Abstract:
An article including a stent including a flap that extends from a tubular support structure, the flap having an arcuate apex.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates generally to implantable medical devices, and particularly to stents that can be used to block aneurysms.  
       BACKGROUND OF THE INVENTION  
       [0002]     An aneurysm is generally a localized blood-filled dilation of a vessel. One method of treating an aneurysm is to place a porous stent in the vessel at the aneurysm site. A porous stent can close an aneurysm over a short period of time, such as a week.  
         [0003]     US Patent Application 20060030929 to Musbach describes a stent that includes an expandable framework and a plurality of rectangular flaps. Adjacent flaps overlap one another to form a wall region of predetermined shape. The stent is delivered to an aneurysm site and positioned such that the wall region blocks fluid flow into the aneurysm.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention seeks to provide a stent with a flap, which may be used to close or cover the ostium in a bifurcation, or block an aneurysm whether in a bifurcation or not, as is described in detail further hereinbelow.  
         [0005]     There is provided in accordance with an embodiment of the present invention an article including a stent including a flap that extends from a tubular support structure, the flap having an arcuate apex. The arcuate apex may adjoin the tubular support structure. For example, the tubular support structure may have ends with a generally circular edge, and the arcuate apex may extend from one of the circular edges.  
         [0006]     In accordance with an embodiment of the present invention the flap and the tubular support structure may have outer surfaces flush with each other. The flap and the tubular structure may have slots to provide flexibility during insertion. The flap may be coated with a polymer such as hydrogel that expands on exposure to a liquid thus providing the capability of closing the slots after insertion. The flap and the tubular support structure may be coated with a polymer such as to carry medication(s) to prevent restenosis in part and promote coagulation in a different part.  
         [0007]     The flap may be gold coated and the tubular support structure may have gold bands to provide enhanced visibility under x-ray observation during insertion.  
         [0008]     In accordance with an embodiment of the present invention the flap and the tubular support structure may be arranged so as to cover the ostium of a simple bifurcation. The flap may be arranged to curve into the bifurcation and the tubular structure may be open at one end to cover the walls of the ostium while the tubular support extends past the bifurcation to provide an anchor and support.  
         [0009]     In accordance with an embodiment of the present invention the flap may have another arcuate apex that adjoins another tubular support structure. The flap may be intermediate ends of the tubular support structures.  
         [0010]     In accordance with an embodiment of the present invention, two or more such stents may be arranged with each other such that their flaps overlap each other.  
         [0011]     In accordance with an embodiment of the present invention, the flap may curve radially outwards away from a longitudinal axis of the tubular support structure.  
         [0012]     In accordance with an embodiment of the present invention the arcuate apex may extend from a side wall of the tubular support structure.  
         [0013]     There is also provided in accordance with an embodiment of the present invention, a catheter including a stent mounting portion, and a rotator operatively coupled to the stent mounting portion with a coupling, the rotator being operative to rotate the stent with the stent mounting portion.  
         [0014]     There is also provided in accordance with an embodiment of the present invention a method including introducing a guidewire into a main lumen of a bifurcation, the guidewire including an outer slender tube with at least one deformable portion and an actuator disposed through a length of the outer slender tube and connected to the at least one deformable portion, introducing a catheter, with a stent deployed therewith, over the guidewire, the stent including a flap that extends from a tubular support structure, the flap having an arcuate apex, using the actuator to expand the at least one deformable portion outwards and thereby anchor the catheter in place, and expanding the stent, wherein the flap goes around an ostium of the bifurcation into a branch lumen of the bifurcation. The method may further include rotating the stent, and/or rotating and orienting the flap to block an aneurysm. A branch stent may be introduced from the catheter into the branch lumen. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:  
         [0016]      FIG. 1  is a simplified illustration of a stent with a tubular support structure and an end flap, constructed and operative in accordance with an embodiment of the present invention;  
         [0017]      FIG. 2  is a simplified illustration of a stent with two tubular support structures and an intermediate flap extending therebetween, constructed and operative in accordance with an embodiment of the present invention;  
         [0018]      FIG. 3  is a simplified illustration of two of the stents of  FIG. 1  with the flaps overlapping each other, in accordance with an embodiment of the present invention;  
         [0019]      FIG. 4  is a simplified illustration of a stent with a tubular support structure and an end flap that curves outwards, constructed and operative in accordance with an embodiment of the present invention;  
         [0020]      FIG. 5  is a simplified illustration of two of the stents of  FIG. 4  with the flaps overlapping each other, in accordance with an embodiment of the present invention;  
         [0021]      FIG. 6  is a simplified illustration of a stent with a tubular support structure and a side flap, constructed and operative in accordance with an embodiment of the present invention;  
         [0022]      FIGS. 7A, 7B  and  7 C are simplified sectional illustrations of a catheter useful in delivering the stents of the invention, in accordance with an embodiment of the present invention; and  
         [0023]      FIGS. 8A, 8B ,  8 C,  8 D and  8 E are simplified illustrations of implanting a stent of the present invention at a bifurcated site, in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0024]     Reference is now made to  FIG. 1 , which illustrates a stent  10 , constructed and operative in accordance with an embodiment of the present invention.  
