Abstract:
An endoprosthesis includes a structure which is self-expandable from a reduced profile to an expanded profile. The structure has one or more longitudinal portions and a transverse central plane about which the one or more longitudinal portions are symmetric. A removable sheath retains the one or more longitudinal portions in the reduced profile. A release structure is coupled to the sheath for removal thereof from the one or more longitudinal portions to provide the self-expansion thereof to the expanded profile. A method for implanting the endoprosthesis into a body of a patient includes inserting the structure which is covered by the sheath into the body of the patient such that the structure has the reduced profile. The release structure is then actuated for removing the sheath from the one or more longitudinal portions to provide the self-expansion to the expanded profile.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/221,590, filed Jun. 30, 2009, the contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to an endoprosthesis and, more specifically, to an endoprosthesis including an expandable medical structure covered by a removable sheath. 
       BACKGROUND OF THE INVENTION 
       [0003]    An endoprosthesis is implantable in the body of a patient, such as a blood vessel or other body cavity. The endoprosthesis includes a medical structure, such as a stent, which is compressible against restoring spring forces to a cross section which is reduced relative to an expanded cross section for the implantation. The medical structure may automatically expand to the expanded cross section for the implantation following removal of the restraining forces providing the compression. 
         [0004]    The medical structure of the endoprosthesis may be compressed to the reduced cross section by being surrounded by a removable sheath which includes at least one thread. The thread extends away from the sheath when the sheath retains the medical structure in the radially compressed position. The thread is retractable from the sheath. Retraction of the thread from the sheath causes removal thereof from the medical structure resulting in the expansion thereof from the radially compressed position to the expanded cross section for implantation. The sheath may be defined by a meshwork produced by crocheting, knitting, tying, or other methods of mesh formation. The meshwork may be unraveled by retraction of the thread which removes the sheath from the compressed medical structure. 
         [0005]    The expansion of the medical structure, which results from removal of the sheath, may generate forces which displace the medical structure longitudinally relative to the body cavity within which the endoprosthesis is located. Any forces, and the resultant displacement of the medical structure, are preferably limited. 
       SUMMARY OF THE INVENTION 
       [0006]    The endoprosthesis of the present invention includes a medical structure which is self-expandable from a reduced profile to an expanded profile. The reduced profile provides for inserting the medical structure into a body of a patient. The expanded profile provides for implanting the medical structure in the body of the patient. The medical structure has one or more longitudinal portions and a transverse central plane about which the one or more longitudinal portions are often symmetric. The present invention, however, is not so limited. For example, the medical structure may have a flare or varied diameter portion at one end or both ends, have tapered portions, have step portions, and/or the like. A removable sheath may cover the one or more longitudinal portions of the medical structure, and retains the one or more longitudinal portions in the reduced profile. The removable sheath may conform to the shape of the stent. A release structure is coupled to the sheath for removal thereof from the one or more longitudinal portions of the medical structure to provide the self-expansion of the one or more longitudinal portions to the expanded profile. A method for implanting the endoprosthesis into a body of a patient includes inserting the medical structure which is covered by the sheath into the body of the patient such that the medical structure has the reduced profile. Following the insertion, the release structure is actuated for removing the sheath from the one or more longitudinal portions of the medical structure to provide the self-expansion to the expanded profile. 
         [0007]    The endoprosthesis provides for the removal of the sheath from selected longitudinal portions of the medical structure. The expansion of the selected portions may be coordinated to limit the forces which may be generated to longitudinally displace the medical structure relative to the body cavity within which the endoprosthesis is located. For example, the coordination of the selected longitudinal portions may provide for the medical structure to expand in a selected longitudinal direction which limits any longitudinal displacement of the medical structure relative to the body cavity. 
         [0008]    These and other features of the invention will be more fully understood from the following description of specific embodiments of the invention taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    In the drawings: 
           [0010]      FIG. 1  is a schematic view of the endoprosthesis of the present invention, the endoprosthesis being shown as including a stent and a sheath, the stent being illustrated as having a reduced profile from being compressed by the sheath; 
           [0011]      FIG. 2  is a schematic view of the endoprosthesis of  FIG. 1 , the sheath being shown as partially removed such that portions of the stent are expanded to an expanded profile; 
           [0012]      FIG. 3  is a schematic view of the endoprosthesis of  FIG. 1 , the sheath being shown as partially removed further such that larger portions of the stent are expanded to the expanded profile; 
           [0013]      FIG. 4  is a schematic view of the endoprosthesis of  FIG. 1 , the sheath being shown as completely removed such that the entire stent is expanded to the expanded profile; 
           [0014]      FIG. 5  is a schematic view of the endoprosthesis of  FIG. 1 , showing the relative positions of the connections of the release structures to the sheath, and the directions of the removal of the sheath from the stent; 
           [0015]      FIG. 6  is a schematic view of an alternative embodiment of the endoprosthesis of  FIG. 1 , showing the relative positions of the connections of the release structures to the sheath, and the directions of the removal of the sheath from the stent; 
           [0016]      FIG. 7  is a schematic view of a further alternative embodiment of the endoprosthesis of  FIG. 1 , showing the relative positions of the connections of the release structures to the sheath, and the directions of the removal of the sheath from the stent; 
           [0017]      FIG. 8  is a schematic view of a further alternative embodiment of the endoprosthesis of  FIG. 1 , showing the relative positions of the connections of the release structures to the sheath, and the directions of the removal of the sheath from the stent; 
           [0018]      FIG. 9  is a schematic view of a further alternative embodiment of the endoprosthesis of  FIG. 1 , showing the relative positions of the connections of the release structures to the sheath, and the directions of the removal of the sheath from the stent; and 
           [0019]      FIG. 10  is a schematic view of a further alternative embodiment of the endoprosthesis of  FIG. 1 , showing the relative positions of the connections of the release structures to the sheath, and the directions of the removal of the sheath from the stent. 
       
    
    
       [0020]    Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring to the drawings and more specifically to  FIG. 1 , the endoprosthesis  10  is used with a delivery system  12 . The delivery system  12  includes an elongate inner structure  14  on which the endoprosthesis  10  is mounted. The delivery system  12  includes radiopaque markers  15  which are fixed to the elongate inner structure  14 . 
         [0022]    The endoprosthesis  10  includes a medical structure which, as shown in  FIGS. 1 to 4 , is an elongate tubular stent  16 . Embodiments of the medical structure, other than the stent  16 , are possible. The stent  16  is self-expandable from a reduced profile  18  to an expanded profile  20 . Self-expandable stents include those that have a spring-like action which causes the stent to radially expand, or stents which expand due to the memory properties of the stent material for a particular configuration at a certain temperature. The stent  16  has proximal and distal ends  22 ,  24 , and a transverse central plane  30  which intersects the stent midway between the proximal and distal ends  22 ,  24 . 
