Patent Application
20130123912
The present disclosure pertains to medical devices, and methods for manufacturing medical devices. More particularly, the present disclosure pertains to medical devices for delivering a replacement heart valve.
A wide variety of intracorporeal medical devices have been developed for medical use, for example, intravascular use. Some of these devices include guidewires, catheters, medical device delivery systems (e.g., for stents, grafts, replacement valves, etc.), and the like. These devices are manufactured by any one of a variety of different manufacturing methods and may be used according to any one of a variety of methods. Of the known medical devices and methods, each has certain advantages and disadvantages. There is an ongoing need to provide alternative medical devices as well as alternative methods for manufacturing and using medical devices.
The invention provides design, material, manufacturing method, and use alternatives for medical devices including medical device delivery systems. An example medical device delivery system may include an outer sheath. An inner catheter may be disposed within the outer sheath. The inner catheter may have a distal end. A tube extension may be coupled to the distal end of the inner catheter and may extend distally therefrom. The tube extension may include a crush resistance support member.
An example percutaneous valve delivery system may include an outer sheath. An inner catheter may be disposed within the outer sheath. The inner catheter may include a reduced outer diameter distal portion. A guidewire tube extension may extend distally from the reduced outer diameter distal portion. A support member may be coupled to the guidewire tube extension. A nose cone may be attached to the guidewire tube extension. A handle may be attached to the outer sheath. The handle may be configured to shift the outer sheath between a first position and a second position relative to the inner catheter. A valve implant may be releasably coupled to the inner catheter.
Another example percutaneous valve delivery system may include an outer sheath. An inner catheter may be disposed within the outer sheath. The inner catheter may have a distal end. A replacement valve implant may be releasably coupled to the inner catheter. A guidewire tube extension may be coupled to the inner catheter and may extend distally from the distal end of the inner catheter. A support element may be coupled to the guidewire tube extension. The support member may include a crush resistance member and a tensile strength member. The crush resistance member may include a metallic braid. The tensile strength member may include one or more longitudinally-extending aramid strands. A nose cone may be attached to the guidewire tube extension. A handle may be attached to the outer sheath. The handle may be configured to shift the outer sheath between a first position and a second position relative to the inner catheter.
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures, and Detailed Description, which follow, more particularly exemplify these embodiments.
The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:
While the invention is 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 the invention 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 invention.
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 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 include numbers that are rounded to the nearest significant figure.
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).
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.
Diseases and/or medical conditions that impact the cardiovascular system are prevalent in the United States and throughout the world. Traditionally, treatment of the cardiovascular system was often conducted by directly accessing the impacted part of the system. For example, treatment of a blockage in one or more of the coronary arteries was traditionally treated using coronary artery bypass surgery. As can be readily appreciated, such therapies are rather invasive to the patient and require significant recovery times and/or treatments. More recently, less invasive therapies have been developed, for example, where a blocked coronary artery could be accessed and treated via a percutaneous catheter (e.g., angioplasty). Such therapies have gained wide acceptance among patients and clinicians.
Some relatively common medical conditions may include or be the result of inefficiency, ineffectiveness, or complete failure of one or more of the valves within the heart. For example, failure of the aortic valve can have a serious effect on a human and could lead to serious health condition and/or death if not dealt with. Treatment of defective heart valves poses other challenges in that the treatment often requires the repair or outright replacement of the defective valve. Such therapies may be highly invasive to the patient. Disclosed herein are medical devices that may be used for delivering a medical device to a portion of the cardiovascular system in order to diagnose, treat, and/or repair the system. At least some of the medical devices disclosed herein may be used to deliver and implant a replacement heart valve (e.g., a replacement aortic valve). In addition, the devices disclosed herein may deliver the replacement heart valve percutaneously and, thus, may be much less invasive to the patient. The devices disclosed herein may also provide a number of additional desirable features and benefits as described in more detail below.
