Abstract:
Systems, devices, and methods including balloon catheters are described. In one embodiments, a balloon catheter assembly may comprise a tubular member having a proximal portion and a distal portion with a lumen extending between the proximal portion and the distal portion and a balloon member having a proximal waist portion, a distal waist portion, and an expandable region therebetween, the balloon member disposed proximate the distal portion of the tubular member and bonded to tubular member. The assembly may further comprise a first sleeve member covering a first portion of the tubular member and a portion of the balloon member proximal waist portion and a second sleeve member covering a second portion of the tubular member and a portion of the first sleeve member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/257,952 filed on Nov. 20, 2015, the disclosure of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosure is directed to balloon catheter devices and methods for forming balloon catheters. More particularly, the disclosure is directed to balloon catheter devices and methods for bonding catheter balloons to catheter shafts. 
       BACKGROUND 
       [0003]    Medical devices comprising catheter shafts and catheter balloons are used in an increasingly widening variety of applications including vascular dilatation, stent delivery, drug delivery, delivery and operation of sensors and surgical devices such as blades, and the like. The desired physical property profile for the balloons used in these devices varies according to the specific application, but for many applications a high strength robust balloon is necessary and softness and trackability properties are highly desirable. An application where high strength balloons, and more particularly balloons with high burst pressures, are useful is in the reopening of stenosis, for instance stenoses that develop at or in long-term shunts, ports or grafts employed for repeated blood access. 
       BRIEF SUMMARY 
       [0004]    The disclosure is directed to several alternative designs, materials and methods of manufacturing medical device structures and assemblies, and uses thereof. In a first illustrative embodiment, a balloon catheter assembly may comprise a tubular member having a proximal portion and a distal portion with a lumen extending between the proximal portion and the distal portion and a balloon member having a proximal waist portion, a distal waist portion, and an expandable region therebetween, the balloon member disposed proximate the distal portion of the tubular member and bonded to tubular member. In at least some additional embodiments, the assembly may further comprise a first sleeve member covering a first portion of the tubular member and a portion of the balloon member proximal waist portion and a second sleeve member covering a second portion of the tubular member and a portion of the first sleeve member. 
         [0005]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may be in contact with the first portion of the tubular member and the portion of the balloon member proximal waist portion. 
         [0006]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may not cover any part of the second portion of the tubular member. 
         [0007]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve member may be in contact with the second portion of the tubular member and the portion of the first sleeve member. 
         [0008]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the melting point of the first sleeve may be greater than the melting point of the second sleeve. 
         [0009]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve member may cover at least part of the first portion of the tubular member. 
         [0010]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the assembly may further comprise a fiber layer disposed over the balloon member, the fiber layer may cover at least a portion of the balloon member proximal waist portion, and wherein the first sleeve further may cover a portion of the fiber layer. 
         [0011]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may be in contact with the fiber layer. 
         [0012]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the balloon member may have a burst pressure greater than 1000 psi. 
         [0013]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may cover between 0.1 mm and 1.5 mm of the tubular member. 
         [0014]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may cover 0.5 mm of the tubular member. 
         [0015]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may cover between 2 mm and 5 mm of the balloon member proximal waist portion. 
         [0016]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may cover at least 3 mm of the balloon member proximal waist portion. 
         [0017]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may have a trapezoidal cross-section. 
         [0018]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may be longer along one edge than an opposite edge by between 0.25 mm and 1.75 mm. 
         [0019]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may be longer along one edge than an opposite edge by between 0.75 mm and 1.25 mm. 
         [0020]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve member may be between 0.5 mm to 5 mm long. 
         [0021]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve member may be between 1 mm to 2 mm long. 
         [0022]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve may cover between 0.1 mm and 1.5 mm of the tubular member. 
         [0023]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve may contact between 0.1 mm and 1.5 mm of the tubular member. 
         [0024]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve may cover 0.5 mm of the tubular member. 
         [0025]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve may contact 0.5 mm of the tubular member. 
         [0026]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve may cover between 0.1 mm and 1.5 mm of the first sleeve member. 
         [0027]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve may cover between 0.5 mm and 1 mm of the first sleeve member. 
         [0028]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve member may comprise a polyethylene terephthalate (PET) material. 
         [0029]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the second sleeve member may comprise a polyether block amide (PEBA) material. 
