anchoring member  140  is configured to anchor the inner cover  122  within the aneurysm  10  in the neck portion  16 . The inner anchoring member  140  provides a relatively rigid body that supports the inner cover  122  and reduces the likelihood that the inner cover  122  will be displaced from the neck portion  14  by the fluid pressure of the blood in the blood vessel  12 . 
     According to an exemplary embodiment, the inner anchoring member  140  includes one or more loops of a coil formed from a suitable biocompatible metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.). The metal coil may be similar to the coils that are typically utilized in an endovascular coiling procedure. The inner anchoring member  140  is coupled to the inner cover  122  and includes at least one coil that contacts the interior surface  15  of the aneurysm  10 . The loops of the inner anchoring member  140  do not fill the entire internal volume  14  or a substantial portion of the internal volume  14 . Instead, the inner anchoring member  140  may include only a small number of loops. In one exemplary embodiment, the inner anchoring member  140  may include a single loop of the coil. In another embodiment, the anchoring member  140  includes a large number of loops substantially filing the internal volume  14 . The orientation, number, and size of the loops of the inner anchoring member  140  may vary depending on the size and shape of the aneurysm  10 . 
     Referring now to  FIG. 5 , the inner cover  122  and the inner anchoring member  140  are shown disposed within a catheter  30  according to an exemplary embodiment. The inner cover  122  is coupled to a distal end  36  of the push wire  32  and is housed, in a collapsed configuration, within the lumen of the catheter  30 . In the collapsed configuration, the peripheral portion  124  of the inner cover  122  is upstream (e.g., closer to the distal end  34 ) compared to a central portion  126  to which the push wire  36  is coupled on a first surface  144 . The inner anchoring member  140  is coupled to a second surface  146  of the inner cover  122  opposite the first surface  142  and is disposed within the lumen of the catheter  30  upstream of the inner cover  122 . 
     The occlusion device  120  including the inner cover  122  and the inner anchoring member  130  is deployed within the aneurysm  10  similar to the process described above with reference to  FIGS. 3A-3E . With the distal end  34  of the catheter  30  positioned proximate to the neck portion  16  of the aneurysm  10 , the push wire  32  is moved within the lumen relative to the catheter  30 . The push wire is moved to cause the anchoring member  40  to reach the internal volume  14  and coil within the internal volume. 
     In one embodiment, the push wire  32  has a circular solid cross section and anchoring member  140  has a coiled cross section (e.g., like a telephone cord) to facilitate coiling in the internal volume  14 . In one embodiment, the push wire  32  and the anchoring member  140  have a circular solid cross section. In one embodiment, the push wire  32  and anchoring member have a coiled solid cross section. 
     After coiling of the anchoring member is complete, the inner anchoring member  140  is pushed out of the catheter and into the internal volume  14 , where is contacts the interior surface  15  of the aneurysm  10 . The push wire  32  is moved further until the inner cover  122  begins to emerge from the end  34  of the catheter  30  to expand into an expanded configuration within the internal volume  14 . The catheter  30  and/or the push wire  32  is then retracted until the inner cover  122  is seated against the interior surface  15  of the aneurysm  10  and held in place by the inner anchoring member  140 . The distal end  36  of the push wire  32  is detached from the first surface  146  of the inner cover  122  such that the catheter  30  and the push wire  32  may be withdrawn from the blood vessel  12  while the inner cover  22  remains in the neck portion  16  of the aneurysm  10  with the inner anchoring member  140  coupled to the second surface  146 . 
     Referring to  FIG. 6 , in one exemplary embodiment, the anchoring member  140  may have a variable stiffness. For example, the inner anchoring member  140  may be relatively pliable at a proximal end  146  and relatively stiff at a distal end  148 . The relatively stiff distal end  146  may be configured to provide additional support to strengthen the walls of the aneurysm  10 . The stiffer portions of the inner anchoring member  140  may be utilized as framing members to create a structure in the internal volume  14  of the aneurysm while the more pliant portions are utilized to fill in the internal volume of the aneurysm and support the inner cover  122 . The stiffness of the inner anchoring member  140  may be controlled in a variety of ways, such as by varying the thickness of the coil, the radius of the coil, and/or by varying the material used to form the coil. 
     The more pliant portions of the inner anchoring member may include a removable sheathe or layer to facilitate the positioning of the stiffer portions of the inner portions of the anchoring member  140  within the aneurysm  10 . The sheathe may be removed once the distal end  148  and the stiffer portions of the inner anchoring member  140  are positioned. 
