Balloon expandable delivery system with actuated valve retention

Abstract

A delivery system for an expandable prosthetic heart valve is provided. The delivery system includes an elongated inner member and a distal stop and a proximal stop, both disposed on the elongated inner member. At least one of the proximal stop and the distal stop is fixed to the elongated inner member. The delivery system includes a flexible member disposed about the elongated inner member and having a distal end, a central region, and a proximal end, and an inflatable balloon disposed over the flexible member. The flexible member is configured such that when the heart valve is crimped onto the central region, the central region compresses and the proximal and distal regions of the flexible member expand radially to prevent axial movement of the valve.

Description

[Technical field]

[0001] The present disclosure relates to medical devices, and more particularly to prosthetic heart valve delivery systems and methods for using such medical devices. [Background technology]

[0002] Heart valve surgery is used to repair or replace diseased heart valves. A wide variety of endovascular valve replacement procedures and delivery systems have been developed. Some of these systems include valves with self-expanding stent elements. Other systems include balloon-expandable stent elements. These devices and systems may be used according to any of a variety of methods. Known medical devices and methods each have certain advantages and disadvantages. There is a continuing 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 alternative uses for medical devices and systems. An exemplary delivery system for an expandable prosthetic heart valve includes an elongated inner member, a distal stop and a proximal stop, the distal stop being disposed on the elongated inner member, the proximal stop being spaced apart from the distal stop and disposed on the elongated inner member, at least one of the proximal stop and the distal stop being secured to the elongated inner member, a flexible member disposed around the elongated inner member, the flexible member having a distal end secured to the distal stop, a central region, and a proximal end secured to the proximal stop, and an inflatable balloon disposed over the flexible member, the flexible member configured such that when the heart valve is crimped onto the central region, the central region compresses and the proximal and distal regions of the flexible member radially expand to prevent axial movement of the heart valve.

[0004] Alternatively or additionally to the above embodiments, the inner elongate member defines a guidewire lumen. Alternatively or additionally to any of the above embodiments, the flexible member is biased to a relaxed configuration in which the central region is spaced apart from the inner elongate member.

[0005] Alternatively or additionally to any of the above embodiments, when in the relaxed configuration, the outer diameters of the central region, proximal region, and distal region are substantially the same. Alternatively or additionally to any of the above embodiments, the flexible member is a coil.

[0006] Alternatively or additionally to any of the above embodiments, the flexible member is a braid. Alternatively or additionally to any of the above embodiments, the delivery system further comprises a woven mesh disposed over the braid.

[0007] Alternatively or additionally to any of the above embodiments, the flexible member is a frame including a plurality of struts circumferentially spaced about the elongate inner member, each strut having a straight region and a bent region.

[0008] Alternatively or additionally to any of the above embodiments, the proximal stop is fixed to the elongate inner member and the distal stop is slidable relative to the elongate inner member, and the delivery system further comprises a pull wire fixed to the distal stop and extending proximally therefrom, wherein pulling the pull wire proximally transitions the flexible member from a biased relaxed configuration in which the central region is spaced apart from the elongate inner member to a compressed configuration in which the central region is adjacent to the elongate inner member and the distal and proximal regions of the frame are radially expanded.

[0009] Alternatively or additionally to any of the above embodiments, the frame includes protrusions on inner surfaces of at least some of the plurality of struts, the protrusions being configured to slide along the elongate inner member when the central region of the frame compresses and the proximal and distal regions expand.

[0010] Alternatively or additionally to any of the above embodiments, the delivery system further comprises a prosthetic heart valve crimped onto the central region, with the proximal and distal regions of the flexible member extending radially outward beyond an outer diameter of the crimped heart valve.

