US20090138073A1 - Bifurcation Stent Assembly - Google Patents

Abstract

A stent assembly comprises a stent and a side branch flap. The stent has a substantially tubular body which defines a primary lumen and is comprised of a plurality of interconnected stent members. Adjacent stent members define a plurality of stent openings that extend through the body and which are in fluid communication with the primary lumen. At least one stent opening is a side branch opening. The side branch flap is a non-tubular body having a planar structure. A first region of the planar structure is overlappingly positioned across a portion of the side branch opening prior to deployment. A second region of the planar structure is engaged to a portion of the body of the stent immediately adjacent to the perimeter of the side branch opening. When the assembly is deployed the first region of the flap is displaced radially outward from the side branch opening.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This Application is a continuation of U.S. application Ser. No. 11/155,155, filed Jun. 17, 2005, which is hereby incorporated herein by reference in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
• Not Applicable
BACKGROUND OF THE INVENTIONDescription of the Related Art
• Stents, grafts, stent-grafts, vena cava filters, expandable frameworks, and similar implantable medical devices, collectively referred to hereinafter as stents, are radially expandable endoprostheses which are typically intravascular implants capable of being implanted transluminally and enlarged radially after being introduced percutaneously. Stents may be implanted in a variety of body lumens or vessels such as within the vascular system, urinary tracts, bile ducts, fallopian tubes, coronary vessels, secondary vessels, etc. Stents may be used to reinforce body vessels and to prevent restenosis following angioplasty in the vascular system. They may be self-expanding, expanded by an internal radial force, such as when mounted on a balloon, or a combination of self-expanding and balloon expandable (hybrid expandable).
• Within the vasculature it is not uncommon for stenoses to form at a vessel bifurcation. A bifurcation is an area of the vasculature or other portion of the body where a first (or parent) vessel is bifurcated into two or more tubular component vessels. Where a stenotic lesion or lesions form at such a bifurcation, the lesion(s) can affect only one of the vessels (i.e., either of the tubular component vessels or the parent vessel) two of the vessels, or all three vessels.
• Many of the bifurcated stents that have been disclosed are segmented, and include a primary branch and at least one secondary branch which is positioned adjacent to and/or partially within the primary branch. Often such segmented systems employ multiple catheters and/or balloons to deploy all of the stent segments. Other bifurcated stents include single structure stents wherein the stent is comprised of a trunk with two or more branches extending therefrom. Still other stent configurations employ a single substantially tubular stent which has a specialized side-branch opening through which an additional stent or structural component may be deployed.
• In spite of the many bifurcated stents that have been disclosed, there remains a need for a stent suitable for treatment of a vessel bifurcation wherein the side branch vessel is provided with improved coverage particularly in the region of the contra-lateral wall, opposite the carina, without the added strain typically associated with standard tubular structures.
• All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
• Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
• A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.
BRIEF SUMMARY OF THE INVENTION
• In at least one embodiment, the present invention is directed to a stent assembly comprising a stent. The stent has a tubular body which defines a primary flow path or lumen therethrough. The body of the stent is made up of any of a variety of patterns of interconnected strut members, connecting members, etc. The pattern of struts and/or connectors of the body define a plurality of cells or openings through the body wall. At least one of the cells is a specialized opening, which provides fluid communication between the primary lumen of the stent and a branch vessel of a vessel bifurcation.
• In some embodiments, exemplary configurations of a pattern that the stent body may include, are shown and/or described in the following U.S. Pat. Nos.: 6,746,479, 6,478,816, 6,471,720, 6,334,870, 6,261,319, 6,818,014, 6,348,065, 5,922,021, 6,235,053, and 6,123,721, the entire contents of each of which are incorporated herein by reference.
• In some embodiments, exemplary configurations, shapes, sizes, etc. of a side branch opening that the stent may include are shown and/or described in the following U.S. Patents and publications: U.S. Pat. Nos. 6,835,203, 6,706,062, 6,325,826, 6,210,429, and 2003-0055483-A1, the entire contents of each of which are incorporated herein by reference.