System 10 may generally be described as a catheter system that includes an outer sheath or catheter 12 and an inner catheter or tube 14 (a portion of which is shown in
In use, system 10 may be advanced percutaneously through the vasculature to a position adjacent to an area of interest. For example, system 10 may be advanced through the vasculature to a position adjacent to a defective aortic valve. During delivery, implant 16 may be generally disposed in an elongated and low profile “delivery” configuration within outer sheath 12. Once positioned, outer sheath 12 may be refracted to expose implant 16. Implant 16 may be actuated in order to expand implant into a generally shortened and larger profile “deployed” configuration suitable for implantation within the anatomy. When implant 16 is suitably deployed within the anatomy, system 10 can be removed from the vasculature, leaving implant 16 in place to function as, for example, a suitable replacement for the native aortic valve. In at least some interventions, implant 16 may be deployed within the native valve (e.g., the native valve is left in place and not excised). Alternatively, the native valve may be removed and implant 16 may be deployed in its place as a replacement.
Outer sheath 12 may be formed from a singular monolithic tube or unitary member. Alternatively, outer sheath 12 may include a plurality of layers or portions. One or more of these layers may include a reinforcing structure such as a braid, coil, mesh, combinations thereof, or the like.
The dimensions and materials utilized for the various layers of outer sheath 12 may also vary. For example, inner liner 26 may include a polymeric material such as fluorinated ethylene propylene (FEP) and may have a thickness in the range of about 0.00254 to 0.0127 cm (0.001 to 0.005 inches) or about 0.00762±0.00254 (0.003±0.001 inches), intermediate layer 28 may include a polymer material such as polyether block amide (e.g., PEBAX 6333) and may have a thickness in the range of about 0.00254 to 0.0127 cm (0.001 to 0.005 inches) or about 0.00508±0.00254 (0.002±0.001 inches), outer coating 34 may include a polymer material such as polyether block amide (e.g., PEBAX 7233) and may have a thickness in the range of about 0.00254 to 0.0254 cm (0.001 to 0.01 inches). In some embodiments, outer coating 34 may vary in thickness. For example, along proximal portion 20 outer coating 34 may have greater thickness, such as about 0.0127 to about 0.0508 cm or about 0.02159 cm (0.005 to 0.02 inches or about 0.0085 inches), than along distal portion 22 and/or distal tip 24, which may be about 0.0127 to about 0.0508 cm or about 0.01651 cm (e.g., about 0.005 to 0.02 inches or about 0.0065 inches). These are just examples as other suitable materials may be used.
The form of distal tip 24 may also vary. For example, in at least some embodiments, inner liner 26 (i.e., a 2.5 mm section thereof) may be extended up and around the distal end of outer sheath 12 (e.g., around reinforcement 30 and topcoat 32). A ring member (not shown) made from a suitable material such as a 55D polyether block amide (e.g., 55D PEBAX) may be disposed over inner liner 26 and heat bonded to form distal tip 24. This may form the funnel-like shape of distal tip 24.
Reinforcement 30 may also vary in form. In at least some embodiments, reinforcement 30 may take the form of a braid, coil, mesh, or the like. For example, in some embodiments, reinforcement 30 may include a metallic braid (e.g., stainless steel). In some of these embodiments, reinforcement 30 may also include additional structures such as one or more longitudinally-extending strands. For example, reinforcement 30 may include a pair of longitudinally-extending aramid and/or para aramid strands (for example, KEVLAR®) disposed on opposite sides of the braid. These strands may or may not be woven into portions or all of the braid.