         [0023]    The stent  16  or stent filaments forming stent  16  may be formed of any suitable implantable material, including without limitation nitinol, stainless steel, cobalt-based alloy such as Elgiloy®, platinum, gold, titanium, titanium alloys, tantalum, niobium, polymeric materials and combinations thereof. Useful polymeric materials may include, for example, polyesters, including polyethylene terephthalate (PET) polyesters, polypropylenes, polyethylenes, polyurethanes, polyolefins, polyvinyls, polymethylacetates, polyamides, naphthalane dicarboxylene derivatives, natural silk, polyvinyl chloride, polytetrafluoroethylene, including expanded polytetrafluoroethylene (ePTFE), fluorinated ethylene propylene copolymer, polyvinyl acetate, polystyrene, poly(ethylene terephthalate), naphthalene dicarboxylate derivatives, such as polyethylene naphthalate, polybutylene naphthalate, polytrimethylene naphthalate and trimethylenediol naphthalate, polyurethane, polyurea, silicone rubbers, polyamides, polycarbonates, polyaldehydes, natural rubbers, polyester copolymers, styrene-butadiene copolymers, polyethers, such as fully or partially halogenated polyethers, and copolymers and combinations thereof. Further, useful and nonlimiting examples of polymeric stent materials include poly(L-lactide) (PLLA), poly(D,L-lactide) (PLA), poly(glycolide) (PGA), poly(L-lactide-co-D,L-lactide) (PLLA/PLA), poly(L-lactide-co-glycolide) (PLLA/PGA), poly(D,L-lactide-co-glycolide) (PLA/PGA), poly(glycolide-co-trimethylene carbonate) (PGA/PTMC), polydioxanone (PDS), Polycaprolactone (PCL), polyhydroxybutyrate (PHBT), poly(phosphazene) poly(D,L-lactide-co-caprolactone) PLA/PCL), poly(glycolide-co-caprolactone) (PGA/PCL), polyphosphate ester) and the like. Wires made from polymeric materials may also include radiopaque materials, such as metallic-based powders, particulates or pastes which may be incorporated into the polymeric material. For example the radiopaque material may be blended with the polymer composition from which the polymeric wire is formed, and subsequently fashioned into the stent as described herein. Alternatively, the radiopaque material and/or radiopaque markers may be applied to the surface of the metal or polymer stent. In either embodiment, various radiopaque materials and their salts and derivatives may be used including, without limitation, bismuth, barium and its salts such as barium sulphate, tantulaum, tungsten, gold, platinum and titanium, to name a few. Additional useful radiopaque materials may be found in U.S. Pat. No. 6,626,936, which is herein incorporated in its entirely by reference. Metallic complexes useful as radiopaque materials are also contemplated. The stent may be selectively made radiopaque at desired areas along the wire or made be fully radiopaque, depending on the desired end-product and application. Further, the stent filaments may have an inner core of tantalum, gold, platinum, iridium or combination of thereof and an outer member or layer of nitinol to provide a composite wire for improved radiocapicity or visibility. Desirably, the inner core is platinum and the outer layer is nitinol. More desirably, the inner core of platinum represents about at least 10% of the wire based on the overall cross-sectional percentage. Moreover, nitinol that has not been treated for shape memory such as by heating, shaping and cooling the nitinol at its martensitic and austenitic phases, is also useful as the outer layer. Further details of such composite wires may be found in U.S. Patent Application Publication 2002/0035396 A1, the contents of which is incorporated herein by reference. Preferably, the stent filaments are made from nitinol, or a composite wire having a central core of platinum and an outer layer of nitinol. 
         [0024]    The stent  16  may include one or more coiled stainless steel springs, helically wound coil springs including a heat-sensitive material, or expanding stainless steel stents formed of stainless steel wire in a zig-zag pattern. The stent  16  may be capable of radially expanding by radial or circumferential distension or deformation. The stent  16  may self-expand at one or more specific temperatures as a result of the memory properties of the material included in the stent for a specific configuration. Nitinol is a material which may be included in the stent  16  for providing radial expansion thereof by the memory properties of the nitinol based on one or more specific temperatures or the superelastic properties of nitinol. 
         [0025]    The endoprosthesis  10  includes a tubular sheath  32  within which is located the stent  16  in coaxial relation therewith. The internal cross-sectional area of the sheath  32  is less than the outer cross-sectional area of the expanded profile  20  of the stent  16 . Consequently, location of the stent  16  within the sheath  32  compresses the stent. The internal cross-sectional area of the sheath  32  is sized such that location of the stent  16  within the sheath compresses the stent to the reduced profile  18 . The stent  16  is retained in the reduced profile  18  by the sheath  32 . Any number of sheaths  32  may suitably be used. Further, the dimensions of sheaths  32  are also non-limiting. Further, if more than one sheath  32  is used, then the sheaths  32  may or may not overlap one and another. Further, if more than one sheath  32  is used, then the sequence of removal of the sheaths  32  may be in any suitable order, typically dependent upon the particular delivery procedure used by a practitioner. 
         [0026]    The endoprosthesis  10  includes a release structure  34  which provides for removal of the sheath  32 . Removal of the sheath  32  provides for self-expansion of the stent  16  to the expanded profile  20 . 
         [0027]    The stent  16 , sheath  32 , and release structure  34  are typically formed of monofilament or braided suture. The suture may be impregnated or coated with a lubricant such as polytetrafluoroethylene (PTFE) or silicone. The sheath  32 , and release structure  34  may be formed of biocompatible materials, such as biocompatible polymers including those which are known. Such polymers may include fillers such as metals, carbon fibers, glass fibers or ceramics. Also, such polymers may include olefin polymers, polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, expanded polytetrafluoroethylene, fluorinated ethylene propylene copolymer, polyvinyl acetate, polystyrene, poly(ethylene terephthalate), naphthalene dicarboxylate derivatives, such as polyethylene naphthalate, polybutylene naphthalate, polytrimethylene naphthalate and trimethylenediol naphthalate, polyurethane, polyurea, silicone rubbers, polyamides, polycarbonates, polyaldehydes, natural rubbers, polyester copolymers, styrene-butadiene copolymers, polyethers, such as fully or partially halogenated polyethers, copolymers, and combinations thereof. Also, polyesters, including polyethylene terephthalate (PET) polyesters, polypropylenes, polyethylenes, polyurethanes, polyolefins, polyvinyls, polymethylacetates, polyamides, naphthalane dicarboxylene derivatives, and natural silk may be included in the stent  16 , sheath  32 , and release structure  34 . 
         [0028]    The stent  16 , sheath  32 , and release structure  34  may be treated with a therapeutic agent or agents. “Therapeutic agents”, “pharmaceuticals,” “pharmaceutically active agents”, “drugs” and other related terms may be used interchangeably herein and include genetic therapeutic agents, non-genetic therapeutic agents and cells. Therapeutic agents may be used singly or in combination. A wide variety of therapeutic agents can be employed in conjunction with the present invention including those used for the treatment of a wide variety of diseases and conditions (i.e., the prevention of a disease or condition, the reduction or elimination of symptoms associated with a disease or condition, or the substantial or complete elimination of a disease or condition). 