• As indicated, the references cited above are provided to illustrate some examples of stent patterns and cell configurations suitable for use in the present invention. The invention is not limited to the examples cited and may include combinations of patterns and configurations which can include those disclosed above, as well as others.
• In some embodiments of the invention the stent is part of a stent assembly which includes a stent and at least one secondary piece or flap. In at least one embodiment the flap(s) is a planar (rather than a tubular) structure which is positioned immediately adjacent to the side branch opening of the stent. In at least one embodiment the flap is defined by a pattern of interconnected struts or members which define a plurality of openings or cells therethrough. The pattern of the flap may be similar or different to that of the stent body.
• In at least one embodiment the flap has two dimensional shape similar to that of a truncated cone.
• In some embodiments the flap comprises three regions: two side regions and a medial region in between. In at least one embodiment the pattern of the side regions are similar to one another whereas the pattern of the medial region is different than that of the side regions. The patterns may differ by providing the regions with different materials, different strut configurations, different cell sizes and shapes, etc.
• In some embodiments the flap is at least partially overlapped by the body of the stent. When preparing the stent assembly for use the flap is initially positioned upon a delivery catheter and the stent is then placed over the flap such that the flap is substantially positioned across the side branch opening. In at least one embodiment, at least three edges of the flap remain engaged to the body of the stent adjacent to the side branch opening when the assembly is in the fully expanded or deployed state.
• In at least one embodiment, when the assembly is in the deployed state, at least a portion of the flap is pushed outward from the circumferential plane of the stent to engage or be positioned adjacent to the contra-lateral wall of a side branch vessel. Other configurations of the stent and flap are included in embodiments of the invention. For example, the flap may be engaged to the distal aspect of the side branch opening of the stent, for positioning adjacent to the carina when deployed. In some embodiments multiple flaps may be utilized at the side branch opening to provide complete or near-complete coverage of the ostium of the side branch vessel.
• In some embodiments the flap is constructed from one or more wires woven or otherwise formed into the desired pattern of members which define the flap. In some embodiments the pattern of the flap is provided by cutting the flap from a sheet of suitable stent material, in accordance with a desired pattern; molding the flap, wherein the mold defines the desired pattern; is cut from a tubular member, etc.
• These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a further understanding of the invention, its advantages and objectives obtained by its use, reference should be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there is illustrated and described a embodiments of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
• A detailed description of the invention is hereafter described with specific reference being made to the drawings.
• FIG. 1 is a longitudinal side, cross-sectional view of an embodiment of the invention shown in the environment of a vessel bifurcation prior to deployment of the assembly.
• FIG. 2 is a perspective view of a stent of the type shown inFIG. 1
• FIG. 3 is a partial perspective view of the stent assembly depicted inFIG. 1.
• FIG. 4 is a detailed view of an embodiment of the flap section of the assembly shown inFIGS. 1 and 3.
• FIG. 5 is transverse cross-sectional view of a region of the embodiment shown inFIG. 1.
• FIG. 6 is a longitudinal side, cross-sectional view of the embodiment shown inFIG. 1 wherein the assembly is shown being deployed.
• FIG. 7 is a longitudinal side, cross-sectional view of the assembly shown isFIG. 6 following its deployment at a vessel bifurcation and withdrawal of the delivery system.
• FIG. 8 is a partial perspective view of an embodiment of the invention shown in its environment of use.
DETAILED DESCRIPTION OF THE INVENTION
• While this invention may be embodied in many different forms, there are described in detail herein specific embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated.
• For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated.
• Referring now to the drawings which are for the purposes of illustrating embodiments of the invention only and not for purposes of limiting same, in the embodiment shown inFIG. 1, astent delivery system10 is shown, having acatheter12, which is configured to deliver astent assembly20 to abifurcation104 of vessels, such as theprimary vessel100 andsecondary vessel102 shown.