In general, inner catheter 14 may take the form of an extruded polymer tube. Other forms are also contemplated including other polymer tubes, metallic tubes, reinforced tubes, or the like including other suitable materials such as those disclosed herein. In some embodiments, inner catheter 14 is a singular monolithic or unitary member. In other embodiments, inner catheter 14 may include a plurality of portions or segments that are coupled together. The total length of inner catheter may be in the range of about 60 to 150 cm, or about 80 to 120 cm, or about 100 to 115 cm, or about 112±0.02 cm. Just like outer sheath 12, inner catheter 14 may also be curved, for example adjacent to the distal end thereof. In some embodiments, inner catheter 14 may have one or more sections with a differing hardness/stiffness (e.g., differing shore durometer). For example, inner catheter may have a proximal region 44a and an intermediate region 44b. Proximal region 44a may include a generally stiff polymeric material such as a 72D polyether block amide (e.g., 72D PEBAX) and may have a length in the range of about 60 to 150 cm, or about 80 to 120 cm, or about 100 to 115 cm, or about 109.5±0.02 cm. Intermediate region 44b may include a 40D polyether block amide (e.g., 40D PEBAX) and may have a length in the range of about 5 to 25 mm, or about 10 to 20 mm, or about 15±0.01 mm. Section 42 may also differ from regions 44a/44b and, in some embodiments, may include a 72D polyether block amide (e.g., 72D PEBAX) and may have a length in the range of about 0.5 to 2 cm (5 to 20 mm), or about 0.8 to 1.5 cm (8 to 15 mm), or about 1±0.001 cm (10±0.01 mm). These are just examples.
Inner catheter 14 may include one or more lumens. For example,
Disposed within first lumen 46 may be push-pull rods 84 (not shown in
Fourth lumen 52 may be used to house a non-stretch wire 60. The form of non-stretch wire 60 may vary. In some embodiments, non-stretch wire 60 may take the form of a stainless steel braid. The non-stretch wire 60 may optionally include a pair of longitudinally-extending aramid and/or para aramid strands (for example, KEVLAR®) disposed on opposite sides of the braid. In general, rather than being “disposed within” fourth lumen 52, non-stretch wire 60 may be embedded within fourth lumen 52. In addition, non-stretch wire 60 may extend to a position adjacent to distal end portion 38 but not fully to the distal end of inner catheter 14 as illustrated in
Inner catheter 14 may also include a guidewire tube extension 62 that extends distally from distal end portion 38. A nose cone 64 is attached to guidewire tube extension 62. Nose cone 64 generally is designed to have an atraumatic shape. Nose cone 64 may also include a ridge or ledge 66 that is configured to abut the distal tip 24 of outer sheath 12 during delivery of implant 16.
Attachment between implant 16 and inner catheter 14 (and/or outer sheath 12) may be effected through the use of a three finger coupler 78. Coupler 78 may generally include a cylindrical base (not shown) that is attached to inner catheter 14 (e.g., disposed about and attached to reduced outer diameter section 42). Projecting distally from the base are three fingers that are each configured to engage with implant 16 at posts 72 and buckles 76. A collar 80 may further assist in holding together these structures. A guide 82 may be disposed over each of the fingers and may serve to keep the fingers of coupler 78 associated with push-pull rods 84 extending adjacent to coupler 78. Finally, a pin release assembly 86 may be a linking structure that keeps posts 72, buckles 76, and push-pull rods 84 associated with one another. Pin release assembly 86 includes a plurality of individual pins 88 that may be joined together via a coiled connection 90 and held to a pin release mandrel 92 with a ferrule 94.
During delivery, implant 16 is secured at the distal end of inner catheter 14 by virtue of the association of the fingers of coupler 78 being coupled with a projecting proximal end of buckles 76 (and being held in place with collar 80 disposed over the connection) and by virtue of pins 88 securing together push-pull rods 84 and posts 72. When implant 16 is advanced within the anatomy to the desired location, outer sheath 12 may be withdrawn (e.g., moved proximally relative to inner catheter 14) to expose implant 16. Then, push-pull rods 84 can be used to expand and “lock” implant 16 in the expanded or deployed configuration by proximally retracting push-pull rods 84 to pull posts 72 into engagement with buckles. Finally, pins 88 can be removed, thereby uncoupling push-pull rods 84 from posts 72, which allows implant 16 to be released from system 10 and deployed in the anatomy.
When implant 16 reaches the intended target site within the anatomy, a clinician can proximally retract push-pull rod 84, thereby moving the proximal ends of posts 72 toward the distal ends of buckles 76 in order to expand implant 16. Ultimately, push-pull rod 84 can be retracted sufficiently far enough to lock post 72 with buckle 76 so as to lock implant in an expanded configuration suitable for implantation within the anatomy.
