Abstract:
A stent assembly comprises a second stent body and a substantially tubular first stent body defining a first lumen and containing a side branch opening. In an undeployed state, the second stent body is at least partially comprised of rings having peaks and valleys at least some of the valleys of adjacent rings being interconnected by bridges. In an expanded state, the rings of the second stent body define a second lumen opening in fluid communication with the first lumen. The second lumen has superior body vessel coverage and is flexible enough to form an oblique angle relative to the longitudinal axis of the first stent body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH  
       [0002]     Not Applicable  
       FIELD OF THE INVENTION  
       [0003]     In some embodiments this invention relates to implantable medical devices, their manufacture, and methods of use. Some embodiments are directed to delivery systems, such as catheter systems of all types, which are utilized in the delivery of such devices.  
       BACKGROUND OF THE INVENTION  
       [0004]     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 implanted 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).  
         [0005]     Stents 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.  
         [0006]     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 branch 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 branch vessels or the parent vessel) two of the vessels, or all three vessels. Many prior art stents however are not wholly satisfactory for use where the site of desired application of the stent is juxtaposed or extends across a bifurcation in an artery or vein such, for example, as the bifurcation in the mammalian aortic artery into the common iliac arteries.  
         [0007]     The art referred to and/or described above is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.  
         [0008]     All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.  
         [0009]     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.  
         [0010]     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  
       [0011]     At least one possible embodiment is directed to a stent comprising a tubular body having a sidewall with a plurality of openings therethrough. A portion of the sidewall has a plurality of rings which are concentric and interconnected, including a first ring and a second ring. Both rings have peaks and valleys. A first connector extending from a valley of the first ring to the valley of the second ring connects the rings.  
         [0012]     At least one possible embodiment is directed to a stent wherein the first and second rings are connected by a plurality of connectors, the connectors extending from one valleys of the first ring to valleys of the second ring.  
         [0013]     At least one possible embodiment is directed to a stent wherein each of the concentric rings has a plurality of peaks and valleys, each two adjacent concentric rings connected by at least one connector which extends from a valley of one of the two adjacent rings to a valley of the other of the two adjacent rings.  
         [0014]     At least one possible embodiment is directed to a stent wherein each of the concentric rings has a plurality of peaks and valleys, each two adjacent concentric rings connected by a plurality of connectors which extend from valleys of one of the two adjacent rings to valleys of the other of the two adjacent rings.  
         [0015]     At least one possible embodiment is directed to a stent in which the peaks and valleys of the concentric rings are out of phase with each other.  
         [0016]     At least one possible embodiment is directed to a stent in which at least one connector is more rigid than at least one ring.  
         [0017]     At least one possible embodiment is directed to a stent in which at least one ring is more rigid than at least one connector.  
         [0018]     At least one possible embodiment is directed to a stent in which at least one connector and at least one concentric ring are constructed out of different materials.  
         [0019]     At least one possible embodiment is directed to a stent in which the connectors are connected to every other valley of at least one ring.  
         [0020]     At least one possible embodiment is directed to a bifurcated stent having a tubular sidewall, the sidewall including an expandable sidebranch portion, the expandable sidebranch portion having a plurality of rings which are concentric and interconnected, including a first ring and a second ring. Both rings have peaks and valleys. A first connector extending from a valley of the first ring to the valley of the second ring connects the rings.  
         [0021]     At least one possible embodiment is directed to a bifurcated stent in which the first and second rings are connected by a plurality of connectors, the connectors extending from one valleys of the first ring to valleys of the second ring.  
         [0022]     At least one possible embodiment is directed to a bifurcated stent in which the first ring defines the outermost end of the expandable sidebranch portion.  
         [0023]     At least one possible embodiment is directed to a bifurcated stent in which the peaks and valleys of the concentric rings are out of phase with each other.  
         [0024]     At least one possible embodiment is directed to a bifurcated stent in which at least one connector is more rigid than at least one ring.  
         [0025]     At least one possible embodiment is directed to a bifurcated stent in which at least one ring is more rigid than at least one connector.  
         [0026]     At least one possible embodiment is directed to a bifurcated stent in which at least one connector and at least one concentric ring are constructed out of different materials.  
         [0027]     At least one possible embodiment is directed to a bifurcated stent in which the connectors are connected to every other valley of at least one ring.  