         [0030]    Additionally, or alternatively, in any of the embodiments according to the first illustrative embodiment, the first sleeve and the second sleeve comprise a single co-extruded sleeve. 
         [0031]    In a second illustrative embodiment, a balloon catheter assembly may comprise a tubular member having a proximal portion and a distal portion with a lumen extending between the proximal portion and the distal portion and a balloon member having a proximal waist portion, a distal waist portion, and an expandable region therebetween, the balloon member disposed proximate the distal portion of the tubular member and bonded to the tubular member. In some additional embodiments, a first bond may bond the balloon member proximal waist portion to the tubular member, the first bond may comprise a first layer on top of the balloon member proximal waist portion and a second layer on top of the first layer. Additionally, at least a portion of the first layer may contact the tubular member, and at least a portion of the second layer may contact the tubular member. 
         [0032]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, at least a portion of the second layer may extend proximal of the proximal end of the first layer. 
         [0033]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the melting point of the second layer may be lower than the melting point of the first layer. 
         [0034]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the first layer may be in contact with the tubular member and the balloon member proximal waist portion. 
         [0035]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may be in contact with the tubular member and the first layer. 
         [0036]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the assembly further comprise a fiber layer disposed over the balloon member, the fiber layer may cover at least a portion of the balloon member proximal waist portion, and wherein the first layer may cover a portion of the fiber layer. 
         [0037]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the first layer may be in contact with the fiber layer. 
         [0038]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the balloon member may have a burst pressure greater than 1000 psi. 
         [0039]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the first layer may cover between 0.1 mm and 1.5 mm of the tubular member. 
         [0040]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the first layer may cover 0.5 mm of the tubular member. 
         [0041]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the first layer may cover between 2 mm and 5 mm of the balloon member proximal waist portion. 
         [0042]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the first layer may cover at least 3 mm of the balloon member proximal waist portion. 
         [0043]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may be between 0.5 mm to 5 mm long. 
         [0044]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may be between 1 mm to 2 mm long. 
         [0045]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may cover between 0.1 mm and 1.5 mm of the tubular member. 
         [0046]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may contact between 0.1 mm and 1.5 mm of the tubular member. 
         [0047]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may cover 0.5 mm of the tubular member. Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second layer may contact 0.5 mm of the tubular member. 
         [0048]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second sleeve may cover between 0.1 mm and 1.5 mm of the first layer. 
         [0049]    Additionally, or alternatively, in any of the embodiments according to the second illustrative embodiment, the second sleeve may cover between 0.5 mm and 1 mm of the first layer. 
         [0050]    Additionally, or alternatively, in further embodiments according to the second illustrative embodiment, the first layer of the first bond may comprise a polyethylene terephthalate (PET) material. 
         [0051]    Additionally, or alternatively, in further embodiments according to the second illustrative embodiment, the second layer of first bond may comprise a polyether block amide (PEBA) material. 
         [0052]    In a third illustrative embodiment, a method of bonding an expandable balloon onto a catheter shaft may comprise inserting a portion of a catheter shaft through an expandable balloon member, the expandable balloon member comprising a proximal waist portion, a distal waist portion, and an expandable region therebetween, positioning a first sleeve member over at least a portion of the balloon member proximal waist portion, and heating the first sleeve member. In some embodiments, the method may further comprise positioning a second sleeve member over at least a portion of the first sleeve member and heating the second sleeve member to bond the second sleeve member to the catheter shaft. 
         [0053]    Additionally, or alternatively, in further embodiments according to the third illustrative embodiment, a first portion of the first sleeve member may be disposed directly over a portion of the catheter shaft and a second portion of the first sleeve member is disposed directly over the portion of the balloon member proximal waist portion. 
         [0054]    Additionally, or alternatively, in further embodiments according to the third illustrative embodiment, a first portion of the second sleeve member may be disposed directly over a portion of the catheter shaft and a second portion of the second sleeve member may be disposed directly over the portion of the first sleeve member. 
         [0055]    Additionally, or alternatively, in further embodiments according to the third illustrative embodiment, the first sleeve member and the second sleeve member may comprise a single, co-extruded sleeve member. 
