Abstract:
Embodiments of the invention described herein include an aneurysm occlusion assist device comprising a main body effective for providing support to a blood vessel, defining an open volume sized to permit substantially unimpeded blood flow when the main body is implanted in a bifurcated aneurysm.

Description:
FIELD 
       [0001]    The inventive subject matter described herein relates to an aneurysm occlusion assist device embodiments and to method embodiments for making the aneurysm occlusion assist device and method repairing an aneurysm. 
       COPYRIGHT 
       [0002]    A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the products, processes and data as described below and in the tables that form a part of this document: Copyright 2007, Neurovasx, Inc. All Rights Reserved. 
       BACKGROUND OF THE INVENTION 
       [0003]    An aneurysm is a balloon-like swelling in a wall of a blood vessel. Aneurysms result in weakness of the vessel wall in which it occurs. This weakness predisposes the vessel to tear or rupture with potentially catastrophic consequences for any individual having the aneurysm. Vascular aneurysms are a result of an abnormal dilation of a blood vessel, usually resulting from disease and/or genetic predisposition which can weaken the arterial wall and allow it to expand. Aneurysm sites tend to be areas of mechanical stress concentration so that fluid flow seems to be the most likely initiating cause for the formation of these aneurysms. 
         [0004]    Aneurysms in cerebral circulation tend to occur in an anterior communicating artery, posterior communicating artery, and a middle cerebral artery. The majority of these aneurysms arise from either curvature in the vessels or at bifurcations of these vessels. The majority of cerebral aneurysms occur in women. Cerebral aneurysms are most often diagnosed by the rupture and subarachnoid bleeding of the aneurysm. 
         [0005]    Cerebral aneurysms are most commonly treated in open surgical procedures where the diseased vessel segment is clipped across the base of the aneurysm. While considered to be an effective surgical technique, particularly considering an alternative which may be a ruptured or re-bleed of a cerebral aneurysm, conventional neurosurgery suffers from a number of disadvantages. The surgical procedure is complex and requires experienced surgeons and well-equipped surgical facilities. Surgical cerebral aneurysm repair has a relatively high mortality and morbidity rate of about 2% to 10%. 
         [0006]    Current treatment options for cerebral aneurysm fall into two categories, surgical and interventional. The surgical option has been the long held standard of care for the treatment of aneurysms. Surgical treatment involves a long, delicate operative procedure that has a significant risk and a long period of postoperative rehabilitation and critical care. Successful surgery allows for an endothelial cell to endothelial cell closure of the aneurysm and therefore a cure for the disease. If an aneurysm is present within an artery in the brain and bursts, this creates a subarachnoid hemorrhage, and a possibility that death may occur. Additionally, even with successful surgery, recovery takes several weeks and often requires a lengthy hospital stay. 
         [0007]    A presentation of a technique referred to as the “Sacred Technique” at an ASNR poster exhibit P129 at the Univ. of Iowa demonstrated a technique in which a stent was placed into an aneurysm to provide a base structure to assist in coil placement. This technique was specific for bifurcated aneurysms shown at  10  in prior art  FIG. 1  as the stent  12  entered the aneurysm in an up-down configuration rather than a side configuration as shown in prior art  FIG. 1 . 
         [0008]    In order to overcome some of these drawbacks, interventional methods and prostheses have been developed to provide an artificial structural support to the vessel region impacted by the aneurysm. The structural support must have an ability to maintain its integrity under blood pressure conditions and impact pressure within an aneurysmal sac and thus prevent or minimize a chance of rupture. U.S. Pat. No. 5,405,379 to Lane, discloses a self-expanding cylindrical tube which is intended to span an aneurysm and result in isolating the aneurysm from blood flow. While this type of stent-like device may reduce the risk of aneurysm rupture, the device does not promote healing within the aneurysm. Furthermore, the stent may increase a risk of thrombosis and embolism. Additionally, the wall thickness of the stent may undesirably reduce the fluid flow rate in a blood vessel. Stents typically are not used to treat aneurysms in a bend in an artery or in tortuous vessels such as in the brain because stents tend to straighten the vessel. 
         [0009]    U.S. Pat. No. 5,354,295 to Guglielmi et al., describes a type of vasoclusion coil. Disadvantages of use of this type of coil are that the coil may compact, may migrate over time, and the coil does not optimize the patient&#39;s natural healing processes. 
     