         [0028]     At least one possible embodiment is directed to a bifurcated stent being expandable from an unexpanded state to an expanded state, wherein in the unexpanded state the stent has a diameter less than that of the diameter in the expanded state. The bifurcated stent comprises: a substantially tubular primary body defining a primary circumferential plane, a primary outer surface, a primary lumen and having a primary longitudinal axis extending therethrough and has a side opening and a side branch assembly engaged to the primary body opposite the side opening. The side branch assembly comprises at least two ring members. In the unexpanded state the at least two ring members are positioned substantially within the primary circumferential plane. In the expanded state at least one ring member is positioned external to the first circumferential plane and the at least two ring members define a secondary circumferential plane, a secondary lumen, and having a secondary longitudinal axis extending therethrough. The secondary lumen is in fluid communication with the primary lumen and the secondary longitudinal axis forms an oblique angle with the primary longitudinal axis. The ring members are interconnected by connectors and comprising a plurality of peaks and valleys, at least one of the connectors connecting the valley of one ring member to the valley of another ring member.  
         [0029]     At least one possible embodiment is directed to a bifurcated stent in which one half of all the valleys of at least one ring members are connected to one half of the ring members of at least one other ring member.  
         [0030]     These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof.  
         [0031]     However, for further understanding of the invention, its advantages and objectives obtained by its use, reference can be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there is illustrated and described embodiments of the invention. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0032]     A detailed description of the invention is hereafter described with specific reference being made to the drawings.  
         [0033]      FIG. 1  is a view of an unexpanded bifurcated stent having a side branch assembly with bridged rings.  
         [0034]      FIG. 2  is a view of an expanded bifurcated stent having a side branch assembly with bridged rings.  
         [0035]      FIG. 3  is a view of a bifurcated stent with long bridges.  
         [0036]      FIG. 4  is a detailed view of the side branch assembly of a bifurcated stent assembly made of rings connected by valley-valley bridges. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]     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.  
         [0038]     For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated.  
         [0039]     Depicted in the figures are various aspects of the invention. Elements depicted in one figure may be combined with, and/or substituted for, elements depicted in another figure as desired.  
         [0040]     Referring now to  FIG. 1  there is shown a tubular body which is an unexpanded bifurcated stent  1  extending along a first longitudinal axis  16  having a first stent body  10  with at least one side opening  18  along its sidewall. Although this illustration shows a first stent body  10  having a plurality of struts  5  forming columns  7 , the invention encompasses all stent structures currently known in the art. In the expanded state, the first stent body will define a first fluid lumen  14 .  
         [0041]     First stent body  10  can be constructed from any suitable biocompatible material including but not limited to polymers, stainless steel, platinum, gold, cobalt, chromium, niobium etc. It can also be constructed out of one or more combinations and/or alloys of these materials.  
         [0042]     An improved side branch assembly  30  is connected to first stent body  10  adjacent to the side opening  18 . As illustrated in  FIG. 2 , when the stent is in its expanded state, the side branch assembly  30  will define a second fluid lumen  34  in fluid communication with the first fluid lumen  14  with a second longitudinal axis extending therethrough. The region of the side branch assembly  30  that is generally connected to the first stent body  10  by connectors  39  in the expanded state comprises an end of the second fluid lumen  34  and is referred to as the “ostium”  38 . The opposite end of the expanded second fluid lumen  34  is the outermost end  40 . For purposes of this application and in particular when describing the drawings, when discussing a set of items, the item described as “ostial” is the item of the set closest to the ostium and the item described as “outermost” is the item of the set furthest away from the ostium.  
         [0043]     The side branch assembly  30  of  FIGS. 1 and 2  comprises a plurality of rings or ring members  33 . As illustrated in  FIG. 1 , when the stent  1  is in an unexpanded state, each ring is positioned in a nested arrangement. For purposes of this application the term “nested” includes but is not limited to concentric, stacked, overlapping, and adjacent ring arrangements. The rings may surround a center point  31 . As the stent  1  expands, at least one ring  33  is either self expanded or pushed by an expansion mechanism such as a balloon away from the ostium  38  and into the body vessel branch. The extension of the rings  33  forms a generally serial configuration and defines at least a portion of a generally tubular secondary fluid lumen  34  in fluid communication with the first fluid lumen  14 . At least a portion of the secondary fluid lumen  34  is located between an ostial ring closest to the ostium  38  and an outermost ring  40 . Some or all of the rings can be connected to each other by ring-ring connectors  37  or to the first stent body by ring-stent connectors  39 . In one possible embodiment, each ring is connected to an adjacent ring by a connector  37  and only the ostial ring is connected to the first stent body by a connector  39 .  
         [0044]     Referring now to  FIG. 3  there is shown a detailed illustration of a side branch assembly designed according to the current state of the art. It features rings  33 , connectors  37 , and connectors  39 . The rings are all in phase with each other and the inter ring connectors  37  can be characterized as connecting the peak  50  of one ring to the valley  52  of another. This design also features connectors  37  and connectors  39  extending into all of the rings and connecting with the first stent body  10 .  