[0011] Another exemplary delivery system for an expandable prosthetic heart valve comprises an elongate inner member defining an inner lumen, a distal stop and a proximal stop, the distal stop secured to the elongate inner member and the proximal stop secured to the elongate inner member and spaced apart from the distal stop, a flexible member disposed about the elongate inner member, the flexible member having a distal end secured to the distal stop, a central region and a proximal end secured to the proximal stop, the flexible member being biased to a relaxed configuration in which the central region is spaced apart from the elongate inner member, and an inflatable balloon disposed over the flexible member, the flexible member configured such that when the heart valve is crimped onto the central region, the central region transitions from the relaxed configuration to a compressed configuration in which the central region is adjacent the elongate inner member and the proximal and distal regions of the flexible member radially expand to impede axial movement of the heart valve.

[0012] Alternatively or additionally to any of the above embodiments, when in the relaxed configuration, the outer diameters of the central region, proximal region, and distal region are substantially the same. Alternatively or additionally to any of the above embodiments, the flexible member is a coil.

[0013] Alternatively or additionally to any of the above embodiments, the flexible member is a braid. Alternatively or additionally to any of the above embodiments, the delivery system further includes a woven mesh disposed over the braid.

[0014] Alternatively or additionally to any of the above embodiments, the delivery system further includes a prosthetic heart valve crimped onto the central region, with the proximal and distal regions of the flexible member extending radially outward beyond an outer diameter of the crimped heart valve.

[0015] A further exemplary delivery system for an expandable prosthetic heart valve includes an elongate inner member, a distal stop secured to the elongate inner member and a proximal stop spaced from the distal stop and secured to the elongate inner member, a flexible member disposed about the elongate inner member, the flexible member having a distal portion secured to the distal stop and a separate proximal portion secured to the proximal stop, the distal portion and the proximal portion being longitudinally spaced apart, the proximal section of the distal portion and the distal section of the proximal portion defining a central region configured to receive the heart valve, and an inflatable balloon disposed over the flexible member, the flexible member configured such that when the heart valve is crimped onto the central region, the proximal portion of the flexible member moves proximally to a radially expanded configuration and the distal portion of the flexible member moves distally to a radially expanded configuration, thereby preventing axial movement of the heart valve.

[0016] Alternatively or additionally to the above embodiments, the distal and proximal portions of the flexible member are frames including a plurality of struts circumferentially spaced about the elongate inner member, each strut having a straight region and a curved region.

[0017] Alternatively or additionally to any of the above embodiments, the delivery system further includes a plurality of protrusions disposed on an inner surface of at least some of the plurality of struts, the plurality of protrusions configured to slide along the elongate inner member as the plurality of struts move axially when the distal and proximal portions of the flexible member transition to the radially expanded configuration.

[0018] The above summary of some embodiments, aspects, and / or examples is not intended to describe each embodiment or every implementation of the present disclosure. The following figures and detailed description more particularly exemplify these embodiments. [Brief description of the drawings]

[0019] The present disclosure can be more fully understood from the following detailed description of various embodiments considered in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 illustrates a prior art heart valve retention device. [Diagram 2] FIG. 2 illustrates an exemplary heart valve delivery system before the valve is crimped onto the central region. [Diagram 3] FIG. 3 illustrates the heart valve delivery system of FIG. 2 with the valve crimped onto the central region. [Figure 4] FIG. 4 illustrates another exemplary heart valve delivery system in a relaxed configuration. [Diagram 5] FIG. 5 illustrates the heart valve delivery system of FIG. 4 with the valve crimped onto the central region. [Figure 6] FIG. 6 illustrates a further exemplary heart valve delivery system in a relaxed configuration. [Figure 7] FIG. 7 illustrates the heart valve delivery system of FIG. 6 with the heart valve crimped onto the central region. [Figure 8] FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. [Figure 9] FIG. 9 illustrates an additional exemplary heart valve delivery system in a relaxed configuration. [Figure 10] FIG. 10 illustrates the heart valve delivery system of FIG. 9 with the heart valve crimped onto the central region. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] While aspects of the present disclosure are susceptible to various modifications and alternative forms, details 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 present disclosure to the particular embodiments described. On the contrary, the present invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0021] For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. All numerical values ​​are assumed to be modified by the term "about" in this specification, whether or not expressly indicated. The term "about" in the context of numerical values ​​generally refers to a range of numbers that a person of ordinary skill in the art would consider equivalent to the stated value (e.g., having the same function or result). In many cases, the term "about" may include numbers that are rounded to the nearest significant figure. Other uses of the term "about" (e.g., in contexts other than numerical values) can be assumed to have their normal customary definitions as understood from and consistent with the context of this specification, unless otherwise specified.