         [0056]    The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the aspects of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0057]    The aspects of the disclosure may be further understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: 
           [0058]      FIG. 1  is a perspective view of an exemplary balloon catheter in accordance with the disclosure; 
           [0059]      FIG. 2  is a cross-section of a region of the balloon of  FIG. 1  depicting multiple layers of the balloon; 
           [0060]      FIG. 3  is a partial cross-section of another region of the balloon of  FIG. 1  depicting a bond securing the balloon to the shaft of  FIG. 1 ; 
           [0061]      FIG. 4  is a partial cross-section of an alternative bond securing the balloon to the shaft of  FIG. 1 ; 
           [0062]      FIG. 5  depicts a step in the process of forming a bond of the present disclosure including positioning a sleeve over a balloon and a shaft; 
           [0063]      FIG. 6  depicts a result of applying heat to the sleeve of  FIG. 5  to shrink the sleeve over the balloon and the shaft; 
           [0064]      FIG. 7  depicts another step in the process of forming a bond of the present disclosure including positioning a second sleeve over a balloon, a shaft, and a first sleeve; 
           [0065]      FIG. 8  depicts a result of applying heat to the second sleeve of  FIG. 7  to shrink and/or melt the second sleeve over the balloon, the shaft, and the first sleeve; 
           [0066]      FIG. 9A  depicts an example co-extruded sleeve that may be used to form any of the bonds of the present disclosure; and 
           [0067]      FIG. 9B  is a cross-sectional view of the co-extruded sleeve of  FIG. 9A  taken along line A-A. 
       
    
    
       [0068]    While the aspects of the disclosure are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
       DETAILED DESCRIPTION 
       [0069]    For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
         [0070]    Definitions of certain terms are provided below and shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
         [0071]    All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure. 
         [0072]    The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
         [0073]    Although some suitable dimensions, ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed. 
         [0074]    As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include or otherwise refer to singular as well as plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed to include “and/or,” unless the content clearly dictates otherwise. 
         [0075]    The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary. 
         [0076]      FIG. 1  depicts exemplary balloon  100 . Balloon  100  may be mounted onto shaft  102 , and both balloon  100  and shaft  102  may be part of a larger catheter structure. In some embodiments, shaft  102  may have a length of about 20-250 cm and an outside diameter of approximately 1-10 French, depending upon the desired application. In some cases, shaft  102  may be part of a microcatheter that is adapted and/or configured for use within small anatomies of the patient. For example, shaft  102  and balloon  100  may be part of a catheter that is configured to navigate to target sites located in tortuous and narrow vessels such as, for example, to sites within the neurovascular system, certain sites within the coronary vascular system, or to sites within the peripheral vascular system such as superficial femoral, popliteal, or renal arteries. In some cases, the target site is a neurovascular site and may be located within a patient&#39;s brain, which is accessible only via a tortuous vascular path. However, it is contemplated that shaft  102  and balloon  100  may be used with catheters configured for use in other target sites within the anatomy of a patient. An exemplary catheter that may be utilized in accordance with the various embodiments as described herein is shown and described in U.S. Pat. No. 8,182,465, which is incorporated herein by reference in its entirety for all purposes. 
         [0077]    Shaft  102  may include one or more lumens, for example a guidewire lumen and/or an inflation lumen. At least one lumen may terminate within balloon  100  to provide a conduit for inflation media to be delivered to and from balloon  100  in order to inflate and deflate balloon  100 . Where shaft  102  includes a guidewire lumen, the guidewire lumen may run through balloon  100 . In some embodiments, shaft  102  and balloon  100  may be delivered to a target site within a patient over a guidewire by sliding shaft  102  and balloon  100  over the guidewire. 
         [0078]    Balloon  100  may generally comprise waist regions  103 ,  104 , cone regions  106 ,  108  and body region  110 . In some instances, balloon  100  may have an especially high burst pressure in order to be used in particular treatments, such as opening stenosed or otherwise obstructed arteries, vessels, or other lumens. However, it should be understood that the uses of the balloons and techniques of this disclosure are not limited to the specific use recited herein. The disclosed balloons and techniques may be useful in a multitude of situations. 
         [0079]    To achieve a high burst pressure, in some embodiments, balloon  100  may be a multi-layered balloon, as seen in  FIG. 2 .  FIG. 2  depicts close-up of region  10  as depicted in  FIG. 1 , including a close-up of the structure of example balloon  100 . As can be seen, balloon  100  may comprise multiple layers. 
