Balloon Expansion-Type Delivery System with Uniform Expansion

Abstract

A delivery system for delivering an expandable medical device is provided. The delivery system includes a catheter shaft, a proximal stop coupled to the catheter shaft, an inner tube coupled to the proximal stop and extending distally from the proximal stop, a distal stop coupled to the inner tube, and a balloon disposed across the distal stop, the inner tube, and the proximal stop. The inner tube defines an inflation lumen and has a plurality of openings extending through a sidewall of the inner tube and into the inflation lumen. The distal stop includes at least one channel extending through a sidewall of the distal stop and into the lumen. The distal stop is configured to allow inflation fluid to flow through the inner tube and the at least one channel into a distal region of the balloon.

Description

Technical Field

[0001] The present disclosure relates to medical devices, and more particularly, to balloon-expandable medical device delivery systems and methods for using such medical devices. This application claims the benefit of priority of U.S. Provisional Application No. 63 / 242,206, filed Sep. 9, 2021, the entire disclosure of which is incorporated herein by reference.

Background Art

[0002] A variety of medical procedures and delivery systems for delivering and deploying balloon-expandable medical devices have been developed. Some of these systems include artificial heart valves with stents and stent elements. These devices and systems can be used according to any one of a variety of methods. Each of the known medical devices and methods has specific advantages and disadvantages. There is still a need to provide alternative medical devices and systems, as well as alternative methods for manufacturing and using medical devices.

Summary of the Invention

[0003] The present disclosure provides designs, materials, manufacturing methods, and use alternatives for medical devices and systems. An exemplary delivery system for an expandable medical device includes a catheter shaft, a proximal stop coupled to the catheter shaft, and an inner tube coupled to the proximal stop and extending distally from the proximal stop, the inner tube defining an inflation lumen and having a plurality of openings extending through the sidewall of the inner tube and into the inflation lumen, a distal stop coupled to the inner tube, the distal stop having a lumen and at least one channel extending through the sidewall of the distal stop and into the lumen, an inflatable balloon disposed over the distal stop, the inner tube, and the proximal stop, wherein the distal stop is configured to allow inflation fluid to flow through the inner tube and the at least one channel into a distal end region of the balloon.

[0004] Alternatively or additionally to the above embodiments, the at least one channel extends distally and obliquely from the lumen within the distal stop to an opening on the outer surface of the distal stop.

[0005] Alternatively or additionally to any of the above embodiments, the openings are located beneath the distal end region of the balloon. Alternatively or additionally to any of the above embodiments, the proximal end of the distal stop flares outwardly, defining a distal gap between the outer surface of the inner tube and the inner surface of the distal stop.

[0006] Alternatively or additionally to any of the above embodiments, the proximal end of the distal stop is inclined radially outwardly from the longitudinal axis of the distal stop, defining a plurality of spaced fingers.

[0007] Alternatively or additionally to any of the above embodiments, the plurality of openings penetrating the inner tube include a proximal opening penetrating the proximal end region of the inner tube and a distal opening penetrating the distal end region of the inner tube.

[0008] Alternatively or additionally to any of the above embodiments, the central region of the inner tube between the proximal end region and the distal end region has no opening. Alternatively or additionally to any of the above embodiments, the distal end of the proximal stop flares outwardly, defining a proximal gap between the outer surface of the inner tube and the inner surface of the proximal stop.

[0009] Alternatively or additionally to any of the above embodiments, the distal end of the inner tube is adjacent to the at least one channel. Alternatively or additionally to any of the above embodiments, at least some of the plurality of openings penetrating the inner tube are located within the distal gap and some openings are located within the proximal gap.

[0010] Alternatively or additionally to any of the above embodiments, the outer surface of the inner tube defines a raised helical coil. Alternatively or additionally to any of the above embodiments, the outer surface of the inner tube defines a plurality of longitudinal grooves.

[0011] Alternatively or additionally to any of the above embodiments, the proximal constriction of the balloon is fixed to the catheter shaft, and the distal constriction of the balloon is fixed to the distal stop distal to the at least one channel.