• Thestent assembly20 is comprised of a primary framework orstent30 and a side branch member orflap40.
• An embodiment of thestent30 is illustrated inFIG. 2. The stent may be any type or configuration of stent desired. The example shown inFIG. 2 is comprised of a substantially hollowtubular body31 which defines anstent lumen32 open at both ends of the stent. Thebody31 is made up of a plurality of interconnectingstent members34 of whichadjacent members34 define openings orcells33 which extend through thebody31 and are in communication with thelumen32.
• Themembers34 may have any of a variety or lengths, widths, thicknesses, etc.Members34 may be curved, straight, bent, and/or otherwise configured. In someembodiments members34 are characterized as struts, connectors, bands, and/or other stent structures, and arranged accordingly. Thecells33 defined by themembers34 may likewise have any of a variety of sizes, shapes, and/or configurations as desired.
• In at least one embodiment thecells33 andmembers34 are configure to provide thebody31 with a somewhat regular or visually recognizable pattern or geometry.
• In the various embodiments however, one of thecells33 is a specialized cell which provides thestent lumen32 with fluid communication to theside branch vessel102 of thebifurcation100, such as in the manner shown inFIG. 7. This specialized cell or side-branch opening35 is often a cell which has a different shape and/or size than the remainingcells33, and in at least oneembodiment opening35 will have a greater area than at least some of thecells33 adjacent thereto. The particular physical dimensions of theside branch opening35 will often depend on the specific anatomy of the bifurcation, and as such its characteristics are highly variable.
• In the various embodiments shown and described herein, theflap40 is configured to be engaged to thestent30 both before and after deployment, wherein at least a portion of theflap40 in the deployed state extends radially outward from the side branch opening35 to engage, or be positioned adjacent to, the contra-lateral wall106 (opposite the carina108) of thesecondary vessel102.
• In some embodiments when theflap40 engages the distal aspect, orside80, of the side branch opening of the stent, for positioning adjacent to thecarina108 when deployed. In some embodimentsmultiple flaps40 may be utilized at the side branch opening35 to provide complete or near-complete coverage of both the contra-lateral wall106 and thecarina108, such as is depicted inFIG. 8. In the embodiment shown inFIG. 8 aflap40 is engaged to and disposed about both thedistal side80 as well as theproximal side82 of theside branch opening35.
• In at least one embodiment when thestent30 andflap40 are fully deployed, a portion of thestent30 and a portion of theflap40 are overlappingly engaged and are both pushed against the contra-lateral wall106.
• Unlike the tubular body of thestent30, theflap40 is a substantially planar structure which is prior to deployment is positioned immediately adjacent to the side branch opening35 of thestent30, such as in the manner depicted inFIGS. 1 and 3. During and subsequent to deployment, a portion of theflap40 is take on a substantially cowl-like shape, such as is shown inFIG. 3, which extends radially outward from thestent30.
• In at least one embodiment, theflap40, when viewed from ‘above’ as a two dimensional planar structure, has a somewhat frusto-conical or truncated conical shape, such as is shown inFIG. 4. When viewed in this manner theflap40 has a plurality ofsides41 which define the plane of the flap. In the various embodiments of the invention at least one of thesides41 of the flap is engaged to thebody31 or at least onestent member34 which define the side-branch opening35. In the embodiment depicted inFIGS. 1 and 3 for example, theflap40 has at least threesides41 which remain engaged to thebody31 of thestent30 before, during, and after deployment of theassembly20, such as in the manner depicted inFIGS. 1-3 and6-7.
• Theflap40 may be somewhat similar to thestent30 in its construction, having a plurality of interconnected members, in this case,flap members44, which define a plurality offlap cells43. The configuration, pattern, size, shape, and/or other characteristics of theflap members44 andflap cells43 may be similar or different to the corresponding characteristics of thestent members34 andstent cells33, such as have been previously described. For example, as is shown inFIG. 4, theflap members44 and theflap cells43 define at least one visually recognizable pattern on theflap40. This ‘flap’ pattern may be visually similar (or distinct) to (from) a pattern on thetubular body31 of thestent30, such as is defined by thestent members34 andstent cells33 in the manner previously described.
• Such similar or differing geometry between theflap40 andstent30 may be selected to provide theassembly20 with varying trackability, rigidity, flexibility, etc.