[0022] 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 several suitable dimensions, ranges, and / or values ​​for various components, features and / or specifications have been disclosed, those skilled in the art inspired by this disclosure will understand that the desired dimensions, ranges and / or values ​​may deviate from those expressly disclosed.

[0023] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used herein and in the appended claims, the term "or" is generally used in the sense of including "and / or," unless the content clearly dictates otherwise. For ease of understanding, it should be noted that certain features of the present disclosure may be described in the singular even though those features may be multiple or repeated within the disclosed embodiment(s). Each instance of a feature may include and / or be encompassed by the singular disclosure unless expressly stated to the contrary. For purposes of 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 may be equally applicable to any and / or all of the components present in more than one instance, unless expressly stated to the contrary. In addition, not all instances of some elements or features are shown in each figure for clarity.

[0024] Relative terms such as "proximal," "distal," "advance," "retract," and variations thereof may be considered generally with respect to the placement, orientation, and / or movement of various elements relative to a user / operator / operator of a device, with "proximal" and "retract" indicating or referring to being closer to or toward the user, and "distal" and "advance" indicating or referring to being farther from or away from the user. In some instances, the terms "proximal" and "distal" may be assigned arbitrarily to facilitate understanding of the present disclosure, and such examples will be readily apparent to one of ordinary skill in the art. Other relative terms such as "upstream," "downstream," "inflow," and "outflow" refer to the direction of fluid flow within a body lumen, a lumen such as a blood vessel, or within a device.

[0025] The term "extent" may be understood to mean the maximum measurement of a stated or specified dimension, unless the extent or dimension in question is preceded by "minimum" or the extent or dimension in question is identified as "minimum", and "minimum" may be understood to mean the minimum measurement of a stated or specified dimension. For example, an "outer extent" may be understood to mean the maximum outer dimension, a "radial extent" may be understood to mean the maximum radial dimension, a "longitudinal extent" may be understood to mean the maximum longitudinal dimension, and so on. Each instance of "extent" may be different (e.g., axial, longitudinal, lateral, radial, circumferential, etc.) and will be clear to one of skill in the art from the context of the particular use. In general, a "extent" may be considered the maximum possible dimension measured according to the intended use, while a "minimum extent" may be considered the minimum possible dimension measured according to the intended use. In some examples, "area" may generally be measured orthogonally in a plane and / or cross-section, but may also be measured in different manners, including but not limited to, angularly, radially, circumferentially (e.g., along an arc), etc., as is apparent from the particular context.

[0026] The terms "monolithic" and "unitary" shall generally refer to one or more elements made up of or consisting of a single structure or base unit / element. Monolithic and / or unitary elements shall exclude structures and / or features made by assembling or otherwise joining together multiple separate elements.

[0027] It should be noted that references herein to "embodiments," "some embodiments," "other embodiments," and the like, indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments necessarily include that particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of one of ordinary skill in the art to effect the particular feature, structure, or characteristic in connection with other embodiments, unless expressly stated to the contrary, whether or not explicitly described. That is, the various individual elements described below, even if not explicitly shown in a particular combination, are contemplated as being combinable or configurable with one another to form other additional embodiments or to complement and / or enhance the described embodiments, as would be understood by one of ordinary skill in the art.