[0012] Alternatively or additionally to any of the above embodiments, the delivery system further includes an artificial heart valve crimped to the balloon on the inner tube between the proximal stop and the distal stop.

[0013] Another exemplary delivery system for an expandable medical device includes a catheter shaft, a proximal stop coupled to the catheter shaft, an inner tube having a proximal end coupled to the proximal stop and defining an inflation lumen, and a distal stop coupled to the distal end of the inner tube. The distal stop has at least one channel that extends through the sidewall of the distal stop and is in fluid communication with the inflation lumen of the inner tube. The expandable balloon has a proximal end fixed to the catheter shaft and a distal end fixed to the distal stop distal to the at least one channel. The inner tube includes a plurality of openings that penetrate the sidewall of the inner tube. The plurality of openings include a proximal opening within a proximal end region of the inner tube that is at least partially covered by the proximal stop and a distal opening within a distal end region of the inner tube that is at least partially covered by the distal stop. The proximal stop and the distal stop are configured such that inflation fluid can flow from the inflation lumen through the proximal opening and the distal opening and further through the at least one channel to the proximal and distal regions of the balloon for uniform inflation of the balloon.

[0014] Alternatively or additionally to any of the above embodiments, each channel extends distally and is inclined from the inner surface of the distal stop to an opening in the outer surface of the distal stop.

[0015] Alternatively or additionally to any of the above embodiments, the proximal end of the distal stop flares outwardly to define a distal gap between the outer surface of the inner tube and the inner surface of the distal stop, and the distal opening of the inner tube is located within the distal gap.

[0016] Alternatively or additionally to any of the above embodiments, the distal end of the proximal stop flares outwardly, defining a proximal gap between the outer surface of the inner tube and the inner surface of the proximal stop, and the proximal opening of the inner tube is located within the proximal gap.

[0017] Alternatively or additionally to any of the above embodiments, the outer surface of the inner tube defines a raised helical coil. A further exemplary delivery system for an expandable medical device includes a catheter shaft, a proximal stop coupled to the catheter shaft, and an inner tube coupled to the proximal stop, the inner tube defining an inflation lumen and having a plurality of proximal openings extending through the sidewall of the inner tube, at least some of the plurality of proximal openings being located beneath the distal end of the proximal stop within a proximal gap between the outer surface of the inner tube and the inner surface of the proximal stop; a distal stop having a lumen coupled to the distal end of the inner tube, the distal stop having at least one channel extending through the sidewall of the distal stop and sloping distally; and an expandable balloon disposed across the distal stop, the inner tube, and the proximal stop. The distal stop is configured to allow inflation fluid to flow through the inner tube and the at least one channel into the distal end region of the balloon.

[0018] The summaries of some of the above-described embodiments, aspects, and / or examples are not intended to describe every embodiment or all implementations of the present disclosure. The drawings and detailed description illustrate these embodiments more specifically.

[0019] The present disclosure can be more fully understood by considering the following detailed description of various embodiments in connection with the accompanying drawings.

Brief Description of the Drawings

[0020]

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[0021] Aspects of the present disclosure are capable of various modifications and alternative forms, and specific forms thereof are shown by way of example in the drawings and will be described in detail below. However, it is not intended to limit the aspects of the present disclosure to the specific embodiments described below. Further, all modifications, equivalents, and alternative forms falling within the spirit and scope of the present disclosure are intended to be encompassed.

[0022] For the terms defined below, these definitions shall apply unless otherwise defined in the claims or elsewhere in this specification. All numerical values are assumed to be modified by the term "about", whether or not explicitly indicated in this specification. The term "about" refers to a range of numerical values that a person of ordinary skill in the art would generally consider to be equivalent (e.g., having the same function or result) in the context of the numerical value. In many cases, the term "about" may include numbers rounded to the nearest significant digit. Other uses of the term "about" (e.g., in contexts other than numerical values) may be assumed to have their ordinary conventional definitions (one or more) that are understood from and consistent with the context of this specification, unless otherwise specified.