         [0080]    In some embodiments, balloon  100  may include at least base layer  120 . Base layer  120  may be made from typical balloon materials such as one or more polymers (some examples of which are disclosed below), a metal-polymer composite, and the like, or other suitable material. Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane (for example, Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS 50A), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. Of course, these are just a few exemplary materials. In general, base layer  120  may be comprised of any suitable polymer, copolymer, or curable material. In some instances, the base layer  120  may include a single layer of material, whereas in other instances base layer  120  may further comprise a multi-layer structure itself, including a plurality of layers of materials. For instance, base layer  120  may be formed as a co-extrusion or tri-layer extrusion in some instances. 
         [0081]    In some embodiments, balloon  100  may further include fiber layer  121 . Fiber layer  121  may be formed from any suitable technique to create a web pattern. For example, fiber layer  121  may be braided, woven, or wound in any different manner to create a web pattern. Additionally, fiber layer  121  may be formed from one, or multiple, of many different suitable materials. In general, the specific chosen material or materials, along with the specific chosen web pattern, can influence the distension properties of balloon  100 . In some embodiments, fiber layer  121  may be formed separately from base layer  120  and later disposed over base layer  120 . However, in other embodiments, fiber layer  121  may be formed directly over base layer  120 . For example, the chosen material of fiber layer  121  may be woven or wound or otherwise formed into a web pattern directly over base layer  120 . 
         [0082]    Example suitable materials for fiber layer  121  include polyester, polyolefin, polyamide, polyurethane, liquid crystal polymer, polyimide, carbon, glass, mineral fiber or a combination thereof. Polyesters include polyethyleneterephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT). Polyamides include nylons and aramids such as Kevlar®. Liquid crystal polymers include Vectran®. Polyolefins include ultrahigh molecular weight polyethylene, such as Dyneema,® sold by DSM Dyneema BVm Heerlen, Netherlands, Spectra® fibers, sold by Honeywell, and very high density polyethylene, and polypropylene fibers. Elastomeric fibers can be used in some cases. In some specific embodiments of the invention, the fibers are high strength materials which have a very low elongation and creep, such as aramid, liquid crystal polymer, or ultrahigh molecular weight polyethylene. Fibers comprising carbon nanotubes or carbon nanofibers may be suitable. Other carbon materials may also be suitable in some applications. It should be understood that these are only some example materials that may be suitable for use in fiber layer  121 . 
         [0083]    In some embodiments, as shown in  FIG. 2 , balloon  100  may include a top layer  122 . However, top layer  122  may not be present in all embodiments. Where top layer  122  is included, top layer  122  may comprise a protective layer covering fiber layer  121 . In some embodiments, top layer  122  may comprise a low-friction layer, which may allow balloon  100  to be advanced more readily through various body lumens. 
         [0084]    Another factor aside from the addition of a fiber layer that can influence the burst pressure of balloon  100  is the bond between balloon  100  and shaft  102 . For instance, in some embodiments, balloon  100  may be formed separately from shaft  102  and later bonded to shaft  102 . In some embodiments, balloon  100  may generally comprise a distensible tube-like structure that is slid over shaft  102 . Once in place, waist regions  103 ,  104  of balloon  100  may be bonded to shaft  102  to create a secure connection between balloon  100  and shaft  102 . The specific materials used to create the bond, along with the specific process chosen to create the bond, can influence the burst pressure of balloon  100 . 
         [0085]      FIG. 3  depicts one example bond that may be used to bond balloon  100  to shaft  102  in order to impart balloon  100  with a high burst pressure. Specifically,  FIG. 3  depicts a close-up of region  20  of  FIG. 1  including proximal balloon waist portion  103 , with balloon  100  and layers  131 ,  132  of bond  118  shown in partial cross-section. Balloon wall  130  represents a cross-section of balloon  100  of  FIG. 1 . It should be understood that, although balloon wall  130  is only shown as a single layer, balloon wall  130  may represent the multi-layer structure depicted in  FIG. 2 . That is, even though balloon wall  130  is shown in  FIG. 3  as a single layer, balloon wall  130  may include at least a base layer and a fiber layer as described with respect to  FIG. 2 . 