         [0029]    Non-limiting examples of useful therapeutic agents include, but are not limited to, adrenergic agents, adrenocortical steroids, adrenocortical suppressants, alcohol deterrents, aldosterone antagonists, amino acids and proteins, ammonia detoxicants, anabolic agents, analeptic agents, analgesic agents, androgenic agents, anesthetic agents, anorectic compounds, anorexic agents, antagonists, anterior pituitary activators and suppressants, anthelmintic agents, anti-adrenergic agents, anti-allergic agents, anti-amebic agents, anti-androgen agents, anti-anemic agents, anti-anginal agents, anti-anxiety agents, anti-arthritic agents, anti-asthmatic agents, anti-atherosclerotic agents, antibacterial agents, anticholelithic agents, anticholelithogenic agents, anticholinergic agents, anticoagulants, anticoccidal agents, anticonvulsants, antidepressants, antidiabetic agents, antidiuretics, antidotes, antidyskinetics agents, anti-emetic agents, anti-epileptic agents, anti-estrogen agents, antifibrinolytic agents, antifungal agents, antiglaucoma agents, antihemophilic agents, antihemophilic Factor, antihemorrhagic agents, antihistaminic agents, antihyperlipidemic agents, antihyperlipoproteinemic agents, antihypertensives, antihypotensives, anti-infective agents, anti-inflammatory agents, antikeratinizing agents, antimicrobial agents, antimigraine agents, antimitotic agents, antimycotic agents, antineoplastic agents, anti-cancer supplementary potentiating agents, antineutropenic agents, antiobsessional agents, antiparasitic agents, antiparkinsonian drugs, antipneumocystic agents, antiproliferative agents, antiprostatic hypertrophydrugs, antiprotozoal agents, antipruritics, antipsoriatic agents, antipsychotics, antirheumatic agents, antischistosomal agents, antiseborrheic agents, antispasmodic agents, antithrombotic agents, antitussive agents, anti-ulcerative agents, anti-urolithic agents, antiviral agents, benign prostatic hyperplasia therapy agents, blood glucose regulators, bone resorption inhibitors, bronchodilators, carbonic anhydrase inhibitors, cardiac depressants, cardioprotectants, cardiotonic agents, cardiovascular agents, choleretic agents, cholinergic agents, cholinergic agonists, cholinesterase deactivators, coccidiostat agents, cognition adjuvants and cognition enhancers, depressants, diagnostic aids, diuretics, dopaminergic agents, ectoparasiticides, emetic agents, enzyme inhibitors, estrogens, fibrinolytic agents, free oxygen radical scavengers, gastrointestinal motility agents, glucocorticoids, gonad-stimulating principles, hemostatic agents, histamine H2 receptor antagonists, hormones, hypocholesterolemic agents, hypoglycemic agents, hypolipidemic agents, hypotensive agents, HMGCoA reductase inhibitors, immunizing agents, immunomodulators, immunoregulators, immunostimulants, immunosuppressants, impotence therapy adjuncts, keratolytic agents, LHRH agonists, luteolysin agents, mucolytics, mucosal protective agents, mydriatic agents, nasal decongestants, neuroleptic agents, neuromuscular blocking agents, neuroprotective agents, NMDA antagonists, non-hormonal sterol derivatives, oxytocic agents, plasminogen activators, platelet activating factor antagonists, platelet aggregation inhibitors, post-stroke and post-head trauma treatments, progestins, prostaglandins, prostate growth inhibitors, prothyrotropin agents, psychotropic agents, radioactive agents, repartitioning agents, scabicides, sclerosing agents, sedatives, sedative-hypnotic agents, selective adenosine A1 antagonists, adenosine A2 receptor antagonists (e.g., CGS 21680, regadenoson, UK 432097 or GW 328267), serotonin antagonists, serotonin inhibitors, serotonin receptor antagonists, steroids, stimulants, thyroid hormones, thyroid inhibitors, thyromimetic agents, tranquilizers, unstable angina agents, uricosuric agents, vasoconstrictors, vasodilators, vulnerary agents, wound healing agents, xanthine oxidase inhibitors, and the like, and combinations thereof. 
         [0030]    Useful non-genetic therapeutic agents for use in connection with the present invention include, but are not limited to,
   (a) anti-thrombotic agents such as heparin, heparin derivatives, urokinase, clopidogrel, and PPack (dextrophenylalanine proline arginine chloromethylketone);   (b) anti-inflammatory agents such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine and mesalamine;   (c) antineoplastic/antiproliferative/anti-miotic agents such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, and thymidine kinase inhibitors;   (d) anesthetic agents such as lidocaine, bupivacaine and ropivacaine;   (e) anti-coagulants such as D-Phe-Pro-Arg chloromethyl ketone, an RGD peptide-containing compound, heparin, hirudin, antithrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors and tick antiplatelet peptides;   (f) vascular cell growth promoters such as growth factors, transcriptional activators, and translational promotors;   (g) vascular cell growth inhibitors such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin;   (h) protein kinase and tyrosine kinase inhibitors (e.g., tyrphostins, genistein, quinoxalines);   (i) prostacyclin analogs;   (j) cholesterol-lowering agents;   (k) angiopoietins;   (l) antimicrobial agents such as triclosan, cephalosporins, aminoglycosides and nitrofurantoin;   (m) cytotoxic agents, cytostatic agents and cell proliferation affectors;   (n) vasodilating agents;   (o) agents that interfere with endogenous vasoactive mechanisms;   (p) inhibitors of leukocyte recruitment, such as monoclonal antibodies;   (q) cytokines;   (r) hormones;   (s) inhibitors of HSP 90 protein (i.e., Heat Shock Protein, which is a molecular chaperone or housekeeping protein and is needed for the stability and function of other client proteins/signal transduction proteins responsible for growth and survival of cells) including geldanamycin;   (t) smooth muscle relaxants such as alpha receptor antagonists (e.g., doxazosin, tamsulosin, terazosin, prazosin and alfuzosin), calcium channel blockers (e.g., verapimil, diltiazem, nifedipine, nicardipine, nimodipine and bepridil), beta receptor agonists (e.g., dobutamine and salmeterol), beta receptor antagonists (e.g., atenolol, metaprolol and butoxamine), angiotensin-II receptor antagonists (e.g., losartan, valsartan, irbesartan, candesartan, eprosartan and telmisartan), and antispasmodic/anticholinergic drugs (e.g., oxybutynin chloride, flavoxate, tolterodine, hyoscyamine sulfate, diclomine);   (u) bARKct inhibitors;   (v) phospholamban inhibitors;   (w) Serca 2 gene/protein;   (x) immune response modifiers including aminoquizolines, for instance, imidazoquinolines such as resiquimod and imiquimod;   (y) human apolioproteins (e.g., AI, AII, AIII, AIV, AV, etc.);   (z) selective estrogen receptor modulators (SERMs) such as raloxifene, lasofoxifene, arzoxifene, miproxifene, ospemifene, PKS 3741, MF 101 and SR 16234;   (aa) PPAR agonists, including PPAR-alpha, gamma and delta agonists, such as rosiglitazone, pioglitazone, netoglitazone, fenofibrate, bexaotene, metaglidasen, rivoglitazone and tesaglitazar;   (bb) prostaglandin E agonists, including PGE2 agonists, such as alprostadil or ONO 8815Ly;   (cc) thrombin receptor activating peptide (TRAP);   (dd) vasopeptidase inhibitors including benazepril, fosinopril, lisinopril, quinapril, ramipril, imidapril, delapril, moexipril and spirapril;   (ee) thymosin beta 4;   (ff) phospholipids including phosphorylcholine, phosphatidylinositol and phosphatidylcholine; and   (gg) VLA-4 antagonists and VCAM-1 antagonists.