• The stent and/or the flap may be made from any suitable biocompatible materials including one or more polymers, one or more metals or combinations of polymer(s) and metal(s). Examples of suitable materials include biodegradable materials that are also biocompatible. By biodegradable is meant that a material will undergo breakdown or decomposition into harmless compounds as part of a normal biological process. Suitable biodegradable materials include polylactic acid, polyglycolic acid (PGA), collagen or other connective proteins or natural materials, polycaprolactone, hylauric acid, adhesive proteins, co-polymers of these materials as well as composites and combinations thereof and combinations of other biodegradable polymers. Other polymers that may be used include polyester and polycarbonate copolymers. Examples of suitable metals include, but are not limited to, stainless steel, titanium, tantalum, platinum, tungsten, gold and alloys of any of the above-mentioned metals. Examples of suitable alloys include platinum-iridium alloys, cobalt-chromium alloys including Elgiloy and Phynox, MP35N alloy and nickel-titanium alloys, for example, Nitinol.
• The stent and/or the flap may be made of shape memory materials such as superelastic Nitinol or spring steel, or may be made of materials which are plastically deformable. In the case of shape memory materials, the stent and/or the flap may be provided with a memorized shape and then deformed to a reduced diameter shape. The stent and/or the flap may restore itself to its memorized shape upon being heated to a transition temperature and having any restraints removed therefrom.
• The stent may be created by methods including cutting or etching a design from a tubular stock, from a flat sheet which is cut or etched and which is subsequently rolled or from one or more interwoven wires or braids. Any other suitable technique which is known in the art or which is subsequently developed may also be used to manufacture the inventive stent and/or the flap disclosed herein.
• In some embodiments the stent and/or the flap, the delivery system or other portion may include one or more areas, bands, coatings, members, etc. that is (are) detectable by imaging modalities such as X-Ray, MRI, ultrasound, etc. In some embodiments at least a portion of the stent and/or adjacent assembly is at least partially radiopaque.
• In at least one embodiment, such as is depicted inFIG. 4, theflap40 may be characterized as having at least two regions, referred to hereinafter as abranch region50 and anengagement region52, wherein the pattern offlap members44 and /orflap cells43 are different between regions. In the embodiment shown for example, the branch region has significantlylarger cells43 than theadjacent engagement regions52. Alternatively, thebranch region50 can be characterized has having a lower density offlap members44 than theadjacent engagement regions52.
• In at least one embodiment the wall thickness of theengagement region52 is different than that of thebranch region50. For example, in some embodiments the wall thickness of the engagement region is thinner than thebranch region50.
• One of ordinary skill in the art will recognize that by changing the construction, material composition, configuration, etc. of the regions of the of theflap40, as well as thestent30, the regions can be provided with any of a variety of similar or different expansion characteristics as may be desired.
• For example, in the embodiment shown inFIG. 4, thebranch region50, is provided with a lower density offlap members44 than theadjacent regions52 so that thebranch region50 will have less resistance to expansion than the adjacent regions when a deployment force is exerted against the flap as a whole.
• Deployment of thestent assembly20 into a vessel bifurcation may be achieved in a variety of ways. In the embodiment shown inFIGS. 1,5 and6, theassembly20 is incorporated into thestent delivery system10 which is advanced to thebifurcation104. Theassembly20 is positioned on astent retaining region60 of astent delivery catheter12 in a reduced diameter or predeployed state such as is shown. In at least one embodiment, where thestent30 is a balloon expandable stent, thestent retaining region60 is at least partially comprised of an expandable member orballoon62.
• Balloon62 may be a typical angioplasty, stent delivery balloon or other inflatable member which may be used or incorporated into a catheter assembly. Theballoon62 may be constructed of any suitable balloon material known to those of skill in the art. Commonly employed materials include the thermoplastic elastomeric and non-elastomeric polymers and the thermosets including the moisture curable polymers.