         [0045]     For purposes of this application, the term “in phase” means the rings  33  are generally concentric and project towards and away from the center point  31  at relatively similar rotational positions along their perimeters. In contrast, “out of phase” means the rings  33  are not in similar rotational positions. When rings are in phase, a connector  37  oriented along a vector generally directed towards the center point  31  is referred to as a peak-valley connection. Similarly, a connector  37  connecting two out of phase rings is referred to as a valley-valley connection.  FIG. 3  features peak-valley connectors  37  and  FIG. 4  features valley-valley connectors  37 .  
         [0046]     Referring now to  FIG. 4  there is shown a detailed illustration of an embodiment for the improved side branch assembly  30 . At least two of the rings  33  comprise a plurality of peaks  50  and valleys  52  connected by struts  54  extending along the rings&#39;  33  perimeter. The rings  33  themselves are interconnected by at least one connector  37  connecting the valley  52  of one ring  33  to the valley  52  of an adjacent ring  33 . By using valley-valley connectors  37  to link the rings  33 , the extent of coverage the expanded side branch assembly provides to the body vessel increases. In addition, by replacing long connectors  37  of  FIG. 3  with a multiplicity of shorter connectors  37  more widely distributed between different regions of the rings  33 , the expanded side branch assembly  30  of  FIG. 4  has greater flexibility than the side branch assembly of  FIG. 3 .  
         [0047]      FIG. 4  is a representational illustration of the improved side branch assembly  30 , but there are number of alternative designs that this invention encompasses.  FIG. 4  contains three rings  33  a first and a third in phase with each other and a second exactly out of phase with the first and the third. The rings need not be exactly in phase with each other. In addition, the figure shows rings with eight peaks, eight valleys, four ring-ring connectors, and four ring-stent connectors and that every other valley is interconnected. Any number of connectors can be used. The figure also shows the connectors connecting a given ring to a less ostial ring are located on the valley immediately counterclockwise to a valley with an ostial connector or bridge. This relative positioning of the bridges and/or connectors is not an essential feature of the invention. This invention at a minimum encompasses a side branch assembly  30  with at least two rings each having at least two valleys, one connector and one bridge connecting the two valleys.  
         [0048]     Although the figure shows a single side branch opening and a singe side branch assembly, there can be multiple side branch openings and side branch assemblies.  
         [0049]     The sizes of the side branches can vary as well having larger, smaller or the same area, end-on-end length, or circumference in the extended or unextended states. Multiple side branch openings can be positioned anywhere along the length of the first stent body  1  and can be coaxially positioned relative to one another.  
         [0050]     In embodiments wherein the side branch assembly  30  is configured to be self expanding, the stent  1  can be designed such that first body stent struts  5  can partially cover and restrain the side branch assembly  30  in the unexpanded state. In such an embodiment, as the first stent body  10  expands (whether through balloon expansion or by self expansion) its movement will move the covering struts  5  from the side branch assembly  30 , allowing the side branch assembly to self-expand. In the case of a balloon expandable side branch assembly  30 , the stent  1  can also be designed so that the unexpanded first stent struts  5  can at least partially cover the side branch assembly  30  and can be moved away as the first stent body  10  expands. As mentioned before, this inventive concept is not limited to stents comprising struts and can be accomplished with any stent structure in which in the unexpanded state the stent has a structural component adjacent to the structural components of the side branch assembly and in the expanded state the structural components are moved away from the side branch assembly.  
         [0051]     One way to vary the degree of structural strength or flexibility that the expanded side branch assembly  30  will have is by constructing various parts of the side branch assembly  30  out of materials with different properties. For example, the connectors  39 , connectors  37 , and rings  33  can each be constructed out of different materials with differing structural strength or flexibility. In addition, each ring  33 , each connector  37 , or each connector  39 , can be made out of similarly different materials.  
         [0052]     The inventive stents 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, niobium alloys, cobalt-chromium alloys including Elgiloy and Phynox, MP35N alloy and nickel-titanium alloys, for example, Nitinol.  
         [0053]     The inventive stents 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 may be provided with a memorized shape and then deformed to a reduced diameter shape. The stent may restore itself to its memorized shape upon or after being heated to a transition temperature and having any restraints removed therefrom.  
         [0054]     The inventive stents 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 stents disclosed herein.  
         [0055]     In some embodiments the stent, the delivery system or other portion of the assembly 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.  
         [0056]     In some embodiments the at least a portion of the stent is configured to include one or more mechanisms for the delivery of a therapeutic agent. Often the agent will be in the form of a coating or other layer (or layers) of material placed on a surface region of the stent, which is adapted to be released at the site of the stent&#39;s implantation or areas adjacent thereto.  
         [0057]     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.  
         [0058]     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. The various elements shown in the individual figures and described above may be combined or modified for combination as desired. 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”.  
         [0059]     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 claim  1  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.  
         [0060]     This completes the description of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.