[0023] The recitation of numerical ranges by endpoints includes all numbers within that range including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Although some preferred dimensions, ranges, and / or values for various components, features, and / or specifications are disclosed, one of ordinary skill in the art who has reviewed the present disclosure will understand that the desired dimensions, ranges, and / or values may deviate from those explicitly disclosed.

[0024] As used in this specification and the claims, the singular form "one" includes a plurality of referents unless the context clearly dictates otherwise. The term "or" as used in this specification and the claims is generally used in the sense of "and / or" unless the context clearly dictates otherwise. For ease of understanding, some features of the present disclosure may be described in the singular, even though those features may be plural or repeated in the disclosed embodiment(s). Each example of a feature may include and / or be encompassed by a singular disclosure unless explicitly stated to the contrary. For brevity and clarity, not all elements of the present disclosure are necessarily shown in each figure or described in detail below. However, it will be understood that the following description is equally applicable to any and / or all of a plurality of components that are present, unless explicitly stated to the contrary. Also, for clarity, not all examples of some elements or features are shown in each figure.

[0025] Relative terms such as "proximal", "distal", "advancing", "retreating", and their derivatives may generally be considered with respect to the positioning, direction, and / or movement of various elements relative to the user / operator / pilot of the device, where "proximal" and "retreating" indicate or refer to being closer to or toward the user, and "distal" and "advancing" indicate or refer to being farther from or away from the user. In some instances, the terms "proximal" and "distal" may be arbitrarily assigned for ease of understanding of the present disclosure, and such instances will be readily apparent to those skilled in the art. Other relative terms such as "upstream", "downstream", "inflow", "outflow" refer to the direction of fluid flow within a lumen such as a body lumen, blood vessel, or within a device.

[0026] The term "range" can be understood to mean the maximum measured dimension of a dimension described or specified, unless the dimension or dimension in question is preceded by "minimum" which can be understood to mean the minimum measured value of the dimension described or identified, or is specified as "minimum". For example, "outer range" can be understood to mean the maximum outer dimension. Also, for example, "radial range" can be understood to mean the maximum radial dimension. Also, for example, "longitudinal range" can be understood to mean the maximum longitudinal dimension. Each example of "range" can be various (e.g., axial, longitudinal, transverse, radial, circumferential, etc.) and may be apparent to those skilled in the art from the context of each use. Generally, "range" can be considered the largest possible dimension measured according to the intended use, and "minimum range" can be considered the smallest possible dimension measured according to the intended use. In some examples, "range" can generally be measured at right angles within a plane and / or in a cross-section, but can be measured in various ways, such as at an angle, radially, circumferentially (e.g., along an arc), etc., without being limited to these, as may be apparent from the specific context.

[0027] The terms "monolithic" and "single" generally refer to one or more elements made of or consisting of a single structure or base unit / element. Monolithic and / or single elements are intended to exclude structures and / or mechanisms made by assembling or joining together a plurality of separate elements.

[0028] Note that references to "embodiments", "some embodiments", "other embodiments", etc. in this specification indicate that the described embodiments may include certain features, structures, or characteristics, but not all embodiments necessarily include those specific features, structures, or characteristics. Also, such phrases do not necessarily refer to the same embodiment. Further, if a specific feature, structure, or characteristic is described in relation to an embodiment, a person skilled in the art would recognize that, unless explicitly stated to the contrary, whether or not explicitly described, that specific feature, structure, or characteristic may result in relation to other embodiments. That is, the various individual elements described below are intended to be combinable or arrangeable with each other to form other additional embodiments or to complement and / or enhance the described embodiments, even if not explicitly shown in a specific combination, so that they can be understood by a person skilled in the art.