Sheathing aid 112, as the name suggests, may be used to aid in the sheathing of implant 16 into outer sheath 12. In addition, sheathing aid 112 may aid in the initial sheathing of implant 16 (e.g., removing implant 16 from a packaging container such as a bottle and pulling implant 16 into outer sheath 12) and in re-sheathing implant 16 during repositioning and/or retraction of implant 16 within the area of interest. Sheathing may be accomplished via the arrangement and positioning of the various petals 116/118. For example,
Extending through and proximally from sheath adapter 130 is inner catheter 14. A proximal end of inner catheter 14 is attached (e.g., fixedly attached) to an interior body or diverter 136. Diverter 136 is attached to a support body 140. In general, diverter 136 and/or support body 140 may have one or more passageways or lumens formed therein. In some embodiments, push-pull rods 84 and/or pin release mandrel 92 may extend through respective passageways. Alternatively, the proximal ends of push-pull rods 84 and/or pin release mandrel 92 may each be attached to a shaft or hypotube (e.g., solid in cross-section, tubular, etc.), and each of the shafts may extend through the one or more passageways. For example, a first shaft or hypotube 142 and a second shaft or hypotube 144 may extend through the passageways in diverter 136, and in some embodiments, the first shaft or hypotube 142 extends through a first passageway and the second shaft or hypotube 144 extends through a second passageway that is separate or distinct from the first passageway. In at least some embodiments, first shaft 142 is attached to pin release mandrel 92. In at least some embodiments, second shaft 144 is attached to push-pull rods 84. It should be noted that at in least some embodiments of system 10, three push-pull rods 84 are utilized. In these embodiments, the three push-pull rods 84 come together (e.g., brought into contact with one another or otherwise brought into relatively close proximity with one another) adjacent to the distal end of inner catheter 14 and enter first lumen 46. At one or more positions along their length, push-pull rods 84 may be attached to one another. For example, in some embodiments, push-pull rods 84 may be welded together about 10.16 cm (about 4.00 inches) from their distal ends. In some embodiments, push-pull rods 84 may be welded together proximate their proximal ends in addition to or instead of the distal weld. Proximally thereafter, push-pull rods 84 may extend to second shaft 144.
A hypotube (e.g., hypotube liner 58 disposed along guidewire lumen 52) may extend through diverter 136 within a passageway therein and then be “diverted” around a portion of diverter 136 and support body 140, and ultimately be extended to a position at the proximal end of handle 18 so as to provide a user access to guidewire lumen 52. Proximal flush port 128 may be disposed on support body 140 that can be used to flush the lumens of inner catheter 14 and, for example, may function similarly to distal flush port 126.
At their respective proximal ends, first shaft 142 may be secured to a slider 146 and second shaft 144 may be secured to a force limiter body 150. The connections between the various components may include a number of different types of connections including mechanical bonding (e.g., pinning, threading, interference fit, etc.), adhesive bonding, thermal bonding, etc. Slider 146 may be slidable relative to force limiter body 150. In some embodiments, slider 146 may be selectively locked to force limiter body 150, thereby preventing relative movement between the slider 146 and the force limiter body 150. Force limiter body 150 may be secured to a push-pull rod carriage 152, which may be threaded onto lead screw 134. Thus, movement of lead screw 134 can cause movement of push-pull rod carriage 152 and force limiter body 150 and thus, push-pull rods 84 (via second shaft 144). Some additional details regarding this motion can be found herein.
In general, force limiter body 150 forms or defines a stop point that provides tactile feedback (e.g., resistance to further rotation of control knob 122) to the user indicating that push-pull rods 84 have been retracted proximally a sufficient distance to lock posts 72 with buckles 76. To verify proper locking, a clinician may use an appropriate visualization technique to visualize proper locking (e.g., the relative positioning of the posts 72 and the buckles 76). A chock 148 may be positioned adjacent to slider 146 to selectively lock slider 146 to force limiter body 150. In order to allow pin release mandrel 92 to be proximally retracted to pull pins 88, chock 148 can be rotated or otherwise moved to a secondary position or configuration. When in this configuration, chock 148 no longer forms a barrier to further movement of, for example, slider 146 and pin release mandrel 92. Accordingly, with chock 148 no longer acting as an impediment, slider 146 and pin release mandrel 92 can be proximally retracted to facilitate deployment of implant 16 by allowing pins 88 to be pulled.