 
The non-genetic therapeutic agents may be used individually or in combination, including in combination with any of the agents described herein.
   
 
         [0064]    Further examples of non-genetic therapeutic agents, not necessarily exclusive of those listed above, include taxanes such as paclitaxel (including particulate forms thereof, for instance, protein-bound paclitaxel particles such as albumin-bound paclitaxel nanoparticles, e.g., ABRAXANE), sirolimus, everolimus, tacrolimus, zotarolimus, Epo D, dexamethasone, estradiol, halofuginone, cilostazole, geldanamycin, alagebrium chloride (ALT-711), ABT-578 (Abbott Laboratories), trapidil, liprostin, Actinomcin D, Resten-NG, Ap-17, abciximab, clopidogrel, Ridogrel, beta-blockers, bARKct inhibitors, phospholamban inhibitors, Serca 2 gene/protein, imiquimod, human apolioproteins (e.g., AI-AV), growth factors (e.g., VEGF-2), as well derivatives of the forgoing, among others. 
         [0065]    Useful genetic therapeutic agents for use in connection with the present invention include, but are not limited to, anti-sense DNA and RNA as well as DNA coding for the various proteins (as well as the proteins themselves), such as (a) anti-sense RNA; (b) tRNA or rRNA to replace defective or deficient endogenous molecules; (c) angiogenic and other factors including growth factors such as acidic and basic fibroblast growth factors, vascular endothelial growth factor, endothelial mitogenic growth factors, epidermal growth factor, transforming growth factor α and β, platelet-derived endothelial growth factor, platelet-derived growth factor, tumor necrosis factor α, hepatocyte growth factor and insulin-like growth factor; (d) cell cycle inhibitors including CD inhibitors, and (e) thymidine kinase (“TK”) and other agents useful for interfering with cell proliferation. DNA encoding for the family of bone morphogenic proteins (“BMP&#39;s”) are also useful and include, but not limited to, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1), BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and BMP-16. Currently desirably BMP&#39;s are any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 and BMP-7. These dimeric proteins can be provided as homodimers, heterodimers, or combinations thereof, alone or together with other molecules. Alternatively, or in addition, molecules capable of inducing an upstream or downstream effect of a BMP can be provided. Such molecules include any of the “hedgehog” proteins, or the DNA&#39;s encoding them. 
         [0066]    Vectors for delivery of genetic therapeutic agents include, but not limited to, viral vectors such as adenoviruses, gutted adenoviruses, adeno-associated virus, retroviruses, alpha virus (Semliki Forest, Sindbis, etc.), lentiviruses, herpes simplex virus, replication competent viruses (e.g., ONYX-015) and hybrid vectors; and non-viral vectors such as artificial chromosomes and mini-chromosomes, plasmid DNA vectors (e.g., pCOR), cationic polymers (e.g., polyethyleneimine, polyethyleneimine (PEI)), graft copolymers (e.g., polyether-PEI and polyethylene oxide-PEI), neutral polymers such as polyvinylpyrrolidone (PVP), SP1017 (SUPRATEK), lipids such as cationic lipids, liposomes, lipoplexes, nanoparticles, or microparticles, with and without targeting sequences such as the protein transduction domain (PTD). 
         [0067]    Cells for use in connection with the present invention may include cells of human origin (autologous or allogeneic), including whole bone marrow, bone marrow derived mono-nuclear cells, progenitor cells (e.g., endothelial progenitor cells), stem cells (e.g., mesenchymal, hematopoietic, neuronal), pluripotent stem cells, fibroblasts, myoblasts, satellite cells, pericytes, cardiomyocytes, skeletal myocytes or macrophage, or from an animal, bacterial or fungal source (xenogeneic), which can be genetically engineered, if desired, to deliver proteins of interest. 
         [0068]    Numerous therapeutic agents, not necessarily exclusive of those listed above, have been identified as candidates for vascular treatment regimens, for example, as agents targeting restenosis (antirestenotics). Such agents are useful for the practice of the present invention and include one or more of the following:
   (a) Ca-channel blockers including benzothiazapines such as diltiazem and clentiazem, dihydropyridines such as nifedipine, amlodipine and nicardapine, and phenylalkylamines such as verapamil;   (b) serotonin pathway modulators including: 5-HT antagonists such as ketanserin and naftidrofuryl, as well as 5-HT uptake inhibitors such as fluoxetine;   (c) cyclic nucleotide pathway agents including phosphodiesterase inhibitors such as cilostazole and dipyridamole, adenylate/Guanylate cyclase stimulants such as forskolin, as well as adenosine analogs;   (d) catecholamine modulators including α-antagonists such as prazosin and bunazosine, β-antagonists such as propranolol and α/β-antagonists such as labetalol and carvedilol;   (e) endothelin receptor antagonists such as bosentan, sitaxsentan sodium, atrasentan, endonentan;   (f) nitric oxide donors/releasing molecules including organic nitrates/nitrites such as nitroglycerin, isosorbide dinitrate and amyl nitrite, inorganic nitroso compounds such as sodium nitroprusside, sydnonimines such as molsidomine and linsidomine, nonoates such as diazenium diolates and NO adducts of alkanediamines, S-nitroso compounds including low molecular weight compounds (e.g., S-nitroso derivatives of captopril, glutathione and N-acetyl penicillamine) and high molecular weight compounds (e.g., S-nitroso derivatives of proteins, peptides, oligosaccharides, polysaccharides, synthetic polymers/oligomers and natural polymers/oligomers), as well as C-nitroso-compounds, O-nitroso-compounds, N-nitroso-compounds and L-arginine;   (g) Angiotensin Converting Enzyme (ACE) inhibitors such as cilazapril, fosinopril and enalapril;   (h) ATII-receptor antagonists such as saralasin and losartin;   (i) platelet adhesion inhibitors such as albumin and polyethylene oxide;   (j) platelet aggregation inhibitors including cilostazole, aspirin and thienopyridine (ticlopidine, clopidogrel) and GP IIb/IIIa inhibitors such as abciximab, epitifibatide and tirofiban;   (k) coagulation pathway modulators including heparinoids such as heparin, low molecular weight heparin, dextran sulfate and β-cyclodextrin tetradecasulfate, thrombin inhibitors such as hirudin, hirulog, PPACK(D-phe-L-propyl-L-arg-chloromethylketone) and argatroban, FXa inhibitors such as antistatin and TAP (tick anticoagulant peptide), Vitamin K inhibitors such as warfarin, as well as activated protein C;   (l) cyclooxygenase pathway inhibitors such as aspirin, ibuprofen, flurbiprofen, indomethacin and sulfinpyrazone;   (m) natural and synthetic corticosteroids such as dexamethasone, prednisolone, methprednisolone and hydrocortisone;   (n) lipoxygenase pathway inhibitors such as nordihydroguairetic acid and caffeic acid;   (o) leukotriene receptor antagonists; (p) antagonists of E- and P-selectins;   (q) inhibitors of VCAM-1 and ICAM-1 interactions;   (r) prostaglandins and analogs thereof including prostaglandins such as PGE1 and PGI2 and prostacyclin analogs such as ciprostene, epoprostenol, carbacyclin, iloprost and beraprost;   (s) macrophage activation preventers including bisphosphonates;   (t) HMG-CoA reductase inhibitors such as lovastatin, pravastatin, atorvastatin, fluvastatin, simvastatin and cerivastatin;   (u) fish oils and omega-3-fatty acids;   (v) free-radical scavengers/antioxidants such as probucol, vitamins C and E, ebselen, trans-retinoic acid, SOD (orgotein) and SOD mimics, verteporfin, rostaporfin, AGI 1067, and M 40419;   (w) agents affecting various growth factors including FGF pathway agents such as bFGF antibodies and chimeric fusion proteins, PDGF receptor antagonists such as trapidil, IGF pathway agents including somatostatin analogs such as angiopeptin and ocreotide, TGF-β pathway agents such as polyanionic agents (heparin, fucoidin), decorin, and TGF-β antibodies, EGF pathway agents such as EGF antibodies, receptor antagonists and chimeric fusion proteins, TNF-α pathway agents such as thalidomide and analogs thereof, Thromboxane A2 (TXA2) pathway modulators such as sulotroban, vapiprost, dazoxiben and ridogrel, as well as protein tyrosine kinase inhibitors such as tyrphostin, genistein and quinoxaline derivatives;   (x) matrix metalloprotease (MMP) pathway inhibitors such as marimastat, ilomastat, metastat, batimastat, pentosan polysulfate, rebimastat, incyclinide, apratastat, PG 116800, RO 1130830 or ABT 518;   (y) cell motility inhibitors such as cytochalasin B;   (z) antiproliferative/antineoplastic agents including antimetabolites such as purine antagonists/analogs (e.g., 6-mercaptopurine and pro-drugs of 6-mercaptopurine such as azathioprine or cladribine, which is a chlorinated purine nucleoside analog), pyrimidine analogs (e.g., cytarabine and 5-fluorouracil) and methotrexate, nitrogen mustards, alkyl sulfonates, ethylenimines, antibiotics (e.g., daunorubicin, doxorubicin), nitrosoureas, cisplatin, agents affecting microtubule dynamics (e.g., vinblastine, vincristine, colchicine, Epo D, paclitaxel and epothilone), caspase activators, proteasome inhibitors, angiogenesis inhibitors (e.g., endostatin, angiostatin and squalamine), olimus family drugs (e.g., sirolimus, everolimus, tacrolimus, zotarolimus, etc.), cerivastatin, flavopiridol and suramin;   (aa) matrix deposition/organization pathway inhibitors such as halofuginone or other quinazolinone derivatives, pirfenidone and tranilast;   (bb) endothelialization facilitators such as VEGF and RGD peptide;   (cc) blood rheology modulators such as pentoxifylline and   (dd) glucose cross-link breakers such as alagebrium chloride (ALT-711).
 
These therapeutic agents may be used individually or in combination, including in combination with any of the agents described herein.
   
 
         [0098]    Numerous additional therapeutic agents useful for the practice of the present invention are also disclosed in U.S. Pat. No. 5,733,925 to Kunz, the contents of which is incorporated herein by reference. 
         [0099]    A wide range of therapeutic agent loadings may used in connection with the dosage forms of the present invention, with the pharmaceutically effective amount being readily determined by those of ordinary skill in the art and ultimately depending, for example, upon the condition to be treated, the nature of the therapeutic agent itself, the tissue into which the dosage form is introduced, and so forth. 
         [0100]    The delivery system  12  provides for location of the stent  16  within the body of the patient by mounting the stent  10  on the inner structure  14  in coaxial relation therewith. The stent  16  is longitudinally positioned relative to the inner structure  14  such that the longitudinal center of the stent has generally the same axial position as one of the radiopaque markers  15 . The sheath  32  is placed over the stent  16  for compression thereof to the reduced profile  18 . The delivery system  12  and endoprosthesis  10  mounted thereon is moved to the desired location within the body of the patient. The positioning of the stent  16  is facilitated by the radiopaque markers  15 , such as the radiopaque marker which has generally the same axial position as the longitudinal center of the stent. An advantageous application of the stent  16  is for the treatment of a stricture within a vessel in the body of the patient. The treatment may be provided by employing the delivery system  12  to locating the endoprosthesis  10  within the vessel or lumen such the stent  16  is located at the stricture. The stent  16  may be more beneficially located by positioning the radiopaque marker  15 , which has generally the same axial position as the longitudinal center of the stent, at generally the same axial position as the longitudinal center of the stricture. 
         [0101]    The sheath  32  is defined by one or more sutures  36  woven into one or more sections of crocheted material  38  which retains the stent  16  in the reduced profile  18 , as shown in  FIGS. 1 to 3 . As used herein, sutures  36  may be described as filaments  36 , including monofilaments and/or multifilaments. Any suitable suture or filament material may be used with the present invention. The cross-sectional configuration of the suture or filament material may also include any suitable configuration. Embodiments of the crocheted material  38  are disclosed in U.S. Pat. Nos. 5,653,748 and 6,019,785, which are hereby incorporated by reference herein. The crocheted material  38  is woven such that one or more end portions of the sutures  36 , which define corresponding release structures  34 , extend away from the crocheted material. The weaving of the sutures  36  into the crocheted material  38  provides for displacement of the one or more release structures  34  away from the crocheted material to cause unraveling thereof. Alternative embodiments of the release structure  34  are possible which cause unraveling or other removal of the woven material or other structure of the sheath  32  from the stent  16 . Other embodiments of the sheath  32  are possible, including but limited to, other patterns and structures including braids, weaves, twists and/or knots. 
         [0102]    The sheath  32  includes a proximal section  46  of the crocheted material  38  which surrounds the stent  16  in coaxial relation therewith such the proximal section is located between the proximal end  22  and transverse central plane  30 , as shown in  FIG. 1 . The proximal section  46  has proximal and distal ends  48 ,  50 . The release structure  34  includes a proximal release structure  52  defined by a suture  36  which is woven into the proximal section  46  and extends from the proximal end  48 . The proximal release structure  52  is defined by a portion of a single suture  36  the weaving of which forms the proximal section  46 . The weaving of the proximal release structure  52  into the proximal section  46  provides for displacement of the proximal release structure in a direction  54  which is away from the proximal section to cause unraveling thereof. The unraveling of the proximal section  46  commences from the proximal end  48  and proceeds in an axial direction  56  relative to the sheath  32  toward the distal end  50 . However, any unraveling scheme is contemplated with various stents and/or steps, points or aspects of delivery. 