         [0086]    In some embodiments according the present disclosure, bond  118  may comprise multiple layers in order to attach balloon wall  103  to shaft  102 . First layer  131  may be comprised of a relatively high-temperature melting point material and may contact balloon wall  130  directly. Some example materials that may be suitable for first layer  131  include polyethylene terephthalate (PET) material, materials comprising polyimide, various fluoropolymers such as polytetrafluoroethylene (PFTE), perfluoroalkoxy alkane (PFA), fluorinated ethylene propylene (FEP), or still other materials. 
         [0087]    In some embodiments, first layer  131  may directly cover, and may contact, at least a portion of balloon wall  130  proximate proximal balloon waist region  103  for a length  141 . In different embodiments, length  141  may range between about 2 mm and about 5 mm. In more specific embodiments, length  141  may be about 2 mm, about 3 mm, about 4 mm, about 5 mm, or any other suitable length. In still further embodiments, length  141  may be greater than about 5 mm, such as between about 6 mm and about 10 mm, or even greater. 
         [0088]    Additionally, in some embodiments, first layer  131  may extend proximally of balloon wall  130  to cover and contact at least a portion of shaft  102 . For instance, first layer  131  may cover and/or contact shaft  102  for a length  142 . Length  142  may range between about 0.1 mm and about 0.5 mm. In more specific embodiments, length  142  may be about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, or any other suitable value. In still other embodiments, length  142  may be greater than 0.5 mm, such as between about 0.6 mm and about 2 mm. 
         [0089]    In further embodiments, bond  118  may also include second layer  132 . Second layer  132  may have a relatively low-temperature melting point. For instance, second layer  132  may have a melting point temperature that is lower than at least the melting point temperature of first layer  131 . Some example materials that second layer  132  may comprise include a polyether block amide (PEBA) material. One specific PEBA material is sold under the name PEBAX®  7233 . However, it should be understood that other materials with the desired properties may also be used. In at least some embodiments, the material or materials used to form second layer  132  may be the same material or materials used to form balloon  100 . 
         [0090]    In some embodiments, second layer  132  may cover and directly contact at least a portion of first layer  131 . For example, second layer  132  may cover and/or directly contact first layer  131  for a length  144 . Length  144  may range between about 0.5 mm and about 2.5 mm. In more specific embodiments, length  144  may be about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 2.5 mm, or any other suitable value. 
         [0091]    In at least some embodiments that include second layer  132 , second layer  132  may also cover at least a portion of balloon wall  130  in the proximal balloon waist region  103 . In some embodiments, second layer  132  may not contact balloon wall  130  directly. Instead, second layer  132  may overlay at least a portion of first layer  131  that is in direct contact with balloon wall  130 . Where second layer  132  covers at least a portion of balloon wall  130 , second layer  132  may cover balloon wall  130  for a length  145 . Length  145  may range between about 0.5 mm and about 2.5 mm. In more specific embodiments, length  145  may be about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 2.5 mm, or any other suitable value. 
         [0092]    In at least some embodiments, second layer  132  may extend proximal of first layer  131  and may contact shaft  102  directly. For instance, as shown in  FIG. 3 , second layer  132  may cover and contact shaft  102  directly for a length  143 . In some embodiments, length  143  may range between about 0.1 mm and about 0.5 mm. In more specific embodiments, length  143  may be about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, or any other suitable value. In still other embodiments, length  143  may be greater than 0.5 mm, such as between about 0.6 mm and about 2 mm. In an example, second layer  132  may cover and/or directly contact balloon  103  distal of first layer  131 . In some embodiments, second layer  132  may cover and/or directly contact balloon  103  distal of first layer  131  a length that may range between about 0.5 mm and about 2.5 mm. In more specific embodiments, second layer  132  may cover and/or directly contact balloon  103  distal of first layer  131  a length that may be about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 2.5 mm, or any other suitable value. 
         [0093]    In order to create bond  118 , first layer  131  and second layer  132  may be applied in separate steps. Heat may additionally be applied to shrink and compress layers  131  and/or  132  (and balloon wall  130  in proximal balloon waist region  103 ) around shaft  102  and/or to melt layers  131  and/or  132  to shaft  102 .  FIG. 4  depicts an example alternative structure of bond  118 , bond  118   a.  In the example of  FIG. 4 , shaft  102  and second layer  132  may have similar melting points. As part of the bonding process, heat having a temperature greater than the melting points of shaft  102  and second layer  132  may be applied. This applied heat may cause the materials of shaft  102  and second layer  132  to flow together creating a secure connection between balloon wall  130  and shaft  102 , as seen in region  135 . 
