Abstract:
A system for treatment of a vessel lesion comprises an expandable balloon and at least one cutting blade engaged to an exterior surface of the balloon. At least a portion of the cutting blade has a substantially serpentine configuration defined by a plurality of interconnected peaks and troughs wherein each trough is in closer proximity to the balloon than each peak.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH  
       [0002]     Not Applicable  
       BACKGROUND OF THE INVENTION  
       [0003]     Arterial blockages, which are also called stenosis, lesions, stenotic lesions, etc, are typically caused by the build-up of atherosclerotic plaque on the inside wall of an artery. In fact, several such stenoses may occur contiguously within a single artery. This can result in a partial, or even complete, blockage of the artery. As a result of the danger associated with such a blockage, several methods and procedures have been developed to treat stenoses. One such method is an angioplasty procedure which uses an inflatable balloon to dilate the blocked artery. A typical inflatable angioplasty device, for example, is disclosed in U.S. Pat. No. 4,896,669.  
         [0004]     Angioplasty balloons have enjoyed widespread acceptance in the treatment of stenoses. Recent studies, however, have indicated that the efficacy of the dilation of a stenosis is enhanced by first, or simultaneously, incising the material that is creating the stenosis. Consequently, recent developments have been made to equip angioplasty balloons with cutting edges, or atherotomes, which are intended to incise a stenosis during the dilation procedure. For example, U.S. Pat. No. 5,196,024; U.S. Pat. No. 5,616,149 and U.S. Pat. No. 5,797,935, the entire contents of each of which are incorporated herein by reference, respectively describe an inflatable angioplasty balloon having a number of atherotomes mounted longitudinally on the surface of the balloon. Upon inflation of the balloon, the atherotomes induce a series of longitudinal cuts into the surface of the stenotic material as the balloon expands to dilate the stenosis. As a result of such cuts, the stenosis is more easily dilated, and the likelihood of damaging the artery during dilation is reduced.  
         [0005]     Blades in many existing cutting balloon assemblies tend to be fairly rigid, particularly in the axial direction. The rigid axial structure of the blade naturally limits the blades ability to elongate with the underlying balloon material during balloon expansion at high pressure. As a result, stress between the comparatively axially rigid blade and the elongating balloon may lead to stress therebetween. This stress can lead to de-lamination of the blade and/or adhesive from the balloon. The effect of balloon elongation is more pronounced in larger diameter balloons than in smaller diameter balloons, and is further amplified in longer balloon lengths as well. As such, it has been necessary, particularly in larger vessel applications, to limit the materials of blade equipped balloons to those that are fairly stiff such as PET, PEN, etc. in order to minimize axial elongation.  
         [0006]     Existing blades also tend to be fairly rigid in the transverse direction as well. This has the affect of limiting the flexibility of the balloon as it is advanced through the tortuous confines of a vessel or other body lumen.  
         [0007]     In light of the above it would be desirable to provide a cutting blade for use with a cutting balloon that is more flexible, and which does not interfere with or is compatible with the expansion characteristics of the balloon to which it may be mounted.  
         [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]     The present invention is directed to several embodiments. In at least one embodiment the invention is directed to a medical balloon for use with a catheter or similar device, wherein the medical balloon is equipped with at least one cutting blade.  
         [0012]     In some embodiments one or more portions of the cutting blade or blades define a serpentine path or shape relative to the surface of the balloon upon which the blade is mounted. A serpentine path extends radially outward from the balloon surface and then back toward the balloon surface in a repeating pattern.  
         [0013]     In at least one embodiment the serpentine path is provided by a plurality of adjacent undulations. In at least one embodiment adjacent undulations define a substantially S-shaped segment of the blade.  
         [0014]     In at least one embodiment the blade has multiple serpentine regions, each of which define a separate serpentine path. Each serpentine region is separated by a region of the blade which is not serpentine. The non-serpentine regions may be characterized as being linear, and while such regions may define a path having one or more bends or curves to accommodate the shape of the balloon (e.g. the transition form the balloon waist to the balloon cone, the transition from the balloon cone to the balloon body, etc.) such regions do not define a serpentine path.  
         [0015]     In some embodiments the blade employs separate serpentine regions each of which extend along the surface of a balloon cone, and a serpentine region which extends along the surface of at least a portion of the balloon body. Such cone serpentine regions of the blades and the body serpentine regions of the blade may have similar or different serpentine shapes or pathways. For example, in at least one embodiment, the cone serpentine regions define a path having a shallower height and/or a longer wavelength than the body serpentine region.  