         [0103]    The sheath  32  includes a distal section  58  of the crocheted material  38  which surrounds the stent  16  in coaxial relation therewith such the distal section is located between the distal end  24  and transverse central plane  30 , as shown in  FIG. 1 . The distal section  58  has proximal and distal ends  60 ,  62 . The release structure  34  includes a distal release structure  64  defined by a suture  36  which is woven into the distal section  58  and extends from the distal end  62 . The distal release structure  64  is defined by a portion of a single suture  36  the weaving of which forms the distal section  58 . The weaving of the distal release structure  64  into the distal section  58  provides for displacement of the distal release structure in a direction  66  which is away from the distal section to cause unraveling thereof. The unraveling of the distal section  58  commences from the distal end  62  and proceeds in an axial direction  68  relative to the sheath  32  toward the proximal end  60 . However, any unraveling scheme is contemplated with various stents and/or steps, points or aspects of delivery. 
         [0104]    The distal section  58  has axial and transverse dimensions which are generally the same as the axial and transverse dimensions of the proximal section  46 . The axial locations of the proximal and distal sections  46 ,  58  are symmetrical relative to the transverse central plane  30 . The proximal and distal sections  46 ,  58  are located relative to the stent  16  such that the distal and proximal ends  50 ,  60  are separated axially from the transverse central plane  30 . Alternative embodiments of the sheath  32  are possible in which the distal and proximal ends  50 ,  60  extend to the transverse central plane  30  such that the distal and proximal ends  50 ,  60  contact one another. 
         [0105]    The corresponding dimensions of the proximal and distal sections  46 ,  58 , the axial locations thereof relative to the transverse central plane  30 , and the locations of the proximal and distal release structures  52 ,  64  at the proximal and distal ends  48 ,  62  provide for unraveling of the proximal and distal sections at generally the same rates in the axial directions  56 ,  68  toward the transverse central plane when the proximal and distal release structures are simultaneously displaced in the directions  54 ,  66  away from the proximal and distal sections. As shown in  FIG. 5 , the portions of the proximal and distal release structures  52 ,  64  which are remote from the sheath  32  are displaced proximally relative thereto in the directions  54 ,  66 . 
         [0106]    The inner structure  14  has an interior longitudinal cavity through which the proximal and distal release structures  52 ,  64  extend in the proximal direction. The inner structure  14  has one or more ports through which the proximal and distal release structures  52 ,  64  may extend from the proximal and distal sections  46 ,  58  into the cavity. The present invention, however, is not so limited. For example, the proximal and distal release structures may be external to the delivery device. The inner structure  14  has one or more grooves or channels formed on the inner surface thereof. The proximal and distal release structures  52 ,  64  are located in the grooves or channels and translate therein through the cavity in the inner structure  14 . The proximal and distal release structures  52 ,  64  may be located in separate, respective channels or grooves, or may be commonly located in a single channel or groove. The proximal and distal release structures  52 ,  64  are available for manipulation by the user at a location on the inner structure  14  which is sufficiently remote from the proximal and distal sections  46 ,  58 . 
         [0107]    In alternative embodiments of the proximal and distal release structures  52 ,  64 , the portions thereof which are remote from the sheath  32  are displaced in distal or other directions relative to the sheath  32 . 
         [0108]    An alternative embodiment of the endoprosthesis  10   a  is shown in  FIG. 6 . Parts illustrated in  FIG. 6  which correspond to parts illustrated in  FIGS. 1 to 5  have, in  FIG. 6 , the same reference numeral as in  FIGS. 1 to 5  with the addition of the suffix “a”. In this alternative embodiment, the proximal section  46   a  is woven such that the proximal release structure  52   a  extends from the distal end  50   a . The proximal release structure  52   a  is defined by a portion of a single suture  36   a  the weaving of which forms the proximal section  46   a . The weaving of the proximal release structure  52   a  into the proximal section  46   a  can provide for displacement of the proximal release structure in a direction  54   a  which is away from the proximal section to cause unraveling thereof. The unraveling of the proximal section  46   a  may commence from the distal end  50   a  and proceeds in an axial direction  56   a  relative to the sheath  32   a  toward the proximal end  48   a.    
         [0109]    The distal section  58   a  is woven such that the distal release structure  64   a  extends from the proximal end  60   a . The distal release structure  64   a  is defined by a portion of a single suture  36   a  the weaving of which forms the distal section  58   a . The present invention, however, is not so limited. For example, multiple filaments may be utilized as the suture  36   a . The weaving of the distal release structure  64   a  into the distal section  58   a  provides for displacement of the distal release structure in a direction  66   a  which is away from the distal section to cause unraveling thereof. The unraveling of the distal section  58   a  commences from the proximal end  60   a  and proceeds in an axial direction  68   a  relative to the sheath  43   a  toward the distal end  62   a.    
         [0110]    The corresponding dimensions of the proximal and distal sections  46   a ,  58   a , the axial locations thereof relative to the transverse central plane  30   a , and the locations of the proximal and distal release structures  52   a ,  64   a  at the distal and proximal ends  50   a ,  60   a  can provide for unraveling of the proximal and distal sections at generally the same rates in the axial directions  56   a ,  68   a  away from the transverse central plane when the proximal and distal release structures are simultaneously displaced in the directions Ma,  66   a  away from the proximal and distal sections. 
         [0111]    As shown in  FIG. 6 , the portions of the proximal and distal release structures  52   a ,  64   a  which are remote from the sheath  32   a  are displaced proximally relative to the sheath in the directions Ma,  66   a . Alternative embodiments may provide for displacement of the proximal and distal release structures  52   a ,  64   a  distally relative to the sheath  32   a , or in other directions. 
         [0112]    An alternative embodiment of the endoprosthesis  10   b  is shown in  FIG. 7 . Parts illustrated in  FIG. 7  which correspond to parts illustrated in  FIGS. 1 to 5  have, in  FIG. 7 , the same reference numeral as in  FIGS. 1 to 5  with the addition of the suffix “b”. In this alternative embodiment, the proximal section  46   b  is woven such that the proximal release structure  52   b  extends from the proximal end  48   b  and a supplemental proximal release structure  70  extends from the distal end  50   b . The proximal and supplemental proximal release structures  52   b ,  70  are defined by portions of a single suture  36   b  the weaving of which forms the proximal section  46   b . The weaving of the proximal and supplemental proximal release structures  52   b ,  70  into the proximal section  46   b  can provide for displacement of the release structures in the directions  54   b ,  72  which are away from the proximal section to cause unraveling thereof. The unraveling of the proximal section  46   b  which results from the displacement of the proximal release structure  52   b  may commence from the proximal end  48   b  and proceeds in an axial direction  56   b  relative to the sheath  32   b  toward the transverse central plane  30   b . The unraveling of the proximal section  46   b  which results from the displacement of the supplemental proximal release structure  70  may commence from the distal end  50   b  and proceeds in an axial direction  74  relative to the sheath  32   b  away from the transverse central plane  30   b . The weaving of the proximal section  46   b  can provide for the respective unravelings thereof which result from the displacements of the proximal and supplemental proximal release structures  52   b ,  70  to meet at an axial location between the proximal and distal ends  48   b ,  50   b  to complete the unraveling of the proximal section. 