[0029] For clarity purposes, throughout the specification and / or claims, a certain numerical nomenclature (e.g., first, second, third, fourth, etc.) may be used to name and / or distinguish between various described features and / or features of the claims. This numerical nomenclature is not intended to be limiting and is merely illustrative. In some embodiments, for simplicity and clarity, changes and deviations from the previously used numerical nomenclature may occur. That is, a feature identified as a "first" element may later be referred to as a "second" element, a "third" element, etc., or may be completely omitted, and / or different features may be referred to as the "first" element. The meaning and / or designation in each case may be apparent to a person skilled in the art.

[0030] The following description should be read with reference to the drawings, which are not necessarily to scale, but like elements are numbered the same in different drawings. The detailed description and drawings are intended to illustrate, not limit, the present disclosure. One of ordinary skill in the art will recognize that the various elements described and / or illustrated can be arranged in various combinations and configurations without departing from the scope of the present disclosure. The detailed description and drawings show exemplary embodiments of the present disclosure. However, for clarity and ease of understanding, not all features and / or elements may be shown in each drawing, and it is understood that features and / or elements may exist independently of each other unless otherwise specified.

[0031] Delivering a balloon-expandable medical device, such as a stent or replacement heart valve, requires inflating a balloon to achieve deployment of the medical device. Accurate placement of the medical device can depend on uniform or symmetric inflation of the balloon. Many balloon catheters rely on inflating the balloon from an inflation lumen that terminates at the proximal end of the balloon, which results in the proximal end of the balloon inflating before the distal end. Thus, the medical device can be deployed in a proximal-to-distal orientation, which can lead to undesirable placement of the medical device. Even when the inflation lumen has a fluid port disposed within the balloon, if the device occludes the inflation port under the device, the proximal end of the balloon will inflate first, and symmetric deployment of the medical device clamped or crimped onto the inflation lumen may not be achieved. In particular, when deploying a replacement heart valve, such as in transcatheter aortic valve implantation (TAVI), proper alignment is desired. Asymmetric balloon inflation can result in poor valve alignment during deployment.

[0032] Figure 1 shows some elements of an exemplary delivery system 100 for deploying a balloon-expandable medical device. The delivery system 100 can include a catheter shaft 105, a proximal stop 130 coupled to the catheter shaft, an inner tube 110 coupled to the proximal stop 130, and a distal stop 120 coupled to the distal end of the inner tube 110. A nose cone 150 can be coupled to the distal end of the distal stop 120. An inflatable balloon 140 can be disposed over the distal stop 120, the inner tube 110, and the proximal stop 130. The distal stop 120 can include at least one channel 122 configured to deliver inflation fluid to the distal end region 142 of the balloon 140. The distal side neck of the balloon 140 can be coupled to the distal stop 120 at a location distal to the channel 122. In some embodiments, the distal side neck of the balloon 140 can be coupled to the enlarged distal end region 127 of the distal stop 120. A proximal strain relief element 107 can be coupled to the proximal end of the proximal stop 130 and the catheter shaft 105. The proximal side neck of the balloon 140 can be coupled to the strain relief element 107 or the catheter shaft 105. In some embodiments, one or more marker bands 109 can be provided on the distal stop 120, the proximal stop 130, or any other region of the delivery system.

[0033] Figure 2 shows details of the distal stop 120. The distal stop 120 may define a lumen 121 configured to receive the distal end of the inner tube 110 and at least one channel 122 that extends through the sidewall from an opening 123 on the outer surface into the lumen 121. In the example shown in Figure 2, the distal stop 120 has three channels 122 spaced around the outer periphery. The distal stop 120 may have an enlarged distal end region 127 to which the distal neck of the balloon may be joined. The proximal end 124 of the distal stop 120 may be shaped to flare outwardly. Also, the distal stop 120 may include a plurality of spaced fingers 125 that are inclined radially outwardly from the longitudinal axis of the distal stop. In some embodiments, the fingers 125 may be compressible and may be made of a soft elastomeric material. In one example, the distal stop 120 including the fingers 125 may be made of a material having a Shore D of 65 - 75. An exemplary material is flexible polyurethane (FPU50) having a Shore D of 71, which is often used in 3D printing.