     In one embodiment, the stiffness of the inner anchoring member  140  may transition smoothly or incrementally along the length of the inner anchoring member  140  between the distal end  148  and the proximal end  146 . In other exemplary embodiments, the inner anchoring member  140  may include two or more distinct zones or portions, each with a different stiffness or other characteristic. The inner anchoring member  140  may include markers or other indicators to delineate the transition from one zone to another. In one embodiment, the indicators may be external, such as indicators provided on an outer shaft coupled to the push wire, each of the outer indicators corresponding to the transition from a zone with a first stiffness to a zone with a second stiffness. In another embodiment, the indicators may be internal, such as radiopaque indicators (e.g., a platinum coating) on the inner anchoring member  140  between the zones. 
     In one embodiment, the anchoring member  140  with a variable stiffness can be utilized without the inner cover  122 . In such an embodiment, the anchoring member  140  fills the internal volume  14 . In one embodiment, a number of anchoring members  140  can be utilized. In one embodiment, the first employed anchoring member  140  has a varying stiffness (e.g., thickness) that is greater than the varying stiffness (e.g., thickness) of the next employed anchoring member. 
     Referring now to  FIG. 7-10 , an occlusion device  220  is shown according to an exemplary embodiment disposed in the neck portion  26  of the aneurysm  20  to disrupt or halt the flow of blood flow between the vessel  22  and the internal volume  24  of the aneurysm  20 , thereby reducing the likelihood that the aneurysm  20  will rupture. The occlusion device  220  is configured to be low profile device, minimizing disruptions to surrounding bodies, such as a side branch  28  of the blood vessel  22 . The occlusion device  220  may be configured to be biodegradable or bioabsorbable material and may be configured to promote endothelialization. 
     The occlusion device  220  includes an inner cover  222  (e.g., plate, membrane, etc.) disposed within the internal volume  14  of the aneurysm  10  and similar to the inner cover  22  described above and an inner anchoring member  240  disposed within the aneurysm  10  and similar to the inner anchoring member  140  described above. The inner anchoring member  240  is configured to anchor the inner cover  222  within the aneurysm  20  in the neck portion  16 . The occlusion device  220  further includes an outer anchoring member  250  disposed in the within the blood vessel  12  proximate the aneurysm  10 . The outer anchoring member  250  provides a relatively rigid body that supports the inner cover  222  and reduces the likelihood that the inner cover  222  will be displaced from the neck portion  14  by the fluid pressure of the blood in the blood vessel  12 . 
     Referring to  FIG. 7 , according to an exemplary embodiment, the outer anchoring member  250  includes a loop  252  of a coil formed from a suitable biocompatible metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.). The metal coil may be similar to the coils that are typically utilized in an endovascular coiling procedure. The loops  252  is coupled to the inner cover  222  and contacts the wall  13  of the blood vessel  12  in one embodiment. The loop  252  is oriented perpendicular to the flow of blood through the blood vessel  12  in one embodiment. Multiple coils or loops  252  can be utilized in one embodiment. 
     Referring to  FIG. 8 , according to an exemplary embodiment, the outer anchoring member  250  includes a first loop  254  and a second loop  256 . The loops  254  and  256  may be loops of a coil formed from a suitable biocompatible metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.). At least one of the loops  254  and  256  are coupled to the inner cover  222  and contact the wall  13  of the blood vessel  12 . The first loop  254  extends about the inner circumference of the blood vessel  12  such that it is oriented perpendicular to the flow of blood through the blood vessel  12 . The second loop  256  is oriented parallel to the flow of blood through the blood vessel  12 . The second loop  256  is formed of a coil having a fairly small diameter and does not substantially impede the flow of blood through the blood vessel. In other embodiment, the outer anchoring member  250  may include more than two loops. The orientation, number, and size of the loops may vary depending on the size and shape of the blood vessel  12 . 
     Referring to  FIG. 9 , according to another exemplary embodiment, the outer anchoring member  250  includes a stent  258  formed from a suitable biocompatible metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.) or a suitable biocompatible polymer. The stent  258  is introduced in a collapsed state to the blood vessel  12  proximate the aneurysm  10  via the catheter  30 . Once deployed into the blood vessel  12 , the stent  258  is expanded to compress against the walls of the blood vessel  12 . The stent  258  may be self-expandable or may be expanded with another device, such as an inflatable balloon. All or part of the stent  258  may be coated or covered with a radiopaque material, such as a platinum to allow for visualization of the stent  258  (e.g., during and after the placement of the stent  258 ). 