    
     
       IN THE FIGURES 
         [0010]      FIG. 1  is a cross-sectional view of a prior art assist device for coil placement. 
           [0011]      FIG. 2  is a cross-sectional view of an assist device embodiment of the invention. 
           [0012]      FIG. 3  is a cross-sectional view of the assist device embodiment of  FIG. 2  shown positioned in situ. 
           [0013]      FIG. 4  is a cross-sectional view of another assist device embodiment of the invention. 
           [0014]      FIG. 5  is a cross-sectional view of the assist device embodiment of  FIG. 4  shown positioned in situ. 
           [0015]      FIG. 6  is a cross-sectional view of another assist device embodiment of the invention. 
           [0016]      FIG. 7  is a cross-sectional view of the assist device embodiment of  FIG. 6  shown positioned in situ. 
           [0017]      FIG. 8  is a cross-sectional view of another assist device embodiment of the invention. 
           [0018]      FIG. 9  is a cross-sectional view of the assist device embodiment of  FIG. 8  shown positioned in situ. 
           [0019]      FIG. 10  is a cross-sectional view of another assist device embodiment that includes a microcatheter. 
           [0020]      FIGS. 11   a  and  11   b  are a cross-sectional views of the assist device embodiment of  FIG. 10  in situ. 
           [0021]      FIG. 12  is a cross-sectional in situ view of the assist device embodiment of  FIG. 10  that also includes an embolic material. 
           [0022]      FIG. 13  is a cross-sectional view of one construction embodiment of the assist device embodiment of  FIG. 10 . 
           [0023]      FIG. 14  is a cross-sectional view of another construction embodiment of the assist device embodiment of  FIG. 10 . 
       
    
    