• Examples of suitable materials include but are not limited to, polyolefins, polyesters, polyurethanes, polyamides, polyimides, polycarbonates, polyphenylene sulfides, polyphenylene oxides, polyethers, silicones, polycarbonates, styrenic polymers, copolymers thereof, and mixtures thereof. Some of these classes are available both as thermosets and as thermoplastic polymers. See commonly assigned U.S. Pat. No. 5,500,181, for example, which is incorporated by reference herein in its entirety. As used herein, the term copolymer shall be used to refer to any polymeric material formed from more than one monomer.
• As used herein, the term “copolymer” shall be used to refer to any polymer formed from two or more monomers, e.g. 2, 3, 4, 5 and so on and so forth.
• Useful polyamides include, but are not limited to,nylon 12, nylon 11, nylon 9, nylon 6/9 and nylon 6/6. The use of such materials is described in U.S. Pat. No. 4,906,244, for example, the entire content of which is incorporated by reference herein in its entirety.
• Examples of some copolymers of such materials include the polyether-block-amides, available from Elf Atochem North America in Philadelphia, Pa. under the tradename of PEBAX®. Another suitable copolymer is a polyetheresteramide.
• Suitable polyester copolymers, include, for example, polyethyelene terephthalate and polybutylene terephthalate, polyester ethers and polyester elastomer copolymers such as those available from DuPont in Wilmington, Del. under the tradename of HYTREL®.
• Block copolymer elastomers such as those copolymers having styrene end blocks, and midblocks formed from butadiene, isoprene, ethylene/butylene, ethylene/propene, and so forth may be employed herein. Other styrenic block copolymers include acrylonitrile-styrene and acrylonitrile-butadiene-styrene block copolymers. Also, block copolymers wherein the particular block copolymer thermoplastic elastomers in which the block copolymer is made up of hard segments of a polyester or polyamide and soft segments of polyether.
• Specific examples of polyester/polyether block copolymers are poly(butylene terephthalate)-block-poly(tetramethylene oxide) polymers such as ARNITEL® EM 740, available from DSM Engineering Plastics. and HYTREL® polymers available from DuPont de Nemours & Co, already mentioned above.
• The above materials are intended for illustrative purposes only, and not as a limitation on the scope of the present invention. Suitable polymeric materials available for use are vast and too numerous to be listed herein and are known to those of ordinary skill in the art.
• By expanding theballoon62 from a reduced, predeployed diameter to a greater, deployed diameter, such as is shown inFIG. 6, theballoon62 will exert expansion or deployment forces upon theassembly20. The expansion forces exerted on the assembly are sufficient to expand the assembly to its deployed state within thevessel bifurcation104. Subsequent to the deployment of theassembly20, the catheter is removed from thevessel100 and theassembly20 remains in place to support thebifurcation104 such as in the manner shown inFIG. 7.
• Thesystem10 may be advanced to thebifurcation104 using various mechanisms. For example, in the embodiment shown inFIGS. 1,5 and6, thesystem10 employs acatheter12 which has acatheter shaft64.Shaft64 defines aguidewire lumen66 through which a first orprimary guidewire68 may slidingly pass. In some embodiments theprimary guidewire68 is advanced through theprimary vessel100 and across thebifurcation104. By advancing thecatheter12 along theguidewire68 the system is advanced through theprimary vessel100.
• Alternatively thecatheter12 may be a fixed wire catheter or other type of catheter that is capable of being advanced through the vasculature or other body lumen(s).
• As theassembly20 is intended for deployment at avessel bifurcation104, in at least one embodiment thesystem10 includes one or more mechanisms for aligning the side branch opening of the stent with the ostium of the secondary vessel.
• In the embodiment shown, thesystem10 includes asecondary guidewire housing70 which defines asecondary guidewire lumen72. Thesecondary guidewire lumen72 is constructed and arranged to permit sliding passage of asecondary guidewire74 therethrough. Thesecondary guidewire housing74 may be constructed from any flexible tubular structure suitable for use of tracking along a guidewire.
• In some embodiments the secondary guidewire housing is a tube of material, wherein the material is selected from the group including: PEBAX, peek, polyimide, etc. In at least one embodiment the housing is a braided tube of metal wire or other material, a hypotube having slots or other mechanisms to provide flexibility, or other flexible tubular device.
• In some embodiments thesecondary guidewire74 is advanced through theprimary vessel100 and at thebifurcation104 is advanced into thesecondary vessel102. Once theprimary guidewire68 is in place within theprimary vessel100 and thesecondary guidewire74 is positioned to extend into thesecondary vessel102 such as in the manner shown inFIG. 1, thesystem10 may be advanced along both wires simultaneously.
