Abstract:
A prosthesis sleeve that is deployed within a patient&#39;s vessel at a damaged tissue area. The sleeve includes an inflammatory inducing section that releases materials near the damaged tissue to accelerate or enhance the immune response for a period of time sufficient to result in a smooth layer of repaired tissue.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to International Patent Application No. PCT/US2007/070800, International Filing Date Jun. 8, 2007, entitled Inflammation Accelerating Prosthesis, and to U.S. Provisional Application Ser. No. 60/812,251 filed Jun. 8, 2006 entitled Inflammation Accelerating Prosthesis, both of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Injury to a circulatory structure of a patient (e.g., a blood vessel) due to physical injury (e.g. stent placement or angioplasty procedures) or disease (e.g., atherosclerosis or infection) typically results in an immunologic response to contain, repair and eventually heal the injured tissue. However, in some circumstances this immune healing response can permanently damage the vessels by producing unwanted scar tissue, re-narrowing of an artery (e.g., restenosis) or hardening of the vessels. 
         [0003]    For example, often angioplasty permanently opens previously occluded blood vessels; however, restenosis, thrombosis, or vessel collapse may occur following angioplasty. Restenosis refers to the re-narrowing of an artery after an initially successful angioplasty due to exaggerated healing which causes a proliferation of tissue in the angioplasty area. Thrombosis is a clotting within a blood vessel which may cause infection to tissues supplied by the blood vessel. In order to prevent restenosis and vessel collapse, stents of various configurations have been used to hold the lumen of a blood vessel open following angioplasty. However, stents do not entirely reduce the occurrence of thrombotic abrupt closure due to clotting; stents with rough surfaces exposed to blood flow may actually increase thrombosis, and restenosis may still occur because tissue may grow through and around the lattice of the stent. 
         [0004]    Accordingly, in an effort to treat such undesirable effects and/or conditions, many current treatment techniques have been developed and are presently used which focus on reducing or eliminating these vessel complications by delivering anti-inflammatory materials (e.g., biologically active agents) to an inflamed region of a vessel. Some techniques include applying an anti-inflammatory compound on a stent and positioning the stent within a diseased region of a vessel, allowing the anti-inflammatory compounds to migrate into the tissue. Examples of coated stents can be found in U.S. Pat. No. 6,071,305, which describes directional delivery of a biologically active agent (e.g., anti-inflammatory, as disclosed at column 5, line 8) via a non-biodegradable, expandable stent, wherein the directional delivery occurs via at least one fluid opening in only a portion of the stent by diffusion, in a manner sufficient to “prevent inflammation” (column 4, lines 63-65). 
         [0005]    Additional examples of drug-delivery stents are described U.S. Pat. No. 7,214,383 (the &#39;383 patent), as well as U.S. Patent Publication Nos. 20060099236 and 20060035879 (the &#39;236 Publication and &#39;879 Publication, respectively). The &#39;383 patent describes a stent having a drug composition deposited on the outer lumen surface, which is stated to “reduce inflammatory responses from the body of the patient receiving the stent” (column 1, lines 27-28). Both the &#39;236 Publication and the &#39;879 publication describe stents that have anti-inflammatory properties. Some examples of anti-inflammatory compounds and their delivery can be seen in U.S. Pat. Nos. 6,232,297; 6,514,949; and 6,537,977 and U.S. Applications Nos. 20060099236; 20060035879; 20050278929; 20050055078; 20040225346; 20040219147; 20040039438; and 20010007083; the contents of which are hereby incorporated by reference. 
         [0006]    U.S. Pat. Nos. 6,232,297; 6,514,949; and 6,537,977 (the &#39;297 patent, the &#39;949 patent and the &#39;977 patent, respectively) describe anti-inflammatory compounds and methods that inhibit the effects of or otherwise prevent the mammalian inflammatory response in various ways. The &#39;297 patent describes methods and compounds used for inhibiting the inflammatory response. The &#39;949 patent describes methods and compounds used to protect tissues from the effects of the inflammatory response. The &#39;977 patent describes the use of an agent that enhances the anti-inflammatory effect. 
         [0007]    In each of the above-referenced patents and publications, the importance of preventing or slowing the inflammatory response via application of anti-inflammatory compounds and/or methods are described and addressed. However, in some circumstances, anti-inflammatory compounds can in fact prolong the overall time of the immune response from the patient&#39;s body, leading to long term damage and related complications. 