Handle 18 also includes a rotatable ring 155 with internal teeth that are configured to engage with teeth on a gear 157 coupled to lead screw 134. Ring 155 is coupled to control knob 122 so that rotation of control knob 122 results in analogous motion of ring 155 and thus lead screw 134.
Handle 18 is generally configured for coordinated movement of multiple structures of system 10. For example, handle 18 is configured to allow a user to move outer sheath 12 (e.g., relative to inner catheter 14), move push-pull rods 84, and move pin release mandrel 92. Moreover, handle 18 is configured so that the appropriate structure can be moved at the appropriate time during the intervention so that implant 16 can be delivered in an efficient manner. Some examples of how the coordinated movement of system 10 may occur within handle 18 may be similar to those disclosed in U.S. Patent Application Pub. No. US 2010/0280495, the entire disclosure of which is herein incorporated by reference.
To help facilitate the coordinated movement, handle 18 may include a lost motion barrel 158. Lost motion barrel 158 is configured to engage carriages 132/152 and/or screws associated with carriages 132/152 at different times during the intervention to stop motion (e.g., create “lost motion” of the appropriate carriage).
Eventually, rod screw 152a (e.g., the knob formed therein) reaches an essentially linear thread or pathway formed at the end of lost motion barrel 158. The linear thread allows rod screw 152a to translate along lead screw 134 to a position where rod screw 152a contacts (e.g., is threaded within and abuts) push-pull rod carriage 152. In doing so, rod screw 152a can contact and move proximally push-pull carriage 152. Accordingly, further rotation of lead screw 134 not only causes sheath carriage 132 to move proximally but also causes push-pull rod carriage 152 to move proximally as shown in
In at least some embodiments, lead screw 134 has a plurality of portions, for example a first portion 134a and a second portion 134b, with a differing pitch to its thread. This may allow carriages 132/152 to travel at different rates along lead screw 134. For example, the pitch of lead screw 134 along which sheath carriage 132 translates may be generally more spaced or slanted than at positions adjacent to push-pull rod carriage 152. Accordingly, the coordinated movement of carriages 132/152 also may be configured so that sheath carriage 132 translates along lead screw 134 at a greater rate than push-pull rod carriage 152. Other configurations are contemplated where the above-mentioned configuration is reversed as well as further configurations where the pitch of lead screw 134 is essentially constant or includes a number of different pitch regions.
Sufficient proximal retraction of push-pull rod carriage 152, for example as shown in
To initiate release of pins 88, door 124 may be slid distally along a collar 156 (which is positioned on handle 18) as shown in
Collar 156, via ring 154, is associated with a gear 160 engaged with a secondary screw 162. Notches at a proximal end of collar 156 engage protrusions on ring 154 such that rotation of collar 156 causes corresponding rotation of ring 154 and thus secondary screw 162. The initial rotation of collar 156 is sufficient to rotate chock 148 (e.g., via a mechanical interaction between collar 156 and chock 148 that causes chock 148 to shift) from a first configuration where slider 146 (and, thus, pin release mandrel 92) is selectively locked to force limiter body 150, to a secondary configuration, which permits slider 146 to translate along secondary screw 162 as secondary screw 162 rotates, to proximally retract and pull pins 88 (e.g., via pin release mandrel 92). As seen in
Following deployment of the implant 16, the control knob 122 may be rotated to move the sheath carriage 132 distally within the handle housing 120, thereby moving outer sheath 12 distally relative to inner catheter 14 and three-finger coupler 78 so as to cover or re-sheath the elements of system 10 disposed at the distal end. System 10 may then be removed from the patient's anatomy.