• In the embodiment shown inFIGS. 1 and 3, thesecondary guidewire housing70 extends through the proximal portion of thestent32 lumen and exits thestent30 through the side-branch opening35. This configuration allows thesecondary guidewire housing70 to provide a torquing affect on thesystem10 as it is advanced toward thebifurcation104 along both guidewire. As a result theside branch opening35 will be rotated into alignment with thesecondary vessel102.
• Once the system is aligned in the manner shown inFIG. 1, theassembly20 may be deployed in the manner previously described.
• In at least one embodiment, an example of which is shown inFIG. 5 theflap40, prior to deployment, is positioned directly over theballoon62 and the portion of thesecondary guidewire housing70 adjacent to theside branch opening35. In this configuration thebranch region50 of theflap40 is immediately radially adjacent or ‘on top’ of thesecondary guidewire housing70 and the surroundingregions52 of the flap are radially position upon theballoon62. The sent30 is then mounted over theflap40,balloon62 andhousing70 in the manner previously shown and described.
• In at least one embodiment theside branch opening35 is substantially crossed by theflap40, but there is sufficient area remaining to allow thesecondary guidewire housing70 to exit the side branch opening35 as well.
• In at least some embodiments, at least a portion of theflap40, such as thebranch region50 which covers at least a portion of theside branch opening35 prior to delivery, is particularly flexible. This highly flexible region of theflap40 permits at least thebranch region50 of the flap to be distended into a cowl-like shape which is pushed ‘upward’ or radially outward from thestent20 as thesecondary guidewire housing70 tracks along thesecondary guidewire74 and into thesecondary vessel102, such as in the manner shown inFIGS. 1 and 3.
• The distention or biasing of thebranch region50 of theflap40 provides a number of benefits. For example, where theflap40 is made to be radiopaque, the distention of theflap40 will indicate to an operator that the side branch opening35 of thestent30 is actually aligned with the ostium of the secondary vessel, before the assembly is expanded for delivery. Furthermore, theflap40 will act as a break on thesystem10 halting the advancement of thesystem10 at is pushed against thecarina108 of thebifurcation104.
• When thesystem10 is positioned in the manner shown inFIG. 1, theballoon62 is expanded to deploy theassembly20 in the manner shown inFIG. 6.
• While a balloon having traditional or somewhat uniform expansion characteristics may be used in some embodiments of the invention to deploy theassembly20, in at least one embodiment at least a portion of the balloon adjacent to theside branch opening35 has different expansion characteristics than the remainder of the balloon. In a least one embodiment this portion of the balloon adjacent to theside branch opening35 is configured to push outward through theopening35 to act upon thesecondary guidewire housing70 and or theflap40 directly when the balloon is expanded.
• In some embodiment a therapeutic agent may be placed on thestent30,flap40 and/or other portion of theassembly10 in the form of a coating. Often the coating includes at least one therapeutic agent and at least one polymer.
• In embodiments where the assembly comprises one or more therapeutic agents, an agent or agents present on thestent30 may be similar or different to the agent or agents which may be present on theflap40. The dosage of the agents on the stent and/or flap may vary or be different on different portions of the assembly.
• A therapeutic agent may be a drug or other pharmaceutical product such as non-genetic agents, genetic agents, cellular material, etc. Some examples of suitable non-genetic therapeutic agents include but are not limited to: anti-thrombogenic agents such as heparin, heparin derivatives, vascular cell growth promoters, growth factor inhibitors, Paclitaxel, etc. Where an agent includes a genetic therapeutic agent, such a genetic agent may include but is not limited to: DNA, RNA and their respective derivatives and/or components; hedgehog proteins, etc. Where a therapeutic agent includes cellular material, the cellular material may include but is not limited to: cells of human origin and/or non-human origin as well as their respective components and/or derivatives thereof Where the therapeutic agent includes a polymer agent, the polymer agent may be a polystyrene-polyisobutylene-polystyrene triblock copolymer (SIBS), polyethylene oxide, silicone rubber and/or any other suitable substrate.
• The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.
• Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim1 should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below.
• With this description, those skilled in the art may recognize other equivalents to the specific embodiment described herein. Such equivalents are intended to be encompassed by the claims attached hereto.