         [0113]    The distal section  58   b  is woven such that the distal release structure  64   b  extends from the proximal end  60   b  and a supplemental distal release structure  76  extends from the distal end  62   b . The distal and supplemental distal release structures  64   b ,  76  are defined by portions of a single suture  36   b  the weaving of which forms the distal section  58   b . The weaving of the distal and supplemental distal release structures  64   b ,  76  into the distal section  58   b  can provide for displacement of the release structures in directions  66   b ,  78  which are away from the distal section to cause unraveling thereof. The unraveling of the distal section  58   b  which results from the displacement of the distal release structure  64   b  may commence from the proximal end  60   b  and proceeds in an axial direction  68   b  relative to the sheath  32   b  away from the transverse central plane  30   b . The unraveling of the distal section  58   b  which results from the displacement of the supplemental distal release structure  76  may commence from the distal end  62   b  and proceeds in an axial direction  80  relative to the sheath  32   b  toward the transverse central plane  30   b . The weaving of the distal section  58   b  can provide for the respective unravelings thereof which result from the displacements of the distal and supplemental distal release structures  64   b ,  76  to meet at an axial location between the proximal and distal ends  60   b ,  62   b  to complete the unraveling of the distal section. 
         [0114]    The corresponding dimensions of the proximal and distal sections  46   b ,  58   b , the axial locations thereof relative to the transverse central plane  30   b , the locations of the proximal and supplemental proximal release structures  52   b ,  70  at the proximal and distal ends  48   a ,  50   a , and the locations of the distal and supplemental distal release structures  64   b ,  76  at the proximal and distal ends  60   b ,  62   b , provide for unraveling of the proximal and distal sections at generally the same rates in the axial directions  56   b ,  74 ,  68   b ,  80  toward the respective axial locations between the proximal and distal ends  48   b ,  50   b , and proximal and distal ends  60   b ,  62   b  when the proximal and distal release structures are simultaneously displaced in the directions Mb,  72 ,  66   b ,  78  away from the proximal and distal sections. 
         [0115]    As shown in  FIG. 7 , the portions of the proximal and supplemental proximal release structures  52   b ,  70 , and distal and supplemental distal release structures  64   b ,  76  which are remote from the sheath  32   b  are displaced proximally relative thereto in the directions Mb,  72 ,  66   b ,  78 . Alternative embodiments may provide for displacement of the proximal and supplemental proximal release structures  52   b ,  70 , and distal and supplemental distal release structures  64   b ,  76  distally relative to the sheath  32   b , or in other directions. 
         [0116]    An alternative embodiment of the endoprosthesis  10   c  is shown in  FIG. 8 . Parts illustrated in  FIG. 8  which correspond to parts illustrated in  FIGS. 1 to 5  have, in  FIG. 8 , the same reference numeral as in  FIGS. 1 to 5  with the addition of the suffix “c”. In this alternative embodiment, the proximal section  46   c  is woven such that the proximal release structure  52   c  extends from the proximal end  48   c  and an intermediate structure  82  extends from the distal end  50   c . The proximal release structure  52   c  and intermediate structure  82  may be defined by portions of suture  36   c  the weaving of which forms the proximal section  46   c . The weaving of the proximal release structure  52   c  and intermediate structure  82  into the proximal section  46   c  can provide for displacement of the proximal release structure in a direction  54   c  which is away from the proximal section to cause unraveling thereof. The unraveling of the proximal section  46   c  may commence from the proximal end  48   c  and proceeds in an axial direction  56   c  relative to the sheath  32   c  toward the distal end  50   c.    
         [0117]    The distal section  58   c  is woven such that the distal release structure  64   c  extends from the distal end  62   c  and the intermediate structure  82  extends from the proximal end  60   c . The distal release structure  64   c  and intermediate structure  82  may be defined by portions of a single suture  36   c  the weaving of which forms the distal section  58   c . Consequently, the intermediate structure  82 , proximal and distal sections  46   c ,  58   c , and proximal and distal release structures  52   c ,  64   c , may be defined by portions of a single suture  36   c.    
         [0118]    The weaving of the distal release structure  64   c  and intermediate structure  82  into the distal section  58   c  can provide for displacement of the distal release structure in a direction  66   c  which is away from the distal section to cause unraveling thereof. The unraveling of the distal section  58   c  may commence from the distal end  62   c  and proceeds in an axial direction  68   c  relative to the sheath  32   c  toward the proximal end  60   c.    
         [0119]    The corresponding dimensions of the proximal and distal sections  46   c ,  58   c , the axial locations thereof relative to the transverse central plane  30   c , and the locations of the proximal and distal release structures  52   c ,  64   c  at the proximal and distal ends  48   c ,  62   c  can provide for unraveling of the proximal and distal sections at generally the same rates in the axial directions  56   c ,  68   c  toward the transverse central plane when the proximal and distal release structures are simultaneously displaced in the directions  54   c ,  66   c  away from the proximal and distal sections. Upon completion of the unraveling of the proximal and distal sections  46   c ,  58   c , the proximal and distal release structures  52   c ,  64   c  coincide with the intermediate structure  82 . 
         [0120]    As shown in  FIG. 8 , the portions of the proximal and distal release structures  52   c ,  64   c  which are remote from the sheath  32   c  can be displaced proximally relative thereto in the directions  54   c ,  66   c . Alternative embodiments may provide for displacement of the proximal and distal release structures  52   c ,  64   c  distally relative to the sheath  32   c , or in other directions. 
         [0121]    An alternative embodiment of the endoprosthesis  10   d  is shown in  FIG. 9 . Parts illustrated in  FIG. 9  which correspond to parts illustrated in  FIGS. 1 to 5  have, in  FIG. 9 , the same reference numeral as in  FIGS. 1 to 5  with the addition of the suffix “d”. In this alternative embodiment, the proximal section  46   d  is woven such that the proximal release structure  52   d  extends from the proximal end  48   d  and the distal release structure  64   d  extends from the distal end  50   d . The proximal and distal release structures  52   d ,  64   d  may be defined by portions of a single suture  36   d  the weaving of which forms the proximal section  46   d . The weaving of the proximal release structure  52   d  into the proximal section  46   d  can provide for displacement of the proximal release structure in a direction  54   d  which is away from the proximal section to cause unraveling thereof. The unraveling of the proximal section  46   d  may commence from the proximal end  48   d  and proceeds in an axial direction  56   d  relative to the sheath  32   d  toward the distal end  50   d.    