     The stent  258  is not intended to occlude the neck portion  16  of the aneurysm  10 , but instead forms a structure to facilitate the placement and anchoring of the inner cover  222 . The stent  258  therefore does not need to be as wide as or wider than the neck portion  16 , but may be a relatively short body (e.g., shorter than the width of the neck portion  16  of the aneurysm  10 ). The relatively short length of the stent  258  reduces the likelihood that the outer anchoring member  250  will disrupt surrounding bodies, such as a side branch  18  of the blood vessel  12 . Further, the stent  258  may have a non-dense, relatively open configuration with variable cell morphology which may extend proximally in the blood vessel  12  from the neck portion  16 . In other embodiments, the stent  258  may be a solid member, such as a band formed of a metal or alloy with a relatively thin thickness. 
     In another embodiment, the outer anchoring member  250  may be a temporary member that is removed with the catheter  30  after the occlusion device  320  has been placed in the neck portion  16  of the aneurysm and has been coupled to the walls of the aneurysm  10 . For example, the outer anchoring member may be a balloon that is inflated in the blood vessel  12  proximate the aneurysm to provide a temporary structure to support the inner cover  222 . 
     Referring now to  FIG. 10 , the inner cover  222 , the inner anchoring member  240 , and the outer anchoring member  250  are shown disposed within a catheter  30  according to an exemplary embodiment. The outer anchoring member  250  is coupled to a distal end  36  of the push wire  32  and is housed, in a collapsed configuration, within the lumen of the catheter  30 . The outer anchoring member  250  is coupled to the inner cover  222 , which is housed, in a collapsed configuration, within the lumen of the catheter  30  upstream of the outer anchoring member  250 . The outer anchoring member  250  may be coupled to the inner cover  222 , for example, with an adhesive. In the collapsed configuration, a peripheral portion  224  of the inner cover  222  is upstream of a central portion  226  to which the outer anchoring member  250  is coupled on a first surface  244 . The inner anchoring member  240  is coupled to a second surface  246  of the inner cover  222  opposite the first surface  242  and is disposed within the lumen of the catheter  30  upstream of the inner cover  222 . 
     The occlusion device  220  including the inner cover  222  and the inner anchoring member  230  is deployed within the aneurysm  20  similar to the process described above with reference to  FIGS. 3A-3E . With the distal end  34  of the catheter  30  positioned proximate to the neck portion  26  of the aneurysm  20 , the push wire  32  is moved within the lumen relative to the catheter  30 . The inner anchoring member  240  is pushed out of the catheter and into the internal volume  24 , where is contacts the interior surface  25  of the aneurysm  20 . The push wire  32  is moved further until the inner cover  222  begins to emerge from the end  34  of the catheter  30  to expand into an expanded configuration within the internal volume  24 . The catheter  30  and/or the push wire  32  is then retracted until the inner cover  222  is seated against the interior surface  25  of the aneurysm  20  and held in place by the inner anchoring member  240 . The push wire  32  is moved further until the outer anchoring member  250  emerges from the catheter  30 . The outer anchoring member  250  may be, for example, one or more loops  252 ,  254 , or  256 , or the stent  258 . The distal end  36  of the push wire  32  is detached from the outer anchoring member such that the catheter  30  and the push wire  32  may be withdrawn from the blood vessel  22  while the inner cover  22  remains in the neck portion  26  of the aneurysm  20  with the inner anchoring member  240  coupled to the second surface  246  and the outer anchoring member  250  disposed in the blood vessel  12 . In other embodiments, the push wire  32  may be coupled directly to the inner cover  222  and the outer anchoring member  250  may be deployed separately (e.g., from another catheter). 
     Referring now to  FIG. 11-14 , an occlusion device  320  is shown according to an exemplary embodiment disposed in the neck portion  16  of the aneurysm  10  to disrupt or halt the flow of blood flow between the vessel  12  and the internal volume  14  of the aneurysm, thereby reducing the likelihood that the aneurysm  10  will rupture. The occlusion device  320  is configured to be low profile device, minimizing disruptions to surrounding bodies, such as a side branch  18  of the blood vessel  12 . The occlusion device  320  may be configured to be biodegradable or bioabsorbable material and may be configured to promote endothelialization. 