[0028] For clarity, certain distinguishing numerical nomenclature (e.g., first, second, third, fourth, etc.) may be used throughout the description and / or claims to name and / or distinguish various described and / or claimed features. It should be understood that the numerical nomenclature is not intended to be limiting, but is merely exemplary. In some embodiments, modifications and departures from previously used numerical nomenclature may be made for brevity and clarity. 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 omitted entirely, and / or a different feature may be referred to as the "first" element. The meaning and / or designation in each example will be apparent to one of ordinary skill in the art.

[0029] The following description should be read with reference to the drawings, which are not necessarily to scale, and in which similar elements in different drawings are numbered the same. The detailed description and drawings are intended to illustrate, rather than limit, the present disclosure. Those skilled 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, but the features and / or elements may be understood to be present nonetheless, unless otherwise specified.

[0030] Some mammalian hearts (such as humans) contain four heart valves: tricuspid, pulmonary, aortic, and mitral. Several relatively common medical conditions may include or result in inefficiency, ineffectiveness, or complete malfunction of one or more of the valves in the heart. Another challenge with treating defective heart valves is that they often require repair or complete replacement of the defective valve. Such treatments can be highly invasive to the patient. Disclosed herein are systems, devices, and / or methods that may be used within a portion of the cardiovascular system to diagnose, treat, and / or repair elements such as one or more of the heart valves. At least some of the systems, devices, and / or methods disclosed herein may be used percutaneously and thus may be much less invasive to the patient.

[0031] Delivery of a replacement heart valve into a blood vessel often requires steering a catheter through a complex curve with the valve positioned on a valve retention device. While it is desirable to maintain the valve stationary on the valve retention device, steering the device through a complex curve can cause the valve on the retention device to move. As a result, the valve can become misaligned during deployment.

[0032] 1 shows a conventional valve retention device 10 that can be connected to a delivery catheter (not shown). The valve retention structure can include an inner tube 11 with a retention coil 12. A distal stop 14 and a proximal stop 16 can define a valve retention area 18.

[0033] FIG. 2 illustrates an exemplary heart valve delivery system 100 for delivering a balloon expandable prosthetic heart valve 190. The delivery system 100 may include an elongate inner member 110 and a flexible member 120 disposed about the elongate inner member 110. The elongate inner member 110 may define an inner lumen 113, such as a guidewire lumen. The flexible member 120 may be configured to be compressed and then return to a relaxed, expanded configuration. As shown in FIG. 2, the flexible member 120 may be biased to a relaxed configuration in which a central region 122 of the flexible member 120 is spaced apart from the elongate inner member. In some embodiments, when in the relaxed configuration, the outer diameters of the central region 122, the proximal region 126, and the distal region 124 of the flexible member 120 may be substantially the same. In the example shown in FIG. 2, the flexible member 120 is a coil.

[0034] A distal end of the flexible member 120 may be secured to a distal stop 140 disposed on the elongate inner member 110. A proximal end of the flexible member 120 may be secured to a proximal stop 160 spaced from the distal stop 140 and disposed on the elongate inner member 110. At least one of the distal stop 140 and the proximal stop 160 may be secured to the elongate inner member 110. In some embodiments, both the distal stop 140 and the proximal stop 160 may be secured to the elongate inner member 110. In other embodiments, the distal stop 140 may be slidably disposed on the elongate inner member 110. An inflatable balloon 170 may be disposed over the flexible member 120, the distal stop 140, and the proximal stop 160. Balloon 170 may be secured to inner member 110 or other portion of a delivery catheter (not shown) distal to distal stop 140 and proximal to proximal stop 160. Inflation fluid is delivered to balloon 170 and allowed to flow over inner member 110 and through flexible member 120.

[0035] The prosthetic heart valve 190 may be crimped onto the balloon 170 in the valve-retaining region 180 covering the central region 122 of the flexible member 120. The flexible member 120 may be configured such that when the heart valve 190 is crimped or compressed onto the central region 122 of the flexible member 120, the central region 122 compresses and the distal and proximal ends of the flexible member 120 are secured, thereby radially expanding the distal and proximal regions 124 and 126 of the flexible member 120. See FIG. 3. The flexible member 120 may maintain a fluid path through the central region 122, as indicated by the arrow 128. The radially expanded distal and proximal regions 124 and 126 may prevent axial movement of the heart valve 190 relative to the balloon 170.