As can be appreciated, system 10 may be designed to have a relatively low profile so as to be capable of penetrating deep within the vasculature. Because of this, the interior of system 10 (e.g., within outer sheath 12) may be relatively compact, particularly adjacent interior locations of system 10 that include a greater number of components (e.g., near implant 16). The relative compactness at this location may result in increased compressive forces on some components of system 10. For example, at locations adjacent to implant 16, inward forces may be present along guidewire tube extension 62. Such forces may be sufficient to radially compress or “crush” portions of guidewire tube extension 62. If guidewire tube extension 62 is exposed to these radially inward forces, the lumen within tube 62 may be reduced such that it may be more difficult to pass a guidewire therethrough (and/or for guidewire tube extension 62 to be tracked over a guidewire). Similarly, during sheathing processes, tensile forces may be exerted on portions of system 10. For example, outer sheath 12 may exert a longitudinal force on guidewire tube extension 62 during sheathing and/or resheathing. Such forces could deform guidewire tube extension 62 and/or cause failure along system 10.
System 10 may include one or more features that may help to reduce radially inward forces and/or tensile forces on, for example, guidewire tube extension 62. For example, guidewire tube extension 62 may include support member or structure 180 that is configured to provide increased support (e.g., crush resistance) to guidewire tube extension 62 as shown in
The form of braid 181 may vary, for example, in order to provide guidewire tube extension 62 with the desirable amount of crush resistance and/or tensile strength. One way that braid 181 may vary is in the pic count of the braid. For the purposes of this disclosure, pic count may be understood to be the number of times the wire or wires forming the braid cross one another per unit length (e.g., the number of “pies”). In general, a braid with a relatively low pic count may provide increased tensile strength. However, a low pic count braid may have a relatively low crush resistance. In contrast, a braid with a relatively high pic count may provide increased crush resistance while having a relatively low tensile strength.
In at least some embodiments, guidewire tube extension 62 may include braid 181 (having a relatively high pic count) in order to provide increased crush resistance. For example, guidewire tube extension 62 may include braid 181 having a pic count in the range of about 120-200 pics per inch, or about 140-180 pics per inch, or about 160-170 pics per inch, or about 165 pics per inch. Optionally, guidewire tube extension 62 may also include a relatively low pic count braid (e.g., braid 181′). Such braids may have a pic count in the range of about 50-100 pics per inch, or about 60-80 pics per inch, or about 70-80 pics per inch, or about 78 pics per inch. The combination of braids 181/181′ may provide guidewire tube extension 190 with a desirable balance in crush resistance (e.g., via braid 181) and tensile strength (e.g., via braid 181′).
In addition to variations in pic count, braid 181 may also vary in form. For example, braid 181 may include wires having a substantially round cross-sectional shape, wires having a non-circular cross-sectional shape (triangular, square, rectangular, oval, polygonal, etc.).
In some embodiments, rings 192a/192b/192c may be positioned at locations where various structures of system 10 may have an increased tendency to be compacted and, thus, have a greater propensity to exert crush forces on guidewire tube extension 190. For example, when implant 16 is positioned within outer sheath 12, structures such as posts 72, buckles 76, and/or other structures may tend to take up additional space within outer sheath 12 and form pinch points that tend to exert an increased radially inward force upon guidewire tube extension 190. Accordingly, rings 192a/192b/192c may be positioned at locations along guidewire tube extension 190 adjacent to where posts 72, buckles 76, etc. may be positioned when implant 16 is disposed within outer sheath 12 in order to reduce crush forces adjacent to these locations.
The materials that can be used for the various components of system 10 (and/or other systems disclosed herein) and the various tubular members disclosed herein may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference to outer sheath 12 and/or inner catheter 14. However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to other similar tubular members and/or components of tubular members or devices disclosed herein.
Outer sheath 12 and/or inner catheter 14 may be made from a metal, metal alloy, polymer (some examples of which are disclosed below), a metal-polymer composite, ceramics, combinations thereof, and the like, or other suitable material. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic and/or super-elastic nitinol; 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, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), 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, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like); platinum enriched stainless steel; titanium; combinations thereof; and the like; or any other suitable material.