         [0094]      FIGS. 5-8  depict an example process of forming bond  118  and/or  118   a  to secure balloon  100  to shaft  102 . As mentioned previously, balloon  100  may be formed separately from shaft  102  and later slid onto shaft  102  for bonding.  FIG. 5  depicts balloon  100  disposed on shaft  102  and in position for bonding. Once balloon  100  is in place on shaft  102 , sleeve  133  may be slid over both shaft  102  and at least a portion of balloon  100 . 
         [0095]    In some embodiments, sleeve  133  may be used to create first layer  131  as described in  FIGS. 3 and 4 . For instance, sleeve  133  may comprise one or more of the materials described with respect to first layer  131 . In some particular applications, sleeve  133  may have an inner diameter of about 2.2 mm and may have a wall thickness of about 0.013 mm. However, it should be understood these are example values only. In other embodiments, the inner diameter and wall thickness of sleeve  133  may be greater or less, depending on the specific size of shaft  102  and balloon  100 . 
         [0096]    Although not necessary in all embodiments, sleeve  133  may have a first straight edge  134  opposite a slanted or skived edge  136 . As shown in  FIG. 5 , in profile, this may give sleeve  133  a trapezoidal shape. In some embodiments, sleeve  133  may have differing lengths along a top edge, as indicated by length  167 , and a bottom edge, as indicated by length  166 . In some embodiments, length  167  may range between about 2.5 mm and about 4.5 mm. In more specific embodiments, length  167  may be about 2.5 mm, about 3.0 mm, about 3.5 mm, about 4.0 mm, about 4.5 mm, or any other suitable value. Length  166  may range between about 4.0 mm and about 8.0 mm. In more specific embodiments, length  166  may be about 4.0 mm, about 5.0 mm, about 6.0 mm, about 7.0 mm, about 8.0 mm, or any other suitable value. 
         [0097]      FIG. 5  shows sleeve  133  disposed about balloon  100  in a particular relation to balloon  100  and shaft  102 . For instance, sleeve  133  may be disposed so that sleeve  133  covers shaft  102  for at least a length  160 . Length  160  may correspond to length  142  described with respect to  FIG. 3 , as length  160  may represent the portion of sleeve  133  that covers and directly contacts shaft  102 , forming layer  131 . 
         [0098]    Additionally, where sleeve  133  includes a slanted or skived edge  136 , different portions of sleeve  133  may cover different lengths of balloon  100 . For instance, along the top edge, or short portion, of sleeve  133 , sleeve  133  may be disposed to cover balloon  100  for a length  161 . Length  161  may range between about 2.0 mm and about 4.0 mm. In more specific embodiments, length  161  may be about 2.0 mm, about 2.5 mm, about 3.0 mm, about 3.5 mm, about 4.0 mm, or any other suitable value. 
         [0099]    Along the bottom edge, or long portion, of sleeve  133 , sleeve  133  may be disposed to cover shaft  102  for a length  162 . Length  162  may range between about 3.5 mm and about 7.5 mm. In more specific embodiments, length  162  may be about 3.5 mm, about 4.5 mm, about 5.5 mm, about 6.5 mm, about 7.5 mm, or any other suitable value. 
         [0100]    Once in place, heat may be applied to balloon  100 , shaft  102 , and sleeve  133 , as represented by heat lines  150 . The applied heat temperature may range between about 120 degrees Celsius and about 140 degrees Celsius. The heat may be applied by flowing air having the desired temperature flow over sleeve  133 , shaft  102 , and balloon  100 . In some embodiments, the heat application may last between about 40 seconds and about 80 seconds. It should be understood that these values are only some examples. The specific temperature, time, and method of heat application may be different depending on the specific materials used and the desired properties of balloon  100 . Additionally, alternative heating methods may be used, such as by use of a laser, heat-radiating metallic jaws, RF energy, or even other methods. 