[0034] The cross-sectional view of Figure 3 shows the lumen 121 and one channel 122 of the distal stop 120 shown in Figure 2. Each channel 122 may extend distally and be inclined from the lumen 121 to an opening 123 on the outer surface of the distal stop 120. Also, the distal stop 120 may define a guidewire lumen 129 that extends along the length of the distal stop. The distal end may include an engagement element 128 configured to engage the nose cone 150. In some embodiments, the engagement element 128 includes one or more ridges configured to provide a snap fit with the nose cone 150. In other embodiments, the engagement element 128 may include threads configured to mate with threads on the nose cone. In addition to, or as an alternative to, any snap fit or threaded connection, an adhesive or polymer bond may be used to secure the nose cone 150 onto the distal stop 120.

[0035] FIG. 4 shows the distal end of the inner tube 110 inserted into the lumen of the distal stop 120 adjacent to the channel 122. The inner tube 110 may define an inflation lumen 111 and a plurality of openings 112 that penetrate the sidewall and extend into the inflation lumen 111. The channel 122 is in fluid communication with the distal end of the inflation lumen 111, allowing inflation fluid to flow out of the distal end of the inner tube 110 and through the channel 122 into the distal end region 142 of the balloon. The proximal end 124 of the distal stop having an expanded shape may define a distal gap 126 between the outer surface of the inner tube 110 and the inner surface of the distal stop. In some embodiments, at least some of the plurality of openings 112 may be at least partially covered by the distal stop, while the distal gap 126 may provide a space for the inflation fluid flowing out of the openings 112 to flow proximally along the outer surface of the inner tube 110 and into the balloon.

[0036] FIG. 5 shows a delivery system 100 comprising a deflated balloon 140 and a medical device 170 pressed against the balloon on an inner tube 110 between a proximal stop 130 and a distal stop 120. The distal stop 120 and the proximal stop 130 are not configured to overlap the medical device 170 and / or are not configured to hold the medical device 170. The medical device 170 is held in place by being crimped or pressed against the balloon 140 and the inner tube 110. The proximal end of the inner tube 110 can be disposed within the proximal stop 130. The plurality of openings 112 through the inner tube 110 can include a proximal opening 112P that passes through the proximal end region of the inner tube and a distal opening 112D that passes through the distal end region of the inner tube. The distal end 134 of the proximal stop 130 can be shaped to flare outwardly to define a proximal gap 136 between the outer surface of the inner tube 110 and the inner surface of the proximal stop 130. In some embodiments, at least some of the proximal openings 112P can be at least partially covered by the proximal stop 130, while the proximal gap 136 can provide a space for inflation fluid flowing out of the proximal openings 112P to flow distally along the outer surface of the inner tube 110 and into the balloon. At least some of the distal openings 112D through the inner tube can be located within the distal gap 126. Also, some of the proximal openings 112P can be located within the proximal gap 136. In some embodiments, the central region 114 of the inner tube 110 between the proximal end region and the distal end region of the inner tube may not have any openings.

[0037] FIG. 6 shows the direction of the inflation fluid moving into the balloon 140 through the inner tube 110 during inflation. Arrow 200 indicates the direction of the inflation fluid flowing out from the distal opening 112D and moving into the balloon through the distal gap. Arrow 205 indicates the direction of the inflation fluid flowing out from the proximal opening 112P and moving into the balloon through the proximal gap. Arrow 207 indicates the direction of the inflation fluid flowing out from the opening 123 of the channel located under the distal end region 142 of the balloon. The combination of the distal opening 112D and the channel 122 provides the inflation fluid to the distal end of the balloon. In addition to the inflation fluid flowing out from the proximal opening 112P, this distally-directed inflation fluid can symmetrically inflate the balloon 140 and simultaneously inflate the distal and proximal regions of the balloon.