[0036] FIG. 4 illustrates another exemplary heart valve delivery system 200 in which the flexible member 220 is a braid arranged over the inner member 210. The braid 220 may be formed from a plurality of filaments that may be secured to the distal stop 240 and the proximal stop 260. In some examples, the flexible member 220 may include a textile woven mesh arranged over the braid. For example, the woven mesh may be polytetrafluoroethylene (PTFE). The balloon 270 may extend over the braided flexible member 220 and over the distal stop 240 and the proximal stop 260. The valve 290 may be crimped onto the balloon 270 in the central region 222 of the braided flexible member 220. As shown in FIG. 5, crimping or compressing the valve 290 can compress the braided flexible member 220 in the central region 222 while causing radial expansion of the braided flexible member 220 in the distal region 224 and the proximal region 226.

[0037] 6-8 show an additional exemplary heart valve delivery system 300, in which the flexible member 320 is a frame including a plurality of struts 323 spaced circumferentially around the inner member 310. In some examples, the frame may include two, three, four, five, six, or more struts 323. In the embodiment shown in FIG. 6, the delivery system 300 includes four struts 323. The figure is a cross-sectional view, so the top and bottom struts are visible, and the rear struts are hidden behind the inner member 310. Each strut 323 may include a plurality of straight regions 325 joined together at a bend region 327. As shown, each strut 323 includes five straight regions 325 and six bend regions 327. A balloon 370 may extend over the flexible member 320 and over the distal stop 340 and the proximal stop 360. FIG. 6 illustrates the delivery system 300 in a biased relaxed configuration, in which a central region 322 of the flexible member 320 is spaced apart from the inner elongate member 310.

[0038] The proximal stop 360 may be fixed to the elongate inner member 310 and the distal stop 340 may be slidable relative to the elongate inner member 310. The pull wire 315 may be fixed to the distal stop 340 and extend proximally through or adjacent the elongate inner member 310. Pulling the pull wire 315 proximally when the valve 390 is compressed or crimped onto the balloon 370 at the central region 322 of the flexible member 320 transitions the flexible member 320 from a biased relaxed configuration, as shown in FIG. 6, with the central region 322 adjacent the elongate inner member 310 and the distal and proximal regions of the frame radially expanded, as shown in FIG. 7. The flexible member 320 may maintain a fluid path through the central region 322, as shown by arrow 328. In other embodiments, the pull wires are not present and the radial compression force used to crimp or compress the valve 390 may compress the straight regions 325 of the struts in the central region 322 while causing radial expansion of the distal and proximal regions 324, 326.

[0039] Figure 8 is a cross-sectional view taken along line 8-8 of Figure 7. The cross-sectional view shows the spaced apart struts 323 in an expanded position with the valve 390 compressed over the elongate inner member 310. As shown in Figures 7 and 8, the proximal and distal regions 326, 324 extend radially outward beyond the outer diameter of the crimped heart valve 390, thereby holding the valve 390 securely in place and preventing axial movement of the valve relative to the balloon 370 during delivery.