         [0016]     The blade may be constructed of any material suitable for forming a cutting blade. The body region of the blade defines at least one cutting surface or edge. Regions of the blade adjacent to the body region need not include a cutting surface. As such, in at least one embodiment different regions of the blade define one or more different cross-sectional shapes. In at least one embodiment the body region of the blade defines a substantially triangular shaped cross-section. In at least one embodiment regions of the blade adjacent the body region have rectangular (ribbon), round, ovoid, square or other cross-sectional shape(s).  
         [0017]     In at least one embodiment one or more portions of the blade in close proximity to the balloon surface are engaged to the balloon surface by an adhesive or other mounting material. The adhesive may be any adhesive material suitable for securing a metal, polymer or carbon based blade to the material of the balloon.  
         [0018]     In at least one embodiment portions of the blade engaged to the balloon are defined by the “troughs” of the serpentine path of the body region of the blade. Adjacent “peaks” are then free to flex, bend, or otherwise alter their position as the balloon is expanded, bent or otherwise altered in shape or configuration. This substantial freedom of movement of the peak portions of the body region allow the blade to remain in contact with the balloon regardless of the balloon&#39;s longitudinal expansion or axially transverse bending. In some embodiments the proximal and distal end regions of the blade, which respectively extend over the proximal and distal waists of the balloon are likewise engaged to the balloon and/or adjacent catheter shaft with an adhesive or mounting material. In some embodiments the blade ends are encased in adhesive or mounting material to prevent contact of the blade ends with the lumen wall through which the catheter is advanced.  
         [0019]     As indicated above, a balloon may be equipped with any number of blades as desired. In at least one embodiment for example, the balloon is provided with a single blade, while in other embodiments 2-20 blades may be mounted onto the balloon. Multiple blades may be uniformly or irregularly spaced apart, and may have similar or different shapes, lengths, serpentine paths, etc.  
         [0020]     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 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)  
       [0021]     A detailed description of the invention is hereafter described with specific reference being made to the drawings.  
         [0022]      FIG. 1  is a side view of an embodiment of the invention wherein a balloon is shown with a single serpentine blade.  
         [0023]      FIG. 2  is a cross-sectional view of the embodiment depicted in  FIG. 1 .  
         [0024]      FIG. 3  is a side view of the embodiment shown in  FIG. 1  wherein the balloon includes 2 serpentine blades.  
         [0025]      FIG. 4  is a cross-sectional view of the balloon shown in  FIG. 3   
         [0026]      FIG. 5  is a side view of the embodiment shown in  FIG. 1  wherein the balloon includes 4 serpentine blades.  
         [0027]      FIG. 6  is a cross-sectional view of the balloon shown in  FIG. 5   FIG. 7  is a detailed side view of a serpentine blade such as is shown in  FIGS. 1-6 .  
         [0028]      FIGS. 8-12  are each cross-sectional views of respective portions of the blade shown in  FIG. 7 .  
         [0029]      FIG. 13  is a side view of the embodiment shown in  FIG. 1  wherein the serpentine blades are positioned on the body or working portion of the balloon. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     While this invention may be embodied in many different forms, there are described in detail herein specific preferred 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.  
         [0031]     For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated.  
         [0032]     As indicated above, the present invention is embodied in a variety of forms.  
         [0033]     In at least one embodiment, an example of which is depicted in  FIG. 1 , the invention is directed to a catheter balloon  10  which has at least one serpentine, undulating, or similarly configured blade  12  mounted to the external surface  14  of the balloon. As shown, the blade  12  comprises at least one serpentine region  20 . The majority or all of the blade may have a serpentine configuration, the blade may comprise a single serpentine region or any number of serpentine regions separated by non-serpentine regions. In the example shown in  FIG. 1 , the blade  12  may be characterized as having a number of adjacent serpentine regions: body region  20 , proximal cone region  22  and distal cone region  24 ; as well as one or more linear or non-serpentine regions: proximal end region  30 , proximal cone transition region  32 , distal cone transition region  34 , and distal end region  36 .  
         [0034]     In an alternative embodiment depicted in  FIG. 13 , each blade  12  is in effect a body region  20  having an uninterrupted serpentine configuration extending along at least a portion of only the balloon body  40 .  
         [0035]     As is shown in  FIG. 1  and  FIG. 13  the body serpentine region  20  extends along the exterior surface  14  of at least a portion of the balloon body  40 . The body region  20  may be engaged to the balloon body  40  in any of a variety of ways such as by mechanical engagement, direct welding, through the use of an adhesive, etc. In the embodiment shown an adhesive material  18  is positioned on the surface  14  of the balloon  10  and the body region  20  of the blade  12  is adhesively engaged thereto.  