         [0025]     Stent  10  may include a flap  12  that extends from a tubular support structure  14 . The stent  10  may be self-expanding, constructed of NITINOL, for example, or it may be balloon-expandable, constructed of stainless steel, for example. The stent  10  may be constructed of a suitable mesh or braided design, for example. Stent  10  may be coated, as least partially or full. For example, flap  12  and/or tubular support structure  14  may be coated with a polymer that expands when in contact with a liquid such as Hydrogel. As another example, flap  12  and/or tubular support structure  14  may be coated with a drug-eluting material, such as a polymer coating that emits a coagulation enhancing drug. As another example, flap  12  and/or tubular support structure  14  may be coated with an anti-restenosis drug.  
         [0026]     Flap  12  may have a perimeter that is at least partially arcuate, and may have, for example, an arcuate apex  16  at one or both ends thereof. Tubular support structure  14  may be generally cylindrical in shape with a circular cross-section, although it may have other shapes and cross-sectional shapes, such as but not limited to, elliptic. Flap  12  may be curved about a longitudinal axis  18  so as to define a convex outer surface  20 . The outer surface of flap  12  may be flush with the outer surface of tubular support structure  14 . The radius of curvature of the convex outer surface of flap  12  may be equal to or different than the radius of the cross-section of tubular support structure  14 .  
         [0027]     In the non-limiting embodiment of  FIG. 1 , arcuate apex  16  adjoins tubular support structure  14 . More specifically, in the embodiment of  FIG. 1 , tubular support structure  14  has ends  22  with a generally circular edge, and one of the arcuate apices  16  extends from one of the circular edges.  
         [0028]     Flap  12  and/or tubular support structure  14  may have slots  23  formed therein to provide flexibility during insertion. Flap  12  may be coated with a coating  21 , e.g., a polymer such as hydrogel that expands on exposure to a liquid thus providing the capability of closing the slots after insertion. The coating  21  may be a polymer that carries medication(s) to prevent restenosis in part and promote coagulation in a different part.  
         [0029]     The coating  21  may be a gold coating. For example, flap  12  may be gold coated and the tubular support structure  14  may have gold bands to provide enhanced visibility under x-ray observation during insertion.  
         [0030]     Reference is now made to  FIG. 2 , which illustrates a variation of stent  10 , constructed and operative in accordance with another embodiment of the present invention. In this non-limiting embodiment, the other arcuate apex  16  of flap  12  adjoins another tubular support structure  14 , such that flap  12  is intermediate ends  22  of the tubular support structures  14 .  
         [0031]     Reference is now made to  FIG. 3 . In this embodiment, two stents  10  are arranged with respect to each other such that their flaps  12  overlap each other.  
         [0032]     Reference is now made to  FIG. 4 , which illustrates a variation of stent  10 , called stent  40 , constructed and operative in accordance with another embodiment of the present invention. In this non-limiting embodiment, stent  40  has the same or similar tubular support structure  14  and an end flap  42  that curves radially outwards away from longitudinal axis  18  of tubular support structure  14 . Similar to flap  12 , the flap  42  may have a perimeter that is at least partially arcuate, and may have, for example, an arcuate apex  46  at one or both ends thereof. The arcuate apex  46  may adjoin tubular support structure  14  at an end  22  thereof.  
         [0033]     Reference is now made to  FIG. 5 . In this embodiment, two stents  40  are arranged with respect to each other such that their flaps  42  overlap each other.  