[0040] 9 and 10 show another embodiment of a heart valve delivery system 400, in which the flexible member 420 is a frame 420 including a plurality of struts 423 spaced circumferentially around the inner member 410. In some examples, the frame may include two, three, four, five, six, or more struts 423. In the embodiment shown in FIG. 9, the delivery system 400 includes four struts 423. The figure is a cross-sectional view, so the top and bottom struts are visible, and the rear struts are hidden behind the inner member 410. Each strut 423 may include a plurality of straight regions 425 joined to each other at a bent region 427. The delivery system 400 differs from the delivery system 300 shown in FIGS. 6 and 7 in that the frame 420 has two portions separated longitudinally by a gap 437. The distal portion 430 of the frame 420 may include a distal stop 440 secured to the elongated inner member 410 and a plurality of struts 423 spaced circumferentially around the inner member 410 and secured to the distal stop 440 and extending proximally therefrom. As shown, each strut 423 of the distal portion 430 includes three straight regions 425 and three bent regions 327. The proximal portion 435 of the frame 420 may include a proximal stop 460 secured to the elongated inner member 410 and a plurality of struts 423 spaced circumferentially around the inner member 410 and secured to the proximal stop 460 and extending distally therefrom. As shown, each strut 423 of the proximal portion 435 includes three straight regions 425 and three bent regions 327. The proximal section of the distal portion 430 and the distal section of the proximal portion 435 define a central region 422 configured to receive the heart valve 10 .

[0041] The balloon 470 can extend over the flexible member 420 and over the distal stop 440 and the proximal stop 460. FIG. 9 shows the delivery system 400 in a biased, relaxed configuration in which the gap 437 between the struts 423 of the distal portion 430 and the proximal portion 435 is relatively small and the central region 422 of the frame 420 may be shorter than the valve that is crimped onto the frame 420. In some embodiments, the frame 420 can include a protrusion 421 on an inner surface of at least some of the struts 423. The protrusion 421 can be configured to slide along the elongate inner member 410 as the struts 423 move axially to widen the gap 437.

[0042] 10 shows a delivery system 400 with a valve 490 crimped to the central region 422. When the valve is crimped, the separate distal and proximal portions 430, 435 move axially apart, widening the gap 437 and causing the distal and proximal regions of the frame 420 to expand radially. The flexible member 420 can maintain a fluid pathway through the central region 422, as indicated by arrow 428.

[0043] In any of the above embodiments, one or both of the distal and proximal stops can include a radiopaque material and function as a marker band. It will be understood that the dimensions and angles described in connection with the above examples are merely exemplary, and other dimensions and angles of the transition zone are contemplated. The materials that can be used for the various components of the steerable catheter (and / or other systems or components disclosed herein), as well as the various elements thereof disclosed herein, can include those generally associated with medical devices. For simplicity, the following discussion refers to the cardiac valve delivery system 100 (and variations, systems, or components disclosed herein). However, this is not intended to limit the devices and methods described herein, and the discussion may apply to other cardiac valve delivery systems 200, 300, 400, and elements, members, components, or devices disclosed herein.

[0044] In some embodiments, the heart valve delivery system 100 (and its variations, systems, or components disclosed herein) may be made from metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, combinations thereof, and the like, or other suitable materials. Some examples of suitable metals and metal alloys are stainless steels, such as 444V, 444L, and 314LV stainless steels, mild steels, nickel-titanium alloys, such as linear elastic and / or superelastic Nitinol, cobalt chromium alloys, titanium and its alloys, alumina, materials with diamond-like coatings (DLC) or titanium nitride coatings, other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS:N06625, such as INCONEL® 625, HASTELLOY® C-22®, etc. such as UNS:N06022, 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., 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, etc., cobalt-chromium alloys, cobalt-chromium-molybdenum alloys (e.g., UNS:R44003, such as ELGILOY®, PHYNOX®), platinum strengthened stainless steels, titanium, platinum, palladium, gold, combinations thereof, etc., or any other suitable material.

[0045] As referred to herein, within the family of commercially available nickel-titanium or nitinol alloys, there is a category termed "linear elastic" or "non-superelastic" that is chemically similar to conventional shape memory and superelastic varieties, but may exhibit distinct and useful mechanical properties. Linear elastic and / or non-superelastic nitinol can be distinguished from superelastic nitinol in that linear elastic and / or non-superelastic nitinol does not exhibit a substantial "superelastic plateau" or "flag region" in its stress / strain curve as does superelastic nitinol. Instead, in linear elastic and / or non-superelastic nitinol, as recoverable strain increases, the stress continues to increase substantially linearly, or in a somewhat linear relationship, although not necessarily perfectly linear, or at least more linear than the superelastic plateau and / or flag region seen in superelastic nitinol, until plastic deformation begins. Thus, for purposes of this disclosure, linear elastic and / or non-superelastic nitinol may also be referred to as "substantially" linear elastic and / or non-superelastic nitinol.