     The occlusion device  320  includes an inner cover  322  (e.g., plate, membrane, etc.) disposed within the internal volume  14  of the aneurysm  10  and similar to the inner cover  32  described above. The occlusion device  320  further includes an outer cover  360  disposed in the blood vessel  12  proximate the aneurysm  10 . The outer cover  360  may be coupled to the inner cover  322  provides a relatively rigid body to support the inner cover. The outer cover  360  reduces the likelihood that the inner cover  322  will be displaced from the neck portion  34  by the fluid pressure of the blood in the blood vessel  32 . The outer cover  360  may be utilized instead of or in addition to other devices, such as the inner anchoring member  140  or the outer anchoring member  250  to secure the inner cover  322  in the neck portion  16 . 
     Referring to  FIG. 11 , according to an exemplary embodiment, the outer cover  360  is a relatively thin member (e.g., plate, sheet, etc.) formed from a suitable biocompatible such as a metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.), or a polymer (e.g., PTFE, etc.). According to an exemplary embodiment, the outer cover  360  has a thickness of less than 2 mm. According to a preferred embodiment, the outer cover has 360 has a thickness of less than 1 mm. The outer cover  360  is a low-profile body that does not substantially impede the flow of blood through the blood vessel  12 . The outer cover  360  includes a peripheral portion  362  that contacts the wall  13  of the blood vessel  12  around the neck portion  16  of the aneurysm  10  and a central portion  364  disposed in the neck portion  16 . The central portion  364  may be integrally formed with the inner cover  322  or may be coupled to the inner cover  322  (e.g., with a suitable adhesive). All or part of the outer cover  360  may be coated or covered with a radiopaque material, such as a platinum, to allow for visualization of the outer cover  360  (e.g., during and after the placement of the outer cover  360 ). In embodiment, outer cover  360  is attached to inner cover at a center area having less area than the neck portion  16  (e.g., 90 percent, 75 percent, or 50 percent of the area of the neck portion). In one embodiment, the center area has a circular shape. 
     The outer cover  360  is not intended to occlude the neck portion  16  of the aneurysm  10 , but instead forms a structure to facilitate anchor the inner cover  322 . The outer cover  360  therefore does not need to completely cover the neck portion  16 . The outer cover  360  may therefore be shaped such that portions of the neck portion  160  are uncovered and/or may be formed of a porous material (e.g., a mesh). Referring to  FIG. 12 , in one embodiment, the outer cover  360  may be a sheet that completely covers the neck portion  16  such that the peripheral portion  362  of the outer cover  360  extends about the entirety of the neck portion  16 . 
     Referring to  FIG. 13 , in another embodiment, the outer cover  360  may include multiple segments or sections such as radial lobes  366  that extend outward from the neck portion  16 . Each of the lobes  366  may include a central portion  364  disposed within the neck portion  16  and a peripheral portion  364  extending beyond the neck portion  16  to contact the wall  13  of the blood vessel  12 . 
     Referring to  FIG. 14 , in another embodiment, the outer cover  360  may include a spiral body  368 . The inner loops of the spiral body  368  may form the central portion  364  while the outer loops of the spiral body  368  may form the peripheral portion  362 . 
     The outer cover  360  may be deployed from a catheter in the same procedure as the inner cover  322 . The outer cover  360  may therefore be configured to be collapsible such that it can be coupled to the inner cover  322  and housed within the catheter. The outer cover  360  may be configured such that, within the catheter, the central portion  364  is coupled to the inner cover  322  and positioned upstream of the peripheral portion  362 . The inner cover  322  may be deployed as described with reference to  FIGS. 3A-D . Once the inner cover  322  is deployed from the catheter and positioned in the neck portion  16 , the push wire of the catheter may be advanced further to deploy the outer cover  360 . The fluid pressure of the blood within the blood vessel  12  forces the outer cover  360  against the wall  13  of the blood vessel  12 . In other embodiments, the push wire  32  may be coupled directly to the inner cover  322  and the outer cover  360  may be deployed separately (e.g., from another catheter). 