         [0101]    In general, the applied heat may be lower than the melting point of sleeve  133 . Instead of melting, sleeve  133  may be configured to shrink under the application of heat. For instance, sleeve  133  may comprise a heat-shrink material. Accordingly, when the heat is applied, sleeve  133  may shrink down and compress balloon  100  against shaft  102  forming a first layer of a bond, such as first layer  131  of bond  118  of  FIG. 3 .  FIG. 6  depicts sleeve  133  shrunk down and compressing balloon  100  against shaft  102 . 
         [0102]    In some additional embodiments, after applying heat to shrink sleeve  133 , a second sleeve, sleeve  137  of  FIG. 7  may be positioned over first sleeve  133  and used to create a second layer of a bond, such as, for instance, bond  118  of  FIG. 3 . In some embodiments, second sleeve  137  may be used to create second layer  132  as described in  FIGS. 3 and 4 . For instance, sleeve  137  may comprise one or more of the materials described with respect to second layer  132 . Sleeve  137  may have an overall length  168 . In different embodiments, length  168  may be from between about 0.5 mm and about 5.0 mm. In more specific embodiments, length  168  may be about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 3.0 mm, about 4.0 mm, about 5.0 mm, or any other suitable value. 
         [0103]      FIG. 7  depicts sleeve  137  disposed about balloon  100 , shaft  102 , and sleeve  133  in relation to those other components. For instance, sleeve  137  may be disposed so that sleeve  137  covers shaft  102  for at least a length  165 . Length  165  may correspond to length  143  described with respect to  FIG. 3 , as length  165  may represent the portion of sleeve  137  that covers and directly contacts shaft  102  in the final bond. Additionally, sleeve  137  may be disposed so that sleeve  137  covers sleeve  133  for a length  164 . In different embodiments, length  164  may range between about 0.2 mm and about 2 mm. In more specific embodiments, length  164  may be about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 1.0 mm, about 2.0 mm, or any other suitable value. 
         [0104]    In some additional embodiments, sleeve  137  may further cover a portion of balloon  100 . For example, as shown in  FIG. 7 , sleeve  137  may cover a length  163  of balloon  100 . 
         [0105]    Generally, in some embodiments, sleeve  137  may cover sleeve  133 , which in turn covers balloon  100 . 
         [0106]    In different embodiments, length  163  may range between about 0.1 mm and about 1.0 mm. In more specific embodiments, length  163  may be about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.8 mm, about 1.0 mm, or any other suitable value. However, in still other embodiments, sleeve  137  may not cover any of balloon  100 . Accordingly, in some embodiments, there would be no applicable length  163 . 
         [0107]    Once sleeve  137  has been disposed in the desired position, heat may be applied to sleeve  137  and in the corresponding region around sleeve  137 , as represented by heat lines  151 . In some embodiments, there may be a two-stage heat application. For instance, in a first stage, heated air similar to that described with respect to  FIG. 5  may again be applied once sleeve  137  is in place. 
         [0108]    In the second stage, sleeve  137  and the other components in the corresponding region around sleeve  137  may be placed in a hot-jaws apparatus. The hot-jaws apparatus may comprise two semi-circular components that, when brought together, form a lumen. In some specific embodiments, the lumen of the hot-jaws apparatus may have an inner diameter in the range of about 2.5 mm. However, this is just one example dimension. Other sized hot-jaws may be used in conjunction with shafts and balloons that are smaller or larger. 
         [0109]    Heat may then be applied to the jaws to deliver heat to a localized area (e.g. within the lumen of the jaws). Shaft  102  and balloon  100  may be positioned within the hot-jaws so that sleeve  137  is disposed within the lumen of the hot-jaws. In this manner, heat may be applied locally to sleeve  137  and the region around sleeve  137 . 
         [0110]    In some embodiments, the hot-jaws apparatus may be heated to between about 220 degrees Celsius and about 300 degrees Celsius. Sleeve  137  may be placed between the halves of the hot-jaws apparatus for between about 15 seconds and about 40 seconds. In at least some embodiments, this temperature may be above the melting point temperature of sleeve  137 , and the time of application may be sufficient to cause sleeve  137  to melt. This melting may securely attach sleeve  137  to shaft  102  and sleeve  133 . 
         [0111]    In at least some additional embodiments, the temperature of the hot-jaws may also be above the melting point temperature of shaft  102 . Accordingly, in some embodiments, while in the hot-jaws, shaft  102  may also melt. This reflow of both shaft  102  and of sleeve  137  may allow for mixing of the materials between shaft  102  and sleeve  137  to create a strong bond between sleeve  137  and shaft  102 . 