         [0122]    The distal section  58   d  is woven such that the distal release structure  64   d  extends from the distal end  62   d . The distal release structure  64   d  may be defined by a portion of a single suture  36   d  the weaving of which forms the distal section  58   d . The proximal and distal sections  46   d ,  58   d , and proximal and distal release structures  52   d ,  64   d  may be defined by portions of a single suture  36   d . The weaving of the distal release structure  64   d  into the distal section  58   d  can provide for displacement of the distal release structure in a direction  66   d  which is away from the distal section to cause unraveling thereof. The unraveling of the distal section  58   d  may commence from the distal end  62   d  and proceeds in an axial direction  68   d  relative to the sheath  32   d  toward the proximal end  60   d.    
         [0123]    The extension of the distal release structure  64   d  from the distal ends  50   d ,  62   d , and the locations of the proximal release structure  52   d  and distal release structure at the proximal and distal ends  48   d ,  62   d  can provide for the unraveling of the proximal section  46   d  to be followed by the unraveling of the distal section  58   d . More specifically, the proximal release structure  52   d  can be displaced away from the sheath  32   d  in the direction  54   d  which results in the unraveling of the proximal section  46   d  in the axial direction  56   d  toward the transverse central plane  30   d . Upon completion of the unraveling of the proximal section  46   d , the proximal release structure  52   d  coincides with the distal release structure  64   d . Continued displacement of the proximal and distal release structures  52   d ,  64   d  away from the sheath  32   d  in the directions  54   d ,  66   d  results in the unraveling of the distal section  58   d  in the axial direction  68   d  toward the transverse central plane  30   d.    
         [0124]    As shown in  FIG. 9 , the portion of the proximal release structure  52   d  which is remote from the sheath  32   d  can be displaced proximally relative thereto in the direction  54   d . Alternative embodiments may provide for displacement of the proximal and distal release structures  52   d ,  64   d  distally relative to the sheath  32   d , or in other directions. 
         [0125]    An alternative embodiment of the endoprosthesis  10   e  is shown in  FIG. 10 . Parts illustrated in  FIG. 10  which correspond to parts illustrated in  FIGS. 1 to 5  have, in  FIG. 10 , the same reference numeral as in  FIGS. 1 to 5  with the addition of the suffix “e”. In this alternative embodiment, the proximal section  46   e  is woven such that the proximal release structure  52   e  extends from the proximal end  48   e . The proximal release structure  52   e  may be defined by a portion of a single suture  36   e  the weaving of which forms the proximal section  46   e . The weaving of the proximal release structure  52   e  into the proximal section  46   e  can provide for displacement of the proximal release structure in a direction  54   e  which is away from the proximal section to cause unraveling thereof. The unraveling of the proximal section  46   e  may commence from the proximal end  48   e  and proceeds in an axial direction  56   e  relative to the sheath  32   e  toward the distal end  50   e.    
         [0126]    The distal section  58   e  is woven such that the proximal release structure  52   e  extends from the proximal end  60   e , and the distal release structure  64   e  extends from the distal end  62   e . The proximal and distal release structures  52   e ,  64   e  may be defined by portions of a single suture  36   e  the weaving of which forms the distal section  58   e . Consequently, the proximal and distal sections  46   e ,  58   e , and proximal and distal release structures  52   e ,  64   e  may be defined by portions of a single suture  36   e . The weaving of the distal release structure  64   e  into the distal section  58   e  can provide for displacement of the distal release structure in a direction  66   e  which is away from the distal section to cause unraveling thereof. The unraveling of the distal section  58   e  may commence from the distal end  62   e  and proceeds in an axial direction  68   e  relative to the sheath  32   e  toward the proximal end  60   e.    
         [0127]    The extension of the proximal release structure  52   e  from the proximal ends  48   e ,  60   e , and the locations of the proximal release structure and distal release structure  64   e  at the proximal and distal ends  48   e ,  62   e  can provide for the unraveling of the distal section  58   e  to be followed by the unraveling of the proximal section  46   e . More specifically, the distal release structure  64   e  can be displaced away from the sheath  32   e  in the direction  66   e  which results in the unraveling of the distal section  58   e  in the axial direction  68   e  toward the transverse central plane  30   e . Upon completion of the unraveling of the distal section  58   e , the distal release structure  64   e  coincides with the proximal release structure  52   e . Continued displacement of the proximal and distal release structures  52   e ,  64   e  away from the sheath  32   e  in the directions  54   e ,  66   e  results in the unraveling of the proximal section  46   e  in the axial direction  56   e  toward the transverse central plane  30   e . Directions  54   e  and  66   e  may be opposite directions when the distal section  58   e  is finished being released and the suture may be pulled along direction  66   e . As shown in  FIG. 10 , the portion of the distal release structure  64   e  which is remote from the sheath  32   e  is displaced proximally relative thereto in the direction  66   e . Alternative embodiments may provide for displacement of the distal release structure  64   e  distally relative to the sheath  32   e , or in other directions. 
         [0128]    Various stent types and stent constructions may be employed in the invention. Among the various stents useful include, without limitation, self-expanding stents and balloon expandable extents. The stents may be capable of radially contracting, as well and in this sense can best be described as radially distensible or deformable. Self-expanding stents include those that have a spring-like action which causes the stent to radially expand, or stents which expand due to the memory properties of the stent material for a particular configuration at a certain temperature. Nitinol is one material which has the ability to perform well while both in spring-like mode, as well as in a memory mode based on temperature. Other materials are of course contemplated, such as stainless steel, platinum, gold, titanium and other biocompatible metals, as well as polymeric stents. The configuration of the stent may also be chosen from a host of geometries. For example, wire stents can be fastened into a continuous helical pattern, with or without a wave-like or zig-zag in the wire, to form a radially deformable stent. Individual rings or circular members can be linked together such as by struts, sutures, welding or interlacing or locking of the rings to form a tubular stent. Tubular stents useful in the present invention also include those formed by etching or cutting a pattern from a tube. Such stents are often referred to as slotted stents. Furthermore, stents may be formed by etching a pattern into a material or mold and depositing stent material in the pattern, such as by chemical vapor deposition or the like. Examples of various stent configurations are shown in U.S. Pat. Nos. 4,503,569 to Dotter; 4,733,665 to Palmaz; 4,856,561 to Hillstead; 4,580,568 to Gianturco; 4,732,152 to Wallsten, 4,886,062 to Wiktor, and 5,876,448 to Thompson, all of whose contents are incorporated herein by reference. 
         [0129]    With any embodiment, the endoprosthesis  10  may be used for a number of purposes including to maintain patency of a body lumen, vessel or conduit, such as in the coronary or peripheral vasculature, esophagus, trachea, bronchi colon, biliary tract, urinary tract, prostate, brain, and the like. The devices of the present invention may also be used to support a weakened body lumen or to provide a fluid-tight conduit for a body lumen. 
         [0130]    While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concept described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.