[0038] The outer surface of the inner tube 110 shown in FIGS. 1 and 4 - 6 is smooth, but this outer surface can have any surface structure. FIGS. 7A - 7C show various surface structures of the inner tube 110. As shown in FIG. 7A, in some embodiments, the outer surface of the inner tube 210 can define raised helical coils. These raised coils can result in improved device retention of the pressed medical device. Also, these raised coils can increase the column strength and compression resistance so that the inner tube is not crushed when the medical device 170 is pressed onto the inner tube 210. In the embodiment shown in FIG. 7B, the outer surface of the inner tube 310 defines a plurality of longitudinal grooves. In addition to resulting in an increase in column strength and compression resistance, these grooves can act as channels for directing the flow of the inflation fluid. FIG. 7C shows an embodiment in which the outer surface 410 of the inner tube defines a plurality of bumps or protrusions. The plurality of grooves and the plurality of ridges or protrusions can result in an increase in column strength and compression resistance and prevent damage to the inner tube during pressing of the medical device onto the system.

[0039] In addition to, or as an alternative to, the surface structures shown in FIGS. 7A-7C, inner tube 510 may have a plurality of openings 512 that penetrate the sidewall and extend into the lumen. These openings 512 may be added to, or alternatively replace, the openings 112 of inner tube 110 described above. As shown in FIG. 8, the openings 512 may extend along the entire length of inner tube 510, or alternatively may be present only on the distal region and / or the end region.

[0040] Note that the dimensions and angles described in connection with the above examples are merely exemplary, and other dimensions and angles of the transition region are also contemplated. The various components of the delivery system (and / or other systems or components disclosed herein) and the various materials that can be used for the various elements of those components can generally include those associated with medical devices. In the following description, for the sake of brevity, reference is made to delivery system 100 (and the variations, systems, or components disclosed herein). However, this is not intended to limit the devices and methods described herein, and this description is also applicable to other elements, members, components, or devices disclosed herein.

[0041] In some embodiments, the distal stop 120, inner tube 110, proximal stop 130, and proximal strain relief element 107 can often be made from a material having a shore D of 71, such as flexible polyurethane (FPU50), which is used in 3D printing. The distal nose cone 150, and inner tube 110 in some embodiments, can be made from a thermoplastic polyurethane having a shore A of 70, such as polyurethane elastomer EPU40.

[0042] In some embodiments, portions of the delivery system 100 (and variations, systems, or components thereof disclosed herein) may be made from metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, combinations thereof, or other suitable materials, etc. Some examples of suitable metals and metal alloys include stainless steels such as 444V, 444L, and 314LV stainless steel, mild steel, nickel-titanium alloys such as linear elastic and / or superelastic nitinol, cobalt-chromium alloys, titanium and its alloys, alumina, metals having a diamond-like coating (DLC) or titanium nitride coating, other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS:N06625 such as INCONEL® 625, UNS:N06022 such as HASTELLOY® C-22®, UNS:N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, etc.), nickel-copper alloys (e.g., UNS:N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R44035 such as MP35-N®), nickel-molybdenum alloys (e.g., UNS:N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, cobalt-chromium alloys, cobalt-chromium-molybdenum alloys (e.g., UNS:R44003 such as ELGILOY®, PHYNOX®, etc.), platinum-enriched stainless steel, titanium, platinum, palladium, gold, combinations thereof, or any other suitable material.

[0043] As referred to herein, the family of commercially available nickel-titanium or nitinol alloys includes those that can exhibit useful mechanical properties that are chemically similar but different in type from the conventional shape memory and superelastic types of the category called "linear elastic" or "non-superelastic". Linear elastic and / or non-superelastic nitinol can be distinguished from superelastic nitinol in that it does not exhibit a substantial "superelastic plateau" or "flag region" as shown by superelastic nitinol in its stress / strain curve. Instead, linear elastic and / or non-superelastic nitinol increases in stress substantially linearly, or not necessarily completely linearly but somewhat linearly, as the recoverable strain increases, until plastic deformation begins, or at least in a more linear relationship than the superelastic plateau and / or flag region seen in superelastic nitinol. Thus, for the purposes of the present disclosure, linear elastic and / or non-superelastic nitinol may also be referred to as "substantially" linear elastic and / or non-superelastic nitinol.