         [0112]    Although not necessary in all embodiments, before applying heat to sleeve  137  and the corresponding region around sleeve  137 , a protective heat-shrink layer may be positioned over sleeve  137 , as represented by dashed box  170  in  FIG. 7 . In some embodiments, after heat application by the jot-jaws apparatus, this protective heat-shrink layer may be removed, resulting in the structure depicted in  FIG. 8 . In some embodiments, the resulting bond depicted in  FIG. 8  may have a length  191  and a width or diameter  193 . In some embodiments, length  191  may be about 2.0 mm and width  193  may be about 2.0 mm. However, in other embodiments, length  191  and/or width  193  may be greater or less than 2.0 mm depending on the size of shaft  102  and balloon  100 , and possibly the ultimate desired properties of balloon  100 . 
         [0113]    The bond depicted in  FIG. 8  and other figures of this disclosure may allow balloon  100  to withstand high pressures in the range of 500 psi to 1500 psi, and more specifically in the range of 750 psi to 1250 psi. Pressures in these ranges may make balloon  100  suitable for use in a variety of applications for which balloons that burst under lower pressures would not be suited, such as for opening certain types of strictures within vessels or body lumens. 
         [0114]    Additionally, although  FIGS. 2-8  only depict balloon  100  bonded to shaft  102  along proximal balloon waist portion  103 , in some embodiments, balloon  100  may also be bonded to shaft  102  in a similar manner along distal balloon waist portion  104 . In this manner, both ends of balloon  100  may be bonded to shaft  102  in accordance with the techniques disclosed herein to produce a balloon that can withstand high internal pressures. 
         [0115]      FIGS. 9A-B  depict example co-extruded sleeve  233  that may be used to form any of the bonds described in the present disclosure, for instance bond  118 . In at least some embodiments, sleeve  233  may be similar to sleeve  133  described with respect to  FIG. 5 . For instance, sleeve  233  may have similar shape and be of a similar size and length as sleeve  133 . However, in the example of  FIGS. 9A-B , sleeve  233  may be a co-extruded sleeve comprising multiple layers of different materials instead of a comprising a single layer of material. As can be seen in  FIG. 9B , sleeve  233  may comprise at least two separate layers, outer layer  201  and inner layer  203 . Inner layer  203  may comprise a material similar to those materials described with respect to sleeve  133 . Outer layer  201  may comprise a material similar to those materials described with respect to sleeve  137  in  FIG. 7 . 
         [0116]    In embodiments where sleeve  233  is used to form a bond such as bond  118 , only a single sleeve, sleeve  233 , may be used to form the bond. For example, referring to  FIG. 5 , once balloon  100  has been disposed about shaft  102  at the desired location, sleeve  233  may be positioned over balloon  100  as shown in  FIG. 5 . As with sleeve  133 , heat may be applied to sleeve  233  to shrink sleeve  233  down onto balloon  100  and shaft  102 . Afterwards, balloon  100 , shaft  102 , and sleeve  233  may undergo further heating, such as by being placed in a hot-jaws apparatus. The additional heating by the hot-jaws apparatus may cause outer layer  201  to melt while inner layer  203  remains un-melted. As outer layer  201  melts, a portion of outer layer  201  may flow proximally beyond proximal edge P of sleeve  233  and onto shaft  102 . Once the heat is removed, the melted portion of outer layer  201  may solidify to shaft  102  at a point proximal of inner layer  203  and covers shaft  102 , resulting in bond  118  depicted in  FIGS. 3 and/or 4 . In this manner, a single sleeve may form bond  118 , which may reduce the complexity of the process used to form bond  118 . 
         [0117]    In at least some of embodiments of sleeve  223 , only a portion of sleeve  233  may be a co-extrusion. For instance, outer layer  201  and inner layer  203  may only be coextruded along a proximal portion  206  of sleeve  223 , with only inner layer  203  extending along distal portion  208  toward distal edge D of sleeve  223 . In at least some embodiments, proximal portion  206  may have a length that is similar to the lengths described for sleeve  137  above. 
         [0118]    Those skilled in the art will recognize that aspects of the present disclosure may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present disclosure as described in the appended claims.