         [0008]    In view of these possible complications, alternative treatment methods are needed to reduce or eliminate inflammatory-related complications within a patient&#39;s circulatory system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates a preferred embodiment of an inflammation generating sleeve according to the present invention; 
           [0010]      FIG. 2  illustrates the inflammation generating sleeve seen in  FIG. 1 ; and 
           [0011]      FIG. 3  illustrates another preferred embodiment of an inflammation generating sleeve positioned over a stent according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring to  FIG. 1 , one embodiment according to the present invention provides a prosthesis  10  having a sleeve  12  and an inflammatory portion  14 . The sleeve  12  may act as merely a substrate for the inflammatory portion  14  or may have sufficient structure to apply outward pressure to the inside surface of the inflammatory portion so as to push the inflammatory portion  14  against a lumen wall in a stent-like fashion. The sleeve  12  is preferably constructed from bioabsorbable or biodegradable material, known in the art, such that the sleeve  12  dissolves and is absorbed into the body after the healing response is completed. One preferred example of bioabsorbable material would include a bioabsorbable synthetic polymer. Using a bioabsorbable or biodegradable material limits the impact of the implant and prevents the implant from causing an undesired thrombotic response. The material should be selected and sized to remain in place and exert pressure (if applicable) for a predetermined amount of time according to the application. Factors to consider include the size of the area being treated, the size of the blood vessel, and the amount of flow through the blood vessel. Higher flow typically results in a faster degradation rate. Alternatively, the sleeve  12  may be constructed of a nondegradable material known in the art, such as metals (e.g., Nitinol mesh), if the situation warrants a permanent implant. 
         [0013]    Similarly, the inflammatory portion  14  of the prosthesis  10  is an area containing a bioreactive material, such as a drug, chemical or protein. Almost any material can be used in the inflammatory portion  14  that generates an inflammatory response. Preferably inflammatory materials are selected that easily pass into the nearby tissue of the lumen wall. The inflammatory portion  14  may comprise a bioreactive material coated onto a substrate or the inflammatory portion  14  or simply be an area of the sleeve  12  onto which a bioreactive material is applied. For example, if the sleeve  12  is to constructed of a nondegradable material, it may be desired to utilize a inflammatory portion  14  with a biodegradable substrate. It may also simplify manufacturing to produce a sheet of material with a substrate and a bioreactive agent applied thereto for forming individual inflammatory of various shapes or sizes, rather than “painting” various shapes on sleeves  12  using the bioreactive agents. 
         [0014]    Whether the inflammatory portion  14  uses the sleeve  12  as a substrate or contains includes its own substrate, it may be made from any biodegradable or bioabsorbable materials that eventually disperse leaving a smooth, healed internal lumen wall  20 . Any material such as a drug, chemical or protein can be coated, impregnated, or otherwise stored within the inflammatory portion  14  of the sleeve  12  so as to appropriately release into or around the damaged portion. 
         [0015]    Turning now to  FIG. 2 , the prosthesis  10  is shown implanted within a body lumen  16  at or near a damaged portion  18 . The inflammatory portion  14  is preferably positioned at least partially over the area of the lumen wall  20  containing the damaged portion  18 . The inflammatory portion  14  of the prosthesis  10  can be formulated to recognize the body&#39;s natural response to injury. It may also be formulated to release an inflammatory material that enhances and accelerates the inflammatory process. Exemplary inflammatory materials are known to those of skill in the art and may include the substances identified in U.S. Publication No. 2006/0116666 entitled Two-Stage Scar Generation for Treating Atrial Fibrillation, the entire contents of which are hereby incorporated by reference. Thus, the damaged portion  18  will be more quickly healed and permanent damage can be limited, thereby creating a smooth, healed lumen wall  20 . Further, the subsequent immune response may even contain the damaged portion  18 , further limiting long term damage to the lumen wall. Because the inflammatory portion can be sized and shaped for any specific individual application, the accelerated healing response is confined to a discrete region and the damaged portion  18  heals rapidly. 
         [0016]    As seen in  FIG. 3 , the prosthesis  10  is preferably positioned around a stent  22  (either self expanding or balloon expandable) which presses the sleeve  12  of the prosthesis  10  against the inner surface of the lumen wall when both are deployed. In this respect, the stent  22  provides an anchoring force to maintain the location of prosthesis  10  within the lumen  16 . Preferred embodiments of stents contemplated for use in the present invention would include helically-wound wire (e.g., single-stranded, twisted or braided multi-stranded) and welded wires, from metal or plastics including biodegradable plastics such as polylactic acid, shape memory effect materials, superelastic materials and polymers. 
         [0017]    Alternatively, the prosthesis  10  may be deployed alone, without a stent  22 . In this respect, it is preferred that the prosthesis  10  be self-expanding (e.g., composed of a shape memory material such as Nitinol) or mechanically expandable, such as balloon-expandable. 
         [0018]    Alternatively, the inflammatory portion  14  of the prosthesis  10  alone can be positioned over a stent  22  or even incorporated into the structure or coating of a stent  22 . 
         [0019]    Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.