         [0036]     Any suitable adhesive may be utilized as the adhesive material  18 . For example adhesives such as polyurethane, epoxy, cyanoacrylate and/or combinations of such materials may by utilized as the adhesive material  18 . In at least one embodiment, portions of the blade  12  are adhesively engaged to the balloon surface with a polyurethane substrate or pad such as is described in U.S. Pat. No. 5,320,634, the entire contents of which being incorporated herein by reference.  
         [0037]     The nature of the serpentine regions  20 ,  22 ,  24  of the blade  12  is such that each serpentine region comprises a series of adjacent substantially S-shaped segments  50  (highlighted) which extend from a low point or trough  52 , immediately adjacent to the surface  14  of the balloon  10 , to a high point or peak  54 , which is a greater distance radially outward from the balloon  10  than the trough  52 .  
         [0038]     Adjacent peaks  54  and troughs  52  are engaged by arm portions  56  of the blade  12 . Each trough  52  is engaged to the balloon surface  14  by the adhesive material  18 . The arm portions extend from the ends of the troughs  52  to engage the adjacent peaks  54 . The arms  56  provide the peaks  54  with a significant degree of axial and transverse flexibility relative to the troughs  52  engaged to the balloon  10 . As a result, when the balloon is twisted, bent, expanded or lengthened, stress between the blade  12  and the balloon  10  is minimized as the majority of the body serpentine region  20  remains free to move in conjunction/response with the movements of the balloon, while only the discrete and separated troughs  52  remain secured to the balloon  10 .  
         [0039]     Such a configuration provides the cutting balloon  10  with improved resistance to delamination of the blade  12  from the balloon surface  14  by reducing the axial and transverse stress that the balloon/blade interface is subjected to during expansion and/or movement of the balloon.  
         [0040]     In some embodiments where the blade(s)  12  extend beyond the length of the balloon body  40 , such as is shown in  FIGS. 1-5 , one or more blades  12  may be provided with cone regions  22  and  24  which also have a serpentine configuration. The cone regions  22  and  24  can be configured such that they elongate during balloon inflation resulting in a tension within the cone regions. Such tension will facilitate a desirable balloon refold, because during balloon deflation the cone region tension will preferentially draw in the blades  12  to a lower profile than the adjacent balloon folds. The serpentine configuration of the cone regions  22  and  24  provide additional flexibility, particularly in the axial direction, which allows the blade to accommodate expansion and/or elongation of the cones  42  and  44 , respectively, as the balloon  10  is expanded without affecting the position or exerting axial stress on the body region  20  of the blade  12 .  
         [0041]     In order to minimize profile and to aid in balloon folding/refolding, in some embodiments the cone regions  22  and  24  are spaced apart or separated from the body region by a non-serpentine cone transition region  32  and  34 . In other embodiments regions  32  and  34  may be serpentine, linear, or provided with any other configuration desired.  
         [0042]     In at least one embodiment the transition regions  32  and  34  as well as the serpentine cone regions  22  and  24  are not adhesively or otherwise engaged to the balloon surface  14 . By not adhering the respective regions to the balloon, the blade  12  is more readily able to accommodate much greater degrees of change in the shape and configuration of the balloon without placing stress on the body region  20 .  
         [0043]     The end regions, proximal end region  30  and distal end region  36  are also typically non-serpentine in configuration, in order to minimize their profile and to provide greater surface area for engagement to the balloon waists (proximal waist  46  and distal waist  48 ) respectively thereunder. In some embodiments the end regions  30  and  36  may be configured to extend beyond the waists  46  and  48  and engage the catheter shaft  60  directly.  
         [0044]     In at least one embodiment, at least a portion of each end region  30  and  36  of the blade  12 , is completely encased or enclosed by adhesive or other mounting material upon or within the respective waist of the balloon  10  or catheter shaft  60 .  
         [0045]     As is illustrated in  FIGS. 1-6 , the balloon  10  may be equipped with any number of blades  12 , typically between 1 and 20, though other numbers may be provided. In  FIGS. 1-2  for example, the balloon  10  is shown with a single blade  12 . In the embodiment shown in  FIGS. 3-4 , the balloon  10  is provided with a pair of radially opposite blades  12 . In  FIGS. 5-6 , the balloon is provided with four substantially circumferentially equidistant blades  12 .  
         [0046]     While the embodiments shown in  FIGS. 2-6  have blades  12  arranged in a symmetrical fashion about the balloon  10 , such symmetry need not be the case in all embodiments. In some embodiments the blades may be of different or equal lengths; varyingly spaced apart, whether randomly or in accordance with a pattern; or otherwise arranged or positioned about the balloon in accordance with need, desire and/or performance.  