     Referring now to  FIG. 15-16 , an occlusion device  420  is shown according to an exemplary embodiment disposed in the neck portion  16  of the aneurysm  10 . The occlusion device  420  includes an inner cover  422  (e.g., plate, membrane, etc.) disposed within the internal volume  14  of the aneurysm  10 . The occlusion device  420  further includes an inner anchoring member  440  disposed within the aneurysm  10  and/or an outer anchoring member  450 . The inner anchoring member  440  is configured to anchor the inner cover  422  within the aneurysm  10  in the neck portion  16 . According to an exemplary embodiment, the inner anchoring member  440  includes one or more struts or arms formed from a suitable biocompatible metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.). The inner anchoring member  440  is coupled to the inner cover  122  and is configured to extend beyond the periphery of the inner cover  422  to contacts the interior surface  15  of the aneurysm  10 . The inner anchoring member  140  may therefore be used to facilitate the positioning of the inner cover  422  in an aneurysm  10  having a relatively wide neck  16 . The struts or arms of the inner anchoring member  140  do not fill the entire internal volume  14  or a substantial portion of the internal volume  14 . The “mass effect” of the aneurysm  10  is reduced, as the size of the aneurysm  10  is allowed to shrink as the vessel heals, thereby reducing the pressure placed on the surrounding tissue by the aneurysm. The orientation, number, and length of the arms of the inner anchoring member  440  may vary depending on the size and shape of the aneurysm  10 . The arms of the inner anchoring member  440  may be configured to collapse together to be delivered via a microcatheter, similar to the microcatheter  30  described above. 
     Referring still to  FIGS. 15-16 , the outer anchoring member  450  includes first portion  452  (e.g., distal portion) disposed at the neck  16  and coupled to the inner cover  420  and a second portion  454  (e.g., proximal portion) disposed in the vessel  12 . The outer anchoring member  450  is formed from a suitable biocompatible metal or alloy (e.g., platinum, stainless steel, nickel-titanium alloy, etc.) or a suitable biocompatible polymer. All or part of the outer anchoring member  450  may be coated or covered with a radiopaque material, such as a platinum to allow for visualization of the outer anchoring member  450  (e.g., during and after the placement of the outer anchoring member  450 ). The outer anchoring member  450  is introduced in a collapsed (e.g., straightened) state to the blood vessel  12  proximate the aneurysm  10  via a catheter. Once deployed into the blood vessel  12 , the outer anchoring member  450  expands such that at least a portion of the outer anchoring member compresses against the walls of the blood vessel  12 . The outer anchoring member  450  may be formed as a single, continuous spiral, with loops of the spiral being formed to have variable properties (e.g., diameter, thickness, flexibility, etc.). For example, the first portion  452  may be formed to have relatively small diameter, flexible coils while the second portion  454  may be formed to have larger, relatively rigid coils providing an increased outward radial force to facilitate positioning the outer anchoring member  450  along the wall  13  of the blood vessel  12 . 
     Referring to  FIG. 17 , according to another exemplary embodiment, a portion of an outer anchoring member  460  may be formed as a dual spiral. According to other exemplary embodiments, the outer anchoring member may be formed as a wide variety of other shapes (e.g., web-shaped, star-shaped, etc.) to provide a desired flexibility and support for the inner cover at the neck of the aneurysm. 
     Referring to  FIGS. 18A-18B , according to another exemplary embodiment, an inner cover  470  for an occlusion device may be a star-shaped body. The inner cover  470  may be formed (e.g., creased, scored, molded) to fold and collapse along predefined fold lines. 
     Referring now to  FIG. 19 , an occlusion device  480  is shown having an outer anchoring member  482 . The outer anchoring member  482  is a recapturable body that may be variously shaped (e.g., straight, spiral, multi-spiraled, coven, etc.). The outer anchoring member  482  is formed as a relatively open structure having a minimal number of segments that form a framework that is capable of positioning and securing the occlusion device  480  while minimizing contact with the walls of the blood vessel. The open nature of the outer anchoring member  482  has a low risk of jailing a branch blood vessel or otherwise altering the flow of blood through the blood vessel. 
     Referring to  FIG. 20 , an inner anchoring member  494  for an occlusion device  490  is shown according to another exemplary embodiment. The inner anchoring member  494  includes a central wire  496  coupled to the cover  492  and one or more outer wires  498  coupled to the central wire  496 . The outer wires  498  extend outward from the central wire  496  to contact the interior surface  15  of the aneurysm  10 . The inner anchoring member  494  is introduced in a collapsed (e.g., straightened) state to the aneurysm  10  via the catheter  30 . Once deployed into the aneurysm  10 , the catheter  30  is withdrawn, allowing the outer wires  498  to expand outward such that at least a portion of the outer wires  298  contact the inner surface  15  to position and anchor the cover  492  in the neck  16 . 
     The construction and arrangement of the elements of the aneurysm occlusion device as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength, durability, or biocompatibility. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments and medical procedures without departing from the scope of the present invention.