[0046] In some cases, linear elastic and / or non-superelastic Nitinol can also be distinguished from superelastic Nitinol in that superelastic Nitinol can tolerate up to about 8% strain before plastically deforming, whereas linear elastic and / or non-superelastic Nitinol can tolerate up to about 2-5% strain while remaining substantially elastic (e.g., before plastically deforming). Both of these materials can also be distinguished (or differentiated based on their composition) from other linear elastic materials, such as stainless steel, which can only tolerate about 0.2-0.44 percent strain before plastically deforming.

[0047] In some embodiments, the linear elastic and / or non-superelastic nickel-titanium alloy is an alloy that does not exhibit a martensite / austenite phase change detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) analysis over a wide temperature range. For example, in some embodiments, there may be no martensite / austenite phase change detectable by DSC and DMTA analysis in a linear elastic and / or non-superelastic nickel-titanium alloy in the range of about -60 degrees Celsius (°C) to about 120°C. Thus, the mechanical bending properties of such materials may be generally inert to the effects of temperature over this very wide temperature range. In some embodiments, the mechanical bending properties of the linear elastic and / or non-superelastic nickel-titanium alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature, e.g., in that they do not exhibit a superelastic plateau and / or flag region. For example, over a wide temperature range, the linear elastic and / or non-superelastic nickel-titanium alloy maintains its linear elastic and / or non-superelastic properties and / or characteristics.

[0048] In some embodiments, the linear elastic and / or non-superelastic nickel-titanium alloy may be in the range of about 50 to about 60 weight percent nickel, with the remainder essentially titanium. In some embodiments, the composition is in the range of about 54 to about 57 weight percent nickel. One example of a suitable nickel-titanium alloy is FHP-NT alloy, available from Furukawa Techno Materials, Kanagawa, Japan. Other suitable materials may include ULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available from Toyota). In some other embodiments, a superelastic alloy, such as superelastic Nitinol, may be used to achieve the desired properties.

[0049] In at least some embodiments, some or all of the cardiac valve delivery system 100 (and its variations, systems, or components disclosed herein) may be doped with, made from, or include a radiopaque material. A radiopaque material is understood to be a material that can produce a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image assists the user in determining the location of the cardiac valve delivery system 100 (and its variations, systems, or components disclosed herein). Some examples of radiopaque materials include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials loaded with radiopaque fillers, and the like. In addition, other radiopaque marker bands and / or coils may also be incorporated into the design of the cardiac valve delivery system 100 (and its variations, systems, or components disclosed herein) to achieve the same results.

[0050] In some embodiments, the heart valve delivery system 100 (and variations, systems, or components thereof disclosed herein) and / or portions thereof may be made of or include a polymer or other suitable material. Some examples of suitable polymers are polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN® available from DuPont), polyether block esters, polyurethanes (e.g., Polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyether-esters (e.g., ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (e.g., butylene / poly(alkylene ether) phthalates and / or other polyester elastomers such as HYTREL® available from DuPont), polyamides (e.g., DURETHAN® or Elf® available from Bayer), and / or other suitable materials. CRISTAMID® available from Atochem), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA, available, for example, 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 (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 (e.g., EMS AmericanGRILAMID® available from Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefins, polystyrene, epoxies, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS 50A), polycarbonates, ionomers, polyurethane silicone copolymers (e.g., Elast-Eon® from AorTech Biomaterials or ChronoSil® from AdvanSource Biomaterials), biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers, polymer / metal composites, and the like. In some embodiments, the sheath can be blended with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6% LCP.