         [0047]     As is the nature of a “cutting blade” one or more portions of the surface  62  of the blade  12  define one or more cutting edges. In the various embodiments shown herein at least the peak portions  54  of the body region  20  define a single radially outward projecting cutting edge  64 . As is illustrated in  FIG. 7  and in the cross-sectional views provided in  FIGS. 11 and 12  the cutting edge  64  can be formed within the body region  20  with a substantially triangular cross-sectional shape, wherein the edge  64  is formed by the peak or apex  64  of the triangular shaped blade. While it is desired to provide at least the peaks  54  with an edge, in at least one embodiment, as illustrated in  FIG. 12 , the troughs  52  may also be provided with an edge  64  as a consequence of the triangular cross-sectional shape of the region  20 .  
         [0048]     In the embodiments depicted in  FIGS. 1-12 , the portions of the blade  12  adjacent to the body region  20  of the blade need not be provided with an edge, (as such portions are typically not positioned in such a manner so as to contact a lesion site). In some embodiments, those regions of the blade other than the body region  20  (e.g. regions  22 ,  24 ,  30 ,  32 ,  34  and  36 ) of the blade  12  can be configured with a cross-sectional shape different than that of the body region  20 .  
         [0049]     For example, as illustrated in  FIGS. 7-10 , the regions  22 / 24 ,  30 / 36 ,  32 / 34  adjacent to the body region  20  are provided with comparatively thin, or ribbon-like cross-sectional shape, as shown in  FIGS. 8-10 , which provides those portions of the blade adjacent to the body region  20  with a high degree of axial and/or transverse flexibility. It should be understood that the ribbon-like shape shown in  FIGS. 8-10  is an example of a desired shape, others include but are not limited to, round, ovoid, ellipsoid, square, triangular, or any other geometric shape that may be desired.  
         [0050]     The blade  12 , regardless of its cross-sectional shape or shapes may be constructed by any of a variety of manufacturing methods. For example, the blade  12 , or at least the body region  20  may be constructed of metallic or other material wire stock, as it will facilitate the formation of the cutting edge. Other manufacturing techniques include photo-etching, laser cutting, water jet cutting, or flat stock stamping of a desired blade material to form one or more regions of the blade  12 .  
         [0051]     In some embodiments the blade  12  or one or more portions thereof may include one or more areas, coatings, materials, etc. that is (are) detectable by imaging modalities such as X-Ray, MRI or ultrasound. In some embodiments at least a portion of the blade is at least partially radiopaque.  
         [0052]     In at least one embodiment, the blade  12 , and/or the balloon  10  may be configured to deliver one or more therapeutic agents to the lesion site. 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.  
         [0053]     Blade  12 , may be constructed from one or more metals, polymers, combinations of one or more metals and/or polymers, and/or other desired material(s). In at least one embodiment, blade  12  is at least partially constructed of a shape memory material, such as nitinol and/or a shape memory polymer. The blade  12 , may comprise a plurality of separate blade segments or may be a single continuous structure as desired.  
         [0054]     The balloon  10  may be made of any suitable balloon material including compliant and non-compliant materials and combinations thereof. Some examples of suitable materials for constructing the balloon  10  include but are not limited to: low pressure, relatively soft or flexible polymeric materials, such as thermoplastic polymers, thermoplastic elastomers, polyethylene (high density, low density, intermediate density, linear low density), various co-polymers and blends of polyethylene, ionomers, polyesters, polyurethanes, polycarbonates, polyamides, poly-vinyl chloride, acrylonitrile-butadiene-styrene copolymers, polyether-polyester copolymers, and polyetherpolyamide copolymers; copolymer polyolefin material available from E.I. DuPont de Nemours and Co. (Wilmington, Del.), under the trade name Surlyn™; ionomer and a polyether block amide available under the trade name PEBAX™; high pressure polymeric materials, such as thermoplastic polymers and thermoset polymeric materials, poly(ethylene terephthalate) (commonly referred to as PET), polyimide, thermoplastic polyamide, polyamides, polyesters, polycarbonates, polyphenylene sulfides, polypropylene and rigid polyurethane; one or more liquid crystal polymers; and combinations of one or more of any of the above.  
         [0055]     In some embodiments a balloon  10  may be provided with one or more blades having different lengths sizes, shapes, or configurations. For example in at least one embodiment one or more blades on a balloon have a length which extend from at least the body of the balloon and through at least a portion of the balloon waist, while the distal end of the blade terminates before reaching the distal waist. This and other configurations and arrangements of blades should be recognized as falling within the scope of the present invention.  
         [0056]     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.  
         [0057]     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.