[0044] In some cases, superelastic nitinol can tolerate up to about 8% strain before plastic deformation, whereas linear elastic and / or non-superelastic nitinol can be distinguished from superelastic nitinol in that it can tolerate up to about 2 - 5% strain while remaining substantially elastic (e.g., before plastic deformation). Both of these materials can be distinguished from other linearly elastic materials, such as stainless steel, which can only tolerate about 0.2 - 0.44 percent strain before plastic deformation (which can also be distinguished based on its composition).

[0045] In some embodiments, a linear elastic and / or non-superelastic nickel-titanium alloy is an alloy that does not exhibit any martensite / austenite phase change detectable by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) over a wide temperature range. For example, in some embodiments, a linear elastic and / or non-superelastic nickel-titanium alloy has no martensite / austenite phase change detectable by DSC and DMTA in the range of about -60 degrees Celsius (°C) to about 120 °C. Thus, the mechanical bending properties of such materials may generally be little affected by temperature over this very wide temperature range. In some embodiments, the mechanical bending properties of a linear elastic and / or non-superelastic nickel-titanium alloy at ambient temperature or room temperature are substantially the same as the mechanical properties at body temperature, for example in that they do not exhibit a superelastic plateau and / or flag region. For example, a linear elastic and / or non-superelastic nickel-titanium alloy maintains its linear elastic and / or non-superelastic properties and / or characteristics over a wide temperature range.

[0046] In some embodiments, a linear elastic and / or non-superelastic nickel-titanium alloy may be nickel in the range of about 50 to about 60 weight percent, with the balance being essentially titanium. In some embodiments, the composition is nickel in the range of about 54 to about 57 weight percent. An example of a suitable nickel-titanium alloy is the FHP-NT alloy commercially available from Furukawa Techno-Material Co., Ltd. located in Kanagawa Prefecture, Japan. Other suitable materials include ULTANIUM (trademark) (available from Neo-Metrics) and GUM METAL (trademark) (available from Toyota). In some other embodiments, superelastic alloys, such as superelastic Nitinol, may be used to achieve the desired properties.

[0047] In at least some embodiments, some or all of the delivery system 100 (and its variations, systems, or components disclosed herein) may have a radiopaque material added thereto, be made from that material, or include that material. A radiopaque material is known as a material that can produce a relatively bright image with a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image helps the user in determining the location of the delivery system 100 (and its variations, systems, or components disclosed herein). Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials with added radiopaque fillers, and the like. Also, other radiopaque marker bands and / or coils may be incorporated into the design of the delivery system 100 (and its variations, systems, or components disclosed herein) to achieve similar results.

[0048] In some embodiments, the delivery system 100 (and variations, systems, or components thereof disclosed herein) and / or a portion thereof may be made of or include a polymer or other suitable material. Some examples of suitable polymers include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN® available from DuPont), polyether block ester, polyurethane (e.g., polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyether-ester (e.g., ARNITEL® available from DSM Engineering Plastics), ether or ester copolymers (e.g., butylene / poly(alkylene ether) phthalate, and / or other polyester elastomers such as HYTREL® available from DuPont), polyamide (e.g., DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamide, block polyamide / ether, polyether block amide (PEBA, e.g., available under the trade name PEBAX®), ethylene vinyl acetate copolymer (EVA), silicone, polyethylene (PE), Marlex® high density polyethylene, Marlex® low density polyethylene, linear low density polyethylene (e.g., REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon-12 (EMS Americansuch as GRILAMID® available from EMS-GRIVORY, perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS50A), polycarbonate, ionomer, polyurethane silicone copolymer (e.g., Elast-Eon® from AorTech Biomaterials or ChronoSil® from AdvanSource Biomaterials), biocompatible polymers, other suitable materials, mixtures, combinations, and copolymers thereof, polymer / metal composites, etc. may be included. In some embodiments, the sheath is mixable with liquid crystal polymer (LCP). For example, the mixture may contain up to about 6% LCP.