         [0034]     Reference is now made to  FIG. 6 , which illustrates a stent  60 , constructed and operative in accordance with another embodiment of the present invention. Stent  60  fills the ostium of a bifurcation, providing a connection between stents in the branches and may include a flap  62  that extends from a tubular support structure  64  (64 is correct) to cover the junction of the two branches. As with stent  10 , stent  60  may be self-expanding, constructed of NITINOL, for example, or it may be balloon-expandable, constructed of stainless steel, for example. The stent  60  may be constructed of a suitable mesh design, for example.  
         [0035]     Flap  62  may have a perimeter that is at least partially arcuate, and may have, for example, an arcuate apex  66  at one or both ends thereof. Tubular support structure  64  may be generally cylindrical in shape with a circular cross-section, although it may have other shapes and cross-sectional shapes, such as but not limited to, elliptic. Tubular support structure  64  may have an arcuate side cutout  67  corresponding to the arcuate perimeter of flap  62 . (Flap  62  may or may not be formed by cutting out cutout  67  and bending flap  62  outwards.) Flap  62  may curve radially outwards away from a longitudinal axis  68  of tubular support structure  64 . In the non-limiting embodiment of  FIG. 6 , arcuate apex  66  adjoins tubular support structure  64  at an apex of side cutout  67 , such that arcuate apex  66  extends from a side wall of the tubular support structure  64  the combination of support sections  64  and  67  provide covering and support for the ostium of the bifurcation.  
         [0036]     Reference is now made to  FIGS. 7A-7C , which illustrate a catheter  70 , useful in delivering any of the abovementioned stents of the invention, in accordance with an embodiment of the present invention.  
         [0037]     Catheter  70  may include an outer sheath  72  with a stent mounting portion  74  at a distal end thereof for mounting therein a stent, such as stent  10  or any of the other stents of the invention. A rotator  76  may be disposed through the length of sheath  72 . Rotator  76  may be a flexible rod that is operatively coupled to stent mounting portion  74  with a coupling  78 . Rotation of rotator  76  causes rotation of the stent mounting portion  74 , and with it, rotation of the stent mounted therein.  
         [0038]     Reference is now made to  FIGS. 8A-8E , which are simplified illustrations of implanting any of the stents of the present invention at a bifurcated site, in accordance with an embodiment of the present invention.  
         [0039]     In  FIG. 8A , a main lumen  80  (e.g., blood vessel in the brain) is shown with a bifurcation comprising a branch lumen  82  that branches from the main lumen  80  at an osmium  84  (opening of the branch lumen  82 ).  
         [0040]     Reference is now made to  FIGS. 8B and 8C . A guidewire  86  may be introduced into main lumen  80  ( FIG. 8B ). As seen in  FIG. 8C , guidewire  86  may include an outer slender tube  87  with one or more deformable portions  88 . An actuator, e.g., a slender pull wire  89 , may be disposed through the length of outer slender tube  87  and connected to deformable portion(s)  88 . Outer slender tube  87  and its deformable portion(s)  88  may be made of a durable material, such as but not limited to, a plastic, a shape memory alloy (such as a nickel-titanium alloy, e.g., NITINOL), or stainless steel which may be coated with a material such as polytetrafluoroethylene (PTFE). Guidewire  86  may have an outer diameter of about 0.38 mm, but the invention is not limited to this dimension.  
         [0041]     Deformable portion(s)  88  may be in a collapsed orientation for placement in the body lumen. The slender pull wire  89  may serve as an actuator to effect movement of the deformable portion(s)  88  between a collapsed (or contracted, the terms being used interchangeably throughout) orientation and an expanded orientation.  
         [0042]     Referring now to  FIG. 8D , a stent delivery catheter, such as catheter  70 , may be introduced over guidewire  86  and the distal most deformable portion  88  may be expanded outwards by the push or pull action of pull wire  89  that deforms portion  88  outwards. This anchors catheter  70  in place.  
         [0043]     Referring now to  FIG. 8E , in the case of a self-expanding stent, stent  10  may be released and self-expand, or in the case of a balloon-expandable stent, fluid may be introduced to expand the stent  10  (or other stent of the invention). Flap  12  goes around and reinforces the ostium  84  into branch lumen  82 . Rotator  76  ( FIGS. 7A-7C ) may be used to rotate and orientate flap  12  and stent  10  as desired. In this manner, flap  12  may be directed to block an aneurysm, for example. A branch stent may now be introduced and expanded from catheter  70  into branch lumen  82 .  
         [0044]     It is appreciated that various features of the invention which are, for clarity, described in the contexts of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.