As alluded to herein, within the family of commercially available nickel-titanium or nitinol alloys, is a category designated “linear elastic” or “non-super-elastic” which, although may be similar in chemistry to conventional shape memory and super elastic varieties, may exhibit distinct and useful mechanical properties. Linear elastic and/or non-super-elastic nitinol may be distinguished from super elastic nitinol in that the linear elastic and/or non-super-elastic nitinol does not display a substantial “superelastic plateau” or “flag region” in its stress/strain curve like super elastic nitinol does. Instead, in the linear elastic and/or non-super-elastic nitinol, as recoverable strain increases, the stress continues to increase in a substantially linear, or a somewhat, but not necessarily entirely linear relationship until plastic deformation begins or at least in a relationship that is more linear that the super elastic plateau and/or flag region that may be seen with super elastic nitinol. Thus, for the purposes of this disclosure linear elastic and/or non-super-elastic nitinol may also be termed “substantially” linear elastic and/or non-super-elastic nitinol.
In some cases, linear elastic and/or non-super-elastic nitinol may also be distinguishable from super elastic nitinol in that linear elastic and/or non-super-elastic nitinol may accept up to about 2-5% strain while remaining substantially elastic (e.g., before plastically deforming) whereas super elastic nitinol may accept up to about 8% strain before plastically deforming. Both of these materials can be distinguished from other linear elastic materials such as stainless steel (that can also can be distinguished based on its composition), which may accept only about 0.2 to 0.44 percent strain before plastically deforming.
In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) analysis over a large temperature range. For example, in some embodiments, there may be no martensite/austenite phase changes detectable by DSC and DMTA analysis in the range of about −60 degrees Celsius (° C.) to about 120° C. in the linear elastic and/or non-super-elastic nickel-titanium alloy. The mechanical bending properties of such material may therefore be generally inert to the effect of temperature over this very broad range of temperature. In some embodiments, the mechanical bending properties of the linear elastic and/or non-super-elastic nickel-titanium alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature, for example, in that they do not display a super-elastic plateau and/or flag region. In other words, across a broad temperature range, the linear elastic and/or non-super-elastic nickel-titanium alloy maintains its linear elastic and/or non-super-elastic characteristics and/or properties.
In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy may be in the range of about 50 to about 60 weight percent nickel, with the remainder being 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 commercially available from Furukawa Techno Material Co. of Kanagawa, Japan. Some examples of nickel titanium alloys are disclosed in U.S. Pat. Nos. 5,238,004 and 6,508,803, which are incorporated herein by reference. Other suitable materials may include ULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available from Toyota). In some other embodiments, a superelastic alloy, for example a superelastic nitinol can be used to achieve desired properties.
In at least some embodiments, portions or all of outer sheath 12 and inner catheter 14 may also be doped with, made of, or otherwise include a radiopaque material. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user of system 10 in determining its location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with a radiopaque filler, and the like. Additionally, other radiopaque marker bands and/or coils may also be incorporated into the design of system 10 to achieve the same result.
In some embodiments, a degree of Magnetic Resonance Imaging (MRI) compatibility is imparted into system 10. For example, outer sheath 12 and inner catheter 14, or portions thereof, may be made of a material that does not substantially distort the image and create substantial artifacts (i.e., gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they may create artifacts in an MRI image. Outer sheath 12 and inner catheter 14, or portions thereof, may also be made from a material that the MRI machine can image. Some materials that exhibit these characteristics include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nitinol, and the like, and others.
A sheath or covering (not shown) may be disposed over portions or all of outer sheath 12 and inner catheter 14 that may define a generally smooth outer surface for system 10. In other embodiments, however, such a sheath or covering may be absent from a portion of all of system 10, such that outer sheath 12 and inner catheter 14 may form an outer surface. The sheath may be made from a polymer 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. In some embodiments the sheath can be blended with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6 percent LCP.