[0051] It will be understood that the present disclosure is in many respects merely illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps, without exceeding the scope of the present disclosure. This may include, to the extent appropriate, the use of any of the features of one illustrative embodiment used in another embodiment. The scope of the present disclosure is, of course, defined in the language in which the appended claims are expressed.

Claims

1. 1. A delivery system for an expandable prosthetic heart valve, comprising: an elongated inner member; a distal stop and a proximal stop, the distal stop disposed on the inner elongate member, the proximal stop disposed on the inner elongate member and spaced from the distal stop, and at least one of the proximal stop and the distal stop fixed to the inner elongate member; a flexible member disposed about the inner elongate member, the flexible member having a distal end secured to the distal stop, a central region, and a proximal end secured to the proximal stop; an inflatable balloon disposed over the flexible member; Equipped with the flexible member is configured such that when a heart valve is crimped onto the central region, the central region compresses and the proximal and distal regions of the flexible member expand radially to prevent axial movement of the heart valve.

2. The delivery system of claim 1 , wherein the inner elongate member defines a guidewire lumen.

3. The delivery system of claim 1 or 2, wherein the flexible member is biased to a relaxed configuration in which the central region is spaced from the inner elongate member.

4. The delivery system of claim 3 , wherein when in the relaxed configuration, outer diameters of the central region, the proximal region, and the distal region are substantially the same.

5. The delivery system of claim 1 or 2, wherein the flexible member is a coil.

6. The delivery system of claim 1 or 2, wherein the flexible member is a braid.

7. The delivery system of claim 6 , further comprising a woven mesh disposed over the braid.

8. 3. The delivery system of claim 1 or 2, wherein the flexible member is a frame including a plurality of struts circumferentially spaced about the elongate inner member, each strut having a straight region and a curved region.

9. 9. The delivery system of claim 8, wherein the proximal stop is fixed to the elongate inner member and the distal stop is slidable relative to the elongate inner member, the delivery system further comprising a pull wire fixed to the distal stop and extending proximally therefrom, wherein pulling the pull wire proximally transitions the flexible member from a biased relaxed configuration in which the central region is spaced apart from the elongate inner member to a compressed configuration in which the central region is adjacent to the elongate inner member and distal and proximal regions of the frame are radially expanded.

10. 10. The delivery system of claim 9, wherein the frame includes protrusions on inner surfaces of at least some of the plurality of struts, the protrusions configured to slide along the elongate inner member when the central region of the frame compresses and the proximal and distal regions expand.

11. 3. The delivery system of claim 1, further comprising a prosthetic heart valve crimped onto the central region, the proximal and distal regions of the flexible member extending radially outward beyond an outer diameter of the crimped heart valve.

12. 1. A delivery system for an expandable prosthetic heart valve, comprising: an elongate inner member defining an inner lumen; a distal stop and a proximal stop, the distal stop secured to the inner elongate member and the proximal stop secured to the inner elongate member, the proximal stop spaced apart from the distal stop; a flexible member disposed about the inner elongate member, the flexible member having a distal end secured to the distal stop, a central region, and a proximal end secured to the proximal stop, the flexible member being biased to a relaxed configuration in which the central region is spaced apart from the inner elongate member; an inflatable balloon disposed over the flexible member; Equipped with the flexible member is configured such that, when a heart valve is crimped onto the central region, the central region transitions from the relaxed configuration to a compressed configuration in which the central region is adjacent the elongate inner member and proximal and distal regions of the flexible member radially expand to impede axial movement of the heart valve.

13. The delivery system of claim 12 , wherein when in the relaxed configuration, the outer diameters of the central region, the proximal region, and the distal region are substantially the same.

14. 14. The delivery system of claim 12 or 13, wherein the flexible member is a coil.

15. 14. The delivery system of claim 12 or 13, wherein the flexible member is a braid, the system further comprising a woven mesh disposed over the braid.

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