Claims (19)

1. A bifurcation stent assembly having an undepolyed configuration and a deployed configuration, the bifurcation stent comprising:

a stent having a substantially tubular body, a first end, a second end and an intermediate portion therebetween;

the tubular body comprising a plurality of interconnected stent members defining a side branch opening disposed along the intermediate portion of the stent; and

a first side branch flap comprising first and second regions; the first and second regions having a wall thickness, wherein the wall thickness of the first region is thinner than the wall thickness of the second region, and wherein in the undeployed configuration the first side branch flap overlaps at least a portion of the side branch opening.

2. The bifurcation stent assembly ofclaim 1, further comprising a second side branch flap.

3. The bifurcation stent assembly ofclaim 2, wherein the side branch opening comprises a proximal side and a distal side, and wherein the first and second side branch flaps, in combination, are disposed about both the proximal side and the distal side of the side branch opening.

4. The bifurcation stent assembly ofclaim 2, wherein the first side branch flap comprises a different shape than the second side branch flap.

5. The bifurcation stent assembly ofclaim 2, wherein the first side branch flap and the second side branch flap are substantially diametrically opposed to one another across the side branch opening.

6. The bifurcation stent assembly ofclaim 2, wherein at least one of the first and second side branch flaps comprises a biocompatible material.

7. The bifurcation stent assembly ofclaim 2, wherein at least one of the first and second side branch flaps comprises a metal or combination of metals.

8. The bifurcation stent assembly ofclaim 1, wherein the first side branch flap is substantially planar.

9. The bifurcation stent assembly ofclaim 1, wherein the first side branch flap comprises a plurality of cells.

10. The bifurcation stent assembly ofclaim 9, wherein the second region has larger cells than the first region.

11. The bifurcation stent assembly ofclaim 1, wherein the first side branch flap comprises a shape memory material.

12. The bifurcation stent assembly ofclaim 1, wherein in the undeployed configuration, the first side branch flap takes on a substantially cowl-like shape in the deployed configuration.

13. The bifurcation stent assembly ofclaim 1, wherein the first side branch flap comprises a radiopaque coating.

14. A stent delivery system for delivering a bifurcation stent assembly having an undeployed configuration and a deployed configuration, the stent delivery system comprising:

a catheter having a catheter shaft and a stent retaining region, the catheter shaft defining a primary guidewire lumen;

a primary guidewire disposed in the primary guidewire lumen;

an expandable balloon;

a secondary guidewire; and

a stent having a substantially tubular body, a first end, a second end and an intermediate portion therebetween;

the tubular body comprising a plurality of interconnected stent members defining a side branch opening disposed along the intermediate portion of the stent; and

a first side branch flap comprising first and second regions; the first and second regions having a wall thickness, wherein the wall thickness of the first region is thinner than the wall thickness of the second region, and wherein in the undeployed configuration the first side branch flap overlaps at least a portion of the side branch opening.

15. The stent delivery system ofclaim 14, further comprising a second side branch flap.

16. The stent delivery system ofclaim 15, wherein the secondary guidewire is disposed between the first side branch flap and the second side branch flap.

17. The stent delivery system ofclaim 15, wherein in the undeployed configuration, the first and second side branch flaps take on a substantially cowl-like shape in the deployed configuration.

18. The stent delivery system ofclaim 14, wherein the first side branch flap comprises a plurality of cells, and wherein the second region has larger cells than the first region.

19. The stent delivery system ofclaim 14, wherein the expandable balloon comprises a first region and a second region; the first having different expansion characteristics than the second region, wherein the first region is disposed adjacent to the side branch opening.

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