[0049] It should be understood that the present disclosure is merely illustrative in many respects. Without departing from the scope of the present disclosure, details may be changed, particularly with regard to shape, size, and the arrangement of steps. This may include, within the appropriate scope, the use of any feature of an exemplary embodiment in other embodiments. The scope of the present disclosure is, of course, defined by the language of the appended claims.

Claims

1. A delivery system for an expandable medical device, comprising: a catheter shaft; a proximal stop coupled to the catheter shaft; an inner tube coupled to the proximal stop and extending distally from the proximal stop, defining an inflation lumen and having a plurality of openings extending through the sidewall of the inner tube into the inflation lumen; a distal stop coupled to the inner tube, the distal stop having a lumen and at least one channel extending through the sidewall of the distal stop into the lumen; an expandable balloon disposed over the distal stop, the inner tube, and the proximal stop; wherein: the distal stop includes a proximal end having a flared shape that defines a distal gap between the outer surface of the inner tube and the inner surface of the distal stop; the proximal stop includes a distal end having a flared shape that defines a proximal gap between the outer surface of the inner tube and the inner surface of the proximal stop; the distal stop and the proximal stop are configured to allow inflation fluid to flow from the inflation lumen through the proximal gap, the distal gap, and the at least one channel to effect uniform inflation of the balloon.

2. The delivery system of claim 1, wherein the at least one channel extends distally and obliquely from the lumen within the distal stop to an opening in the outer surface of the distal stop.

3. The delivery system of claim 2, wherein the opening in the outer surface of the distal stop is located beneath a distal end region of the balloon.

4. The delivery system of claim 1, wherein the proximal end of the distal stop defines a plurality of spaced fingers that flare radially outwardly from the longitudinal axis of the distal stop.

5. The delivery system of claim 4, wherein the plurality of openings extending through the inner tube include a proximal opening extending through a proximal end region of the inner tube and a distal opening extending through a distal end region of the inner tube.

6. The delivery system of claim 5, wherein a central region of the inner tube between the proximal end region and the distal end region has no openings.

7. The delivery system according to claim 1, wherein a distal end of the inner tube is adjacent to the at least one channel.

8. The delivery system according to claim 1, wherein at least some of the plurality of openings penetrating the inner tube are located within the distal gap, and some of the openings are located within the proximal gap.

9. The delivery system according to claim 1, wherein an outer surface of the inner tube defines a raised helical coil.

10. The delivery system according to claim 1, wherein an outer surface of the inner tube defines a plurality of longitudinal grooves.

11. The delivery system according to claim 1, wherein a proximal constriction of the balloon is fixed to the catheter shaft, and a distal constriction of the balloon is fixed to the distal stop distal to the at least one channel.

12. The delivery system according to any one of claims 1 to 11, further comprising an artificial heart valve crimped to the balloon on the inner tube between the proximal stop and the distal stop.

13. A delivery system for an expandable medical device, comprising: a catheter shaft; a proximal stop coupled to the catheter shaft; an inner tube having a proximal end coupled to the proximal stop and defining an inflation lumen; a distal stop coupled to a distal end of the inner tube, the distal stop having at least one channel extending through a sidewall thereof and in fluid communication with the inflation lumen of the inner tube; an expandable balloon having a proximal end fixed to the catheter shaft and a distal end fixed to the distal stop distal to the at least one channel; and the inner tube includes a plurality of openings penetrating a sidewall of the inner tube, the plurality of openings including proximal openings within a proximal end region of the inner tube at least partially covered by the proximal stop and distal openings within a distal end region of the inner tube at least partially covered by the distal stop. The proximal stop and the distal stop are configured to allow inflation fluid to flow from the inflation lumen, through the proximal opening and the distal opening, and further through the at least one channel, into the proximal and distal regions of the balloon for uniform inflation of the balloon, delivery system.

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