In some embodiments, the exterior surface of the system 10 (including, for example, the exterior surface of outer sheath 12 and inner catheter 14) may be sandblasted, beadblasted, sodium bicarbonate-blasted, electropolished, etc. In these as well as in some other embodiments, a coating, for example a lubricious, a hydrophilic, a protective, or other type of coating may be applied over portions or all of the sheath, or in embodiments without a sheath over portion of outer sheath 12 and inner catheter 14, or other portions of system 10. Alternatively, the sheath may comprise a lubricious, hydrophilic, protective, or other type of coating. Hydrophobic coatings such as fluoropolymers provide a dry lubricity which improves device handling and device exchanges. Lubricious coatings improve steerability and improve lesion crossing capability. Suitable lubricious polymers are well known in the art and may include silicone and the like, hydrophilic polymers such as high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxides, polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics, algins, saccharides, caprolactones, and the like, and mixtures and combinations thereof. Hydrophilic polymers may be blended among themselves or with formulated amounts of water insoluble compounds (including some polymers) to yield coatings with suitable lubricity, bonding, and solubility. Some other examples of such coatings and materials and methods used to create such coatings can be found in U.S. Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference.
The coating and/or sheath may be formed, for example, by coating, extrusion, co-extrusion, interrupted layer co-extrusion (ILC), or fusing several segments end-to-end. The layer may have a uniform stiffness or a gradual reduction in stiffness from the proximal end to the distal end thereof. The gradual reduction in stiffness may be continuous as by ILC or may be stepped as by fusing together separate extruded tubular segments. The outer layer may be impregnated with a radiopaque filler material to facilitate radiographic visualization. Those skilled in the art will recognize that these materials can vary widely without deviating from the scope of the present invention.
The following documents are herein incorporated by reference in their entirety:
U.S. Patent Application Pub No. US 2007/0112355,
U.S. Patent Application Pub No. US 2010/0219092,
U.S. Patent Application Pub No. US 2010/0280495,
U.S. patent application Ser. No. 12/578,447, filed on Oct. 13, 2009 and entitled “Medical Devices and Delivery Systems for Delivering Medical Devices” (Attorney Docket Number: 1001.2627101),
U.S. Patent Application Ser. No. 61/559,914, filed on Nov. 15, 2011 and entitled “Duel Sterilization Containment Vessel” (Attorney Docket Number: 1001.2741100),
U.S. Patent Application Ser. No. 61/559,892, filed on Nov. 15, 2011 and entitled “Improved Bond Between Components of a Medical Device” (Attorney Docket Number: 1001.2742100),
U.S. Patent Application Ser. No. 61/559,941, filed on Nov. 15, 2011 and entitled “Medical Device With One Or More Sheathing Transition Members” (Attorney Docket Number: 1001.2743100),
U.S. Patent Application Ser. No. 61/558,095, filed on Nov. 10, 2011 and entitled “Direct Connect Flush System” (Attorney Docket Number: 1001.2745100),
U.S. Patent Application Ser. No. 61/559,931, filed on Nov. 15, 2011 and entitled “Medical Device With Keyed Locking Structures” (Attorney Docket Number: 1001.2746100),
U.S. Patent Application Ser. No. 61/566,615, filed on Dec. 3, 2011 and entitled “Medical Device Handle” (Attorney Docket Number: 1001.2747100),
U.S. Patent Application Ser. No. 61/577,845, filed on Dec. 20, 2011 and entitled “Medical Device Handle” (Attorney Docket Number: 1001.2748100),
U.S. Patent Application Ser. No. 61/577,880, filed on Dec. 20, 2011 and entitled “Apparatus for Endovascularly Replacing a Heart Valve” (Attorney Docket Number: 1001.2749100),
U.S. Patent Application Ser. No. 61/577,891, filed on Dec. 20, 2011 and entitled “Heart Valve Replacement Catheter” (Attorney Docket Number: 1001.2751100), and
U.S. Patent Application Ser. No. 61/543,521, filed on Oct. 5, 2011 and entitled “Profile Reduction Seal” (Attorney Docket Number: 1001.2752100).
It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the invention. This may include, to the extent that it is appropriate, the use of any of the features of one example embodiment being used in other embodiments. The invention's scope is, of course, defined in the language in which the appended claims are expressed.
| Number | Date | Country | |
|---|---|---|---|
| 61559871 | Nov 2011 | US |