     DESCRIPTION 
       [0024]    Although detailed embodiments of the invention are disclosed herein, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for teaching one skilled in the art to variously employ the aneurysm filler detacher wire embodiments. Throughout the drawings, like elements are given like numerals. 
         [0025]    Referred to herein are trade names for materials including, but not limited to, polymers and optional components. The inventors herein do not intend to be limited by materials described and referenced by a certain trade name. Equivalent materials (e.g., those obtained from a different source under a different name or catalog (reference) number to those referenced by trade name may be substituted and utilized in the methods described and claimed herein. All percentages and ratios are calculated by weight unless otherwise indicated. All percentages are calculated based on the total composition unless otherwise indicated. All component or composition levels are in reference to the active level of that component or composition, and are exclusive of impurities, for example, residual solvents or by-products, which may be present in commercially available sources. 
         [0026]    Embodiments described herein include base structure embodiments for assisting in coil placement into an aneurysm occlusion that minimize impediments to blood flow, such as the struts shown in the prior art structure of  FIG. 1 . One embodiment is shown at  20  in  FIG. 2 . The structure of  FIG. 2  includes extension legs  22  and  24  and support components  26 ,  28 ,  30 , for example, that contact each of the extension legs  22  and  24 . The structure  20  defines an open volume  32  that corresponds to the volume between two branches of a blood vessel, as shown at  30  in  FIG. 3 . The structure  20  can be constructed to define a variety of volumes to accommodate a variety of sizes of side branches. 
         [0027]    The extension legs  22  and  24  are a single, fine wire obstacle rather than multiple struts as is shown in the prior art structure of  FIG. 1 . For some embodiments, the extension legs  22  and  24  and, optionally, the support components  26 ,  28 , and  30  are made of round wire to eliminate sharp edges and to reduce thrombus formation. 
         [0028]    Another base structure embodiment is shown at  40  in  FIGS. 4 and 5 . The base structure embodiment includes a main body coil  42  that defines a plurality of subcoils, such as  46 , and  48  and a space  44  that is sized to minimize blood flow restriction in a blood vessel branch as shown in  FIG. 5 . The structure  20  can be constructed to define a variety of volumes to accommodate a variety of sizes of side branches. For some embodiments, the coil  44  is made of round wire to eliminate sharp edges and to reduce thrombus formation. 
         [0029]    One other base structure embodiment, shown at  50  in  FIGS. 6 and 7 , includes extension legs  52  and  54  and support components  56 ,  58 ,  60 , for example, that contact each of the extension legs  52  and  54 . The structure  50  defines an open volume  62  that corresponds to the volume between two branches of a blood vessel, as shown at  70  in  FIG. 7 . The structure  50  can be constructed to define a variety of volumes to accommodate a variety of sizes of side branches. 
         [0030]    The extension legs  52  and  54  are a single, fine wire obstacle rather than multiple struts as is shown in the prior art structure of  FIG. 1 . For some embodiments, the extension legs  52  and  54  and, optionally, the support components  56 ,  58 , and  60  are made of round wire to eliminate sharp edges and to reduce thrombus formation. 
         [0031]    The structure  50  also includes an adjacent structural component  64  that acts to provide support adjacent the walls of an aneurysm  66 . 
         [0032]    Another embodiment is shown at  70  in  FIGS. 8 and 9 . The base structure embodiment  70  includes a main body coil  72  that defines a plurality of subcoils, such as  72 , and  74  and a space  74  that is sized to minimize blood flow restriction in a blood vessel branch as shown in  FIG. 5 . The structure  70  can be constructed to define a variety of volumes to accommodate a variety of sizes of side branches. For some embodiments, the coil  72  is made of round wire to eliminate sharp edges and to reduce thrombus formation. 
         [0033]    The base structure embodiment  70  also includes a structure  80  that acts to provide support adjacent the walls of an aneurysm  86 . 
         [0034]    All of the embodiments shown herein provide a scaffold or base to the neck of an aneurysm to allow the aneurysm to be filled with the embolic coils or other embolic agents and reduce the likeliness that the coils and other base embodiments will back out of the aneurysm during fill. All of the base embodiments described herein are implantable. Some embodiments may be biodegradable. 
         [0035]    Another aneurysm occlusion assist device is shown at  100  in  FIG. 10 . The embodiment  100  includes a microcatheter  102  and a base structure  104  built into the microcatheter  102 . The microcatheter  102  that includes the base structure  104  has a flat conformation for transport and insertion into an aneurysm. Once positioned within the aneurysm, the microcatheter  100  is activated to an expanded conformation, as shown in  FIG. 11 . In the expanded conformation, the embodiment  100  covers the base of the aneurysm and allows embolic coils  106  or other devices to pass through the microcatheter and fill the aneurysm, as shown in  FIG. 12 . Once the aneurysm is packed with embolic material, the element  100  can be deactivated from an expanded conformation and can be removed, leaving only the embolic material as implant material. 
         [0036]    One image illustrating construction of the embodiment  100  is shown in  FIG. 13 , at  130 . The image  13  shows an inner shaft  132  and an outer shaft  134  that are not connected to each other but can move back and forth relative to one another. The outer shaft  134  is connected to a braid  136  and the braid  136  is connected to a tip  138 . The inner shaft  132  is connected only to the tip  138 . With this embodiment, the outer shaft  134  can be pushed forward relative to the inner shaft  132 , compressing the braid  136 , allowing the braid  136  to expand outward. The braid  136  is, for some embodiments, nitinol and may have shape memory that enhances its ability to expand and take the shape of the neck of an aneurysm. 
         [0037]    Another construction embodiment is shown at  140  in  FIG. 14 . For this construction, a braid  144  is attached to an inner shaft  142  and tip  146 . An outer shaft  148  covers the braid  144  during advancement to an aneurysm and during positioning within the aneurysm. Once positioned, the outer shaft  148  can be moved backwards, exposing the braid  144 , allowing the braid  144  to take a pre-set shape. 
         [0038]    For some embodiments, lubricious materials such as hydrophilic materials may be used to coat the base structure embodiments. One or more bioactive materials may also be included in the composition of the core. The term “bioactive” refers to any agent that exhibits effects in vivo, for example, a thrombotic agent, a therapeutic agent, and the like. Examples of bioactive materials include cytokines; extra-cellular matrix molecules (e.g., collagen); trace metals (e.g., copper); matrix metalloproteinase inhibitors; and other molecules that stabilize thrombus formation or inhibit clot lysis (e.g., proteins or functional fragments of proteins, including but not limited to Factor XIII, C2-antiplasmin, plasminogen activator inhibitor-1 (PAI-1) or the like)). Examples of cytokines that may be used alone or in combination in practicing the invention described herein include basic fibroblast growth factor (bFGF), platelet derived growth factor (pDGF), vascular endothelial growth factor (VEGF), transforming growth factor beta (TGF-β), and the like. Cytokines, extra-cellular matrix molecules, and thrombus stabilizing molecules are commercially available from several vendors such as Genzyme (Framingham, Mass.), Genentech (South San Francisco, Calif.), Amgen (Thousand Oaks, Calif.), R&amp;D Systems, and Immunex (Seattle, Wash.). Additionally, bioactive polypeptides can be synthesized recombinantly as the sequence of many of these molecules are also available, for example, from the GenBank database. Thus, it is intended that embodiments of the invention include use of DNA or RNA encoding any of the bioactive molecules. 
         [0039]    Furthermore, molecules having similar biological activity as wild-type or purified cytokines, matrix metalloproteinase inhibitors, extra-cellular matrix molecules, thrombus-stabilizing proteins such as recombinantly produced or mutants thereof, and nucleic acid encoding these molecules may also be used. The amount and concentration of the bioactive materials that may be included in the composition of the core member may vary, depending on the specific application, and can be determined by one skilled in the art. It will be understood that any combination of materials, concentration, or dosage can be used so long as it is not harmful to the subject. 
         [0040]    The embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and formulation and method of using changes may be made without departing from the scope of the invention. The detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.